Spark Plasma Sintered ZrO_2(Y_2O_3)-Al_2O_3-SrSO_4 Self-lubricating Nanocomposites for High Temperature Tribological Applications

摘要

Spark plasma sintering is employed to synthesize a variety of self-lubricating ZrO_2(Y_2O_3)-Al_2O_3-SrSO_4 matrix nanocomposites by tailoring the chemical compositions and by adjusting the sintering parameters. Different additives are incorporated into the nanocrystalline ceramics of ZrO_2(Y_2O_3)-20wt% Al_2O_3 to evaluate their potentials as effective high temperature solid lubricants from room temperature to 800℃by using a high temperature friction and wear tester in sliding against alumina ball in air. The density, microstructure, hardness and tribological properties of the sintered nanocomposites have been investigated, as contrasted with the unmodified ceramics, to obtain a better understanding of lubrication mechanisms over a wide temperature range. The ZrO_2(Y_2O_3)-Al_2O_3-SrSO_4 composite exhibits steady-state friction coefficients of less than 0.2 and wear rates in the order of 10~(-6) mm~3/Nm over a broad temperature range from room temperature to 800℃.