Cr12MoV钢表面磁控溅射Ti/TiN涂层的摩擦磨损性能研究

采用非平衡磁控溅射方法在Cr12MoV钢表面制备了厚度约为3 μm的Ti/TiN涂层,测定了涂层的显微硬度,并通过划痕试验和摩擦磨损试验考察了涂层同基体的结合强度及其摩擦磨损性能.结果表明:Ti/TiN涂层能够显著提高Cr12MoV钢的表面硬度和承载能力;涂层同Cr12MoV钢基体的结合强度较高,划痕临界载荷高于60 N;与此同时,磁控溅射Ti/TiN涂层可以显著改善Cr12MoV钢的耐磨性能.这是由于磁控溅射Ti/TiN涂层硬度高且与Cr12MoV钢基体的结合强度较高所致.     

Cr12MoV钢离子渗氮和硫、碳、氮复合共渗层摩擦学性能研究

采用离子渗N和S、C、N复合共渗技术在Cr12MoV钢表面制备了由硫化物组成的改性层，考察了改性层在不同润滑条件下的摩擦磨损性能，并采用扫描电子显微镜观察分析试样磨损表面形貌。结果表明：Cr12MoV钢表面经复合共渗处理后形成具有良好储油能力的多孔硫化物层，硫化物层在油润滑条件下可以显著提高Cr12MoV钢表面的摩擦磨损性能。     

Temperature-Dependent Formation of Redox Sites in Molybdenum Trioxide Studied by Electron Paramagnetic Resonance Spectroscopy

The formation and qualification of redox sites in transition metal oxides are always the active fields related to electronics, catalysis, sensors, and energy-storage units. In the present study, the temperature dependence of thermal reduction of MoO₃ was surveyed at the range of 350 ℃ to 750 ℃. Upon reduction, the formed redox species characterized by EPR spectroscopy are the Mo^V ion and superoxide anion radical (O₂^-) when the reduction was induced at the optimal temperature of 300-350 ℃. When heating-up from 350 ℃, the EPR signals started to decline in amplitude. The signals in the range of 400-450 ℃ decreased to half of that at 350 ℃, and then to zero at ~600 ℃. Further treatment at even higher temperature or prolonged heating time at 500 ℃ caused more reduction and more free electrons were released to the MoO₃ bulk, which results in a delocalized means similar to the anti-ferromagnetic coupling. These data herein are helpful to prepare and study the metal-oxide catalysts.     

稀土对铸造Cr12MoV模具钢碳化物形貌及性能的影响

研究了稀土元素对铸造Ｃｒ１２ＭｏＶ模具钢碳化物形貌及性能的影响。实验结果表明，稀土地Ｍ７Ｃ３型共晶碳化物有很强的变质作用，Ｃｒ１２ＭｏＶ模具钢铸态为粗大的网状共生共晶组织，经变质处理，共晶组织细化，离异共昌数量半多；热处理后共晶碳化物粒化且均匀分布，冲击韧性得到了明显提高，耐磨性比锻造Ｃｒ１２ＭｏＶ模具钢高出１倍以上。