Preparation and properties of YBa2Cu3O7−δ/Ag self-lubricating composites

The YBa2Cu3O7−δ/Ag self-lubricating composites were prepared using two raw materials, such as the metallic Ag powder and AgNO3 crystal. The mechanical and the tribological properties from cryogenic to high temperature of the composites were studied. The results show that the friction coefficient of pure YBCO drops abruptly when the temperature is lower than the superconducting transition temperature. The mechanical and tribological properties of YBCO from room to high temperature can be improved due to the Ag doping. At low temperature, the friction coefficient of pure YBCO drops abruptly due to the contribution of the phonon and the electron to the friction. From room temperature to high temperature, the Ag films generated at the contacted zone of composites improve the tribological properties of composites. Due to the finer and better dispersed Ag particles in matrix, the composites prepared from AgNO3 show the better combined properties than the composites prepared from Ag.