Articoli di riviste: "Nickel alloys"

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Mysik, R. K., S. V. Brusnitsyn e A. V. Sulitsin. "Application Of Ni-Mg-Ce Master Alloy Scrap For Inoculation Of Copper-Nickel Alloys". KnE Materials Science 2, n. 2 (3 settembre 2017): 102. http://dx.doi.org/10.18502/kms.v2i2.954.

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<p class="TTPAbstract">The problems of production of copper-nicckel alloys ingots by semicontinuous casting method are analysed. The requirement of grain size refinement in cast alloys macrostructure is shown. It is necessary to reduce the probability of hot cracks formation and increase the fabricability of cast bars during plastic working. The reasonability of fine fraction of Ni-Mg-Ce master alloy application for inoculation of copper-nickel alloys is established. The results of laboratory experiments on the study of master alloy quantity influence the structure and hardness of Cu-5Ni-1Fe, Cu-10Ni-1Fe-1Mn and Cu-30Ni-1Fe-1Mn copper-nickel alloys are presented. On the basis of industrial experiments it is revealed that inoculation of Cu-5Ni-Fe alloy ingots of diameter 200 mm by Ni-Mg-Ce master alloy leads to considerable reducing of macrograin size. It allows to improve mechanical properties of ingots and ensure their uniform distribution in cross section of ingots. It is established that residual magnesium content in alloy must be in range from 0,02 to <br />0,06 wt. %. The use of Ni-Mg-Ce master alloy makes it possible to increase the processability of copper-nickel alloys during plastic working and utilize the fine fraction master alloy scrap inevitably formed during its production.</p>

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Rudenok, V. A., O. M. Kanunnikova, G. N. Aristova e O. S. Tikhonova. "The design and properties of galvanic anticorrosive coatings for important precision parts of farming equipment". IOP Conference Series: Earth and Environmental Science 949, n. 1 (1 gennaio 2022): 012113. http://dx.doi.org/10.1088/1755-1315/949/1/012113.

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Abstract The paper explores the possibility of using a number of nickel alloys in multilayer coatings to decrease nickel consumption and preserve the functional effect of the coating. The following is proved by the graphical calculation technique using experimental data on the galvanic properties of the multilayer coating parts. Nickel-iron, nickel-phosphorus and nickel-tin alloy can be applied as a lower coating layer rather than semi-shiny, shiny or composite nickel. It is advisable to use a nickel-iron alloy as the middle (second) layer, and the concentration of iron depends on the composition of the first and third layers. If a nickel-iron alloy is applied as the material of the first layer, then the second layer may be semi-shiny (Ns-sh) or shiny (Nsh) nickel. The substitution of nickel layers for nickel alloys allows to considerably (about 10%) decrease the cost of a multilayer coating, while the protective properties are remaining the same. The application of the same nickel-containing alloys as single-layer anticorrosive coatings shows a lower level of protective properties.

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Murphy, Michael. "Nickel and nickel alloys". Metal Finishing 94, n. 2 (febbraio 1996): 24–26. http://dx.doi.org/10.1016/s0026-0576(96)93839-8.

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Murphy, Michael. "Nickel and nickel alloys". Metal Finishing 95, n. 2 (febbraio 1997): 26. http://dx.doi.org/10.1016/s0026-0576(97)94207-0.

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MITSUHASHI, Akira. "Nickel Alloys and Cobalt Alloys". Journal of the Japan Society for Technology of Plasticity 54, n. 632 (2013): 812–16. http://dx.doi.org/10.9773/sosei.54.812.

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Radev, D. D. "Nickel-Containing Alloys for Medical Application Obtained by Methods of Mechanochemistry and Powder Metallurgy". ISRN Metallurgy 2012 (14 novembre 2012): 1–6. http://dx.doi.org/10.5402/2012/464089.

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The methods of mechanochemistry, in combination with cold pressing and pressureless sintering, were used to obtain the most popular nickel-based and nickel-containing alloys used in dentistry and implantology. It was shown that the intense mechanical treatment of Ni, Ti, and Cr powders used as reagents, and the application of the above-mentioned simple powder metallurgical technique for densification allows obtaining NiCr and NiTi alloys with controlled structural properties. The nickel-based dental alloys obtained by mechanically activated sintering possess excellent mechanical, technological, and aesthetic properties. These alloys are suitable as dental restorative materials and for production of porcelain veneered constructions like crowns and bridges using the so-called metal-to-ceramic dental technique. It was shown that the method of mechanically assisted synthesis allows obtaining nanosized NiTi alloy at significantly lower temperature in comparison with the traditional high-temperature alloying. It was also shown that after 40 hours intense mechanical treatment of reagents, a direct synthesis of NiTi alloy proceeds. The product has excellent sinterability which enables to produce bodies with controlled porosity appropriate for application in implantology.

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Kutyła, Dawid, Karolina Kołczyk-Siedlecka, Anna Kwiecińska, Katarzyna Skibińska, Remigiusz Kowalik e Piotr Żabiński. "Preparation and characterization of electrodeposited Ni-Ru alloys: morphological and catalytic study". Journal of Solid State Electrochemistry 23, n. 11 (15 ottobre 2019): 3089–97. http://dx.doi.org/10.1007/s10008-019-04374-7.

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Abstract Nickel-ruthenium alloys with various compositions have been deposited by electrodeposition for the first time. Cyclic voltammetry and linear stripping voltammetry measurements show that codeposition of nickel with ruthenium is possible below the potential value of nickel reduction. High-quality alloys containing nickel and ruthenium can be plated at cathodic potentials ranging from − 0.5 to − 1.0 V vs SCE. Deposited coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The diffractograms obtained show that an increase of nickel concentration in alloy will lead to a change in the phase composition and formation of NiRu (100) and (101) phases which is observed to be 78 mas.% Ni. SEM studies confirm the surface homogeneity and presence of small, regular grains. AFM observation allows the estimation of the real surface area of obtained alloys which increase with more negative electrodeposition potentials. Ni-Ru alloys were found to be highly electroactive in the water splitting process, which can be connected with the presence of the NiRu phase and a well-developed electroactive area.

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Glotka, O., e V. Olshanetskii. "Properties of nickel-based superalloys of equiaxial crystallization". Innovative Materials and Technologies in Metallurgy and Mechanical Engineering, n. 1 (14 settembre 2021): 19–23. http://dx.doi.org/10.15588/1607-6885-2021-2-3.

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Purpose. The aim of the work is to obtain predictive regression models, with the help of which, it is possible to adequately calculate the mechanical properties of nickel-based superalloys of equiaxial crystallization, without carrying out preliminary experiments. Research methods. To find regularities and calculate the latest CALPHAD method was chosen, and modeling of thermodynamic processes of phase crystallization was performed. Results. As a result of experimental data processing, the ratio of alloying elements Kg¢ was proposed for the first time, which can be used to assess the mechanical properties, taking into account the complex effect of the main alloy components. The regularities of the influence of the composition on the properties of heat-resistant nickel alloys of equiaxial crystallization are established. The analysis of the received dependences in comparison with practical results is carried out. The relations well correlated with heat resistance, mismatch and strength of alloys are obtained. Scientific novelty. It is shown that for multicomponent nickel systems it is possible with a high probability to predict a mismatch, which significantly affects the strength characteristics of alloys of this class. The regularities of the influence of the chemical composition on the structure and properties of alloys are established. A promising and effective direction in solving the problem of predicting the main characteristics of heat-resistant materials based on nickel is shown Practical value. On the basis of an integrated approach for multicomponent heat-resistant nickel-based alloys, new regression models have been obtained that make it possible to adequately predict the properties of the chemical composition of the alloy, which made it possible to solve the problem of computational prediction of properties from the chemical composition of the alloy. This allows not only to design new nickel-based alloys, but also to optimize the composition of existing brands.

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Al nefawy, Mohamad Yehea, Fouad El dahiye e Mahmoud Al Assaad. "The Effect of Heat Treatments and Nickel Additive on The Microstructure and Tensile Properties of 7075 Aluminum Alloy". Association of Arab Universities Journal of Engineering Sciences 27, n. 2 (30 giugno 2020): 154–61. http://dx.doi.org/10.33261/jaaru.2020.27.2.014.

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The aluminum alloys of the 7xxx series consist of Al with Zn mainly, Mg and Cu. 7xxx aluminum alloys has high mechanical properties making it distinct from other aluminum alloys. The effect of adding Nickel and heat treatments on the microstructure, formed phases and tensile properties of the 7075 aluminum alloy were studied in this paper. Different percentages of nickel [0.1, 0.5, 1] wt% was added to 7075 Aluminum alloy, and various heat treatments (artificial aging T6 and Retrogression and re-aging RRA) was applied on the 7075 alloys that containing nickel. The results obtained by applying of RRA treatment were better than the results of T6 treatment, the tensile properties increased and the microstructure became softer by adding nickel to the studied alloys. The maximum tensile strength of 7075 aluminum alloy was (UTS = 437 Mpa) when RRA heat treatment was applied and 0.5% nickel was added.

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Pereplyotchikov, E. F. "Plasma-powder surfacing of nickel and cobalt alloys on copper and its alloys". Paton Welding Journal 2015, n. 6 (28 giugno 2015): 10–13. http://dx.doi.org/10.15407/tpwj2015.06.02.

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Janoš, Miroslav, e Ivan Mrkvica. "The Milling of Material Inconel 718 with Indexables Cutting Inserts from Sintered Carbide". Technological Engineering 10, n. 1 (1 dicembre 2013): 9–11. http://dx.doi.org/10.2478/teen-2013-0003.

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Abstract In this document I am describing milling possibilities of nickel alloy Inconel 718. In the beginning is described use of nickel alloys in industry and division of nickel alloys. Further is described nickel alloy what I used - Inconel 718, on this material I make all my tests of machi-nability. Further chapters describe recommended cutting materials for nickel alloys milling. Cutters with exchan-geable sintered carbide blade plates were used as cutting tools company Pramet Tools s.r.o. Main goal was inve-stigate durability and wear of indexable cutting inserts for different cutting procedures. It was mainly about different combinations of used cutting speeds and feeds. The final part includes a summary of the results. The results are ones from first steps to definition of effective nickel alloy machining.

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Alasad, Mahmoud, e Mohamad Yahya Nefawy. "The Effect of Heat Treatments and Nickel Additive on The Microstructure and Hardness of 7075 Aluminum Alloy". مجلة جامعة فلسطين التقنية للأبحاث 7, n. 2 (15 settembre 2019): 34–41. http://dx.doi.org/10.53671/pturj.v7i2.76.

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The aluminum alloys of the 7xxx series consist of Al with Zn mainly, Mg and Cu. 7xxx aluminum alloys has high mechanical properties making it distinct from other aluminum alloys. In this paper, we examine the effect of adding Nickel and heat treatments on the microstructure and hardness of the 7075 aluminum alloy. Were we added different percentages of nickel [0.1, 0.5, 1] wt% to 7075 Aluminum alloy, and applied various heat treatments (artificial aging T6 and Retrogression and re-aging RRA) on the 7075 alloys that Containing nickel. By applying RRA treatment, we obtained better results than the results obtained by applying T6 treatment, and we obtained the high values of hardness and a smoother microstructure for the studied alloys by the addition of (0.5 wt%) nickel to alloy 7075.

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Alasad, Mahmoud, e Mohamad Yahya Nefawy. "The Effect of Heat Treatments and Nickel Additive on The Microstructure and Hardness of 7075 Aluminum Alloy". مجلة جامعة فلسطين التقنية خضوري للأبحاث 7, n. 2 (15 settembre 2019): 34–41. http://dx.doi.org/10.53671/ptukrj.v7i2.76.

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The aluminum alloys of the 7xxx series consist of Al with Zn mainly, Mg and Cu. 7xxx aluminum alloys has high mechanical properties making it distinct from other aluminum alloys. In this paper, we examine the effect of adding Nickel and heat treatments on the microstructure and hardness of the 7075 aluminum alloy. Were we added different percentages of nickel [0.1, 0.5, 1] wt% to 7075 Aluminum alloy, and applied various heat treatments (artificial aging T6 and Retrogression and re-aging RRA) on the 7075 alloys that Containing nickel. By applying RRA treatment, we obtained better results than the results obtained by applying T6 treatment, and we obtained the high values of hardness and a smoother microstructure for the studied alloys by the addition of (0.5 wt%) nickel to alloy 7075.

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Margida, Anthony J., Keith D. Weiss e J. David Carlson. "MAGNETORHEOLOGICAL MATERIALS BASED ON IRON ALLOY PARTICLES". International Journal of Modern Physics B 10, n. 23n24 (30 ottobre 1996): 3335–41. http://dx.doi.org/10.1142/s0217979296001781.

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A magnetorheological material containing iron alloy particles demonstrates magnetorheological strength dependent upon the elements of the alloy and relative concentration of the alloy elements. Selected iron/cobalt alloys demonstrate improved yield strength over traditional carbonyl iron based MR materials when the iron-cobalt alloy has an iron-cobalt ratio ranging from about 30:70 to 95:5. The iron-nickel alloys which have an iron-nickel ratio ranging from about 90:10 to 99:1 maintains superior strength over iron-nickel alloys outside that range.

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Khalikov, Albert R., Evgeny A. Sharapov, Vener A. Valitov, Elvina V. Galieva, Elena A. Korznikova e Sergey V. Dmitriev. "Simulation of Diffusion Bonding of Different Heat Resistant Nickel-Base Alloys". Computation 8, n. 4 (30 novembre 2020): 102. http://dx.doi.org/10.3390/computation8040102.

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Currently, an important fundamental problem of practical importance is the production of high-quality solid-phase compounds of various metals. This paper presents a theoretical model that allows one to study the diffusion process in nickel-base refractory alloys. As an example, a two-dimensional model of ternary alloy is considered to model diffusion bonding of the alloys with different compositions. The main idea is to divide the alloy components into three groups: (i) the base element Ni, (ii) the intermetallic forming elements Al and Ti and (iii) the alloying elements. This approach allows one to consider multi-component alloys as ternary alloys, which greatly simplifies the analysis. The calculations are carried out within the framework of the hard sphere model when describing interatomic interactions by pair potentials. The energy of any configuration of a given system is written in terms of order parameters and ordering energies. A vacancy diffusion model is described, which takes into account the gain/loss of potential energy due to a vacancy jump and temperature. Diffusion bonding of two dissimilar refractory alloys is modeled. The concentration profiles of the components and order parameters are analyzed at different times. The results obtained indicate that the ternary alloy model is efficient in modeling the diffusion bonding of dissimilar Ni-base refractory alloys.

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Xiang, Xiong Zhi, Xiao Jun Bai, You Zheng Tang e Fei Niu. "Colour and Nickel Release of Low Nickle White Gold Alloy with Mn Addition". Applied Mechanics and Materials 66-68 (luglio 2011): 1494–99. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.1494.

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In this paper, Au-Zn-Cu-Ni alloy series was take as a benchmark. Nickel element was replaced by Manganese in different ratios. The existing state and distribution law of Manganese, and the effects of the Manganese on microstructure and properties of gold alloys were studied. The mechanism of effects of Manganese on the colour and the release of nickel of gold alloys were discussed.

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Savaşkan, T., Z. Azaklı e H. O. Tan. "Influence of nickel addition on the microstructure, mechanical, and wear properties of Zn‐40Al‐2Cu alloy". Materialwissenschaft und Werkstofftechnik 55, n. 3 (marzo 2024): 279–89. http://dx.doi.org/10.1002/mawe.202300201.

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AbstractTo study the influence of nickel addition on the microstructure, mechanical and lubricated wear properties of Zn‐40Al‐2Cu alloy, one ternary and five quaternary Zn‐40Al‐2Cu‐(0.5‐2.5)Ni alloys were made by permanent mold casting. The wear behavior of these alloys was studied using a block‐on‐cylinder type test machine, after examining their microstructural and mechanical features. The microstructure of Zn‐40Al‐2Cu alloy was comprised of aluminum‐rich α dendrites and a eutectoid α+η phase mixture. The addition of nickel caused the formation of intermetallic Al3Ni particles in the microstructure of this alloy. As the nickel content of alloys increased their hardness, friction coefficient, working temperature, and average surface roughness increased to certain extents but their strength, ductility, impact resistance, and wear volume decreased. However, the values of their wear volume and average surface roughness exhibited opposite changes with increasing nickel content. The worn surfaces of Zn‐40Al‐2Cu‐Ni alloys were observed to be characterized by smearing and scratching marks. Furthermore, the wear and mechanical properties of these alloys were correlated, and the results were discussed in terms of their microstructural features. Finally, it may be concluded that the nickel addition adversely affects the ductility of Zn‐40Al‐2Cu alloy but increases its wear resistance.

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Andreev, V. V., V. V. Vatagin e M. V. Ushkov. "Thermit welding nickel and copper-nickel alloys". Welding International 3, n. 9 (gennaio 1989): 772–73. http://dx.doi.org/10.1080/09507118909446653.

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Калініна, Наталія Євграфівна, Олександр Васильович Калінін, Тетяна Валеріївна Носова, Стелла Ігорівна Мамчур e Наталія Іванівна Цокур. "Розробка технології дисперсного модифікування жароміцних нікелевих сплавів для лопаток газотурбінних двигунів". Aerospace technic and technology, n. 3 (27 maggio 2021): 49–53. http://dx.doi.org/10.32620/aktt.2021.3.06.

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The paper proposes means of improving the properties of nickel alloys for aircraft gas turbine engines by improving the existing alloys. The efficiency of an aircraft engine depends on the quality of the turbine rotor blades, which are made of heat-resistant alloys. According to the studies, the obtained results of pilot tests of a complex of mechanical properties, high-temperature corrosion of a multicomponent high-temperature nickel alloy ХН59МВТКЮЛ (Ni-Cr-W-Co-Al-Ti-Mo systems). The paper proposes the use of modifiers. An effective means of dispersing the structural components of alloys at the macro and micro levels is the modification of multicomponent alloys with dispersed and nano dispersed compositions. Based on titanium nitride powder, a technological regime for modifying nickel melt with dispersed compositions of plasma chemical synthesis has been developed. The modifier was used in tablet form. Investigated different dosages of the modifier: 0.1…0.03 % by weight. The proposed method allows, with minimal losses at the melting stage, to introduce the required amount of modifier. The temperature and time parameters of the modification are 16500С, the modifier action time is 5…7 minutes. Investigations of the complex mechanical properties and the peculiarities of the formation of the structure of the modified alloy have been carried out. According to the research results, significant refinement of the alloy grain was obtained in comparison with the initial state. The modification led to an increase in mechanical properties: strength by 10 %, impact strength by 35...40 %. Comparison of the nano-modified alloy with the obtained one made it possible to increase the corrosion resistance of the ХН59МВТКЮЛ alloy in an oxidizing environment. At a temperature of 1000 0С, the corrosion depth decreased by 15 %. An increase in resistance to high-temperature corrosion is associated with a more uniform distribution of excess phases in the structure of the modified alloy. The mechanism of action of refractory particles of a modifier in a nickel melt, which are the nuclei of primary crystallization, has been established. The results of the work are of practical value in the manufacture of rotor blades from high-quality heat-resistant nickel alloys with increased parameters of heat resistance and heat resistance.

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Khakimov, Iskandar B., Firuz A. Rakhimov, Izatullo N. Ganiev e Ziyodullo R. Obidov. "OXIDATION KINETIC AND ANODIC BEHAVIOR OF Zn22Al ALLOY DOPED WITH NICKEL". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 64, n. 6 (15 maggio 2021): 35–40. http://dx.doi.org/10.6060/ivkkt.20216406.6368.

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The article presents the results of the study of the oxidation kinetics and the anodic behavior of the zinc-aluminum alloy Zn22Al, doped with nickel, in various corrosive environments. The kinetic and energy parameters of the process of high-temperature oxidation of alloys are determined. It is shown that the process of high-temperature oxidation of samples of Zn22Al-Ni alloys is characterized by a monotonic decrease in the true oxidation rate and an increase in the effective activation energy at the content of the alloying component in the initial Zn0.5Al alloy up to 0.5 wt.%. It was found that nickel additives within the studied concentration (0.01-0.5 wt.% ) slightly increases the oxidability of the base alloy Zn22Al at temperatures of 523, 573 and 623 K. It is shown that the dependence of the corrosion potential of zinc-aluminum alloys on the nickel content in them is of the same type, i.e. the additives of the alloying component contribute to the displacement of the corrosion potential in the region of positive values. The influence of the aggressiveness of the corrosive medium on the anodic behavior of alloys when comparing concentrated electrolytes with the increasing concentration of chloride ions in the sodium chloride solution is established. It is determined that the potentials of pitting formation and repassivation of the initial alloys shift to a more positive region with an increase in the nickel concentration in the alloys. The greatest shift of these potentials to the positive region is observed when alloying alloys containing small nickel additives. It is shown that the corrosion products of the studied alloys consist of a mixture of protective oxide films Al2O3, ZnO, NiO, Al2O3·ZnO and Al2O3·Ni2O3. It was found that the alloying of zinc-aluminum alloys with nickel (in the range of 0.01–0.05 wt.%) reduces the corrosion rate of the base alloy by 2-3 times. The proposed alloy compositions can be used as an anode coating for corrosion protection of steel products and structures.

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Hernández-Méndez, F., A. Altamirano-Torres, José G. Miranda-Hernández, Eduardo Térres-Rojas e Enrique Rocha-Rangel. "Effect of Nickel Addition on Microstructure and Mechanical Properties of Aluminum-Based Alloys". Materials Science Forum 691 (giugno 2011): 10–14. http://dx.doi.org/10.4028/www.scientific.net/msf.691.10.

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In this work a comparative study between microstructure and mechanical properties of aluminum-nickel alloys with different contents of nickel was carried out. Alloys were produced by powders metallurgy. Characterization results indicates that the microstructure of the aluminum-nickel alloys present a thin and homogeneous distribution of an intermetallic compound in the aluminum’s matrix, identified as Al3Ni. Furthermore, it was find out that the amount of intermetallic Al3Ni increase as the nickel content in the alloy rises. Regarding the mechanical properties evaluated; it was establishes that the hardness, compression and flexion resistances also were improved due to the presence of the intermetallic compound.

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Mirkovic, Nemanja. "Mechanical properties of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys". Vojnosanitetski pregled 64, n. 4 (2007): 241–45. http://dx.doi.org/10.2298/vsp0704241m.

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Background/Aim. Metal-ceramic bond strength and alloys' elastic modulus clearly determine the potential of alloy application, because the ceramic integrity during mastication depends on these two characteristics. The aim of this study was to evaluate metal-ceramic bond strength and elastic modulus of cobalt-chromium alloys in making porcelainfused- to-metal restorations, regarding the application of the most frequent nickel-chromium alloy. Methods. The research was performed as an experimental study. Six metalceramic samples were made from nickel-chromium alloy (Wiron 99) and cobalt-chromium alloy (Wirobond C), according to the manufactures manuals and instructions from ISO 9693: 1996. Three-point bending test was performed up to the ceramic fracture. The fracture load was measured on an universal testing machine (Zwick, type 1464), with cross-head speed of 0,05mm/min. Results. The results of this study confirmed the significant differences between the metal-ceramic bond strength (p < 0.01) and elastic modulus (p < 0.001) of nickel-chromium and cobalt-chromium alloys, where cobalt-chromium alloys showed higher values for both tested parameters. Conclusion. Cobalt-chromium metal-ceramic alloys can successfully replace nickel-chromium alloys, especially for fabrication of long-span metal-ceramic bridges due to the great flexural strength.

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Wang, Kai, Haoran Qi, Simu Ma, Linrui Wang, Naijun He e Fuguo Li. "Effect of Nickel Addition on Solidification Microstructure and Tensile Properties of Cast 7075 Aluminum Alloy". Crystals 13, n. 11 (17 novembre 2023): 1589. http://dx.doi.org/10.3390/cryst13111589.

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In order to explore the casting technology of a high–strength aluminum alloy, the effects of nickel on the solidified microstructure and tensile properties of a 7075 aluminum alloy were studied. 7075 aluminum alloys without nickel and with 0.6% and 1.2% nickel were prepared by a casting method. The results showed that the increase of Ni content in the 7075 alloys increased the liquidus temperatures, primary α (Al) grains were refined significantly, and the divorced eutectic structure was gradually formed among α (Al) grains with the preformation of the Al3Ni phase. In comparison, the 7075 alloy with 0.6% nickel content had less intergranular shrinkage porosity, and its elongation and ultimate tensile strength was enhanced 45% and 105% higher than those of the as-cast 7075 aluminum alloy, respectively. When the Ni content was increased to 1.2%, the eutectic phases of the alloy became much coarser compared to the other two alloys, and the mechanical properties obviously reduced too.

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Eremin, E. N. "Selection of inoculant additives for modifying nickel alloys". Bulletin of the Karaganda University. "Physics" Series 105, n. 1 (30 marzo 2022): 81–88. http://dx.doi.org/10.31489/2022ph1/81-88.

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Heat-resistant nickel alloys are widely used in the production of castings for aircraft and industrial gas turbine engines. Structural factors are the main determinants of the performance properties of cast nickel alloys. The main disadvantage of castings obtained from these alloys is the coarse-crystalline structure, uneven grain size and columnar crystals in the cross-section. Therefore, the creation of an optimal alloy structure is an important condition for obtaining high properties and ensuring the increased operability of cast parts. Obtaining a fine-grained structure has a beneficial effect on the level of mechanical and operational properties of cast metal. The most promising way to create such a structure is to introduce a small number of additives into the melt that cause heterogeneous formation of crystal nuclei, i.e. modification of the melt with dispersed particles of refractory elements and inocular compounds. To select the type of inocular particles required to initiate crystallization of a particular phase, it is necessary to have a set of data that allows one to form a theoretical understanding of the principles of such a choice. The paper provides a rationale for the selection of the type of particles of inoculators capable of causing the process of artificial changes in the structure of cast metal. For a heat-resistant nickel alloy, the use of refractory particles of ultra-dispersed titanium carbo nitride powder as inoculators are the most effective. When introduced into the melt 0.025 wt. % of such particles, a fine-grained structure of the alloy is obtained, and its ductility in comparison with the unmodified one is more than doubled

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Xu, S., e W. R. Tyson. "Nickel in Structural Alloys". Canadian Metallurgical Quarterly 41, n. 2 (gennaio 2002): 219–30. http://dx.doi.org/10.1179/cmq.2002.41.2.219.

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Curtis, Dick. "Case hardening nickel alloys". Materials & Design 14, n. 6 (gennaio 1993): 349–50. http://dx.doi.org/10.1016/0261-3069(93)90111-8.

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Khayutin, S. G., e I. P. Golyamina. "Nickel-base magnetostrictive alloys". Metal Science and Heat Treatment 39, n. 3 (marzo 1997): 108–10. http://dx.doi.org/10.1007/bf02466277.

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Hanawa, Takao. "Recent Development of New Alloys for Biomedical Use". Materials Science Forum 512 (aprile 2006): 243–48. http://dx.doi.org/10.4028/www.scientific.net/msf.512.243.

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Metallic materials are widely used in medicine not only for orthopedic implants but also for cardiovascular devices and other purposes. New alloys for biomedical use are developed all over the world continuously to decrease corrosion, toxicity and fracture during implantation and increase interfacial and dynamical tissue compatibility. Most of efforts are made to develop titanium alloys, especially in β-type alloys whose Young’s modulus is as low as cortical bone. Nickel-free alloy is also necessary to prevent nickel allergy: nickel-free austenitic stainless steels and shape memory alloys are developed. To increase iocompatibility, the controls of surface morphology and surface treatment or modification are necessary.

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29

Glotka, O. A., e V. Yu Olshanetskii. "Predicting the properties of nickel-based superalloys directional crystallization". Metaloznavstvo ta obrobka metalìv 99, n. 3 (30 settembre 2021): 15–22. http://dx.doi.org/10.15407/mom2021.03.015.

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The aim of this work is to obtain predictive regression models, with which it is possible to adequately calculate the mechanical properties of heat-resistant nickel alloys, without prior experiments. Industrial alloys of directional crystallization of domestic and foreign production were selected for research. The values were processed by the method of least squares to obtain correlations with the receipt of mathematical equations of regression models that optimally describe these dependencies. As a result of processing of experimental data, the ratio of alloying elements which can be used for an estimation of mechanical properties taking into account complex influence of the main components of an alloy is offered for the first time. Since the dimensional mismatch of the lattice parameters is associated with the degree of concentration of solid-soluble hardening of γ- and γ'-phases, the efficiency of dispersion hardening of the alloy, creep rate and other properties, the obtained ratio allows to link these properties with multicomponent systems. Regression models are presented, with the help of which it is possible to calculate dimensional mismatch, strength, heat resistance, number of  phases and density of alloys with high accuracy. The regularities of the composition influence on the properties of heat-resistant nickel alloys of directional crystallization are established. It is shown that for multicomponent nickel systems it is possible to predict with high probability misfit, which significantly affects the strength characteristics of alloys of this class. The decrease in the value of misfit is accompanied by an increase in the solubility of the elements in the -solid solution at a value of the ratio of alloying elements of 1.5 - 1.6. However, an increase in the ratio of alloying elements greater than 2 is accompanied by an increase in misfit, because the -solid solution has reached a maximum of dissolution. The perspective and effective direction in the decision of a problem of forecasting of the basic characteristics influencing a complex of service properties of alloys both at development of new heat-resistant nickel alloys, and at perfection of structures of known industrial marks of this class is shown. Keywords: nickel-based superalloys, dimensional mismatch (γ / γ'- mismatch), strength, heat resistance.

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30

Majewski, Tomasz, e Katarzyna Leszczyńska-Sejda. "Investigation of Application Possibilities of Re-Ni Alloy Powder to Tungsten Heavy Alloys Production". Solid State Phenomena 251 (luglio 2016): 14–19. http://dx.doi.org/10.4028/www.scientific.net/ssp.251.14.

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The experiments results connected to possibilities of use of Re-Ni alloy powder for tungsten heavy alloys production were presented in the paper. This powder was obtained by nickel (II) perrhenate reduction under dissociated ammonia atmosphere. The optimal conditions for the thermal reduction for nickel (II) perrhenate were determined. The production process of investigated sinters contained, among others, cold isostatic pressing and two-staged sintering. Selected results of microstructure investigation and mechanical properties of obtained sinters were shown. Performed research indicated that the application of nickel (II) perrhenate to manufacture tungsten heavy alloys resulted in material with the microstructure typical of tungsten heavy alloys and characterized by high mechanical properties.

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31

Jordan, R. G., M. A. Hoyland e E. A. Seddon. "Photoemission measurements of nickel and nickel-iron alloys". Journal of Physics: Condensed Matter 2, n. 3 (22 gennaio 1990): 779–84. http://dx.doi.org/10.1088/0953-8984/2/3/024.

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32

Luo, J. L., e M. B. Ives. "Pit Propagation of Nickel and Nickel Molybdenum Alloys". Journal of The Electrochemical Society 144, n. 11 (1 novembre 1997): 3907–13. http://dx.doi.org/10.1149/1.1838109.

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Gale, W. F., e E. R. Wallach. "Wetting of nickel alloys by nickel based brazes". Materials Science and Technology 6, n. 2 (febbraio 1990): 170–75. http://dx.doi.org/10.1179/mst.1990.6.2.170.

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34

Pshenichnikov, A. G. "Electrocatalytic properties of nickel and nickel-based alloys". Materials Chemistry and Physics 22, n. 1-2 (giugno 1989): 121–48. http://dx.doi.org/10.1016/0254-0584(89)90034-5.

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35

Abramov, Aleksandr V., Ruslan R. Alimgulov, Anastasia I. Trubcheninova, Arkadiy Yu Zhilyakov, Sergey V. Belikov, Vladimir A. Volkovich e Ilya B. Polovov. "Corrosion of Metals and Nickel-Based Alloys in Liquid Bismuth–Lithium Alloy". Metals 11, n. 5 (13 maggio 2021): 791. http://dx.doi.org/10.3390/met11050791.

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Bismuth–lithium alloys are considered as primary candidates for the reductive extraction step of on-line reprocessing of a molten salt reactor fuel. The corrosion behavior of pure metals and nickel-based alloys was studied in a liquid Bi–Li (5 mol.%) alloy at 650 °C. The tantalum, molybdenum, and corrosion-resistant alloys VDM® Alloy C-4, Hastelloy® G-35®, KhN62M, VDM® Alloy 59 were studied as prospective materials for this liquid metal media. The corrosion rates were determined by gravimetric method as well as chemical analysis of corrosion products in Bi–Li alloy. Microstructure and chemical composition of samples of the materials and Bi–Li alloys containing the corrosion products after the tests were evaluated using inductively coupled plasma–atomic emission spectroscopy, X-ray fluorescence analysis, scanning electron microscopy, and energy dispersive spectroscopy. Metallic tantalum and molybdenum do not chemically interact with liquid Bi–Li alloy; the corrosion rate of these metals is determined only by the solubility in this medium. The corrosion rates of Ta and Mo at 650 °C were 0.09 and 0.07 mm/year, respectively. Nickel alloys are subjected to severe corrosion in liquid Bi–Li alloys due to dissolution of nickel in liquid bismuth. Alloys of this type cannot be used in such an environment.

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36

Nady, Norhan, Noha Salem, Marwa A. A. Mohamed e Sherif H. Kandil. "Iron-Nickel Alloy with Starfish-like Shape and Its Unique Magnetic Properties: Effect of Reaction Volume and Metal Concentration on the Synthesized Alloy". Nanomaterials 11, n. 11 (12 novembre 2021): 3034. http://dx.doi.org/10.3390/nano11113034.

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Iron-nickel alloy is an example of bimetallic nanostructures magnetic alloy, which receives intensive and significant attention in recent years due to its desirable superior ferromagnetic and mechanical characteristics. In this work, a unique starfish-like shape of an iron-nickel alloy with unique magnetic properties was presented using a simple, effective, high purity, and low-cost chemical reduction. There is no report on the synthesis of such novel shape without complex precursors and/or surfactants that increase production costs and introduce impurities, so far. The synthesis of five magnetic iron-nickel alloys with varying iron to nickel molar ratios (10–50% Fe) was undertaken by simultaneously reducing Fe(II) and Ni(II) solution using hydrazine hydrate as a reducing agent in strong alkaline media for 15 min at 95–98 °C. The effect of reaction volume and total metal concentration on the properties of the synthesized alloys was studied. Alloy morphology, chemical composition, crystal structure, thermal stability, and magnetic properties of synthesized iron-nickel alloys were characterized by means of SEM, TEM, EDX, XRD, DSC and VSM. ImageJ software was used to calculate the size of the synthesized alloys. A deviation from Vegard’s law was recorded for iron molar ration higher than 30%., in which superstructure phase of FeNi3 was formed and the presence of defects in it, as well as the dimensional effects of nanocrystals. The saturation magnetization (Ms), coercivity (Hc), retentivity (Mr), and squareness are strongly affected by the molar ratio of iron and nickel and reaction volume as well as the total metal concentration.

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37

Ni, Haitao, Jiang Zhu, Zhaodong Wang, Haiyang Lv, Yongyao Su e Xiyan Zhang. "A brief overview on grain growth of bulk electrodeposited nanocrystalline nickel and nickel-iron alloys". REVIEWS ON ADVANCED MATERIALS SCIENCE 58, n. 1 (1 gennaio 2019): 98–106. http://dx.doi.org/10.1515/rams-2019-0011.

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Abstract This review focuses on grain growth behaviors and the underlying mechanisms of bulk electrodeposited nanocrystalline nickel and nickel-iron alloys. Effects of some important factors on grain growth are described. During thermal-induced grain growth process, grain boundary migration plays a key role. For similar thermal conditions, due to grain boundary mobility with solute drag, limited grain growth occurs in nanocrystalline alloys, as compared to pure metals. Nonetheless, in the case of stress-induced grain growth process, there are a variety of mechanisms in samples having various deformation histories. As an example the grain growth of nanocrystalline nickel and Ni-20%Fe alloy with nearly the same grain-size distribution and average grain size is compared in this paper. Thermal analysis indicates nanocrystalline nickel is much more prone to rapid grain growth than nanocrystalline Ni-20%Fe alloy. Nevertheless, grain growth of nanocrystalline Ni-20%Fe is found to be more pronounced than nanocrystalline nickel during rolling deformation.

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Lin, Hong-Ming, e Thomas F. Kelly. "Quasicrystal structures in submicron spheres of pure nickel and nickel-chromium alloys". Proceedings, annual meeting, Electron Microscopy Society of America 47 (6 agosto 1989): 296–97. http://dx.doi.org/10.1017/s0424820100153452.

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The icosahedral quasicrystal with a fivefold rotation symmetry was first reported in Al-M (M = Cr, Mn, Fe) alloys. Later, quasicrystals with eightfold, tenfold, and twelvefold rotation symmetries were also reported. A twelvefold symmetry has been found in a Ni-70.6 at%Cr alloy and an eightfold symmetry has been found in a Cr-Ni-Si alloy. This indicates a potential for nickel-chromium alloys to form the quasicrystal phase.An intermediate state between crystalline and quasicrystalline states is also discussed by Li, Teng, et. al. in an Al-Cu-Mg alloy due to the coexistence of micro-quasicrystal and micro-crystal grains. When regions larger than 1 nm are measured, a coherent boundary is found between micro-quasicrystal and micro-crystal grains.A diffraction pattern with seemingly twelvefold symmetry is found in pure nickel and Ni-20at%Cr sphere of about 25 nm diameter as shown in Figure 1. The diffraction patterns do not have true twelvefold symmetry but the first diffraction ring is found to have twelve diffracted spots. Similar structures are found in Ni-10at%Cr and shown in Figure 2 with a series of diffraction patterns.

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Ray, R. K. "Rolling textures of pure nickel, nickel-iron and nickel-cobalt alloys". Acta Metallurgica et Materialia 43, n. 10 (ottobre 1995): 3861–72. http://dx.doi.org/10.1016/0956-7151(95)90169-8.

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40

O. Ajibola, Olawale, e Peter A.Olubambi. "Comparative effects of corrosion on electroless -nickel plated A6061 alloys in DOT3 brake fluid". International Journal of Engineering & Technology 7, n. 2 (5 giugno 2018): 927. http://dx.doi.org/10.14419/ijet.v7i2.9612.

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Aluminium alloys used in automobile brake master cylinder pistons wear by corrosion due to contamination and chemical reaction of the contacting brake fluid. The study investigates the corrosion of electroless-nickel (EN) deposition enhanced cast aluminium alloy master cylinder piston surfaces immersed in hydraulic brake oil. Cast specimens were produced from the as-received wrought A6061 alloy scrap by sand casting. EN plated as-received and cast aluminium alloys specimens were immersed fully in brake oil for 1680 hours and corrosion rates were determined every 24 hours. Test samples were characterised using the hardness tester, atomic absorption spectrometer, metallurgical photo-microscope, x-ray diffractometer; and SEM with EDX attachment. Both surfaces corroded in the order of electroless-nickel plated cast aluminium alloy (ENCA) < electroless-nickel plated as-received aluminium alloy (ENAA) at 0.0235 and 0.0251 rates (mg/mm2/y) results which showed improvement in the corrosion resistance with significant influence of electroless-nickel coating in reducing corrosion rates of aluminium alloy in brake oil.

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Taher, Abulmaali M. "Effect of Alloying Elements on the Hardness Property of 90% Copper-10% Nickel Alloy". Materials Science Forum 872 (settembre 2016): 13–17. http://dx.doi.org/10.4028/www.scientific.net/msf.872.13.

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The objective of this study is to investigate the effect of adding some alloying elements (including iron, aluminum, chromium, cobalt, and titanium) to 90 wt. % copper – 10 wt. % nickel alloy on the hardness property. Copper-nickel synthetic alloys were prepared in an induction furnace, in an argon/7% vol. hydrogen atmosphere in cylindrical boron nitride crucibles. They were then homogenized at 950°C for 10 hours in the same protective atmosphere. Vickers hardness measurements, microstructure examination, and Energy Dispersive Spectrometry (EDS) mapping analysis were performed for all synthetic alloys. Hardness measurements results show that the addition of all the alloying elements used in this investigation improve the hardness of the 90 wt. % copper – 10 wt. % nickel alloy. It was concluded that the aluminum was the most effective alloying element on the hardness value for 90 wt. % copper – 10 wt.% nickel alloy.

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42

Qiu, Xing Wu. "Study on Chemical Conversion Treatment and Electroless Nickel Plating on AZ91D Magnesium Alloy". Advanced Materials Research 148-149 (ottobre 2010): 698–701. http://dx.doi.org/10.4028/www.scientific.net/amr.148-149.698.

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AZ91D magnesium alloy were used as the materials in this experiment. The directly electroless nickel plating, the stannate conversion processing and the electroless nickel plating on the surface of the magnesium alloys that have formed the stannate chemical conversion film on their surface were researched. The morphologies, anticorrosion ability and the hardness of plating of the magnesium alloys after chemical conversion processing and plating nickel were analysed by scanning electron microscope, salt droplet experiment, microhardness survey etc. The result of the experiment showed that, the conversion film unions with the substrate well, the conversion coating can avoid intense galvanic corrosion after the expiration of the plating, and enhanced the corrosion resistance of the plating. The nickel plating deposited on the conversion coating has high microhardness which could provide good protection for the magnesium alloys.

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Makuch, Natalia. "The Importance of Phase Composition for Corrosion Resistance of Borided Layers Produced on Nickel Alloys". Materials 13, n. 22 (13 novembre 2020): 5131. http://dx.doi.org/10.3390/ma13225131.

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The plasma paste boriding process was used for production of the borided layers on pure nickel and nickel-chromium alloys. The produced layers consisted of nickel borides only (in the case of nickel) or a nickel and chromium borides mixture (in the case Ni–Cr alloys). The objective of this investigation was to indicate the importance of the presence of chromium for corrosion resistance of non-borided alloys, as well as to indicate the influence of phase composition of borided layers on their corrosion resistance. Pure nickel was characterized by higher corrosion resistance, in comparison to the nickel-based alloys. Increased chromium content in nickel alloys resulted in their high susceptibility for pitting corrosion. All borided samples were characterized by higher corrosion resistance than the non-borided samples. However, the phase composition of borided layers influenced their corrosion resistance. Due to the microstructure which consisted of one type of borides (nickel borides), borided nickel had the highest resistance to corrosion, whereas the presence of chromium borides in layers produced on nickel-chromium alloys caused a decrease in corrosion resistance.

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44

Mercieca, Sven, Malcolm Caligari Conti, Joseph Buhagiar e Josette Camilleri. "Assessment of corrosion resistance of cast cobalt- and nickel-chromium dental alloys in acidic environments". Journal of Applied Biomaterials & Functional Materials 16, n. 1 (26 ottobre 2017): 47–54. http://dx.doi.org/10.5301/jabfm.5000383.

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Background: The aim of this study was to compare the degradation resistance of nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) alloys used as a base material for partial dentures in contact with saliva. Methods: Wiron® 99 and Wironit Extra-Hard® were selected as representative casting alloys for Ni-Cr and Co-Cr alloys, respectively. The alloys were tested in contact with deionized water, artificial saliva and acidified artificial saliva. Material characterization was performed by X-ray diffractometry (XRD) and microhardness and nanohardness testing. The corrosion properties of the materials were then analyzed using open circuit potential analysis and potentiodynamic analysis. Alloy leaching in solution was assessed by inductively coupled plasma mass spectrometry techniques. Results: Co-Cr alloy was more stable than the Ni-Cr alloy in all solutions tested. Leaching of nickel and corrosion attack was higher in Ni-Cr alloy in artificial saliva compared with the acidified saliva. The corrosion resistance of the Co-Cr alloy was seen to be superior to that of the Ni-Cr alloy, with the former exhibiting a lower corrosion current in all test solutions. Microstructural topographical changes were observed for Ni-Cr alloy in contact with artificial saliva. The Ni-Cr alloy exhibited microstructural changes and lower corrosion resistance in artificial saliva. The acidic changes did not enhance the alloy degradation. Conclusions: Ni-Cr alloys are unstable in solution and leach nickel. Co-Cr alloys should be preferred for clinical use.

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Semenova, E. L., N. Yu Rusetskaya, V. M. Petyukh e V. Ye Listovnichiy. "Ruthenium Effect on the Transformation in Equiatomic Titanium-Nickel Alloy". Platinum Metals Review 39, n. 4 (1 ottobre 1995): 174–79. http://dx.doi.org/10.1595/003214095x394174179.

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Martensitic transformations in equiatomic titanium-nickel and titaniumnickel based alloys are of interest because they are associated with the shape memory effect. Equiatomic titanium-nickel, which possesses such superior mechanical properties as high strength, elevated ductility and corrosion resistance, is the most important of several shape memory alloys. Here, the character of the martensitic transformalion in equiatomic titanium-nickel alloy with some of the nickel replaced by ruthenium is discussed. Data are presented on the temperature of the transformation upon heating and cooling, the transformation sequence and the stabilisation of the high temperature phase in TiNi-TiRu alloys, using electrical resistance, thermal expansivity and differential thermal analysis between ~300°C and liquid nitrogen temperatures. Alloys which contained 0.5 to 2 atomic per cent ruthenium were found to undergo a two stage transformation, while the high temperature phase in titanium-nickelruthenium, which has B2-type crystal structure, was stabilised by the addition of 2 atomic per cent ruthenium.

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Zhang, Hui, Yan Liu, Yong Jie Yan, Han Qin Liang, Xue Jian Liu e Zheng Ren Huang. "Wetting Behaviors of Nickel-Based Alloys on Sintered Silicon Carbide Ceramics". Key Engineering Materials 602-603 (marzo 2014): 274–78. http://dx.doi.org/10.4028/www.scientific.net/kem.602-603.274.

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Wetting behaviors of pure nickel and nickel-based alloys on sintered silicon carbide ceramics and their interfacial microstructures were investigated in this presentation. The nickel-based alloys were mainly the commercial nickel-molybdenum-chromium products. The wetting and spreading properties were observed by a real-time thermal optical measurement system under flowing argon-5%hydrogen atmosphere. As temperature increased, the pure nickel cylinder sample had few changes before 1356°C except for the thermal expansion in size and changed to liquid drop-shape when the temperature reached 1366°C. The contact angle was about 90o. And nickel could not contact sintered silicon carbide ceramics well. However, the introduction of molybdenum and/or chromium in the pure nickel was good for the wetting properties of pure nickel on sintered silicon carbide ceramics. The contact angles of nickel-based alloys (B-1, C-1 and C-2) on sintered silicon carbide ceramics after holding 15min at 1400°C were 25o, 12.5o, 11.5o, respectively. And they hardly reduced as temperature increased. The SEM images indicated that the interfacial microstructures of B-1 and C-1 on sintered silicon carbide ceramic substrates were uniform and the dissolved interface near silicon carbide ceramics indicated that they had a good bonding. At the same time, the reciprocal diffusion was clear in the intermediate layer. Besides that, the introduction of chromium was supposed to reduce the diffusion rate of molybdenum from the alloy to the ceramic substrate.

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Stefanovic, Vladimir, Zoran Lazic, Nemanja Mirkovic, Ervin Taso, Nenad Simeunovic e Jovica Nesic. "EDX analyisis of metal-ceramic interfaces of recasted nickel-chromium dental alloys". Chemical Industry 72, n. 3 (2018): 149–56. http://dx.doi.org/10.2298/hemind180103009s.

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This research was performed to establish recasting effects of nickel-chromium dental alloys on the composition of their metal-ceramic interface in making fixed partial dentures. The metal-ceramic interface determines denture functional integrity and prevents damages on ceramics during mastication. Recycling of nickel-chromium alloys is often a practice, without detailed knowledge about possible effects on the composition of the metal-ceramic interface. Investigation of metal-ceramic samples is intended to show if base metal alloys for metal-ceramics are successfully recycled without any composition change in the metal-ceramic interface. The research was performed as an experimental study in which six metal-ceramic samples of nickel-chromium alloy ?Wiron 99? (Bego, Germany) were made. Alloy residues were recycled through twelve casting generations with the addition of 50 wt% of the new alloy on the occasion of every recasting. EDX analysis was performed by using the ?Inca X Sight? apparatus (Oxford Instruments, UK) and a SEM device JSM 6460 LV (JEOL, Japan). This appliance was used in conjunction with the PC software for quantification of chemical elements in order to determine the composition of metal-ceramic interfaces. Results of this research revealed significant differences between compositions of metal-ceramic interfaces in every examined recycle generation. Recasting had a negative effect on alloy components, which concentration is decreasing in the metal-ceramic junction zone. The concentration of cerium in the intermediate phase decreased the most, followed by concentrations of niobium, molybdenum, nickel and chromium. Results showed a permanent reduction of metal components up to the 12th generation of recycling. Cerium concentration (wt%) decreased from 28 to 16.26 %, nickel concentration from 3.31 to 1.82 % and chromium concentration from 2.95 to 2.03 %. Similarly, the molybdenum content decreased from 8.71to 4.68 wt%, while that of niobium from 9.82 to 3.97 wt%. Therefore, recasting of nickel-chromium alloys is not recommended because of changed composition of the metal-ceramic interface of these alloys.

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Mao, Zhe, Jing Li, Shi Liu e Liangyin Xiong. "Effect of Process Control Agent on Microstructures and High-Temperature Oxidation Behavior of a Nickel-Based ODS Alloy". Metals 12, n. 6 (17 giugno 2022): 1029. http://dx.doi.org/10.3390/met12061029.

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Two nickel-based oxide-dispersion-strengthened (ODS) alloys supplemented with different amounts of process control agent (PCA) were prepared. The microstructures including grains and nanometric oxides and the subsequent oxidation behavior of these ODS alloys were investigated. It was found that the distribution of nanometric oxides in the nickel-based ODS alloy is uniform and the grains are refined by adding a proper amount of PCA in the mechanical milling, while the blocking effect on the diffusion of active elements Y, Al and Ti among powders takes place with an excessive amount of PCA, resulting in the precipitation of large-size oxides in local areas of the alloy. After oxidation in air at 1000 °C for 200 h, the oxide scales on the surface of both nickel-based ODS alloys are composed of Cr2O3. As Y-rich oxide particles are precipitated in the matrix, the thickness of the oxide scale is significantly reduced compared with non-ODS alloys. However, due to the influence of grain boundaries on the diffusion of elements, the oxide scale on the surface of an alloy with finer grain size is thicker. The oxidation resistance of ODS alloys strongly depends on the exact manufacturing process.

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Dyakova, Vanya, Yoanna Kostova e Hristina Spasova. "INFLUENCE OF NI AS MINORITY ALLOYING ELEMENT ON THE CORROSION BEHAVIOR OF AMORPHOUS AL-CU-MG ALLOYS IN CHLORIDE SOLUTION". ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 3 (13 giugno 2023): 74–78. http://dx.doi.org/10.17770/etr2023vol3.7201.

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The influence of nickel as minority alloying element on the corrosion behavior of amorphous alloys (Al74Cu16Mg10)99Ni, (Al74Cu16Mg10)98Ni2 and (Al74Cu16Mg10)97Ni3 was investigated. The amorphous alloys were obtained as ribbons by Chill Block Melt Spinning (CBMS). The amorphous structure of the alloys was proven by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The corrosion rate was calculated gravimetric using continuous immersion tests for 360 hours in 3.5% NaCl solution at a temperature of 25oC. The lowest corrosion rate was found in the alloy containing 3 at. % Ni. The chemical composition of the accumulated corrosion products was studied using XRD.The influence of nickel on the local corrosion resistance of the amorphous ribbons of (Al74Cu16Mg10)100-хNiх x = 0, 1, 2, 3% alloys was investigated electrochemically in a solution of 3.5% NaCl at 25°C. Pitting potential (Epitt) and repassivation potential (Erp) were determined. It was found that most resistant to pitting corrosion was the (Al74Cu16Mg10)97Ni3 alloy, which showed the noblest pitting potential (Epitt -0.332 V) and repassivation potential (Erp -0.530 V).All obtained corrosion test results of the nickel-containing amorphous alloys were compared to the base amorphous Al74Cu16Mg10 alloy.

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Anil, Sukumaran, Prasanna Neelakantan e Wadih Nassif. "Evolution of Nickel–titanium Alloys in Endodontics". Journal of Contemporary Dental Practice 18, n. 11 (2017): 1090–96. http://dx.doi.org/10.5005/jp-journals-10024-2181.

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ABSTRACT To improve clinical use of nickel–titanium (NiTi) endodontic rotary instruments by better understanding the alloys that compose them. A large number of engine-driven NiTi shaping instruments already exists on the market and newer generations are being introduced regularly. While emphasis is being put on design and technique, manufacturers are more discreet about alloy characteristics that dictate instrument behavior. Along with design and technique, alloy characteristics of endodontic instruments is one of the main variables affecting clinical performance. Modification in NiTi alloys is numerous and may yield improvements, but also drawbacks. Martensitic instruments seem to display better cyclic fatigue properties at the expense of surface hardness, prompting the need for surface treatments. On the contrary, such surface treatments may improve cutting efficiency but are detrimental to the gain in cyclic fatigue resistance. Although the design of the instrument is vital, it should in no way cloud the importance of the properties of the alloy and how they influence the clinical behavior of NiTi instruments. Clinical significance Dentists are mostly clinicians rather than engineers. With the advances in instrumentation design and alloys, they have an obligation to deal more intimately with engineering consideration to not only take advantage of their possibilities but also acknowledge their limitations. How to cite this article Ounsi HF, Nassif W, Grandini S, Salameh Z, Neelakantan P, Anil S. Evolution of Nickel–titanium Alloys in Endodontics. J Contemp Dent Pract 2017;18(11):1090-1096.

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