Effect of rare earth elements on plasma electrolytic carbonitriding of Ti–6Al–4V alloy

The paper aims to research the effect of rare earth elements on the carbonitriding layer of titanium alloy by establishing a theoretical model between rare earth concentration and atomic diffusion efficiency. It shows that adding rare earth can not only refine the discharge holes, but also reduce surface cracks, which significantly improve the surface quality of the strengthening layer. It is also found that an appropriate amount of rare earth can greatly increase the growth rate of the carbonitriding layer and carbon content near the surface. Furthermore, compared with the conventional plasma electrolytic carbonitriding treatment, adding 2?g?L^?1 cerium oxide can effectively reduce the activation energy of carbon, so as to improve its diffusion ability.     

GCr15轴承钢钢领的探讨

针对国产钢领普遍使用20低碳钢做材质,在使用中存在寿命短、纺纱质量差的弊端,对比了国内普通钢领和采用GCr15轴承钢制造的钢领的各种性能及使用寿命,并对后者的工艺进行了讨论,说明采用GCr15钢制造的钢领能满足目前高速纺纱机的需求,对提高成纱质量提供保证。     

压铸模NQN复合强化

通过对3Cr2W8铝压铸模常规热处理工艺的研究分析 ,提出用NQN复合强化进行改进。从实际生产出发 ,运用化学热处理和常规热处理相结合的方法 ,提高了压铸模的使用寿命 ,并缩短了生产周期 ,降低了生产成本     

硫碳氮共渗及稀土的作用

在渗剂中不加稀土和加入不同量稀土的条件下，对３Ｃｒ２Ｗ８Ｖ钢进行了硫碳氮共渗试验。用金相法和显微硬度法测定了硫碳氮共渗动力学曲线。利用二次离子质谱仪和Ｘ射线光电子能谱仪，对稀土在试样表面分布与存在状态进行了研究。结果表明，适量稀土对硫碳氮共渗具有明显的催渗作用；稀土能渗入钢中，渗入试样表面的稀土以氧化物和固溶态的形式存在；稀土通过促进碳氮硫原子在表面的吸附及破坏表面氮化层，清洁界面，加速硫碳氮共渗     

Characterization and blood compatibility of TiCxN1 − x hard coating prepared by plasma electrolytic carbonitriding

A novel technique to form Ti(C, N) on titanium, named as plasma electrolytic carbonitriding (PEC/N) on cathode was successful used to prepare TiC_xN_1 − x coating. The structure, composition and morphology of the coating were characterized by XRD, XPS and SEM, respectively. The results indicated that TiC_0.3N_0.7 as a new species appears on the surface of the titanium plate, and the thickness of the coating with porous surface morphology increases with the treated time. The blood compatibility of the TiC_0.3N_0.7 coating was evaluated by haemolysis ratios, dynamic blood clotting test, plasma recalcification time and platelet adhesion. The results indicated that the blood compatibility of the plasma-treated titanium with TiC_xN_1 − x coating is significantly improved as compared to the original titanium. Additionally, the results derived from measurements of hardness and corrosion indicated that the coating has excellent mechanical and corrosion-resistant properties.     

TA1纯钛离子碳氮共渗改性层耐磨性能研究

对TA1纯钛进行了离子碳氮共渗。用扫描电镜对离子碳氮共渗的TA1纯钛改性层进行了观察。用X射线衍射仪测定了改性层的物相。用能谱仪对改性层作成分分析。用显微硬度计测定改性层的硬度。用SRV摩擦磨损试验机测定摩擦系数，在往复式磨损试验机上进行，磨损试验。结果表明，经离子碳氮共渗的TA1纯钛表面获得了金黄色、均匀的Ti2N／TiN改性层，显微硬度为840HV0．01。碳氮共渗表面改性层能明显提高纯钛TA1的耐磨性。     

无毒液体碳氮共渗

通过金相、硬度、耐磨性、Ｘ射线衍射、台架试验等测试分析表明：用“８６２”渗剂取代氰盐对低碳钢自行车轴碗、轴档及手工钢锯等零件进行中温无毒液体碳氮共渗，能完全满足其技术性能的要求，具有较好的社会效益和经济效益。     

自保护碳氮共渗膏剂的工艺特性研究

研究了一种自保护碳氮共渗膏剂，探讨了该膏剂的自保护机理、碳热变化和碳扩散距离，测定了碳氮共渗层的成分、相组成、显微组织及性能。试验表明，经该膏剂碳氮共渗处理试样的表面硬度、耐磨性及渗速均优于气体碳氮共渗，该工艺适用于工件的局部碳氮共渗。     

SQP、QPQ及碳氮共渗处理对表面耐磨性的影响

研究了20钢和45钢经SQP、QPQ及碳氮共渗处理后的耐磨性能。通过对样品进行维氏硬度测试、金相组织观察、摩擦磨损实验和观察磨痕,对比了三种不同工艺对材料耐磨性的影响,为以后零件的实际处理选取适当的工艺提供理论基础。从材料学的角度分析了耐磨性能差异的原因,为今后改进工艺提供理论依据。     

快速表面改性技术研究

本文介绍一种快速表面改性技术，碳氮共渗时间只需３￣５ｍｉｎ，共渗层厚度即达０．２￣０．４ｍｍ。本文还分析了放电过程及共渗机理、试样温度与电压的关系以及渗层硬度，得出渗层厚度与电压及时间的关系式。