超导体YBa2Cu3O7-δ的摩擦学特性研究  

Tribological Properties of High Temperature Super Conductor YBa_2Cu_3O_(7-δ)

作　　者：董丽荣[1] 李长生[1] 华敏奇[2] 丁巧党[1] 

机构地区：[1]江苏大学材料摩擦学省重点实验室 [2]中国科学院兰州化学物理研究所,甘肃兰州730000

出　　处：《摩擦学学报》2008年第4期345-350,共6页Tribology

基　　金：国家自然科学基金资助项目(50372026)

摘　　要：采用溶胶-凝胶法制备YBa2Cu3O7-δ和Ag/YBa2Cu3O7-δ超导材料,并分析其相组成及结构,用SFT-4000型高真空超低温摩擦磨损试验机对其从室温至液氮温度范围内的摩擦学特性进行评价.结果表明:在室温条件下,YBa2Cu3O7-δ与不锈钢盘对摩时的摩擦系数在0.50左右,当温度降到超导转变温度以下时,其摩擦系数急剧降低至0.13,最后稳定在0.20以下.添加Ag可以改善YBa2Cu3O7-δ的常温摩擦磨损性能,Ag/YBa2Cu3O7-δ复合材料的摩擦系数低且非常平稳,其中10%Ag/YBa2Cu3O7-δ的摩擦系数为0.20,磨损率为8.96×10-5mm3/(N.m),Ag/YBa2Cu3O7-δ的磨损机制为YBa2Cu3O7-δ硬基底承载与软金属Ag转移膜的润滑作用.The superconductor YBa2 Cu3 O7-δ samples were prepared by sol-gel method. The tribological properties were measured on friction and wear tester from ambient temperature to liquid nitrogen temperature. Results indicate that the friction coefficient of YBa2 Cu3 O7-δ against stainless steel was about 0.5 at ambient temperature and it decreased abruptly to half of the normal state value when the temperature was below superconducting transition temperature of the YBa2 Cu3O7-δ The measurement proves directly the effect of electronic excitation on friction. There were no electric charges accumulating on material surface at superconducting state when resistance fell zero, effect of electron excitation on friction decreased to minimum, so the friction coefficient decreased dramatically. Moreover, Ag/YBa2 Cu3 O7-δ composite samples were prepared by sintering YBa2 Cu3 07.8 with Ag at different mass fraction to improve the tribological properties of YBa2Cu3O7-δ at ambient temperature. The structure and morphology were investigated by XRD, SEM, and the elemental composition of the worn surfaces of Ag/YBa2 Cu3O7-δ composites was determined using EDS. Results show that the Ag particles distributed in the YBa2 Cu3O7-δ matrix, improved the density, flexibility and toughness of Ag,/YBa2Cu3O7-δ composites, and Ag film formed on the surfaces of Ag/ YBa2Cu3O7-δ composites during friction process and lower the friction coefficient. The friction coefficient of 10% Ag/YBa2Cu3O7-δ against stainless steel was about 0.2 and the wear rate was 8.96 × 10^-5 mm3/（ N . m） at ambient temperature, Ag/YBa2Cu3 07.8 composites showed improved tribological properties.

关 键 词：YBA2CU3O7-Δ AG 超导转变温度 摩擦系数 

分 类 号：TB33[一般工业技术—材料科学与工程] TH117.3[机械工程—机械设计及理论]