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1
Fitz, T. "Ion nitriding of aluminium". Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-29382.
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Fitz, T. "Ion nitriding of aluminium". Forschungszentrum Rossendorf, 2002. https://hzdr.qucosa.de/id/qucosa%3A21765.
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Yang, Mei. "Nitriding - fundamentals, modeling and process optimization". Digital WPI, 2012. https://digitalcommons.wpi.edu/etd-dissertations/127.
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Gas nitriding is an important thermochemical surface treatment that is used to improve the wear and corrosion resistance as well as the fatigue endurance of steel parts. Accurate process control is the effective way to ensure the properties reliability of nitriding process. To realize the accurate process control, the nitriding process parameters need to be modeled and controlled to meet the specifications. There has been ongoing effort on the simulation of the gas nitriding process since 1990s. However, most of the work has been done to simulate the gas nitriding process of pure iron due to the limited thermodynamics and kinetics information available on the gas nitriding process of steels. The objective of this project is to develop an accurate and user friendly software model to simulate the gas nitriding process of steels based on the fundamental understanding of thermodynamics and kinetics. In this work, the customized Lehrer diagram which describes the phase stabilities in specified steel as a function of nitriding potential and temperature has been successfully constructed by computational thermodynamics for the first time. Based on the Lehrer diagrams for steels, the compound layer growth model is proposed to simulate the gas nitriding process of steels. By using this model, the properties of the nitrided steels based on the phase constitution, surface nitrogen concentration, nitrogen concentration profile, case depth, as well as growth kinetics can be simulated as a function of the process parameters (temperature, time, and the nitriding atmosphere). The results of the model are in excellent agreement with experimental results.
4
Liu, Wendi. "The effects of contaminants on the gas nitriding of Nitralloy-135". Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-112408-113232/.
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Crust, Glen Alexander. "The nitriding of high speed steel cutting tools". Thesis, University of Plymouth, 1989. http://hdl.handle.net/10026.1/2379.
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There is an interest in industry in cost reduction. Tool wear constitutes an important element in the cost of many metal working processes, not only because of the cost of the tool, but also because of the cost of machine downtime. Saltbath nitriding of high speed steel tools adds only about 1% to the cost of a finished tool, but has been found to confer benefits considerably in excess of this over a range of cutting conditions . A series of cutting tests is described, during which cutting forces and tool temperatures were recorded simultaneously using microcomputer based instrumentation developed at the Polytechnic as part of this study. The shear mechanism for tools with a nose radius is investigated, and methods for evaluating the primary shear plane area are proposed and discussed. The variation in primary shear plane area with chip flow angle is evaluated. The method for predicting chip flow angle from tool geometry is presented, and results from this analysis compared with experimental data . A method for predicting primary shear angle from tool geometry, force measurements and workpiece material properties is developed. A number of methods for measuring tool temperature are described . Temperature distributions obtained from finite element heat transfer analysis are presented, and a mechanism for the catastrophic failure of the toolnose is proposed. A range of cutting conditions is described, over which the performance of high speed steel cutting tools is enhaced by saltbath nitriding.
6
Bennett, Robert. "The plasma nitriding of tool and bearing steels". Thesis, Aston University, 1987. http://publications.aston.ac.uk/11876/.
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There is some evidence to suggest that nitriding of alloy steels, in particular high speed tool steels, under carefully controlled conditions might sharply increase rolling contact fatigue resistance. However, the subsurface shear stresses developed in aerospace bearing applications tend to occur at depths greater than the usual case depths currently produced by nitriding. Additionally, case development must be limited with certain materials due to case spalling and may not always be sufficient to achieve the current theoretical depths necessary to ensure that peak stresses occur within the case. It was the aim of' this work to establish suitable to overcome this problem by plasma nitriding. To assist this development a study has been made of prior hardening treatment, case development, residual stress and case cracking tendency. M2 in the underhardened, undertempered and fully hardened and tempered conditions all responded similarly to plasma nitriding - maximum surface hardening being achieved by plasma nitriding at 450°C. Case development varied linearly with increasing treatment temperature and also with the square root of the treatment time. Maximum surface hardness of M5O and Tl steels was achieved by plasma nitriding in 15% nitrogen/85% hydrogen and varied logarithmically with atmosphere nitrogen content. The case-cracking contact stress varied linearly with nitriding temperature for M2. Tl and M5O supported higher stresses after nitriding in low nitrogen plasma atmospheres. Unidirectional bending fatigue of M2 has been improved up to three times the strength of the fully hardened and tempered condition by plasma nitriding for 16hrs at 400°C. Fatigue strengths of Tl and M5O have been improved by up to 30% by plasma nitriding for 16hrs at 450°C in a 75% hydrogen/25% nitrogen atmosphere.
7
Tsujimura, Hiroyuki. "Electrochemical nitriding in molten LiCL-KCL-Li3N systems". Kyoto University, 2004. http://hdl.handle.net/2433/147418.
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Kyoto University (京都大学)0048
新制・課程博士
博士(エネルギー科学)
甲第10972号
エネ博第83号
新制||エネ||24(附属図書館)
UT51-2004-G819
京都大学大学院エネルギー科学研究科エネルギー基礎科学専攻
(主査)教授 伊藤 靖彦, 教授 八尾 健, 教授 吉田 起國
学位規則第4条第1項該当
8
Wei, Yingying. "Simulation, optimization and development of thermo-chemical diffusion processes". Digital WPI, 2013. https://digitalcommons.wpi.edu/etd-dissertations/145.
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Thermo-chemical diffusion processes play an important part in modern manufacturing technologies. They exist in many varieties depending on the type of diffusing elements used and the respective process objectives and procedures. To improve wear and/or corrosion performance of precisely machined steel components, gas nitriding is selected as the most preferred thermo-chemical surface treatment. Conventional gas nitriding of steels is a multi-hour, sometimes multi-day hardening process carried out at ferritic temperatures and including a complete heat treatment cycle: normalizing, austenitizing, martensitic quenching and tempering. An alternative, subcritical-temperature austenitic nitriding process is evaluated with the purpose of accelerating the treatment and optimizing the hardness and toughness of nitrided layers while minimizing the distortion of steel parts treated. The alternative process involves liquefied nitrogen cryogenic quenching as well as aging. This study presents results of experimental work on AISI 4140 steel, examining the interplay between the nitriding and tempering conditions and phase transformations in both ferritic (525oC) and subcritical, nitrogen-austenitic (610oC) processes. Thermodynamic models, used to design processing conditions, are applied also in the microstructural interpretation of nitrided layers. Results are verified using the SEM, EPMA and EDS techniques. Kinetics of interstitial diffusion, isothermal martensite transformation, as well as dimensional control of nitrided parts is also presented. Carburizing is, by far, the most widely adopted method in surface hardening. Problems with intergranular oxidation (IGO), energy efficiency and carbon footprint of conventional endothermic atmosphere (CO-H2-N2) carburizing is forcing heat treating and manufacturing companies to move toward increasingly capital- and operating-cost expensive, low-pressure (vacuum furnace) carburizing methods. In response, a new activated and alternate carburizing method (A2A carburizing) has recently been developed, bridging the endothermic atmosphere and vacuum processes, where a plasma-activated, oxygen-free, non-equilibrium nitrogen-hydrocarbon gas blend is utilized. The optimization of industrial A2A carburizing processes involves improvement of case uniformity of parts at different locations in the charge as well as between different sides on the parts. Connected to the optimization, a computational fluid dynamics (CFD) study is conducted for examination of gas flow field inside the furnace and trays holding steel parts treated. To mitigate soot in the atmosphere and minimize the poorly carburized contact area between parts, effects of different combinations of nitrogen-hydrocarbons mixture on soot formation in atmosphere, deposition on metal surface and graphite growth at carburizing temperature are investigated. N2- 0.4%C3H8-1%CH4 mixture is proven to be able to provide proper carburizing hardened case with less soot in atmosphere, less coke deposition on metal surface, as well as minimized marginally carburized contact zone. A soot formation mechanism for non-equilibrium atmosphere in A2A carburizing is discussed. The carburizing processes have been investigated for decades, yet it still faces challenges concerning performance, reliability and process control. Since carburized parts must meet tolerances and specifications of particular applications, it is necessary to accurately predict carbon concentration profiles as a function of processing conditions. Proper carbon distribution is critical for satisfactory and reliable service life of carburized parts. Based on experimental work and theoretical developments, a software CarbTool© has been created for atmosphere and low pressure carburizing methods which consider the thermodynamics, mass transfer kinetics and carbon diffusion aspects of the carburizing process and the gas-steel interface condition. The models are capable now to accurately predict the surface carbon concentration and the carbon concentration profile in the steel, i.e. the most important outcomes of the process.
9
Parascandola, S. "Nitrogen transport during ion nitriding of austenitic stainless steel". Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-29591.
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Hubbard, Paul, i paul hubbard@rmit edu au. "Characterisation of a Commercial Active Screen Plasma Nitriding System". RMIT University. Applied Physics, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20090212.161932.
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Nitriding is a plasma based processing technique that is used to improve the surface properties of components and products in many areas including the aerospace, automotive and biomedical industries to name a few. Active Screen Plasma Nitriding (ASPN) is a relatively new nitriding technique which has potential advantages over the more traditional nitriding techniques such as Direct Current (DC) plasma nitriding where high substrate biases can be problematic. However, there is considerable debate as to the mechanism for nitriding in ASPN. This thesis focuses on investigating the mechanism for nitriding in a commercial ASPN system. Commercial ASPN treatments of nitrideable alloy steels were found to be unsatisfactory unless a sufficient bias was applied. The level of bias required to produce a satisfactory nitriding response, in terms of the cross sectional hardness, was found to depend on the concentration of strong alloy nitride forming elements present in the steel. Although active screen material was found to be transferred to the workload, no evidence was found that this process played a significant role in enhancing the nitriding response. The primary mechanism for nitrogen mass transfer in ASPN was found to be dependent on the active screen/workload separation distance. When this separation is small (less than approximately 10cm for the conditions used in this study) then nitrogen mass transfer in the form of energetic ions or neutrals can occur between the active screen and the workload. This allows samples to be treated without a substrate bias. On the other hand, when the active screen/workload separation distance is large (greater than approximately 10cm) as is normally the case in a commercial environment, this mechanism for nitrogen mass transfer breaks down and a substrate bias is essential. In this latter case, nitrogen ions attracted to the workload using a bias is the primary nitrogen mass transfer mechanism and the role of the active screen is primar ily to uniformly heat the workload.
11
Parascandola, S. "Nitrogen transport during ion nitriding of austenitic stainless steel". Forschungszentrum Rossendorf, 2001. https://hzdr.qucosa.de/id/qucosa%3A21786.
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Singh, Omveer. "Investigations of plasma and low energy ion beam nitriding". Thesis, IIT Delhi, 2016. http://localhost:8080/xmlui/handle/12345678/7215.
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Coletta, Marcus Alberto Della. "Comparação do desempenho à abrasão dos aços AISI 4340, 4140, 5140 e 300M nitretados por plasma em diferentes condições". Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-14092016-120013/.
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Os aços de ultra resistência com médio carbono e baixa liga apresentam excelentes propriedades de resistência mecânica e à fadiga além de uma elevada temperabilidade. No entanto, tais aços apresentam o fenômeno da têmpera ou de tratamentos superficiais. O aço 300M foi desenvolvido visando a ampliação desta faixa, permitindo tratamentos em temperaturas em torno de 350ºC viabilizando o emprego da técnica de nitretação do mesmo por plasma sem a consequente fragilização. Neste trabalho comparou-se as características e propriedades do aço 300M nitretado por plasma à 350ºC e 550ºC com os aços de alta-resistência AISI 4340, 4140 e 5140 nitretados à 550ºC. Variou-se as condições de tratamento de forma a verificar a influência do tempo de nitretação e de frequência de pulso nas camadas nitretadas. Verificou-se que a nitretação por plasma demostrou ser bastante efetiva para conferir resistência ao desgaste abrasivo para todos os aços nitretados. O aço 300M nitretado em 350ºC apresentou no ensaio de desgaste abrasivo comportamento similar aos demais aços nitretados em 550ºC, enquanto que o melhor resultado geral foi alcançado pelo 300M nitretado à 550ºC em CC durante 6 horas, devido à formação de uma camada dupla de levada dureza e espessura.The ultrahigh-strength steels with medium carbon and low alloy, like AISI 4340, show excellent tensile strength and fatigue properties further higher hardenability. However, these steels have the phenomenon of tempering embrittlement, that restrict the temperature of treatments after quench or surfaces treatments. The 300M steel was developed aiming the enlargement this area of application, this steel permits treatments in temperatures about 350°C what allowed to use the plasma nitriding without problems with the embrittlement. In this production were compared the properties of the nitrited layers of the 300M nitriding by plasma in 350°C and 550°C with the steels AISI 4340, AISI 4140, AISI 5140 nitriding in 550°C. Plasma nitriding conditions like time and pulse frequency were varied. It was checked that the plasma nitriding showed good performance to improve the resistance to the abrasive wear in ali the steels tested. The 300M steel nitrited in 350°C showed results similar to the others in the pin-on-disk test and the better result occurred to the 300M steel nitrited in 550°C in dC plasma during 6 hours, because of a duble compound lawyer that arouse with a high thickness and high hardness.
14
Hosmani, Santosh S. "Nitriding of iron-based alloys : the role of excess nitrogen". Stuttgart Max-Planck-Inst. für Metallforschung, 2006. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-27675.
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Cleugh, Damien. "Effects of rare earth additions on plasma nitriding of En40B steel". Thesis, University of Birmingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289443.
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Vives, Díaz Nicolás. "Nitriding of iron-based alloys residual stresses and internal strain fields /". [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-33995.
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Clauß, Arno Rainer. "Nitriding of Fe-Cr-Al alloys nitride precipitation and phase transformations /". Stuttgart : Max-Planck-Inst. für Metallforschung, 2008. http://d-nb.info/995395918/34.
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Wang, Xiaolan. "Activated atmosphere case hardening of steels". Digital WPI, 2011. https://digitalcommons.wpi.edu/etd-dissertations/413.
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"Case hardening, a process which includes a wide variety of techniques, is used to improve the wear resistance, by diffusing carbon (carburization), nitrogen (nitriding) and/or boron (boriding) into the outer layer of the steel at high temperature, and then heat treating the surface layer to the desired hardness without affecting the softer, tough interior of the part. In this research, a nitrogen-hydrocarbon gas mixture was used as the process atmosphere for carburizing steels. It can offer a cost and part quality alternative to the conventional endothermic atmosphere and vacuum processes. It can hold the promise for matching the quality of work parts processed in vacuum furnace, i.e. eliminating the intergranular oxidation which normally occurs in the endogas atmosphere. The process control of nitrogen-hydrocarbon atmosphere is also investigated in the research. Modified shim stock method is used to measure the carbon pickup and constant carbon flux modeling tool is used afterwards to predict the carbon profile. With minimum modification, commercially available equipment or sensors can be used to monitor non-equilibrium process atmosphere. Gas nitriding was also studied. For nitriding, the kinetics of the nitriding process with hydrocarbon gases addition and electric arc discharge activation of the nitrogen diluted ammonia atmosphere were investigated. Prior to and during the nitriding, hydrocarbon gases were reacted with metal surface and removed oxidation layers, which can accelerate nitriding process. Overall, nitriding with this unique gas mixture provides an alternative to a long-hour pure ammonia nitriding with more efficient energy utilization. The main objective of this project is to develop the conventional, atmospheric-pressure, low-cost surface hardening treatments for the case hardening of carbon, alloy and stainless steel. The possibility of plasma activation of atmosphere and metal surface to shorten processing time and save energy and time is investigated in this research. The process atmosphere is safer, more efficient, less toxic and less flammable. "
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Schwarz, Benjamin [Verfasser], i Eric Jan [Akademischer Betreuer] Mittemeijer. "Gas nitriding of iron-based alloys / Benjamin Schwarz. Betreuer: Eric Jan Mittemeijer". Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2014. http://d-nb.info/1063335108/34.
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Kirby, A. W. "The reduction of iron content in ferrochromium via the nitriding/leaching route". Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377841.
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Wu, Dandan. "Low-Temperature Gas-Phase Nitriding and Nitrocarburizing of 316L Austenitic Stainless Steel". Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1346900583.
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Soib, Bin Selamat Mohmad. "Laser surface processing of Ti-6Al-4V alloy". Thesis, University of Strathclyde, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366777.
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Han, Meng. "Laser nitriding of metals Influences of the ambient pressure and the pulse duration /". [S.l. : s.n.], 2001. http://webdoc.sub.gwdg.de/diss/2002/han/han.pdf.
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Zhou, Haipo. "Modification of non-metallic inclusions to improve the fatigue properties of nitriding steels". Thesis, University of Canterbury. Mechanical Engineering, 1993. http://hdl.handle.net/10092/6768.
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Nitriding processes are widely used to improve the fatigue properties of steel. Fatigue failures in nitriding steels initiate from sub-surface non-metallic inclusions, which are usually oxide inclusions. It is known that duplex oxysulphide inclusions are less harmful to the fatigue properties of steel than oxide inclusions alone, since the sulphide outer phase acts as a buffer to the oxide in the core, and thus reduces the fatigue-initiating stress influence of oxide inclusions.
Twelve nitriding steel melts were produced, and non-metallic inclusions, modified by adding CaSi cored wire, were investigated. Since calcium has a high vapour pressure and a low solubility in molten steel, it is difficult to effectively modify non-metallic inclusions by the addition of CaSi cored wire in small furnaces. However, it was found that the addition of CaSi cored wire at a lower temperature was favourable to higher calcium injection yield in a small furnace, and it was also observed that the reaction with liquid steel was less violent, resulting in the effective modification of non-metallic inclusions.
Analysis by a scanning electron microscope with energy dispersive X-ray technique showed a proportion of duplex oxysulphide inclusions formed in ingots from 11A, with the remainder being predominantly globular calcium aluminate inclusions.
Specimens for direct stress fatigue testing were produced from steels containing both modified and unmodified inclusions, and the fatigue properties were compared.
It was found that calcium aluminate inclusions had a more deleterious effect on the fatigue properties of steel than alumina inclusions. In calcium modified steels, at lifetimes of more than 5x10⁵ cycles, fatigue cracks always initiated from calcium aluminate inclusions, which were partly or completely debonded from the matrix. The fatigue properties of the calcium modified steel was found to be inferior to those of the unmodified steel.
No duplex oxysulphide inclusions were found among those inclusions which produced fatigue crack initiations, and this indicated that when they were present calcium aluminate inclusions governed the fatigue properties of steel whether or not duplex oxysulphide inclusions were present in the steel.
It is inferred that the fatigue properties of steel can be improved if all large
calcium aluminate inclusions are modified to duplex oxysulphide inclusions.
25
Wang, Danqi. "LOW-TEMPERATURE GAS-PHASE CARBURIZING AND NITRIDING OF 17-7 PH STAINLESS STEEL". Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1386165240.
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Zhecheva, A. Y. "Experimental study and modelling of the process of surface gas nitriding of titanium alloys". Thesis, Queen's University Belfast, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426922.
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Kaklamani, Georgia. "The effect of active screen plasma nitriding on the cellular compatibility of polmeric biomaterials". Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3844/.
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Active Screen Plasma Nitriding (ASPN) is a novel surface engineering technique, the main advantage of which is the capacity to treat homogeneously all kind of materials surfaces of any shape. Here, ASPN is used to modify the surface properties of ionomer glasses and polymers in order to improve the surface cellular compatibility of these materials. A conventional DC nitriding unit has been used together with an AS experimental arrangement. The materials that were treated were an ionomer glass composition and UHMWPE. All treated/untreated samples were seeded with the 3T3 fibroblasts. In order to identify the effect of the plasma treatment, chemical and mechanical properties characterization was conducted. For the cellular samples, SEM, Interferometry, AFM and MTT assay were conducted in order to observe cells’ behavior on the untreated and treated materials. The inert surface of the untreated glass showed good interaction with fibroblasts only after the ASPN treatment which resulted in enhanced fibroblasts attachment and proliferation. The treatment temperature, the length of treatment and the presence of nitrogen had an influence on the surface properties of glass. UHMWPE treated samples chemical characterization showed the formation of C-N and N-H groups resulting in an increase of the functionality of treated surfaces. 3T3 fibroblasts cell culture studies showed that the ASPN treatment had a positive effect on the adhesion and proliferation of cells according to the time of treatment and the increase of the nitrogen concentration in the gas mixture. As a conclusion ASPN treatment can be a very effective method to modify inorganic and organic polymeric surfaces in order to improve cellular compatibility.
28
Носонова, Любов В`ячеславівна, Любовь Вячеславовна Носонова, Liubov Viacheslavivna Nosonova i О. О. Пушкар. "Вплив процесу антикорозійного азотування на властивості валу насоса типу ЦНСс із сталі 38Х2МЮА". Thesis, Вид-во СумДУ, 2010. http://essuir.sumdu.edu.ua/handle/123456789/6426.
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Застосування призначеної технології хіміко-термічної обробки, яка передбачає заміну матеріалу деталі 14Х17Н2 на сталь 38Х2МЮА з подальшим антикорозійним азотуванням дозволяє отримати виріб, який відповідає технічним вимогам на виготовлення - підвищенню корозійної стійкості ,надійності та зносостійкості в процесі експлуатації.
При цитуванні документа, використовуйте посилання http://essuir.sumdu.edu.ua/handle/123456789/6426
29
Fonović, Matej Verfasser], i Eric J. [Akademischer Betreuer] [Mittemeijer. "Nitriding behavior of Ni and Ni-based binary alloys / Matej Fonović. Betreuer: Eric J. Mittemeijer". Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2015. http://d-nb.info/1069107247/34.
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Доненко, В. А. "Дослідження процесу іонного азотування в імпульсному тліючому розряді". Thesis, Чернігів, 2020. http://ir.stu.cn.ua/123456789/21033.
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Доненко, В. А. Дослідження процесу іонного азотування в імпульсному тліючому
розряді : магістерська робота: 131 Прикладна механіка / В. А. Доненко; керівник роботи Болотов Г. П. ; Національний університет «Чернігівська політехніка», кафедра технологій зварювання та будівництва. – Чернігів, 2020. – 84 с.Магістерська робота складається з чотирьох розділів. У першій частині, теоретичній, розглянуті питання пов’язані з фізичними основами процесу іонного азотування, його переваги та недоліки, основні режими азотування деяких металів, дефекти азотування та їх запобігання. У другій частині роботи розглянуто обладнання на якому проводилися досліди, наведено його технічні характеристики. Розглянуто матеріал, що було обрано для дослідів. Розглянуто процес виготовлення зразків матеріалу, розроблена методика вимірювань контрольних зразків. У третій, експериментальній, частині роботи були приведені результати дослідів та режими азотування на яких проводився процес. Наведено фотознімки поверхневої структури зразків, числові значення твердості на різних режимах азотування, досліджено вплив параметрів режиму азотування на мікротвердість та мікроструктуру зразків. У четвертій частині роботи було розглянуто питання охорони праці на робочому місці оператора дифузійної вакуумної установки, проаналізовано основні небезпечні фактори та складено карту умов праці.
The master's dissertation consists of four parts. In the first part, theoretical, the issues are related to the physical basis of the ionic nitriding process, its advantages and disadvantages, the main modes of nitriding of some metals, nitriding defects and their prevention. In the second part of the work the equipment on which experiments were carried out is considered, its technical characteristics are resulted. The material selected for experiments is considered. The process of making material samples is considered, the method of measuring control samples is developed. In the third, experimental, part of the work, the results of experiments and nitriding modes on which the process was carried out were presented. Photographs of the surface structure of the samples, numerical values of hardness at different nitriding modes, the influence of the parameters of the nitriding mode on the microhardness and microstructure of the samples are investigated. In the fourth part of the work, the issue of labor protection at the workplace of the operator of the diffusion vacuum unit was considered, the main dangerous factors were analyzed and a map of working conditions was made.
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Kraszczuk, André. "Caracterização microestrutural, mecânica e tribológica de um aço AISI 440B após os tratamentos de têmpera e nitretação a plasma". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-06122017-081003/.
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Em tribossistemas pode ser necessário o controle do atrito e a minimização do desgaste dos materiais. Dentre as soluções propostas, se encontram tratamentos térmicos e termoquímicos, deposição de filmes finos e formação de revestimentos duplex. O objetivo desse trabalho é entender e comparar como variam a microestrutura, as propriedades mecânicas, o desempenho tribológico e os mecanismos de desgaste em um aço inoxidável martensítico AISI 440B após os tratamentos de i) têmpera e ii) nitretação a plasma pulsada. A caracterização da microestrutura consistiu na identificação das fases por difração de raios - X, observação por microscopia ótica e por MEV-FEG. A caracterização das propriedades mecânicas consistiu em medições de dureza Rockwell C e microdureza Vickers (carga de 100gf). Por fim, o desempenho tribológico e os mecanismos de desgaste foram avaliados através de: a) determinação dos parâmetros de rugosidade por rugosimetria e AFM; b) levantamento das curvas de coeficiente de atrito vs. tempo através do ensaio de desgaste linear cíclico (SRV) sem lubrificação; c) perda de massa dos discos e esferas; d) observação das trilhas de desgaste e das calotas de desgaste por meio de MEV-FEG/EDS; e) levantamento do perfil topográfico da superfície dos discos desgastados e f) profundidade das trilhas através de interferometria ótica. Obteve-se microestrutura da camada nitretada constituída de martensita revenida e nitretos ?\', ? e CrN. A camada nitretada apresentou dureza máxima de 1340 HV0,1 e profundidade de camada NHT de ~100µm. Durante a nitretação a matriz martensítica sofreu revenimento que diminuiu a dureza de 54 HRC (temperado) para 50 HRC. Constatou-se que no tribossistema \"deslizamento a seco entre esfera de AISI 52100 e disco de AISI 440B Temperado\", ocorreram no corpo: i) deformação plástica, ii) abrasão de 3 corpos nas extremidades das trilhas, iii) desgaste oxidativo e iv) delaminação (arrancamento do filme óxido). Já no contra-corpo: i) abrasão suave e ii) adesão de debris óxidos. No tribossistema \"deslizamento a seco de esfera de AISI 52100 contra disco de AISI 440B Nitretado\" ocorreram no corpo: i) microcutting, ii) desgaste oxidativo e iii) delaminação (arrancamento de asperezas e/ou de filme óxido). Já no contra-corpo: i) abrasão severa e ii) adesão de debris óxidos.In tribosystems to control friction and wear is necessary. Several solutions have been developed over the last few years, such as heat treatments, thermo-chemical treatments, thin films deposition and duplex coatings. The purpose of the present work is to understand how the microstructure, mechanical and tribological properties of AISI 440B vary after being subjected to the following treatments i) quenching, ii) plasma nitriding. The approach to study AISI 440B microstructure consisted of XRD (X-Ray Diffraction), optical microscopy and SEM (Scanning electron microscopy). The approach to study AISI 440B mechanical properties consisted of Rockwell C hardness and Vickers microhardness. Finally, the approach to study AISI 440B tribological performance was: a) surface and roughness observations through contact rugosimetry and AFM, b) friction coefficient vs. time curves through unlubricated reciprocating tribological test (ASTM G133-05), c) disc and sphere mass loss, d) wear track and wear cap observations through SEM-FEG/EDS, e) surface profile and wear track depth through optical interferomety. The nitrided layer presented tempered martensite as well as ?, ? and CrN nitrides. The maximum surface hardness was 1340 HV 0,1 and a case depth of ~100 µm was found. Regarding the wear mechanisms, in the \"dry sliding of AISI 52100 sphere against as-quenched AISI 440B discs\" tribosystem, the wear mechanisms acting in the body were: severe wear with i) severe plastic deformation, ii) 3-body abrasion at the ends of the wear tracks, iii) oxidation, and iv) mild delamination (oxide pull-out). Regarding the counterbody, it was found: i) mild abrasion and ii) oxide adhesion. In the \"dry sliding plasma nitrided AISI 440B against AISI 52100 spheres\" tribosystem the body suffered mild wear with i) oxidation and ii) delamination. The counterbody suffered i) strong abrasion and ii) oxide adhesion.
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Clauß, Arno Rainer [Verfasser]. "Nitriding of Fe-Cr-Al alloys : nitride precipitation and phase transformations / vorgelegt von Arno Rainer Clauß". Stuttgart : Max-Planck-Inst. für Metallforschung, 2008. http://d-nb.info/995395918/34.
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Vives, Díaz Nicolás [Verfasser]. "Nitriding of iron-based alloys; residual stresses and internal strain fields / vorgelegt von Nicolás Vives Díaz". Stuttgart : Max-Planck-Inst. für Metallforschung, 2007. http://d-nb.info/995388687/34.
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Amoah, Enoch. "Modification of Chemical Vapor-Deposited Carbon Electrodes with Electrocatalytic Metal Nanoparticles through a Soft Nitriding Technique". Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etd/3616.
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Metal nanoparticles have been widely used for many catalytic and electrocatalytic applications due to their larger surface area-to-volume ratios and higher densities of active sites compared to bulk materials. This has resulted in much interest in understanding the electrocatalytic behavior of metal nanoparticles with respect to their structure. However, most research on this topic has employed collections of nanoparticles. Due to difficulties in controlling and characterizing particle loading and interparticle distance in nanoparticle ensembles, single nanoparticles studies have recently become a topic of great interest. In this study, a soft nitriding technique was applied to chemical vapor-deposited carbon ultramicroelectrodes (UMEs) in order to immobilize ligand-free AuNPs onto the carbon substrate. The feasibility of this method is geared toward studying the properties of single AuNPs immobilized onto carbon nanoelectrodes. The ligand-free AuNPs immobilized onto the nitrided carbon UMEs were highly electrocatalytic toward methanol oxidation.
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Samih, Youssef. "Thermomechanical surface treatments of austenitic stainless steels and their effects on subsequent nitriding during “Duplex” treatments". Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0100/document.
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L’optimisation des microstructures de surface est un facteur primordial pour améliorer les propriétés et la durée de vie des matériaux. Pour le traitement des aciers inoxydables, la nitruration est un procédé adéquat permettant l’augmentation de la dureté et de la résistance à l’usure par formation d’une austénite «expansée» sursaturée en azote. Des travaux récents ont suggéré que l’activation de surface par un traitement mécanique préalable permettait d’augmenter les cinétiques de diffusion de l’azote. Avec des traitements « duplex » de ce type, il doit donc être possible (i) d’augmenter l’épaisseur des couches nitrurées pour un temps de nitruration donné et/ou (ii) de diminuer la température de nitruration et éviter ainsi la formation de nitrures nuisibles à la tenue à la corrosion. La littérature montre toutefois qu’une couche de pollution issue du prétraitement peut affecter l’efficacité de la nitruration. L’objectif de ce travail était d’aider à l’optimisation de la maitrise de différents traitements « duplex » impliquant, avant une nitruration assistée plasma, les traitements mécaniques ou thermomécaniques suivants : le grenaillage ultrasonore (SMAT pour Surface Mechanical Attrition Treatment), le laminage et le traitement par faisceau d’électrons pulsé (HCPEB pour High Current Pulsed Electron Beam). La combinaison des traitements mécaniques et thermochimiques a été essentiellement testée sur deux nuances de l’acier inoxydable austénitique 316L (avec et sans sulfures) et, dans une moindre mesure, sur l’acier AISI 660. Afin de mieux caractériser l’effet des différents paramètres du procédé d’hyperdéformation SMAT (diamètre des billes, durée du traitement, amplitude de vibration, etc.) sur l’évolution de la microstructure, une procédure de caractérisation des couches écrouies utilisant l’EBSD a été proposée. Cette technique, basée pour partie sur l’évolution des Dislocations Géométriquement Nécessaires (GNDs), permet d’évaluer quantitativement l’épaisseur des différents types de couches formées en fonction des paramètres du procédé SMAT. Les natures des pollutions de la surface et leurs origines ont aussi été analysées. Une analyse de l’efficacité des différents types de traitements duplex a ensuite était réalisée en comparant systématiquement des résultats obtenus après nitruration sur des échantillons avec et sans activation de surface. Des analyses par diffraction des rayons X, des observations en microscopies électroniques, des mesures de microdureté ainsi que la mesure des profils de concentration en azote par SDL (Spectrométrie à Décharge Luminescente) ont été mises en œuvre pour quantifier les effets des traitements combinés. Les résultats ont montré la complexité des modifications de structures et la complexité des phénomènes mis en jeuOptimizing the surface microstructure and properties is very important to obtain high performance behaviour. Applying appropriate mechanical and thermochemical treatments has been the prime objective of metallurgists. More recently, and particularly for the stainless steels, the Plasma Nitriding was found to be an efficient technique for enhancing the hardness and wear resistance. However, as the nitriding temperature is about 500 °C, the formation of nitrides on the surface leads to a decrease of the corrosion resistance of these alloys. Recent works have shown that using a mechanical pre-treatment allows to decrease the treatment temperature and duration, and also to enhance the nitrogen diffusion within the stainless steels surfaces. In the present work, performances of different Duplex treatments (mechanical + thermochemical) are studied. The Surface Mechanical Attrition Treatment (SMAT), cold rolling and the High Current Pulsed Electron Beam (HCPEB) are used as surface activators prior to plasma nitriding of stainless steels. Before studying the effect of surface activation on the nitrogen diffusion, the effect of the different SMAT parameters (balls size, balls nature, treatment duration … etc.) on the microstructure is analysed. A new technique based on the notion of Geometrically Necessary Dislocations (GND) is used to depict the thickness of the different SMAT-induced layers and compare the effect of the processing parameters. Then, comparative analysis of the results obtained after nitriding of mechanically deformed samples leads to quantify the effect of the different Duplex treatments. X-Ray Diffraction, Secondary Electron Microscopy associated with Electron BackScattered Diffraction (EBSD), hardness measurement and chemical composition analysis by Glow Discharge Optical Emission Spectroscopy (GD-OES) showed the importance of the surface microstructure and deformation state on the nitrogen diffusion
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Menezes, Caren Machado. "Contribuições do fenômeno de atrito no sistema ferro puro nitretado e pós-oxidado". reponame:Repositório Institucional da UCS, 2017. https://repositorio.ucs.br/handle/11338/3320.
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O controle e a redução de atrito podem auxiliar na elaboração de estratégias de eficiência energética e na redução da emissão de dióxido de carbono (CO2). Apesar de existirem leis fenomenológicas bem estabelecidas para o atrito, não há uma definição da relação das propriedades macroscópicas/microscópicas com as propriedades fundamentais e nanoscópicas. O entendimento dessas correlações e dos mecanismos de dissipação de energia envolvidos no fenômeno de atrito podem ajudar no maior controle do coeficiente de atrito. Neste trabalho, o coeficiente de atrito de sistemas de óxidos na camada mais externa de ferro puro (99,99%) previamente nitretado são investigados visando encontrar relações entre as leis fenomenológicas, propriedades mecânicas e modelos teóricos envolvendo a dissipação energética via fônons. Para isso as amostras foram caracterizadas utilizando espectroscopia de emissão óptica de descarga luminescente (GD-OES), difração de raios X (DRX), tomografia de ponta atômica (APT), microscopia eletrônica de varredura (MEV), microscopia eletrônica de varredura por transmissão (STEM), nanoindentação e
deslizamento unidirecional. Na caracterização experimental foi observada uma redução
gradativa do coeficiente de atrito, a qual foi acompanhada por um aumento do teor de óxido na superfície. Apesar disso, essa tendência não foi observada na evolução das propriedades mecânicas. Logo, os cálculos teóricos baseados em mecanismos de dissipação fonônica aplicados para calcular o coeficiente de atrito representaram bem os valores experimentais. De forma geral, a mudança do coeficiente de atrito pode ser explicada mediante contribuições fonônicas, porém as forças de atrito do presente sistema não são totalmente determinadas por mecanismos fonônicos (sic).Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2017-11-20T19:05:37Z No. of bitstreams: 1 Tese Caren Machado Menezes.pdf: 4117143 bytes, checksum: bdf9c6981c075262a20f692e4bcab86e (MD5)
Made available in DSpace on 2017-11-20T19:05:37Z (GMT). No. of bitstreams: 1 Tese Caren Machado Menezes.pdf: 4117143 bytes, checksum: bdf9c6981c075262a20f692e4bcab86e (MD5) Previous issue date: 2017
Control and reduction of friction can help in the elaboration of strategies of energy efficiency and in the reduction of carbon dioxide (CO2) emission. Although there are well established phenomenological laws for friction, there is no definition of the relationship of macroscopic / microscopic properties to fundamental and nanoscopic properties. The understanding of these correlations as well the mechanisms of energy dissipation involved in the friction phenomenon can help in a greater control of the coefficient of friction. In this work, the coefficient of friction of oxide systems in the outermost layer of pure iron (99.99%) previously nitrided is investigated aiming to find relationships between the phenomenological laws, mechanical properties and theoretical models involving energy dissipation via phonons. For this purpose, samples were characterized using glow discharge optical emission spectroscopy (GD-OES), X-ray diffraction (XRD), atomic probe tomography (APT), scanning electron microscopy (SEM), transmission scanning electron microscopy (STEM), nanoindentation and unidirectional sliding. In the experimental characterization, a gradual reduction of the coefficient of friction was observed, which was accompanied by an increase of the surface oxide content. Despite this, the same trend was not observed in the evolution of the mechanical properties. Therefore, the theoretical calculations based on the mechanisms of phononic dissipation applied to calculate the coefficient of friction well represent the experimental values. In general, the change in the coefficient of friction can be explained by phononic contributions, but the frictional forces of the present system are not totally determined by phononic mechanisms (sic).
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Skonieski, Adão Felipe Oliveira. "Influência da mistura gasosa nos processos de nitretação e nitrocarbonetação a plasma do aço AISI 4140". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2008. http://hdl.handle.net/10183/14369.
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Neste trabalho realizaram-se varias nitretações e nitrocarbonetações a plasma em um aço AISI 4140 temperado e revenido, com o objetivo de avaliar a magnitude do parâmetro “composição gasosa” nas propriedades metalúrgicas das camadas formadas após a nitretação. Para a realização deste trabalho foram necessárias adaptações do forno e experimentos prévios para verificar a influência do posicionamento das peças na câmara. Todas as superfícies nitretadas para o estudo das misturas gasosas, foram caracterizadas quanto aos seguintes parâmetros: dureza superficial, perfis de dureza e de composição química, fases formadas nas primeiras regiões da superfície, espessura da camada branca, tenacidade superficial, rugosidade e morfologia topográfica. As amostras provenientes do estudo das variáveis térmicas da câmara foram estudadas quanto à espessura da camada branca e perfis de dureza e composição química. Encontrou-se que as variáveis térmicas são determinantes em termos de alterações no processo e que, cuidados com simetria, devem ser levados em consideração em estudos similares em equipamentos sem aquecimento auxiliar nas paredes. Verificou-se também amplas variações nas propriedades microestruturais das amostras tratadas sob as diferentes misturas gasosas postas em uso e, foi possível sugerir com base nos resultados e na literatura, aplicações para alguns dos casos estudados.In this work various plasma nitriding and plasma nitrocarburizing treatments with hardened and tempered AISI 4140 steel were carried out. The main aim was evaluating the gas mixture influence on metallurgical properties of plasma nitriding and nitrocarburizing layers. For the realization of this study, furnace adaptations and previous experiments in order to verify the parts position influence on final treatments results were necessary. The samples that were nitrided in previous experiments were characterized concerning of compound layer, hardness and chemical composition profiles. All nitride surfaces, were characterized with the parameters: surface hardness, hardness and chemical composition profiles, phases composition on surface, thickness of compound layer, surface toughness, surface roughness and topographical morphology. It was found that thermal parameters are determinants in order to modify the process. Care must be taken about symmetry with this kind of equipment that have no auxiliary heating wall. Later, large variations on microstructural properties in samples under different gas conditions were verified and applications to some cases were proposed.
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Kutschmann, Pia, Thomas Lindner, Kristian Börner, Ulrich Reese i Thomas Lampke. "Effect of Adjusted Gas Nitriding Parameters on Microstructure and Wear Resistance of HVOF-Sprayed AISI 316L Coatings". MDPI AG, 2019. https://monarch.qucosa.de/id/qucosa%3A34775.
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Gas nitriding is known as a convenient process to improve the wear resistance of steel components. A precipitation-free hardening by low-temperature processes is established to retain the good corrosion resistance of stainless steel. In cases of thermal spray coatings, the interstitial solvation is achieved without an additional surface activation step. The open porosity permits the penetration of the donator media and leads to a structural diffusion. An inhomogeneous diffusion enrichment occurs at the single spray particle edges within the coating’s microstructure. A decreasing diffusion depth is found with increasing surface distance. The present study investigates an adjusted process management for low-temperature gas nitriding of high velocity oxy-fuel-sprayed AISI 316L coatings. To maintain a homogeneous diffusion depth within the coating, a pressure modulation during the process is studied. Additionally, the use of cracked gas as donator is examined. The process management is designed without an additional surface activation step. Regardless of surface distance, microstructural investigations reveal a homogeneous diffusion depth by a reduced processing time. The constant hardening depth allows a reliable prediction of the coatings’ properties. An enhanced hardness and improved wear resistance is found in comparison with the as-sprayed coating condition.
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Lee, Ming-yen, i 李明彥. "A Study of Solid Nitriding". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/26461285490855498843.
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碩士國立臺灣大學
機械工程學研究所
90
In order to understand the characteristics and parameters of solid nitriding, fertilizer contained with CaCN2 and Japan powder were practiced on three different steels: SKD61, SUS304, and S45C. Solid nitriding with different parameters was studied and compared with gas nitriding. In addition, solid and gas nitriding treatments were also implemented on specimens with blind hole. The results are shown as follows: 1. Adequate amount of nitriding powder provides steady nitriding potential, but when over critical amount, it will not lead to better results. 2. It takes more than 12 hours on solid nitriding treatment to get good nitriding effect. 3. Solid nitriding on SKD61 at 520℃ produces high hardness, thick nitriding layer and thin white layer. 4. Higher hardening depth and lower hardness are obtained in solid nitriding with CaCN2; lower hardening depth and higher hardness are obtained in solid nitriding with Japan powder. Moreover, solid nitriding with Japan powder can be practiced on SUS304, while solid nitriding with CaCN2 can’t. 5. Solid nitriding produces less white layer than gas nitriding does at the same treating temperature. 6. Solid nitriding can be practiced on narrow gap, deep blind hole, or local area of specimen, and produces high hardness, thick nitriding layer and similar results on different location. However, gas nitriding is not suitable in the same specimen condition.
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Chen, Chih-Chieh, i 陳志杰. "A study on Solid Nitriding". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/73948699002951691058.
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碩士國立臺灣大學
機械工程學研究所
94
In order to understand the characteristics of solid nitriding, and the feasibility of method applied to steels such as SUS304, JAC1 and SACM645, we heated steel samples in the nitriding powder of a given amounts. The powder would generate active nitrogen that permeated into the steel surface. The purpose of the article was to study the influences of nitriding temperature, nitriding time and composition of the steel on the nitriding depth, the distribution of hardness, the microstructure, and the corrosion-resistance to hot aluminum liquid of the nitriding layer. In addition, the effect of solid nitriding was compared with Gas nitriding. The results were summarized as follows: 1.The solid nitriding could be performed with steels of SUS304, JAC1 and SACM645. SUS304 was the best, JAC1 was the second and SACM645 was the third on the hardening effect of nitriding. 2.The best surface hardness and hardened depth could be obtained for the nitriding time of 12 ~ 15 hours. The surface hardness and hardened depth would not increase significantly for the nitriding time over 15 hours. 3.SUS304 could be nitrided by the nitriding powder at 450℃. Because the low nitriding temperature was not easy to produce white layer and deformation, this method could be applied to the precision machine parts. However, it took more time to get an obvious nitriding layer. 4.In order to gain an effective surface hardness and thick hardening depth, the temperature range from 500℃ to 550℃ was the optimal temperature for the solid nitriding. 5.Steel after solid nitriding could have better corrosion resistance to aluminum liquid. Besides, the corrosion resistance was the best for the steel nitrided at 550℃. 6.The complicated workpiece performed solid nitriding could obtain a more uniform hardening layer than traditional gas nitriding. 7.The solid nitriding was inferior to the traditional gas nitriding on hardening effect, but the solid nitrided layer had better toughness. This feature could improve the brittleness of the gas nitrided layer. Keywords: Solid nitriding, Gas nitriding, Corrosion-resistance test
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CHEN, TING-WEI, i 陳庭煒. "Laser Nitriding and Heat Treatment of Titanium Alloy". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/66809349166618547374.
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碩士國立雲林科技大學
機械工程系
105
Heat treatment is always an indispensable process in the production. In recent years, non-traditional heat treatment process has gradually replaced the traditional heat treatment process, features not only steady quality but also saving time. Laser has a good direction and high energy density, with the short heating time of materials, resulting in small thermal deformation, and also can be used in the specific area of treatment. For example, treatment of a hand tool edge. In this research, the laser is applied to the surface of the titanium alloy for heat treatment. The optical fiber laser is projected on the metal surface by a defocused and focused manner, and the heated surface is reorganized to facilitate alloying. With laser nitriding, the nitriding layer is formed to improve the wear resistance and corrosion resistance of titanium alloy. In addition, adding ultrasound for the material surface modification, and observing the material structure by different laser rates and frequency. According to the result, with the atmospheric environment, Ti-6Al-6V-2Sn gets a clear heat-affected zone after lasering, but it has no phase-change by the defocused manner. With the atmospheric environment and the focused manner, Ti-6Al-6V-2Sn gets some vertical holes under the surface after lasering with 1mm/s of scanning rate and 50kHz of frequency, it gains HV 587±50 of hardness after lasering from the cross-sectional of Ti-6Al-4V with CW mode and 10mm/s of scanning rate. With the nitriding environment and the focused manner, it gains HV 780±50 of hardness and thickness 50μm of nitriding layer after lasering from the cross-sectional of Ti-6Al-4V with CW mode and 10mm/s of scanning rate. With the atmospheric environment and the focused manner, it makes irregular cracks on the surface of Ti-6Al-4V while adding the ultrasound in the heat treatment. The result shows that the laser nitriding can gain the dense and thin nitriding layer, it can be applied to processes such as 3C products or medical equipment, and to improve service life.
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CHEN, TING-WEI, i 陳庭煒. "Laser Nitriding and Heat Treatment of Titanium Alloy". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/r4mdy7.
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碩士國立雲林科技大學
機械工程系
106
Heat treatment is always an indispensable process in the production. In recent years, non-traditional heat treatment process has gradually replaced the traditional heat treatment process, features not only steady quality but also saving time. Laser has a good direction and high energy density, with the short heating time of materials, resulting in small thermal deformation, and also can be used in the specific area of treatment. For example, treatment of a hand tool edge. In this research, the laser is applied to the surface of the titanium alloy for heat treatment. The optical fiber laser is projected on the metal surface by a defocused and focused manner, and the heated surface is reorganized to facilitate alloying. With laser nitriding, the nitriding layer is formed to improve the wear resistance and corrosion resistance of titanium alloy. In addition, adding ultrasound for the material surface modification, and observing the material structure by different laser rates and frequency. According to the result, with the atmospheric environment, Ti-6Al-6V-2Sn gets a clear heat-affected zone after lasering, but it has no phase-change by the defocused manner. With the atmospheric environment and the focused manner, Ti-6Al-6V-2Sn gets some vertical holes under the surface after lasering with 1mm/s of scanning rate and 50kHz of frequency, it gains HV 587±50 of hardness after lasering from the cross-sectional of Ti-6Al-4V with CW mode and 10mm/s of scanning rate. With the nitriding environment and the focused manner, it gains HV 780±50 of hardness and thickness 50μm of nitriding layer after lasering from the cross-sectional of Ti-6Al-4V with CW mode and 10mm/s of scanning rate. With the atmospheric environment and the focused manner, it makes irregular cracks on the surface of Ti-6Al-4V while adding the ultrasound in the heat treatment. The result shows that the laser nitriding can gain the dense and thin nitriding layer, it can be applied to processes such as 3C products or medical equipment, and to improve service life.
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Pao, Wen Lon, i 包文龍. "Ion Nitriding /CAPD Composite CrN hard Coating of SKH51". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/52270566959263814873.
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碩士大同工學院
材料科學(工程)研究所
81
In order to improve wear property of high speed steel SKH51, a combined ion nitriding-cathodic arc plasma deposition (CAPD) processing was studied. Ion Nitriding was performed under care- fully controlled conditions and then a CrN hard coating was de- posited on top of the nitrided surface by CAPD- physical vapor deposition(PVD) method. OM、SEM、EPMA、SAM、XRD and Microhardness tests were carried out to evaluate the characteristics of the combined layers. The thickness of CrN film was measured by kalotest. Rockwell inden- tation analysis was used to qualitatively determine the adhesion of CrN films. Unlubricated friction and wear behaviors of the combined hard-layers against several materials were also invest- igated. The bending strength and deflection toughness of the steel so treated was evaluated by three- point-end test. The results indicated that the combined hard- coating tech- nology effectively increased the surface hardness of SKH51 high speed steel and improved the adhesion of the top CrN hard film to the substrate. Although ion nitriding alone seemed to de- crease the deflection toughness of the material,however,combined layers improved such property. It also exhibited good resistance to wear and low friction coefficient in sliding contact against 304 stainless steel and copper alloy at relatively high loads.
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HU, JIA-RONG, i 胡家榮. "Plasma nitriding effects on fatigue properties of aerospace material". Thesis, 1991. http://ndltd.ncl.edu.tw/handle/89268696507111956198.
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HSIEH, FU HSUAN, i 謝富軒. "Research of High Temperature Gas Nitriding of 410 Stainless Steel". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/22794540660934423995.
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碩士國立臺灣大學
機械工程學研究所
89
In order to understand the behavior of 410 stainless steel under gas nitriding at high temperature. We divided the experiment into three parts in the research: 1.High temperature gas nitriding: Steel samples were heated over A1 transformation temperature. We can discuss the influence of nitriding rate; hardness, distribution and microstructure of 410 stainless steel were investigated from the change of nitriding time, the nitriding temperature, ammonia flow-rate, and the nitriding pressure. 2.High temperature two-stage gas nitriding: After gas nitriding at high temperature, steel samples were treated in traditional gas nitriding at lower temperature. We expect that we can find the best hardness distribution of 410 stainless steel, and apply the result of the research to tapping screws. 3. The comparison of high temperature two stage gas nitriding to traditional gas nitriding: From the hardness distribution view, we analyze this two stage nitriding methods. The results were summarized as followed: 1.After the samples of 410 stainless steel are nitriding at high temperature, the hardness of surface layer becomes softer, because of forming α-Fe phase; the core of the samples can be harden, because of forming martensite structure. 2.After high temperature two-stage gas nitriding, the surface layer hardness distribution of 410 stainless steel is approximately satisfying the requirement of tapping screws. 3.After traditional gas nitriding, the proportion of alloy in 410 stainless steel is high, still can result in the depth of nitriding is deficiency and hardness gradient is too high even the surface layer hardness of 410 stainless steel is extremely hard.
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Huang, Kuo-Chung, i 黃國鐘. "Mechanical Properties Evaluation of Nitriding Steel by Small Punch Test". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/b2er48.
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碩士遠東科技大學
機械工程研究所在職專班
107
The purpose of this study is to investigate the nitriding effect on mechanical properties of alloyed steel after gas nitriding treatment. To compare different nitriding processes, two techniques has been developed, namely indentation microhardness and small punch tests. A correlation has been analyzed to predict the constitutive relation of the test material from these data. The small punch test is instrumented to provide load-displacement data, and these data can be used to determine flow properties of the test material and the measured values were compared with those obtained from Vickers hardness tests. Various properties and strengths of different nitriding layer thicknesses were observed by electron microscopy (SEM) and metallographic microscope (OM) to illustrate the failure mode of the test material. The final result of this series of experiments would be applied to the mechanical industry applications, such as injection molding process.
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Liu, Shie-cheng, i 劉師誠. "Microwave plasma nitriding of stainless steel surface on the biocompatibility". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/24523704544605064013.
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碩士龍華科技大學
工程技術研究所
98
Because hypertension often squeeze into the top ten causes of death, resulting in hypertension for many reasons, including its one of the reasons for blood vessel blockages, and treatment for blood clots, there used to block the vascular stent will be implanted into blood vessels expansion to achieve effective manner to improve. 316 stainless steel and nickel-titanium alloy is the most commonly used vascular stent materials, but materials in vivo release of nickel ions, likely to cause harm to human toxicity. This study mainly to lower nickel content of 303 stainless steel with microwave plasma nitriding and the actual temperature of different nitrogen to obtain better mechanical properties of the surface, anti-bacterial effects and blood compatibility properties.
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Cheng, Chih-Wei, i 鄭至偉. "Improving Wear Resistance of Cold Working Tool Steel by Solid Nitriding". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/51263694242270177534.
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碩士國立臺灣大學
機械工程學研究所
95
The purpose of this study is to understand the characteristics of solid nitriding. The effect of solid nitriding on the wear resistance of cold working tool steel such as SKD11, SKH51 and DC53 will be discussed in this article. The above steel sample was nitrided at various temperatures for different time. Then, the microstructure, hardness distribution, nitrogen contents and wear resistance of the nitrided layer was examined for each solid nitriding condition. Moreover, above experimental data was compared with those of conventional NH3 gas nitriding. The results were summarized as follows: 1.In order to obtain an effective surface hardness and the more dense compound layer, the temperature ranging from 500℃ to 550℃ was the optimal temperature for the solid nitriding. 2.The compound layer of steel after the solid nitriding was rather dense and not easy to crack or spall off. It is not necessary to remove the layer by grinding before application. 3.The steel has hardening effect as long as the solid nitriding temperature over 480℃. The wear resistance of nitrided layer increases with increasing nitriding temperature or time. The dies and machine parts should be nitrided under appropriate conditions depending on their application reguirement. Besides, the wear resistance of the nitrided layer was the best for the steel nitrided at 550℃. As to the steel nitrided at 600℃, the holes will appear in the compound layer and nitrides will become coarse. Therefore, both the surface hardness and the wear resistance will decrease. 4.The nitriding at low temperature 480℃~500℃ was not easy to produce deformation, so this method could be applied to the precision machine parts. 5.The compound layer of solid nitriding was permeated with not only nitrogen but also carbon. Although the nitrided layer was not as thick as that of the gas nitriding, the compound layer had better toughness and wear resistance.This point was similar to Tufftriding.
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Hwang, Horn-Shin, i 黃宏欣. "The study of hybrid treatment of ion nitriding and TiN coating". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/60541851090770306974.
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Rodrigues, Diogo Farias Gonçalves Alexandre. "Plasma nitriding of AA2011 alloy and surface characterization by NDT techniques". Master's thesis, 2015. http://hdl.handle.net/10362/16443.
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Al-Cu alloys are widely used in the aerospace and automotive industries due to their high specific strength in some tempered conditions. However, due to poor corrosion and wear resistance, they are often anodized and/or painted. Plasma nitriding has been proposed as an alternative, though the developments in this technique are still in a recent stage for Al alloys.
Electrical characterization techniques are well implemented NDTs in the industry because of good accuracy associated with lower cost, compared to other methods. Some, like eddy currents and 4-point probe techniques, are often used in coating inspection.
The objective of this study was to perform Al nitriding at low temperatures to minimize the tempering initial condition damage and to assess the feasibility of eddy currents technique as a method for evaluating surface properties.
The work developed can be divided in two stages. The first one was the process tuning, done at the Shibaura Institute of Technology, in Tokyo; and the second was the electrical characterization done in Faculdade de Ciências e Tecnologia, UNL.
Low temperature nitriding of AA2011 alloy specimens was successfully achieved. Electrical conductivity results show that lift-off measurements by eddy currents testing can be related to surface properties.