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Journal articles on the topic 'Aluminum alloy coating'
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1
Zhu, Sheng, Guo Feng Han, Xiao Ming Wang, Yu Xiang Liu, and Zhi Qian Wang. "Electrochemical Characteristics of TiAl Coating on Aluminum Alloy Surface by Supersonic Particles Deposition." Advanced Materials Research 1051 (October 2014): 199–203. http://dx.doi.org/10.4028/www.scientific.net/amr.1051.199.
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In this study, Ti-45Al-7Nb-4V alloy protective coating which base on γ-TiAl phase was deposited on the surface of 5803 aluminum alloy by supersonic particles deposition technology. Researchers observed the micro-structure of the TiAl alloy casting and coating by SEM, and researched the electrochemical characteristics and the galvanic corrosion between TA2 titanium alloy and 5083 aluminum alloy or TiAl alloy casting and coating by electrochemical work station. The results show that,the galvanic corrosion current between 5083 aluminium alloy and TA2 titanium alloy declines from 16.2μA to 0.27μA after TiAl protecting coatings are prepared on the substrates, besides, the corrosion susceptibility drops from E degree to A degree. It also manifests that the 5083 aluminium alloy with Ti-45Al-7Nb-4V coatings can be contacted and utilized with TA2 titanium alloy directly, which tackles the issues of gavanic corrosion prevention between aluminium alloys and titanium alloys.
2
Dong, Xiao Feng, and Xin Mei Li. "Abrasive Wear Performance of Hot-Dipping Al-Mn Alloy Coatings on Q235." Key Engineering Materials 522 (August 2012): 13–16. http://dx.doi.org/10.4028/www.scientific.net/kem.522.13.
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The Q235 steel was modified by hot-dip-aluminizing technique, and Al-Mn alloy layer was obtained on the steel surface. Scan electron microscopy (SEM), X-ray diffraction (XRD) and abrasive wear tester were used to investigate the microstructure and wear performance of the Al-Mn alloy coatings. The results show that the surface of the obtained pure aluminum coatings is acicular, while blocks Al-Mn compounds phase exists in Al-Mn alloys layer, and the Al-Mn alloy layer is composed of Al, FeAl3, Fe2Al5 and MnAl6 phases. The experimental results showed that wear weight loss of aluminum coating is more than Q235 steel. However, after manganese added to the aluminum, Al-Mn alloy coating abrasion wear loss of weight far below the Q235 steel and aluminum coating. And weight loss increases along with Mn content decreases. When worn after 100 h, Al-13% wtMn wear alloy coating weight loss of 45% of Q235 steel, aluminum coating of 35%. So the hot-dipping Al-Mn alloy layer has excellent abrasive wear resistance.
3
Zhu, Sheng, Guo Feng Han, Xiao Ming Wang, Yu Xiang Liu, and Chao Ji Zhou. "Tribological Properties of TiAl Coating on Aluminum Alloy Surface by Supersonic Particles Deposition." Applied Mechanics and Materials 633-634 (September 2014): 870–73. http://dx.doi.org/10.4028/www.scientific.net/amm.633-634.870.
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In this study, Gamma TiAl intermetallic alloy protective coating was deposited on the surface of 5803 aluminum alloy by supersonic particles deposition. Researchers observed the surface morphology of the coating by SEM, and researched tribological properties of the substrate material and the coating by CETR friction and wear tester and Talysurf 5P-120 surface morphology tester. The results show that,the bonding mechanism of the Gamma TiAl intermetallic alloy coating and substrate is mechanical interlocking and metallurgical bonding. The abrasion mechanism of Gamma TiAl intermetallic alloy coating is abrasive Wear. The friction coefficients of the coating are all lower than 5083 alumium alloy. The friction volume of coatings reduced 36.7% than 5083 aluminum alloy with the friction loads 50N. TiAl coating has great function to anti-attrition and wearability.
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Kablov, E. N., K. M. Khmeleva, S. V. Zavarzin, I. A. Kozlov, and S. L. Lonskii. "THE EFFECT OF HEAT TREATMENT ON THE CHARACTERISTICS OF ALUMINIUM-ZINC COATINGS OBTAINED BY THE COLD SPRAY METHOD." Aviation Materials and Technologies, no. 1 (2022): 78–91. http://dx.doi.org/10.18577/2713-0193-2022-0-1-78-91.
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A study was made of the influence of temperature and duration of heat treatment on the formation of diffusion zinc, aluminum and aluminum-zinc coatings. It is shown that at a heat treatment temperature of 400 °C, a three-phase structure in zinc coating is formed. Mutual diffusion occurs on samples with an aluminium-zinc coating with the formation of Al–Zn alloy, samples with an aluminum coating do not undergo structural changes under the studied heat treatment modes. According to the results of corrosion studies it has been revealed that in terms of their properties, mixed aluminum-zinc coatings are closer to the zinc-coated sample than to the aluminum-coated sample.
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Dudareva, N. Yu, and R. F. Gallyamova. "The Effect of Silicon in Al-Si Alloys and Electrical Treatment Modes on Structure and Properties of MAO-Coatings." Solid State Phenomena 299 (January 2020): 737–42. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.737.
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The work shows the influence of the content of silicon in the aluminum alloy and the regimes of micro-arc oxidation (MAO) on the structure and properties of the formed coatings. Treatment of samples from high-silicon aluminum alloys AK12pch (Si ~12 %) and M244 (Si ~25 %) was carried out in two modes, which have different installation capacity MAO. The thickness, micro-hardness, porosity of the formed MAO coatings was investigated. It is established that the increase in the proportion of silicon in the aluminum alloy leads to the formation of MAO coatings of significant thickness (~230 μm), with low micro-hardness (HV ~650) and high porosity (up to ~16 %). Increase 4 times the installation capacity of MAO causes the growth of the thickness of the coating, reduces the porosity of the coating on the alloy AK12pch and increases the porosity of the coating on the alloy M244.
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Zhan, Wen, Xinxiang Li, Xuzhen Qian, Yingpeng Li, Yunhu Ding, Yunhe Zu, Fan Xie, and Feng Tian. "Preparation and Characterization of Synchronous Chemical Conversion Coating on 6061 Aluminum Alloy/7075 Aluminum Alloy/Galvanized Steel Substrates." Metals 12, no. 12 (November 23, 2022): 2011. http://dx.doi.org/10.3390/met12122011.
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This paper aimed to develop synchronous chemical conversion coating on multi-metal substrates with good corrosion resistance to meet the primer process of new energy light vehicle bodies. Titanium/zirconium-based chemical conversion coatings were prepared on 6061 aluminum alloy/7075 aluminum alloy/galvanized steel substrates. By measuring the open circuit potential (OCP), the formation of a muti-metal synchronous conversion coating can be roughly divided into three steps. Potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques showed that the self-corrosion current density of the conversion coating decreased significantly while the resistance increased. The surface morphology and composition of the conversion coatings were observed by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). Additionally, the micro-zone characteristics of conversion coatings were analyzed by an electron probe microanalyzer (EPMA). The synchronous conversion coatings exhibit uniformity and relative smoothness. Additionally, a number of tiny cracks, pores, intermetallic compounds, enrichments and inclusions provide efficient active sites for the nucleation of chemical conversion. Consequently, in the synchronous conversion coating, the structure of aluminum alloy mainly consists of Al2O3/TiO2/ZrO2/ZrF4, while the structure of conversion coating of galvanized steel contains TiO2/Fe2O3/ZrO2.
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Abrashov, Aleksey, Nelya Grigoryan, Yuri Korshak, Tigran Vagramyan, Oleg Grafov, and Yaroslav Mezhuev. "Regularities of the Formation of a Green Superhydrophobic Protective Coating on an Aluminum Alloy after Surface Modification with Stearic Acid Solutions." Metals 11, no. 11 (October 27, 2021): 1718. http://dx.doi.org/10.3390/met11111718.
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It has been shown that solutions of stearic acid in a dimethyl sulfoxide–water binary mixture allow superhydrophobic protective coatings to be created on an aluminum alloy surface with a minimum impact on the environment. The superhydrophobicity and self-cleaning ability of the coating that we developed have been confirmed by measurements of droplet wetting angles and roll-off angles. These properties appear due to the formation of a multimodal micro-rough surface that mainly consists of aluminum stearate. The coatings formed in this manner have been studied by ellipsometry, XPS, and scanning probe microscopy. Their protective ability has been estimated by the “droplet-express” method and in a salt fog chamber. The protective ability of the coating is determined by the DMSO/H2O ratio, the concentration of stearic acid, and the duration and temperature of modification of the aluminum alloy; it is controlled by a competition between the processes of aluminum stearate formation and hydrolysis. It has been shown that adsorption of stearic acid on an aluminum stearate coating increases its permeability and decreases its protective capability. The results presented in this article are useful for optimizing the conditions of applying green superhydrophobic stearate coatings on aluminum alloys in order to achieve a maximum protective effect.
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XUE, WENBIN, YING ZHANG, XINGLI JIANG, and ZHUO YANG. "PREPARATION OF MICROARC OXIDATION COATINGS ON 6061 ALUMINUM ALLOYS AND THEIR THERMAL SHOCK RESISTANCE." Surface Review and Letters 16, no. 03 (June 2009): 393–99. http://dx.doi.org/10.1142/s0218625x09012779.
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The thick ceramic coatings were prepared on 6061 aluminum alloys by microarc oxidation in a silicate electrolyte. The morphology and phase constituent of the coatings with different thickness were studied by scanning electron microscope, and X-ray diffraction. Scratch and thermal shock tests were employed to evaluate the adhesion between the coating and alloy substrate. The maximum microhardness and its position away from alloy/coating interface increases with increasing the coating thickness. The critical scratch force for the coating break was about 55 N in the 50 μm thick coating. Thermal shock resistance of the coatings depend on their thickness and thinner coating has better thermal shock resistance. The coated alloy with 50 μm thick coating can be subjected to 50 times thermal cycles of heating up to 500°C followed by quenching into water.
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Lukauskaitė, Raimonda, Algirdas Vaclovas Valiulis, and Olegas Černašėjus. "Investigation of Cathodic Cleaning Processes of Aluminum Alloy." Solid State Phenomena 220-221 (January 2015): 684–92. http://dx.doi.org/10.4028/www.scientific.net/ssp.220-221.684.
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On covering aluminum and its alloys with coatings resistant to high-temperature corrosion and attrition, abundant technological problems arise. The key problem is a removal of the film of aluminum oxide Аl2O3 from the aluminum substrate. This permanent, chemically continuous film of oxide reduces adhesion between the substrate and the coating. For improving cohesion of the coating with the substrate, an appropriate pre-treatment of aluminum is required. In the paper, cleaning of aluminum alloy AW 5754 by electric discharge is investigated. This method is considered one of most environmentally friendly methods of surface cleaning. The impact of the parameters of aluminum alloy cathodic cleaning on the surface cleaning width, its roughness and free energy of the surface were examined. In addition, the topography, microstructure and chemical composition of the surface of cleaned aluminum alloy were estimated.
10
Xu, Hong Yan, Sen Chang, Xing Zhang, and Zhi Min Zhang. "Study of Aluminum Coating Thermally Sprayed on AZ80 Magnesium Alloy Surface." Materials Science Forum 686 (June 2011): 319–24. http://dx.doi.org/10.4028/www.scientific.net/msf.686.319.
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Aluminum (Al) coating was thermally sprayed on the surface of AZ80 magnesium (Mg) alloy. The Al-coating was deformed at 400°C with different deformation degrees of 15%, 30%, 45%, 60% and 80%. The corrosion properties of the AZ80 Mg alloys coated with Al-coatings were studied by potentiodynamic and galvanic tests in 3.5% NaCl solution; the adhesion strengths between Al-coatings and AZ80 substrate were also measured simultaneously by tensile test. The results showed that, Al-coating could decrease the corrosion rate of AZ80 Mg alloys, and the corrosion rate was related not only with the density of Al-coating but also with the adhesion strength of Al-coating. Before the formation of dense Al-coating, the corrosion rate of Al-coated AZ80 Mg alloys decreased with the increasing of bonding strength of Al-coating; after the formation of dense Al-coating, the corrosion rate of Al-coated AZ80 Mg was mainly determined by the structure of Al-coating. It was also revealed that with the increasing of deformation degree, the corrosion rate of the Al-coated AZ80 Mg alloys first decreased then increased, while the adhesion strength increased gradually. The corrosion rate of AZ80 Mg alloy coated with 60% deformed Al-coating was the lowest, which was only 19% of that of the AZ80 substrate.
11
Zeng, Siqi, and Faguo Li. "Research Status of Aluminum Base Coating on Titanium Alloy." Coatings 13, no. 9 (August 30, 2023): 1525. http://dx.doi.org/10.3390/coatings13091525.
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At present, in the aviation industry, titanium alloy is mainly used to manufacture parts such as compressor discs, blades, and the casings of aircraft engines. When titanium alloys are in service, high temperature is generated due to high-speed running friction, which requires them to have high-temperature oxidation resistance and friction resistance. If they are used in an environment with salt corrosion, titanium alloys will face thermal corrosion, which limits their wider practical applications. At present, there are many methods to protect titanium alloys. This paper mainly includes alumina-based coatings and some preparation methods. The characteristics and functional mechanisms of three functional coatings for the service environment, namely highly temperature-resistant alumina-based coating, thermal corrosion-resistant alumina-based coating, and wear-resistant alumina-based coating, are summarized. Finally, the development direction of composite coatings of titanium and titanium alloys for a complex service environment is suggested.
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Pancrecious, Jerin K., J. P. Deepa, R. Ramya, T. P. D. Rajan, E. Bhoje Gowd, and B. C. Pai. "Ultrasonic-Assisted Electroless Coating of Ni-B Alloy and Composites on Aluminum Alloy Substrates." Materials Science Forum 830-831 (September 2015): 687–90. http://dx.doi.org/10.4028/www.scientific.net/msf.830-831.687.
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Electroless nickel coating is one of the versatile methods to improve the physical properties of aluminium alloys. The increasing demand for high corrosion resistant surface with improved performance leads to the development of poly-alloy and composite coatings with the aid of ultrasonication. In the present study Ni-B alloy and Ni-B-CeO2 composite coatings were made on 356 aluminium alloy surfaces. The variation in structural and mechanical properties of coatings formed under both ultrasonication and magnetic stirring were investigated. Surface analysis by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) has shown the formation of more uniform coating under ultrasonication. The electrochemical polarization tests show enhanced corrosion resistance in ultrasonic assisted coatings.
13
Vovk, S. Y., N. O. Ferents, and D. V. Kharyshyn. "RESEARCH ON THE EFFECT OF PROTECTING COATING ON THE FIRE RESISTANCE OF ALUMINUM ALLOY STRUCTURES." Fire Safety, no. 34 (July 19, 2019): 16–20. http://dx.doi.org/10.32447/20786662.34.2019.03.
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Polyfunctional protective coatings based on filled polysiloxane compositions are technological and can be used to increase the fire resistance of metal structural materials due to high thermomechanical properties, which are determined by stable structural and phase composition. The influence of protective coatings on the basis of polysiloxane-filled oxide components on fire resistance of aluminum alloys is investigated in the work. The choice of the initial compositions for fire protection coatings was carried out with the aim of obtaining of expanded heat-insulating heatresistant layer on the surface of an aluminum alloy at temperatures of 473 K and higher. The methods of physico-chemical analysis have established that when heated more than 473 K as a result of thermo oxidative degradation of polysiloxane with the release of gaseous products, there is an expanding coating with the formation of a fire-proof porous heat-insulating layer on the surface of an aluminum alloy. The coefficient of expanding the coating is within the range of 9.8 ... 12.4. The reliability of the use of physicochemical criteria when choosing the component composition of the coating and the effectiveness of the fire protection function is estimated from the results of the test on the aluminum alloy AMG6 and on the model of its thermal conductivity. 20 Пожежна безпека, №34, 2019 A model of thermal conductivity of a protective coating is proposed, which consists of a layer that limits heat transfer through a two-layer wall. When exposed to the aluminum plate of the heat flow, it is heated to the depth of the coating, which leads to its expanding and the formation of a thermal barrier. The dynamics of temperature distribution during a fire on the protective coating of an aluminum alloy is predicted by simulating the heat transfer process in a homogeneous solid by a mathematical model. The theoretical and practical researches have established the dependence of the parameter of heating the protected aluminum alloy to the critical temperature, depending on the thickness of the coating. The presence on the surface of a protected alloy coating, based on the filled polysiloxane, changes the process of heat transfer to its surface, which increases the fire resistance of the structure by 3 ...4 times.
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Wang, Zhehan, Tao Fu, Bing Xie, Huajun Wang, Pingyuan Ye, and Xudong Pan. "Self-Lubricating Property of TiB2-Ni Coating in the Hot Forging Die of Aluminum Alloy." Coatings 12, no. 6 (June 13, 2022): 829. http://dx.doi.org/10.3390/coatings12060829.
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Hot die forging is a forging forming method widely used in the automobile industry, shipbuilding, and the aerospace industry. In the hot die forging process of aluminum alloy, the “mold sticking” defect often occurs and results in low productivity and short die life. Herein, we prepared TiB2 reinforced nickel-based coatings by the combined use of a plasma transferred arc and plasma melt injection method, and investigated the morphology and properties of composite coatings in hot forging die conditions. The results showed that the nickel-based coating reinforced with TiB2 generated boron-rich self-lubricating products during the sliding with aluminum alloy, and the adhered aluminum alloy on a coating surface has significantly reduced quantity and transformed morphology from rough plough to smooth layer with the increase of TiB2, which is beneficial to the surface quality of the aluminum alloy counterface. The results of this research provide valuable guidelines for the design and preparation of the coatings applied in the mold in hot die forging of aluminum alloys.
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Oki, Makanjuola, Adesoji Adeolu Adediran, Olayinka Saheed, and Ogunsola Opeyemi. "Development and performance of hybrid coatings on aluminium alloy." Journal of Electrochemical Science and Engineering 7, no. 3 (August 15, 2017): 131. http://dx.doi.org/10.5599/jese.347.
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<p class="PaperAbstract"><span class="hps"><span lang="EN-US">From gravimetric studies, hybrid nano-coatings, based on permanganate/fluoride/glycerol conversion coating solutions formed on aluminum alloy by immersion procedures developed rapidly at a rate which decreased with time of treatment and was about 16 mg in weight after a period of three minutes. The morphology of the coating during scanning electron microscopic (SEM) examinations revealed randomly shaped coating materials with mud cracking patterns, characteristics of dried out coatings derived from gel-like materials. Analyses of the coating using EDX attachment in the SEM showed that it was composed essentially of aluminum, oxygen and manganese compounds, probably hydrated. The corrosion resistance of the coating out-performed ‘bare’ aluminum alloy specimens exposed to natural environment and 1 M sodium chloride solution. The coating improved the paint adhesion characteristics of the substrate aluminum alloy.</span></span></p><p><em><em><br /></em></em></p>
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Drewien, C. A., R. G. Buchheit, K. R. Zavadil, and T. E. Neil. "Copper enrichment on Al 2024 surface after de-oxidizing treatment." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 860–61. http://dx.doi.org/10.1017/s0424820100150137.
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Coatings of lithium-aluminum-carbonate-hydroxide are being developed for corrosion protection of aluminum alloys against atmospheric and saline environments. Coating is performed by immersion of the aluminum part into a lithium carbonate-lithium hydroxide solution of pH=11.5. Before coating, the aluminum alloy is degreased in trichloroethylene, cleaned in a sodium carbonate-sodium silicate bath, and de-oxidized in nitric acid containing ammonium biflouride. Coating of most aluminum alloys is easily accomplished, and the coatings pass the ASTM B117 salt spray test. However, aluminum alloys that contain copper, specifically 2024-T3 and 7075-T6, yield coatings that fail the salt spray test, i.e. pitting and general corrosion is observed. Photographs of coatings after 168 hr salt spray exposure are shown in Figure 1 for Al 1100 and 2024-T3 alloys. A study has been undertaken to determine the influence of copper upon the corrosion properties of the coating.The surface of 2024-T3 was analyzed after each processing step in order to determine if copper enrichment at the specimen surface was occurring.
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He, Long, Ye Fa Tan, Bin Cai, Hua Tan, Li Gao, and Zhong Wei Zhang. "Research on Friction and Wear Properties of Plasma Spraying Ni-Base Alloy Coatings on Aluminum Alloy Surfaces." Advanced Materials Research 538-541 (June 2012): 207–13. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.207.
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In order to improve the wear resistance and extend service life of aluminum alloy parts, the Ni-base alloy anti-wear coatings were prepared on the surfaces of 7A05 aluminum alloy by plasma spraying technology. The microstructure and interface of the coatings were analyzed, and the friction and wear properties of Ni-base alloy coatings and aluminum alloy substrates were investigated under dry friction condition at room temperature. The research results show that the main phases of Ni-base alloy coating are γ-Ni, CrB and Cr23C6. The thicknesses of diffusion layers existing between intermediate layer and coating, intermediate layer and substrate are respectively 15μm and 20μm. The bonding types of the coating and the substrate are mechanical combination accompanied with partially metallurgical combination. When wore against GCr15 steel balls, the average friction coefficient of the Ni-base alloy coatings is 11.6% lower than that of the aluminum alloy substrates, and the average wear loss of the former is 9.3mg, which is only 1/3 of that of the latter. With the increase of loads, the wear mechanisms of the Ni-base alloy coatings change from slightly micro-cutting wear and fatigue wear to abrasive wear and micro-fracture wear, while those of the aluminum alloy substrates are mainly adhesive wear and abrasive wear as well as slight oxidation wear.
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Titu, Aurel Mihail, Sandor Ravai-Nagy, and Alina Bianca Pop. "Research on the Influence of Coating Technologies on Adhesion Anti-Corrosion Layers in the Case of Al7175 Aluminum Alloy." Coatings 13, no. 6 (June 6, 2023): 1054. http://dx.doi.org/10.3390/coatings13061054.
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A key element in ensuring the service life and strength of aluminum alloys in many industrial applications is the adhesion of anti-corrosion coatings. The aim of this study is to analyze how coating processes affect the adhesion of anti-corrosion coatings on aluminum alloy 7175. In other words, the influence of the nature of the elementary layers that form the anti-corrosion coating was studied for the following: the anodic layer, the primer, and the topcoat. To learn more about the different coating technologies and how they affect adhesion, a thorough literature review was carried out. In addition, a case study using electrocoating and thermal spraying was conducted to show the impact of coating processes on adhesion. The results showed that electrodeposition, as opposed to thermal spraying, improved the adhesion of anti-corrosion coatings. In the case of the aluminum alloy analyzed, there is a significant difference in terms of the adhesion strength of the anti-corrosion coatings. This resistance is influenced by both the anodic coating (BSA TSA SAA) and the type of primer and topcoat used (water-based or solvent-based). The correct choice of anode coat and primer and topcoat can lead to an increase (or decrease) in the adhesion strength of the paint coat by 20%. In conclusion, this study highlights how crucial it is to select the best coating process to maximize the adhesion and durability of aluminum alloys under corrosion conditions.
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Algahtani, Ali, Essam Mahmoud, Sohaib Khan, and Vineet Tirth. "Experimental Studies on Corrosion Behavior of Ceramic Surface Coating using Different Deposition Techniques on 6082-T6 Aluminum Alloy." Processes 6, no. 12 (November 26, 2018): 240. http://dx.doi.org/10.3390/pr6120240.
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Aluminum alloys cannot be used in aggressive corrosion environments application. In this paper, three different surface coating technologies were used to coat the 6082-T6 aluminum alloy to increase the corrosion resistance, namely Plasma Electrolytic Oxidation (PEO), Plasma Spray Ceramic (PSC) and Hard Anodizing (HA). The cross-sectional microstructure analysis revealed that HA coating was less uniform compared to other coatings. PEO coating was well adhered to the substrate despite the thinnest layer among all three coatings, while the PSC coating has an additional loose layer between the coat and the substrate. X-ray diffraction (XRD) analysis revealed crystalline alumina phases in PEO and PSC coatings while no phase was detected in HA other than an aluminum element. A series of electrochemistry experiments were used to evaluate the corrosion performances of these three types of coatings. Generally, all three-coated aluminum showed better corrosion performances. PEO coating has no charge transfer under all Inductive Coupled Plasma (ICP) tests, while small amounts of Al3+ were released for both HA and PSC coatings at 80 °C. The PEO coating showed the lowest corrosion current density followed by HA and then PSC coatings. The impedance resistance decreased as the immersion time increased, which indicated that this is due to the degradation and deterioration of the protective coatings. The results indicate that the PEO coating can offer the most effective protection to the aluminum substrate as it has the highest enhancement factor under electrochemistry tests compared to the other two coatings.
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Fang, Ying Ze, Xiao Ping Zhou, and Feng Xu. "Microstructures and Mechanical Properties of Aluminum Coating Produced by Friction Stir Processing." Advanced Materials Research 1095 (March 2015): 612–15. http://dx.doi.org/10.4028/www.scientific.net/amr.1095.612.
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This Four passes processing to the thermal spray aluminum coating on the aluminum alloy surface,based on friction stir processing (FSP). Applications SEM, EDS and micro hardness testing to analysis the coatings that have been processed and haven't been processed. The results show that , after the friction stir processing,dense ultrafine grained aluminum with the sizes less than 200nm is obtain ,and replace original laminated and porous coating . Fusion utilizes between the coating and the substrate, the gap between coating and substrate have disappear. The alloy elements in the substrate diffuse to the coating.
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Lin, Ci, Surender Maddela, William G. Fahrenholtz, and Matthew J. O'Keefe. "Deposition of Cerium-Based Conversion Coatings on Aluminum Alloy 380." International Journal of Corrosion 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/760284.
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Cerium-based conversion coatings were deposited on as-cast aluminum alloy 380 substrates by a spontaneous immersion process. In this study, the effects of rinsing temperature prior to immersion in the coating deposition solution were studied with respect to the surface morphology, electrochemical response, and corrosion resistance of the coatings. Panels rinsed at25°Cprior to coating had large cracks and holes in the coating. In contrast, panels rinsed at100°Cprior to coating had a uniform coating morphology with fewer, smaller cracks. Electrochemical testing revealed that coatings deposited on substrates rinsed at100°Chad higher impedance (~80 kΩ·cm2) and lower corrosion current (~0.34 μA/cm2) compared to coatings deposited on substrates rinsed at25°C, which had 10 kΩ·cm2impedance and 2.7 μA/cm2corrosion current. Finally, ASTM B117 salt spray testing showed that rinsing at100°Cprior to coating resulted in cerium-based conversion coatings that could resist the formation of salt tails for at least 8 days.
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Thunaipragasam, Selvakumaran, Aniket Bhanudas Kolekar, Koli Gajanan Chandrashekhar, Rohit Pandey, Mohammad Shahid, K. Rajesh, P. Ragupathi, Asheesh Kumar, and Balkeshwar Singh. "Investigation of Mechanical Behavior and Surface Characteristics of Cold Spray Metallized B4C/AA7075 Composites Coated by AZ64 Alloy through Plasma Electrolytic Oxidation." Journal of Nanomaterials 2023 (April 20, 2023): 1–11. http://dx.doi.org/10.1155/2023/7267093.
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Metallized cold-spray coatings were employed to make B4C/AA7075 and aluminum + plasma electrolytic oxidation (PEO) duplex coatings on AZ64. In addition, the phase structure, mechanical characteristics, wear, and PEO ceramic coatings examine the corrosion resistance. According to the findings, the PEO ceramic coating comprises α-aluminum oxide and γ-aluminum oxide, with some remnants of B4C still being preserved. PEO ceramic coatings outperformed their corresponding CS counterparts regarding mechanical characteristics and wear resistance. For example, the PEO-B4C coating achieved a hardness of 13.8 GPa and an elastic modulus of 185.5 GPa, which were 21.0% and 23.5%, respectively, more significant than the comparable values for the coating with CS. The PEO-B4C coating was 58% and 15.7% less abrasive than the equivalent CS coating due to its lower wear rate of 4.84 × 10−5 mm3/Nm and relatively lower of 0.64. The density of corrosion current in the PEO-treated B4C-AA7075 coating (3.735 × 106 A/cm2) is similar to the corrosion current density in the untreated CS coatings. Finally, compared to untreated CS B4C-AA7075, the coating’s mechanical characteristics and wear resistance are considerably enhanced by the PEO treatment.
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Gao, Yuhang, Xiaohong Chen, Ping Liu, Honglei Zhou, Shaoli Fu, Wei Li, Xinkuan Liu, Fengcang Ma, Yanbo Zhu, and Jiayan Wu. "Influence of high-temperature aluminizing treatment on the corrosion resistance of 90/10 copper-nickel alloy." Anti-Corrosion Methods and Materials 68, no. 5 (August 20, 2021): 365–72. http://dx.doi.org/10.1108/acmm-04-2021-2467.
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Purpose This study aims to investigate the effect of coatings prepared by the addition of copper-aluminum alloy powder on the corrosion behavior of 90/10 copper-nickel alloy. Design/methodology/approach Coatings of copper-aluminum alloy powder at different contents (Wt.% = 50%, 60%, 70% and 80%) were prepared by the high-temperature heat treatment process. The microstructure and component of the coatings were characterized by scanning electron microscope, X-ray diffraction, energy dispersive spectrometer and X-ray photoelectron spectroscopy. The electrochemical properties of the coating were explored by electrochemical impedance spectroscopy. Findings The results show that the aluminized layer was successfully constructed on the surface of 90/10 copper-nickel alloy, the composition of the coating was composed of copper-aluminum phase and aluminum-nickel phase, the existence of the aluminum-nickel phase was formed by the diffusion of Ni elements within the substrate and because of the diffusion, the Al-Ni phase was distributed in the middle and bottom of the coating more. The Al-Ni phase is considered to be the enhanced phase for corrosion resistance. When the copper-aluminum alloy powder content is 70 Wt.%, the corrosion resistance is the best. Originality/value The enhancement of corrosion resistance of 90/10 copper-nickel alloy by the copper-aluminum alloy powder was revealed, the composition of the aluminized layer and the mechanism of corrosion resistance were discussed.
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Drewien, C. A., M. O. Eatough, D. R. Tallant, C. R. Hills, and R. G. Buchheit. "Lithium-aluminum-carbonate-hydroxide hydrate coatings on aluminum alloys: Composition, structure, and processing bath chemistry." Journal of Materials Research 11, no. 6 (June 1996): 1507–13. http://dx.doi.org/10.1557/jmr.1996.0188.
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A new corrosion resistant coating, being designed for possible replacement of chromate conversion coatings on aluminum alloys, was investigated for composition, structure, and solubility using a variety of techniques. The stoichiometry of the material, prepared by immersion of 1100 Al alloy into a lithium carbonate-lithium hydroxide solution, was approximately Li2Al4CO3(OH)12 · 3H2O. Processing time was shown to be dependent upon the bath pH, and consistent coating formation required supersaturation of the coating bath with aluminum. The exact crystal structure of this hydrotalcite material, hexagonal or monoclinic, was not determined. It was shown that both the bulk material and coatings with the same nominal composition and crystal structure could be formed by precipitation from an aluminum supersatured solution of lithium carbonate.
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Karzhavin, V. V., L. V. Maltsev, and V. V. Bakina. "Study on Surface Layers of Aluminum and Titanium Alloys and Analysis of their Scuff Resistance." Solid State Phenomena 284 (October 2018): 1248–51. http://dx.doi.org/10.4028/www.scientific.net/ssp.284.1248.
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To reduce the risk of scoring copper or zinc coatings were applied to the samples in molten salts at a temperature of 350-500°C. Using ion sputtering and Auger electron spectroscopy the depth of the surface layers and the grain size in the coating were determined. Samples were plates 0.5-0.7 mm thick made of titanium and aluminum alloys. For copper-coated alloys a coating zone up to 10 μm and a diffuse zone up to 6 μm which is intermediate between the coating and the substrate can be distinguished in the surface layers. For zinc-coated aluminum alloys there is one zone of 5-7 μm which is an aluminum-zinc alloy of variable composition across depth. Thus, a soft metal formed on the surface of the titanium and aluminum alloys when processed in the salt melt is connected to the base metal with metallic bonds. Moreover, the higher the temperature and the longer the holding time in the salt melt, the thicker the coating is. While investigating the score resistance a dependence of the friction moment change on the path travelled to a score appearance was obtained. It has been established that the score resistance of the titanium and aluminum alloys is directly dependent on the inhomogeneity factor which is sharply increased when there is a softer (compared with the base metal) coating on the surface of the metal processed. Experimental stamping-drawing of cups made of the titanium alloy workpieces preliminary copper-coated in the salt melt was carried out. The production cycle was significantly reduced, and the surface quality of the products after the coating removal was high, the scoring was not observed. Thus, the use of soft (compared with the base metal) metal coatings applied in salt melts is promising for titanium and aluminum alloys.
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Hou, Bin, and Lizhi Zhu. "The study on performances of environment-friendly colorless chemical conversion coatings on aluminum alloy." Journal of Physics: Conference Series 2539, no. 1 (July 1, 2023): 012049. http://dx.doi.org/10.1088/1742-6596/2539/1/012049.
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Abstract With the increasingly high requirements on the appearance of electronic equipment and environmental protection, conventional chromate chemical conversion coatings on aluminum alloys gradually showed some shortcomings, such as the color difference in appearance and harm to human health and the environment in the process. In this paper, three kinds of environment-friendly colorless chemical conversion coatings (LANTH-613, ALTRCHR-250, YMT-631) were prepared by using 5056 and 6061 aluminum alloy samples and visually observing the appearance of the coatings. Then, the performances of the coatings, such as the morphology, corrosion resistance, electrical contact resistance, and paint adhesion, were characterized by scanning electron microscope, salt spray test, electrical contact resistance test, and cross-cut test, respectively. As a result, we proposed YMT-631 colorless chemical conversion coating could be used alone as a long-term protective coating for aluminum alloy parts that require the natural appearance of aluminum in electronic equipment, by which corrosion resistance and adaptability in the harsh environment could be significantly improved.
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Huang, Wei, Di Li, Tian Liang Zheng, and Min Guo. "A Novel Anti-Corrosion Coating for Aluminium Alloy." Materials Science Forum 519-521 (July 2006): 723–28. http://dx.doi.org/10.4028/www.scientific.net/msf.519-521.723.
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A novel environmental protective water based metallic coating was developed for aluminum alloys, which mainly contains metal flake, silicate and silane. The coating's properties were investigated by neutral salt spray test, micro-hardness testing, adhesion test and electrochemical technique etc. Meanwhile the coating's surface and microstructure was observed by scanning electron microscopy (SEM). Furthermore, the film forming matter was examined by Fourier transform infrared spectroscopy (FTIR) test. Results showed that an excellent adhesive, heat-resisting, protective coating for aluminum alloy could be achieved by this technique. An interpenetrating polymer network (IPN) was formed in the coating by means of cross linking reaction of organosilicone and inorganic silicate. In thesis, the film forming mechanism and protection of coating were also discussed.
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Wang, Yun Long, Miao Wang, and Zhao Hua Jiang. "Synthesis and Characterization of Aluminum Nitride Ceramic Coating on Aluminum Alloy by Plasma Electrolytic Oxidation in CO(NH2)2 Electrolyte." Advanced Materials Research 557-559 (July 2012): 1664–67. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.1664.
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aluminum nitride ceramic coating were obtained on LY12 aluminum alloy by plasma electrolytic oxidation in CO(NH2)2 electrolyte. The microstructure of the ceramic coating including phase and elements composition, surface and cross section morphology were investigated. The properties of the ceramic coatings such as surface roughness, thickness and bonding strength were primarily studied. The results show that the ceramic coating on LY12 aluminum alloy surface was AlN coating with the thickness of 12 um. The AlN ceramic coating showed rough and porous. The average diameter of the pores was 6 um and the surface roughness was 1.5 um. The bonding strength of the coating was 18 ± 2 MPa.
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Jia, Rui Ling, Hong Ping Duan, Feng Guo, Xi Wei Zhai, and Ya Hong Liang. "Study on the Corrosion Resistance and Wear Resistance of Micro-Arc Oxidation Coatings on the Clad Plate of Aluminum and Magnesium Alloy." Advanced Materials Research 189-193 (February 2011): 1248–52. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.1248.
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Aluminium plate was cladded to magnesium alloy plate by using the explosive welding. The bonding morphology and composition of the explosive cladding plate was inspected by SEM and EDS. There is a wave bonding at the interface between aluminum plate and magnesium alloy plate. Then ceramic coatings were directly prepared on the surface of aluminum and magnesium alloy by micro-arc oxidation (MAO) in the same solution and at the same time. The microstructure and composition of MAO coatings were studies by SEM and EDS. The corrosion and wear resistance of MAO coatings on the two sides of the clad plate were investigated by salt spray tests and friction-wear test. The results show that the MAO coating on the Al surface consists of Al, O and Si elements, while MAO coating on the Mg surface consists of Mg, O and Si elements. The corrosion resistance of MAO coating on the Al surface was better than that on Mg surface of the explosive clad plate. The MAO coatings both on the Al surface and on the Mg surface can obviously improve the wear resistance of substrate.
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Wu, Yan Bo, Si Si Zeng, and Peng Sun. "Comparison of Two Different Chemical Conversion Coating on Aluminum Alloy." Advanced Materials Research 146-147 (October 2010): 208–11. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.208.
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In this paper, we made two different chemical conversion coatings on aluminum alloy by TiOSO4 and Na2WO4. The morphology of the chemical conversion surface layers were observed by scanning electron microscopy (SEM). The microcosmic phase structures were characterized using X-ray diffraction (XRD). Electrochemical method was used to study the coatings corrosion resistance. The results indicated that the two conversion coatings were crystal structure material, the surface of coating were both show pothole structure. TiOSO4 coating have better corrosion resistance than Na2WO4 coating.
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Subbotin, Oleksandr, Valery Bilozerov, Oleg Volkov, Valeria Subbotinа, and Vadym Shevtsov. "FRICTION PROPERTIES OF MАO COATINGS ON ALUMINUM ALLOYS." Bulletin of the National Technical University «KhPI» Series: Engineering and CAD, no. 2 (December 28, 2022): 59–63. http://dx.doi.org/10.20998/2079-0775.2022.2.07.
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Aluminum alloys are widely used in mechanical engineering due to their physical and mechanical properties. However, their low wear resistance and burr resistance limit their use in friction nodes. In this regard, parts made of aluminum alloys operating under conditions of sliding friction require surface strengthening, which determines the friction wear parameters. Research works in this direction allow increasing the reliability and service life of friction nodes. Ensuring the compatibility of friction pairs allows reducing the coefficient of friction and, as a result, to increase wear resistance. One of the effective methods of forming wear-resistant coatings on aluminum alloys is the method of micro-arc oxidation (MAO). The use of micro-arc discharges as highly concentrated energy sources to create conditions for high-temperature electrotechnical processes and phase transformations in the surface layer makes it possible to form structures based on high-temperature oxides on the surface of metals, which provides qualitatively new surface properties: high hardness, wear resistance, corrosion resistance in various environments. However, the use of oxide coatings in bearings is mainly due to their high wear resistance and corrosion resistance. Information on the antifriction properties of aluminum oxide-based coatings is limited. The purpose of this work is to determine the coefficient of friction of MAO-coatings on D16 aluminum alloy in a pair with cast iron, steel and MAO-coating under conditions of oil and water lubrication, and to find out the feasibility of using MAO technology to create sliding bearings. The formation of MAO coatings was carried out in an alkaline-silicate electrolyte in the cathodic-anodic mode. The structure and morphology of the working layer of the MAO-coating surface, which works in friction pairs with cast iron, steel and MAO-coating under conditions of oil and water lubrication, was investigated. The benefit of the available porosity of the working layer of the MAO coating, which is 5-10% and contributes to the retention of lubricant in the friction zone, is shown. The phase composition, hardness of the coatings were studied and the coefficient of sliding friction was determined on the SMC-2 friction machine according to the "disk-pad" scheme when using water and oil as lubricants; the load varied from 0.2 to 2 kN, the nominal pressure from 1 to 11 MPa. It was established that the MAO coating has a crystalline structure, the phase composition is high-temperature modifications of aluminum oxide (α-Al2O3 and γ- Al2O3), and the hardness is 18000-20000 MPa. It was established that the coefficient of sliding friction of gray cast iron - MAO-coating, steel - MAO-coating and MAO on MAO decreases to the value of 0.01 - 0.013 under lubrication conditions. It was found that in a pair of MAO-coating - MAO-coating, anti-friction properties are manifested both under conditions of lubrication with oil and water. The low coefficient of friction for the coating-coating pair in the case of water lubrication is explained by the high hydrophilic properties of the oxide contacting surfaces, which makes it possible to recommend them for use in sliding bearings (liners) of hydroturbines. A conclusion was drawn regarding the reasons for the low coefficient of friction of the studied samples. Keywords: D16 aluminum alloy, cast iron, steel, micro-arc treatment, coating, phase composition, crystal structure, aluminum oxides, coating thickness, coating hardness, friction coefficient, antifriction properties
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Petrova, Larisa, Victor Alexandrov, and Maxim Morshchilov. "Factors of quality increase in protective chromium coatings on aluminum alloys obtained through pyrolytic precipitation." Science intensive technologies in mechanical engineering 2020, no. 10 (October 30, 2020): 3–9. http://dx.doi.org/10.30987/2223-4608-2020-10-3-9.
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There are considered the problems of control parameter detection in the process of pyrolytic chromium coatings on aluminum alloy and the investigation of their impact upon coating structure, strengthening indices, adhesion strength, and also upon kinetics of coating growth. The investigations have shown that the method mentioned is promising for aluminum alloy surface strengthening, and also it allows obtaining chromium coatings with high hardness and thick constant possessing increased wear-resistance.
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Vijayakumar, T., T. Senthilvelan, and R. Venkatakrishnan. "Wear Behaviour of Polyurethane Coated Aerospace Aluminium Alloy (7075)." Applied Mechanics and Materials 813-814 (November 2015): 252–56. http://dx.doi.org/10.4028/www.scientific.net/amm.813-814.252.
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This paper envisages to predict the life of an aircraft coating using high strength precipitation hardening 7000 series aluminum alloys, such as 7075 which is used extensively in aerospace industry. Aerospace aluminum alloy 7075 has been researched upon especially for aircraft materials. The intention of protective coating is to save the aerospace aluminium alloy 7075 metal surface from weatherability and, at the same time, to obtain the required degree of cosmetic finish for the object. One was epoxy polyamide as primer layer and other was the polyurethane as top-coat layer of coating through conventional spray type on aluminum alloy 7075 substrates. Epoxy polyamide is useful binders for aircraft primers. Top-coats have also been prepared, but polyurethane is still the choice for aircraft coating. This coating system is typically comprised, of a primer layer and a topcoat layer. The ability of the polyurethane coating is to prevent corrosion, weatherability depends on its anti-corrosive pigments and its adhesion to the substrate. All these factors are widely variable with the geographic location and season such as temperature, wind, oxygen and atmospheric pollutants. The effect of structural and process variable on wear resistance of polyurethane coating was analyzed to determine the maximum wear rate using DOE software optimum samples were prepare according to best level of each factor and its morphology was examined by scanning electron microscope (SEM).
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Singh, Dalip, Veena Dhayal, and D. C. Agarwal. "Evaluate Mechanical Behavior of Alumina Coated Aluminum Alloy Using Slow Strain Rates Test in 3.5% of NaCl Solution." Materials Science Forum 969 (August 2019): 242–46. http://dx.doi.org/10.4028/www.scientific.net/msf.969.242.
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This work is concerned with the investigation of the capability of alumina coatings, deposited over aluminum alloy by dip coating methods to improve mechanical properties. Alumina coatings were deposited using oxime-modified aluminum (III) isopropoxide as a sol-gel precursor. The Scanning electron microscopy (SEM-EDX) images of the coated samples suggest deposition of uniform and crack free alumina coatings. The mechanical property of the bare, and dip coated aluminum alloy were investigated by the slow strain rate test in 3.5% of NaCl solution. The coated sample indicate higher ultimate tensile strength, it’s reflect the protective behavior of coating.
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Li, Shengchun, and Changhong Liu. "Preparation of the wear and corrosion-resistant coating using a composite process of laser surface texturing technology and plasma electrolytic oxidation." AIP Advances 13, no. 3 (March 1, 2023): 035204. http://dx.doi.org/10.1063/5.0136460.
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In this study, a composite process consisting of laser surface texture imitating fish scale shapes and plasma electrolytic oxidation (PEO) was used on the surface of aluminum alloy metals to prepare wear- and corrosion-resistant coatings. Before the conventional plasma electrolytic oxidation, the laser was used to prepare the imitation fish scale shape texture on the aluminum alloy surface. It was found that the PEO coating could cover the splash ablation particles left by the laser, while the imitation fish scale shape structure was enough to improve the tribological properties of the PEO coating, and the coating prepared by the combination of the two processes had a more stable friction coefficient, excellent corrosion resistance, and good resistance to abrasion corrosion. In this paper, the microstructure and composition of the coatings were characterized by metallurgical microscopy, XRD, and energy dispersive spectroscopy (EDS), and the protection mechanism and the physical model of the coatings prepared by the composite process were presented and discussed. In summary, the use of the composite process provides a feasible idea for improving the performance of aluminum alloys.
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Liu, Eryong, Furong Wang, Shuangming Du, Zhixiang Zeng, Huiling Du, and Yaping Bai. "Effect of Cr2O3 on the microstructure and tribological performance of sprayed Fe-based coating on cylinder liner." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 234, no. 3 (August 25, 2019): 435–47. http://dx.doi.org/10.1177/1350650119870964.
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Improving the vehicle efficiency by weight reduction and friction loss has become the severe challenge to machinery manufacturers. Generally, replacing heavy cast iron engine component by aluminum alloys played a key role in reducing fuel consumption and pollutants emission, but the durability in poor mechanical properties of aluminum alloys restricted its application in severe conditions of engine cylinder. In order to improve the tribological properties of aluminum cylinder liner, Cr2O3-added Fe-based coating was prepared by plasma spraying technology, and the effect of Cr2O3 on the microstructure and tribological performance of sprayed coating was investigated in this study. All the Cr2O3-added coatings improved mechanical properties significantly, such as hardness and wear resistance compared to that of Fe-based alloy. However, appropriate content of Cr2O3 was beneficial to wear resistant but the excessive Cr2O3 deteriorated the wear resistance under dry sliding condition. The degradation was likely generated by the embrittlement of the Cr2O3 reinforcements, weaker interface of Cr2O3/matrix, and the inherent lamellar structure of sprayed coating. As a result, Fe-based coating with 30 wt.% Cr2O3 provided excellent mechanical properties and can be substitute for the application in aluminum alloy cylinder liner.
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Riquelme, Ainhoa, Pilar Rodrigo, María Dolores Escalera-Rodriguez, and Joaquin Rams. "Wear Resistance of Aluminum Matrix Composites’ Coatings Added on AA6082 Aluminum Alloy by Laser Cladding." Coatings 12, no. 1 (December 29, 2021): 41. http://dx.doi.org/10.3390/coatings12010041.
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Ceramic-reinforced metal matrix composites are known for their high wear resistance. A coating based on these materials would be helpful to improve the wear behavior of aluminum alloys. Laser cladding has been used to deposit a coating consisting of an aluminum alloy reinforced with SiC particles on an AA6082 aluminum alloy. Laser cladding is a very energetic technique that causes the SiC particles to react with the molten aluminum to form Al4C3, which degrades the particles and reduces the properties of the coating. The formation of this detrimental compound was successfully achieved with the addition of Silicon and Titanium to the composite matrix. The microstructures of the newly developed material were characterized and the wear behavior was studied under dry sliding conditions on a pin-on-disc tribometer. The relationship between the microstructure and wear behavior was identified. The absence of Al4C3 in the Al40Si/SiC and Al12Si20Ti/SiC coatings’ microstructures resulted in an abrasion mechanism instead of a delamination mechanism. The wear behavior changed along the sliding distances. During the first 200 m of sliding distances, the wear rate of all coatings was lower than the uncoated one due to their higher microhardness. For longer sliding distances, the wear resistance of the uncoated AA6082 was higher than the coated ones due to the formation of a lubricant oxide layer on the AA6082 worn surface. For 1000 m of wear distances, the wear behavior was different for each coating. The wear rate of the Al12Si/SiC coating continued growing due to the delamination mechanism and the presence of Al4C3 that acted as starting crack points. The wear rate of the Al40Si/SiC coating decreased due to the formation of a thin, superficial oxide layer. The wear rate of the Al12SiTi/SiC progressively decreased along the sliding distance to below the substrate wear rate.
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Wu, Shang-Kun, Wei Yang, Wei Gao, Yu-Hong Yao, Yong Zhang, and Jian Chen. "Characterization of MAO + Cu Composite Coatings on Aluminum Alloy." Coatings 11, no. 10 (September 28, 2021): 1172. http://dx.doi.org/10.3390/coatings11101172.
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Novel composite coatings were fabricated on 6061 aluminum alloy substrates by two steps combining micro-arc oxidation (MAO) plus electroless copper plating (Cu). Different MAO + Cu composite coatings were compared. Cu continuously and evenly covered an aluminum oxide surface during processing thus changing the surface topography. The adhesion of MAO + Cu composite coating was tested by the pull-out method. The best adhesion strength of the composite coating can reach industrial requirements. The effects of the composite coatings on friction were investigated using a ball-on-disc test method. It is found that copper in composite coatings plays a lubricating effect during the wear process under dry sliding. Furthermore, the mechanisms by which the observed advantages were produced are discussed.
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Shvetsov, Oleg, and Sergey Kondrat’ev. "Performance of Protective Coatings for Aluminum Alloys in the Operating Conditions of Oil Production Equipment." E3S Web of Conferences 225 (2021): 05003. http://dx.doi.org/10.1051/e3sconf/202122505003.
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The paper investigates wear resistance and corrosion resistance of protective coatings of D16 aluminum alloy under conditions that simulate operation of drill pipes. The paper also presents microstructure of coatings, electrochemical potential and corrosion rate of D16 aluminum alloy with various coatings. We evaluated adhesion and wear resistance of these coatings. D16 alloy with a tungsten carbide coating has the widest range of service properties and can be used to effectively protect the surface of aluminum drill pipes during operation operation.
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Dileep, B. P., V. Ravi Kumar, Mrudula Prashanth, and M. V. Phanibhushana. "Effect of Zinc Coating on Mechanical Behavior of Al 7075." Applied Mechanics and Materials 592-594 (July 2014): 255–59. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.255.
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The addition of zinc to aluminum with magnesium or copper produces heat treatable alloys of highest strength which can be used for structural applications. This work is an attempt to investigate any improvement in hardness and fracture toughness by coating aluminum 7075 alloy with zinc. The zinc coated aluminum 7075 alloy was fabricated using Time Dependent Electro-Plating Technique. The thickness of the coating is a function of time. The varying thickness of zinc coating was obtained based on the time estimates, which includes 10, 15 and 20 microns. Specimens were prepared according to ASTM standards, which were then tested for mechanical properties such as surface hardness, tensile strength and fracture toughness at different loading conditions. The results, when compared to the uncoated aluminum alloy showed significant improvement in Hardness (87 RHN). The hardness increased slightly compared to that of uncoated surface and showed no increase with the increase in the thickness of coating. The yield stressof zinc coated aluminum alloy increased (587.11 N/mm2) when compared to uncoated aluminum alloy 7075 - T6 (537.12 N/mm2), with an increase in brittleness. The fracture toughness test on CT specimen under plain strain condition for coated specimen showed an increase in KIC value by 7.25 % compared to that of uncoated aluminum 7075–T6 alloy. Optical microscopy analysis shows that there is a good bonding of zinc coating on aluminum.
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Wang, Peng, and Dayong Cai. "Study of the Protection of Aluminum Alloy Surfaces by a Graphene-Modified Fluorocarbon Anticorrosive Coating." International Journal of Photoenergy 2020 (October 22, 2020): 1–8. http://dx.doi.org/10.1155/2020/8835737.
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Graphene-modified anticorrosion coatings have become a hot spot in the field of metal protection due to the large-scale promotion of aluminum alloys, which are prone to corrosion in marine and atmospheric environments. The protection of aluminum alloy surfaces by a graphene-modified anticorrosive coating was explored in this study by applying a graphene-modified anticorrosive coating to an aluminum alloy surface to test its resistance to corrosion. Dispersion-treated reduced graphene oxide (rGO) was used to modify the epoxy resin and fluorocarbon resin. It was found, by using a scanning electron microscopy (SEM) and the microstructure of the coating made by the Raman Spectroscopy Institute, that the addition of rGO could effectively improve the porosity of the epoxy primer, and the electrochemical workstation was able to resist the graphene-modified anticorrosive coating. The corrosion performance was quickly characterized, the polarization curve and the AC impedance curve were fitted, and it was found that the self-corrosion current density ( J corr ) of the graphene-modified anticorrosive coating was the smallest ( 1.190 × 10 − 7 A / c m 2 ) when 0.6% of rGO was added; the impedance modulus ( ∣ Z ∣ ) was the largest (104), the capacitive reactance arc radius was the largest, and the coating resistance was the largest after fitting (15517 Ω). When 0.8% of rGO was added, the dispersion coefficient was large, and it had a good physical insulation performance. The main reason for the reduction of the corrosion resistance was that the agglomeration of rGO made the aluminum alloy matrix and the external corrosive environment form a highly conductive circuit, thereby accelerating the corrosion of the aluminum alloy matrix.
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Sun, Haiou, Liangcai Li, Zhongyi Wang, Bin Liu, Meng Wang, and Yunliang Yu. "Corrosion Behaviors of Microarc Oxidation Coating and Anodic Oxidation on 5083 Aluminum Alloy." Journal of Chemistry 2020 (November 20, 2020): 1–11. http://dx.doi.org/10.1155/2020/6082812.
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The microarc oxidation (MAO) coating and anodic oxidation coating were prepared on 5083 aluminum alloy. The surface morphology, elemental composition, and electrochemical behavior of the two coatings were analyzed. The results proved that the corrosion resistance of the MAO coating is superior than that of the anodic oxidation coating. The protective ability of the coating deteriorated gradually with the increase in immersion time. The corrosion process is controlled by ion diffusion throughout the coatings.
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Winter, Lisa, and Thomas Lampke. "Influence of Hydrothermal Sealing on the High Cycle Fatigue Behavior of the Anodized 6082 Aluminum Alloy." Coatings 12, no. 8 (July 29, 2022): 1070. http://dx.doi.org/10.3390/coatings12081070.
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For aluminum alloys, anodizing is a common electrochemical surface treatment to allow for protection against corrosion and wear. The produced conversion layers are first sealed in industrial processes to further enhance the corrosion protection by closing the coating surface pores. In their lifetime, anodized components often undergo cyclic loadings. However, despite the relevance of a sealing treatment, there is a lack of systematic studies regarding its influence on the fatigue behavior of anodized aluminum components. In this work, a 6082-aluminum alloy was anodized in sulphuric acid and the effect of the anodizing treatment with and without further hydrothermal sealing on the fatigue strength was investigated. The thickness and Martens hardness of the coatings were determined and the coating appearance in non-sealed and sealed conditions was analyzed by scanning electron microscopy prior to and after cyclically loading at R = −1. The fatigue strength was significantly decreased by the anodizing treatment, when compared to the bare substrate. However, hydrothermal sealing had a positive influence as the anodized and sealed condition attained a fatigue strength in the range of the bare aluminum. Distinct differences regarding the coating appearances, thickness, and hardness were not observed when comparing the non-sealed and the sealed conditions. After fatigue loading, numerous pronounced radial cracks were present in the anodic coating, but the number of cracks were significantly lower for the hydrothermally sealed coating. Fatigue failure occurred due to propagation of one crack from the coating towards the substrate, resulting in single-point crack initiation, which was similar to the fatigue fracture behavior of the bare aluminum substrate.
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Норман, А., A. Norman, В. Смоленцев, V. Smolentsev, В. Золотарев, and V. Zolotaryov. "Modification of surface layer in aluminum alloys by electroerosion coating." Science intensive technologies in mechanical engineering 1, no. 4 (April 30, 2016): 14–21. http://dx.doi.org/10.12737/18097.
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The mechanism of plating on low-melting alloys (for example, aluminum) cast-iron coatings having a high fusion temperature is considered. By means of this method one achieves in light aluminum alloy parts higher performance attributes to which belong reliable protection of parts with a coating against aggressive influence of chemically active substances. Besides, antifriction properties of parts operating in friction units are improved. The technological modes are developed and a coating process is designed. The example of the method offered is shown.
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Zhao, Kun, Wan Chang Sun, Chun Yu Miao, Hui Cai, Ju Mei Zhang, and Li Bin Niu. "Microstructure and High-Temperature Oxidation of Ni-Si3N4 Composite Coatings by Pulse Electrodeposition." Materials Science Forum 817 (April 2015): 421–25. http://dx.doi.org/10.4028/www.scientific.net/msf.817.421.
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Nickel matrix and Si3N4 micron particles were co-deposited on the aluminum alloy by pulse electro-deposition for high temperature performance. Meanwhile, the oxidation resistance was evaluated through the high temperature oxidation test. The phase structure, micrographs and components of the composite coatings were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) together with energy dispersive spectroscopy (EDS) respectively. The results indicated that Si3N4 particles were uniformly distributed across the coating and there were no pores and cracks or other defects at the coating/substrate interface. Ni-Si3N4 composite coatings are characterized by pyramidal micro-crystallite structure. The thickness of Ni-Si3N4 composite coatings were up to 80 μm for 2h. The results also revealed that the Ni-Si3N4 composite coatings presented better oxidation resistance than the pure Ni coating and aluminum alloy at high temperature. After oxidation at 673 K for 8h, the oxidation resistance of Ni-Si3N4 composite coatings presented the improved oxidation resistance behavior compared to pure Ni and the aluminum alloy, respectively.
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Lee, Cheng Kuo, Chi Lun Teng, An Hung Tan, Ching Yi Yang, and Sheng Long Lee. "Electroless Ni-P/Diamond/Graphene Composite Coatings and Characterization of their Wear and Corrosion Resistance in Sodium Chloride Solution." Key Engineering Materials 656-657 (July 2015): 51–56. http://dx.doi.org/10.4028/www.scientific.net/kem.656-657.51.
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The purpose of the present study is to evaluate the effect of the electroless Ni-P/diamond/graphene composite coating on the structure and surface hardness of 2024-T6 aluminum alloy as well as their effect on the corrosion and wear resistance of the alloy in 3.5 % NaCl solution. The electroless Ni-P plating solution was prepared by adding different size diamond (6-12 μm and 0.2 μm) and nanographene into the electroless Ni-P plating solution to obtain Ni-P/diamond, Ni-P/graphene and Ni-P/daimond/graphene composite coatings for comparison. Experimental results indicated that the Ni-P/diamond, Ni-P/graphene and Ni-P/daimond/graphene composite coatings can be successfully electroless deposited on anodized 2024-T6 aluminum alloy. The anodically oxidized films, that formed on the aluminum alloy using phosphoric acid as the electrolyte, was porous with high density of pores, and thus could enhance the adhesion of the composite coatings. The Ni-P/daimond/graphene hybrid coating had a higher hardness as well as better corrosion and wear resistance of 2024-T6 alloy in 3.5 wt.% NaCl solution as compared with other composite coatings. When the combination of nanographene and smaller diamond particles added this beneficial effect was significantly raised, especially the composite coating was further vacuum annealed at 400 °C for 24 h to obtain a more smooth and defect-free coating structure.
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Wada, Tadahiro, Jun Nakanishi, Yasuhiro Miki, Makoto Asano, Koji Iwamoto, and Hiroyuki Hanyu. "Surface Modification of Aluminum Alloy Using Plasma Based Ion Implantation and Deposition." Advanced Materials Research 488-489 (March 2012): 960–66. http://dx.doi.org/10.4028/www.scientific.net/amr.488-489.960.
Full textAbstract:
Aluminum alloys are used for mechanical parts, but the alloys have poor wear-resistance. To increase their wear resistance, a hard coating is applied to the surface of the alloys. Diamond-like carbon (DLC) is applied in surface modification technology due to its superior mechanical characteristics. In this study, in order to achieve effective surface modification to improve the wear resistance of the aluminum alloys, a new coatings-system was designed. This coating-substrate system is a multilayer coating-substrate system, which consists of nitriding pretreatment of the substrate, the intermediate layer of the silicon-based film and the outer layer of the DLC film. This new coating-system was used to deposit DLC film on three kinds of aluminum alloys that have different Si contents. In order to determine the influence of the Si contents on the mechanical properties of the DLC film, SEM observation of the cross section of the coating layer, the adhesion and the wear resistance of the layer were experimentally investigated. The results were as follows: (1) In the case of the DLC un-coated aluminum alloys, the rapid progress of the friction coefficient in the case of 10-N load was found at the short sliding distance. (2) The hardness of the DLC film was not decreased with the increase of Si contents. And the increase of Si contents did not have a negative influence upon the hardness of the DLC film. (3) The frictional coefficient of the Al-4%Si alloy was the smallest, the frictional coefficient of the DLC film was decreased with the increase of Si contents, and it was effective for improvement of the frictional coefficient to increase Si contents. The new coating-substrate system is effective for improving the adhesion between the substrate of the aluminum alloy and the DLC film. Moreover, the increase of Si contents was effective for the decrease in the frictional coefficient.
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Lee, Byeong Woo. "Effect of diffusion coatings on the high temperature properties of nickel-chromium-superalloys." International Journal of Modern Physics B 32, no. 19 (July 18, 2018): 1840056. http://dx.doi.org/10.1142/s0217979218400568.
Full textAbstract:
The halide-activated pack cementation method was utilized to deposit aluminide or silicide coatings on Inconel 617 and Hastelloy X superalloys. Aluminide and silicide diffusion coatings were formed at 850[Formula: see text]C for 2 h in nitrogen atmosphere, using a pack mixture containing pure aluminum (Al) or silicon (Si) and aluminum oxide (Al2O3) powders with activators of NH4Cl and AlF3. Aluminide-coated alloys showed homogeneous and uniform microstructures. Al diffused into the alloy inwards and aluminide diffusion coatings of [Formula: see text]17 [Formula: see text]m thick were formed inside the alloy. It was shown that the Al coatings played a key role in blocking off the excessive corrosion products at a high temperature for the alloys. The enhanced thermal stability and improved wear resistance were achieved in the aluminide coatings. In contrast to the aluminide coating, the silicide coating played a negative role, unable to provide the protective layer. The microstructural evolution and thermal stability of the aluminide- and silicide-coated alloys have been elucidated.
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Yin, Yu Jun, Shu Hua Li, Da Wei Shen, Yuan Yuan Zu, and Chang Zheng Qu. "Effects of Al2O3 Nanoparticles on Microstructure and Performance of Ceramic Coatings by Micro-Arc Oxidation." Key Engineering Materials 537 (January 2013): 92–96. http://dx.doi.org/10.4028/www.scientific.net/kem.537.92.
Full textAbstract:
A dense ceramic oxide coating approximately 45 µm thick was prepared on a Ly12 aluminum alloy by micro-arc oxidation in an alkali-phosphate electrolytic solution. Coating thickness and surface roughness (Ra) were measured after the coating had been synthesized. The effects of Al2O3 Nanoparticles in electrolyte on phase composition, microstructure and microhardness of the micro-arc oxidation ceramic coatings on Ly12 aluminum alloy were investigated by means of XRD, SEM and hardness experimentation. The results show that the ceramic coatings become more dense and its microhardness increased by adding Al2O3 Nanoparticles in electrolyte. In addition, the roughness of the micro-arc oxidation ceramic coatings is obviously improved by addition of Al2O3 Nanoparticles.
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Zhou, Qi, Hong Yan Liu, Xiu Lian Cheng, and Guang Sen Zhang. "Zirconate Conversion Coatings on Al Alloy by Electrochemical Method." Advanced Materials Research 460 (February 2012): 86–89. http://dx.doi.org/10.4028/www.scientific.net/amr.460.86.
Full textAbstract:
Chromium-free conversion coatings were generated to replace chromate chemical process by electrolysis treatment LY12 aluminum alloy in zirconate solution. Film thickness, dropping test, the adhesion between aluminum and paint film were tested for single-factor experiments and orthogonal to seek better electrolysis process. The paint adhesion is the first grade for electrochemical conversion solution containing complexing agents, or it is the second grade without complexing agents. When DNS complexing agent is 2 ~ 5g/L, film corrosion resistance rises with the increasing content of complexing agent. If voltage is too low, corrosion resistance of conversion coating is poor; voltage is too high, the films form powders. Better formulations for zirconate conversion coating are: 5g/L DNS complexing agent, 10V voltage, treatment temperature is 40°C. Electrochemical conversion coating is thinner than chemical conversion, but the corrosion resistance is better because the electrochemical conversion coatings are smoother and compacter than the chemical conversion coating. The paint films on electrochemical conversion coating are smoother than the chemical one. Two kinds of conversion coatings have very good adhesion with paint film up to the first level. Electrochemical conversion coatings thickness is 2.5 μm, bubble time of NaOH-glycerine solution on them is up to 92s.