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研究了合成人造金刚石用Ni70Mn25Co5触媒合金C、N、B三元共渗及其对合成人造金刚石质量和产量的影响,并与单独渗C、渗N、渗B合金进行了对比,结果表明,该合金三元共渗比单独渗合成的人造金刚石的性能更高,单产比渗C者低,比渗N、渗B者高,接近于原始合金。 相似文献
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触媒合金渗硼对合成人造金刚石性能的影响 总被引:5,自引:0,他引:5
本文研究了触媒合金渗硼对合成人造金刚石性能的影响。结果表明,采用渗硼触媒合成金刚石,可提高金刚石的抗压强度、耐热性和优质粗晶粒百分比,但却使金刚石的单次合成产量降低。 相似文献
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B-C-N系超硬材料的研究进展 总被引:7,自引:0,他引:7
超硬材料的合成是目前材料科学研究领域的热门课题之一,近年来,由于碳基和硼基超硬材料的理论设计和发现,引起了人们在实验3和理论上对硬度与金刚石接近,基至超过金刚石的材料研究兴趣。在B-C-N系超硬材料中,除了金刚石和立方氮化硼(c-BN)以外,α-CaN4,立方氮碳化硼以及富勒烯等材料,也正日益受到国际材料界的重视,本文就B-C-N系超硬材料的最新研究进展做一综述。 相似文献
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研究了Nb含量x对Fe_(76.5-x)Cu_(1.0)Nb_xSi_(13.5)B_(9.0)纳米软磁合金的结构与磁性影响。研究结果表明,当N6含量x约为3at%时,合金的软用性能最高;随Nb含量x的增加,最佳软磁性能下合金显微组织结构中的αFe-Si纳米晶晶粒尺寸D、Si含量、体积分数V_c均呈下降趋势,非晶相的短程有序范围δ增大;合金的磁性除与αFe-Si纳米晶有关外,还与合金中非晶相密切相关。用新近提出的双相无规磁各向异性模型讨论了合金的磁性与结构的关系。 相似文献
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本文综合分析了立方氮化硼(c-BN)膜的制备方法,介绍了c-BN膜的结构及其机械、电学、光学和热学性能。最后总结了c-BN膜在机械和电子领域的应用概况。 相似文献
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The corrosion properties of S-phase surface layers formed in AISI 316LVM (ASTM F138) and High-N (ASTM F1586) medical grade
austenitic stainless steels by plasma surface alloying with nitrogen (at 430°C), carbon (at 500°C) and both carbon and nitrogen
(at 430°C) has been investigated. The corrosion behaviour of the S-phase layers in Ringer’s solutions was evaluated using
potentiodynamic and immersion corrosion tests. The corrosion damage was evaluated using microscopy, hardness testing, inductive
coupled plasma mass spectroscopy and X-ray diffraction. The experimental results have demonstrated that low-temperature nitriding,
carburising and carbonitriding can improve the localised corrosion resistance of both industrial and medical grade austenitic
stainless steels as long as the threshold sensitisation temperature is not reached. Carburising at 500°C has proved to be
the best hardening treatment with the least effect on the corrosion resistance of the parent alloy. 相似文献
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The hydrogenation of Ib-type single crystalline diamond with grain size of several tens of micrometers, synthesized by high-pressure and high-temperature (HPHT) sintering, was carried out by hydrogen plasma treatment in a hot-filament chemical vapor deposition (HFCVD) system. After exposure to air, the surface conductivity of (001) and (111) facets of HPHT single crystalline diamond was measured. The influences of hydrogenation duration, temperature and gas pressure on the surface conductivity of (001) and (111) facets have been investigated. The measurement results show that the variation of hydrogenation conditions has a noticeable effect on the surface conductivity of single crystalline diamond, which is closely related to the formation of a chemical vapor deposition (CVD) regrowth layer on the facets induced by hydrogen plasma treatment process. In addition, (001) surface exhibits higher electrical conductivity than (111) surface, which is mainly attributed to less nitrogen concentration on the (001) surface than on the (111) surface. 相似文献
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采用等离子渗氮技术提升TC4钛合金的耐磨性并探究最优渗氮温度。利用LDM 1-100型等离子渗氮设备,在650,700,750,800,850℃和900℃温度下对TC4钛合金进行渗氮处理,保温时间均为10 h。利用光学显微镜、扫描电子显微镜、白光三维形貌仪、X射线衍射仪和显微硬度计分别对不同温度渗氮试样的微观组织结构、表面形貌、表面粗糙度、相结构和硬度进行表征。利用CETR UMT-3型多功能摩擦磨损试验机测试等离子渗氮后TC4钛合金的摩擦学性能。结果表明:TC4钛合金表面显微硬度和粗糙度随温度升高而增大,在900℃渗氮后TC4钛合金表面显微硬度达到了1318HV 0.05,约为基体(360HV 0.05)的4倍。硬度的升高是由于渗氮后试样表面形成了硬质氮化物相(TiN和Ti2N相),且随着渗氮温度升高氮化物的含量增加。相较于低温渗氮(低于750℃)的试样,850℃和900℃渗氮试样的承载能力显著提升。与原始TC4试样相比,渗氮处理后试样的磨损体积显著降低。当渗氮温度为850℃时,试样磨损体积为未处理试样磨损体积的1.2%(1 N),3.0%(3 N)和62.2%(5 N),试样的耐磨性提升更为显著。 相似文献
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A needle-like structure of AlN is observed in Fe-31 Mn-9Al-0.87C-xCr (x=0, 3 and 6) alloys at 1000° C in a nitrogen atmosphere. The reaction front of nitriding moves parabolically with time. The nitriding rate is evaluated on the basis of the penetration depth of the nitriding layer at various lengths of time, and is found to be increased with increasing chromium content in the alloy. A quasi-steady state diffusion model is employed to investigate the nitriding kinetics by nitrogen migration through the alloy matrix. The nitriding rate depends on the solubility of nitrogen as well as the diffusivity of nitrogen in the alloy system. It is argued that the solubility of nitrogen predominates the nitriding, and thus the growth of AlN prevails in the austenitic phase instead of ferrite, due to the higher nitrogen solubility in austenite. In addition, the chromium alloying into the Fe-Al-Mn system increases the lattice parameter, which leads to a higher solubility of nitrogen, and hence a higher nitriding rate is obtained. 相似文献
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Incoloy 825 alloy is an alloy with high corrosion resistance but it has low strength and hardness. Increasing of hardness of the alloy is important for its wear resistance. In this study, Incoloy 825 alloy was boronized to increase its hardness. The boronizing process was carried out using the box boronizing method at 900 and 950 °C for 2, 4 and 6 h. The coating thickness that occurred by boronizing increased with the increase in temperature and time. The thickness of boride layers depending on temperature and process time was ranged from 35 to 170 μm. The presence of borides (e.g., FeB, Fe2B, CrB, NiB) was confirmed by X-ray diffraction (XRD) analysis technique. The boron compounds have shown the random distribution. The microhardness has decreased along the coating thickness (towards to the matrix). 相似文献
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《Materials at High Temperatures》2013,30(2):148-154
AbstractOwing to high temperature comprehensive properties, Fe–Cr–Ni alloys are designed to operate in corrosive gaseous environments of ethylene pyrolysis furnace. However, most premature failed tubes were caused by carburisation. In the present study, based on the Fick’s second law and equilibrium constant method, study on the carburised layer evolution of HP40Nb and KHR45A alloys by pack carburising experimental investigation and numerical simulation by MATLAB software were carried out. The results show that the experimental and simulated data agree with each other acceptably. The carburising layer rate of KHR45A alloy is much smaller than that of HP40Nb alloy due to higher contents of Cr and Ni element in the former. With increasing operating temperature ranging from 1000 to 1100°C, the maximum service lives of the two alloys sharply decrease. 相似文献
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The nanoindentation test has been applied to evaluate the mechanical properties such as hardness, elastic moduli and deformation behaviors of Fe4N iron nitride layers produced on Armco iron and En40B steel by plasma nitriding, and PVD-TiN coatings deposited on En40B with or without prior plasma nitriding treatment. Results showed that the Fe4N layer produced on En40B exhibits higher hardness than that on Armco iron. This is attributed to the effect of the alloy compositions, especially Cr element. However, similar elastic modulus values to that of bulk ferrous alloys have been found for Fe4N layers produced on both Armco iron and En40B. Under lower loads, TiN coatings on nitrided substrate behave quite the same in hardness and elastic modulus as TiN coatings on untreated En40B. Whilst with increasing indentation load and depth, duplex treated (i.e., combined plasma nitriding and PVD-TiN coating) En40B possesses higher composite hardness, elastic modulus and load bearing capacity than TiN coated base material. 相似文献
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C.Z.Gu X.Jiang 《材料科学与工程学报》2000,18(Z2):653-656
Epitaxial CoSi2 (001) layers, deposited on Si (001) substrate by molecular beam allotaxy (MBA), were used as substrate for diamond deposition in order to realise new applications. The results indicate that, in a microwave plasma chamber, diamond can be nucleated with a higher density on CoSi2 at lower temperatures using a bias enhanced method. High quality, [001]-textured diamond films can be synthesized on CoSi2 (001) using the [001] textured growth conditions. So far an epitaxial growth of diamond on CoSi2 cannot be observed. Statistically, a rotating angle distribution of diamond grains around the [001] axis in an [001]-textured film shows, however, preferred in-plane orientations of 13°, 22°, 45° and 77° relative to the CoSi2 [011]axis. The structural and chemical analyses show that no Co and Si element diffusion from the CoSi2 substrate into the diamond film can be detected. 相似文献
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X. Y. Ai H. L. Lin B. Zhang J. W. Lv R. P. Liu 《Materials Science & Technology》2018,34(11):1303-1308
A hydrogen-free nitriding method through double glow plasma metallurgy is exploited and a nitrided layer was formed on ZrTiAlV alloy. The nitrided layer was characterised through X-ray diffraction, optical microscopy, scanning electron microscopy and energy-dispersive spectroscopy techniques, as well as through Vickers hardness and friction and wear tests. Results showed that the nitrided layer is 580?µm thick, homogeneous and dense. It mainly consists of TiN, Ti2N and ZrN phases. The hardness of the nitrided layer on the surface of the ZrTiAlV alloy is nearly 2.5 times higher than that of the ZrTiAlV substrate. The friction coefficient and wear resistance of the alloy considerably improved after nitriding. 相似文献
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为了提高金刚石-铜合金复合材料的界面粘结强度,本文用差热分析(DTA)、X射线衍射分析、SEM观察及磨削试验研究了金刚石表面的Ti镀层对金刚石-铜基合金复合材料界面结构及性能的影响.结果表明,在600~1200℃镀Ti层与金刚石发生界面反应,在金刚石表面外延生成岛状TiC,从而实现了金刚石与铜基合金的冶金结合.镀Ti金刚石与铜合金的粘结强度可达8×107Pa.用镀Ti金刚石制成的铜基合金磨块对花岗岩的磨削比与不镀钛金刚石相比提高30%. 相似文献