电弧离子镀氮化钛铝铬涂层的900℃氧化

氮化物金属陶瓷涂层由于具有高的硬度和化学稳定性，成为近年来防护涂层的研究热点。利用脉冲偏压电弧离子镀技术在压气机叶片用1Cr11Ni2W2MoV热强不锈钢基体上沉积了（Ti0．5Al0．5）N、（Ti0．45Al0．45Cr0．1）N和（Ti0．35Al0．35Cr0．3）N亚稳金属陶瓷涂层，研究了涂层的组织、结构和900℃下的氧化行为。3种涂层均为B1NaCl结构，（220）为主要的织构取向。在900℃静态空气中（Ti0．5Al0．5）N氧化严重，添加Cr的涂层表现出优异的抗氧化性。     

Residual stress influence on fatigue lifetimes of electroplated AISI 4340 high strength steel

Residual stresses play an important role in the fatigue lives of structural engineering components. In the case of near surface tensile residual stresses, the initiation and propagation phases of fatigue process are accelerated; on the other hand, compressive residual stresses close to the surface may increase fatigue life. In both decorative and functional applications, chromium electroplating results in excellent wear and corrosion resistance. However, it is well known that it reduces the fatigue strength of a component. This is due to high tensile internal stresses and microcrack density. Efforts to improve hard chromium properties have increased in recent years. In this study, the effect of a nickel layer sulphamate process, as simple layer and interlayer, on fatigue strength of hard chromium electroplated AISI 4340 steel hardness – HRc 53, was analysed. The analysis was performed by rotating bending fatigue tests on AISI 4340 steel specimens with the following experimental groups: base material, hard chromium electroplated, sulphamate nickel electroplated, sulphamate nickel interlayer on hard chromium electroplated and electroless nickel interlayer on hard chromium electroplated. Results showed a decrease in fatigue strength in coated specimens and that both nickel plating interlayers were responsible for the increase in fatigue life of AISI 4340 chromium electroplated steel. The shot peening pre-treatment was efficient in reducing fatigue loss in the alternatives studied.     

微波促进铬(Ⅲ)催化降解甲基橙的研究

重金属与难降解有机污染物形成复合污染物,一些重金属离子也能催化H2O2产生·OH。利用微波加热的热效应和非热效应,以甲基橙溶液为模拟偶氮染料废水,研究了微波功率、微波辐射时间、pH值、Cr（Ⅲ）和H2O2浓度等因素对甲基橙脱色率的影响。研究表明,Cr（Ⅲ）能与H2O2形成类Fenton试剂,产生·OH,在微波的促进作用下,矿化有机物的原理。1 000 mg.L^-1的甲基橙溶液,在H2O2浓度为12.0 mmol.L^-1、5 mmol.L^-1Cr^3＋溶液、pH=3、微波功率700 W下加热5 min,甲基橙脱色率达93%。     

Cr、Si、Mn、Cu对中低铬白口铸铁抗磨蚀性能的影响

应用磷酸盐石墨铸型浇注中低铬白口铸铁试样 ,用正交试验对它们的抗腐蚀耐磨性进行了研究。分析表明 :试样有较好的抗腐蚀耐磨性 ,最佳成分配比浇注出的试样的抗腐蚀耐磨性为正火态 2 0 #钢的 3倍 ,充分反映了磷酸盐石墨铸型的激冷能力好 ;中低铬白口铸铁的抗腐蚀耐磨性随着铬含量的增加而升高 ;硅的含量以低于 2 %为佳 ,锰和铜的含量分别以在 2 %～ 3%范围和在 1%～ 2 %范围为佳。     

磷酸盐陶瓷浆料的研究与应用

选用高铬刚玉为耐火骨料、磷酸盐等为粘结剂、氧化镁为固化剂，通过正交试验，确定了磷酸盐陶瓷浆料的最佳配比，并考察了陶瓷浆料的多种性能，进行了精密铸件的生产应用。结果表明：该陶瓷浆料性能优良，成本低廉，具有广泛的应用价值。     

Computer Experiment on Deformation of Nanocrystals of the Chromium-Niobium System. Part 2. Mechanical Properties

Molecular-dynamic simulation of the process of stretching of chromium and niobium nanocrystals and chromium-niobium bicrystals was performed to a pair-potential approximation. The authors obtained and analyzed the dependences of the potential energy, the number of pair interactions, work of deformation, stress, reduction in the cross-sectional area, and Poissons ratio on the strain with various orientations of nanocrystals with respect to the tensile force. They calculated the characteristics of elasticity, yielding, and strength of nanocrystals.__________Translated from Problemy Prochnosti, No. 2, pp. 5 – 18, March – April, 2005     

还原铬渣做水泥混合材

从理论和实践两个方面阐述了还原铬渣做水泥混合材的可行性。研究对比了掺加还原铬渣前后两种水泥制品的各种性能指标，得出了还原铬渣替代水泥混合材的最佳掺加量。结果表明，还原铬渣掺加量为水泥总质量的3％时，各项数值均符合GBl75—1999标准。水泥制品溶出的六价铬远远小于废水最大允许排放量。     

高铬离心复合铸铁轧辊的非正常失效及预防

简单介绍高铬离心复合铸铁轧辊的技术特性和失效形式,并分析非正常失效的原因,同时针对非正常失效提出预防措施.     

Structure formation during sintering in the presence of a liquid phase in Cr-Cu-metal of the iron family systems. II. Systems Cr-Cu-Ni(Co, Fe)

Features of structure and phase formation in Cr-Cu-Ni(Co, Fe) systems during liquid-phase sintering in a vacuum of (2–4) · 10⁻³ Pa at 1200 and 1270°C are studied. It is shown that with introduction of elements of the iron family into molten copper there is dispersion of refractory particles and formation at the boundary with the readily melting component of a transition layer whose structure and composition are determined by the nature of the addition. Growth of refractory particles during liquid-phase sintering of composites of the system Cr-Cu-Ni is controlled by diffusion of elements into the solid phase of the transition layer. __________ Translated from Poroshkovaya Metallurgiya, Nos. 7–8(450), pp. 19–25, July–August, 2006.     

Development of New WearResistant Surface Coating at Elevated Temperature

Because of good oxidation resistance at high temperature and excellent mechanical properties of Ni3Al and high hot hardness, and good oxidation resistance of chromium carbide, chromium carbide particle reinforced Ni3Al matrix composite would possess excellent wear resistance at elevated temperature. Cr3C2NiAlNi welding wire was produced by pressureless sintering process in vacuum. When the welding wire was welded on the surface of carbon steel, under the action of the physical heat of arc, NiAl reacted with nickel to form Ni3Al and carbide particle reinforced Ni3Al matrix composite was formed on the welding layers. Cr3C2 was dissolved during welding and dispersed Cr7C3 was formed, which strengthened the Ni3Al matrix significantly. The Cr7C3Ni3Al interface was broadened, and a zone of interdiffusion and a new phase M23C6 were formed, indicating that a good bond has been formed. The hardness of Cr7C3/Ni3Al composite at room and elevated temperatures is much higher than that of stellite alloys. In addition, Cr7C3/Ni3Al composite possesses better high temperature oxidation resistance than stellite 12 alloy. So Cr7C3/ Ni3Al composite can become an attractive potential candidate for elevated temperature wearresistant surface material.