Microstructure, Mechanical and Tribological Properties of Ag/Bi2Sr2CaCu2O x Self-lubricating Composites

Ag/Bi2Sr2CaCu2O (x) self-lubricating composites were successfully fabricated by a facile powder metallurgy method. The structure and morphology of the as-synthesized composites and the worn surface after tribometer testing are characterized by using X-ray diffraction and scanning electron microscopy together with energy dispersive spectrometry. The results indicated that self-lubricating composites are composed of superconductor phase and Ag phase. Moreover, the effects of Ag on mechanical and tribological properties of the novel composites were investigated. The friction test results showed that the friction coefficient of the pure Bi2212 against stainless steel is about 0.40 at ambient temperature and abruptly decreases to about 0.17 when the temperature is cooled to 77 K. The friction coefficients of the composites from room temperature to high temperature were lower and more stable than those of pure Bi2Sr2CaCu2O (x) . When the content of Ag is 10 wt.%, the Ag/Bi2Sr2CaCu2O (x) composites exhibited excellent tribological performance, the improved tribological properties are attributed to the formation of soft metallic Ag films at the contacted zone of the composites.