Design and fabrication of laminated–graded zirconia self-lubricating composites

A new design method to achieve the integration of structure and lubricating function in ceramic was proposed by combining the functionally graded material (FGM) concept with the bionic design of ZrO2(3Y) ceramic. ZrO2(3Y)–Al2O3/ZrO2(3Y)/solid lubricant (SL) FGMs were prepared, and gradient exponent p was defined to determine the distribution of SL in the materials. The mechanical and tribological properties of the composites with different p were studied. ZrO2(3Y)–Al2O3/ZrO2(3Y)/SL FGM shows excellent self-lubricating performance over a broad temperature from room temperature to 800 °C, and the bending strength of the sample with the p of 2 is four times higher than that of monolithic ZrO2(3Y)/SL composites. The variation of p causes the change in the residual tensile stress generated from the thermal mismatch, and further influences the mechanical property of the materials.