Effects of Si-Al Solid Solution on the Dry Sliding Behaviors of Ti3AlC2 at 300 ℃

Author of the article:ZENG Qingyan1,2, XUE Longqi1,2,3, WANG Chuanchao1,2, WANG Jinjin1,2, DU Chengfeng1,2,3, YU Hong1,2

Author's Workplace：1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China; 2. Center of Advanced Lubrication and Seal Materials, Northwestern Polytechnical University, Xi'an 710072, China; 3. Queen Mary University of London Engineering School, Northwestern Polytechnical University, Xi'an 710072, China

Key Words：MAX ceramics; solid solution; grain size; phase composition; dry-sliding behaviors

Abstract：Hot-pressing of elemental powders has been applied for preparing a series of Ti3Al1-xSixC2(x=0.2,0.4,0.6) ceramics with different Si contents. The crystal structure and phase composition of the products were characterized by X-ray diffraction and Rietveld refinement. Meanwhile, the surface morphologies and grain distribution were analysed via confocal microscopy and scanning electron microscopy. The tribological performance of the products was evaluated through dry sliding on a tribometer with a ball-on-disk configuration. Consequently, the addition of Si greatly reduces the grain size of Ti3Al1-xSixC2, whereas the purity of the sample decreases as well. The contents of Ti5Si3 and TiC impurities increase with increasing Si content. Meanwhile, the hardness of the ceramics increases with a higher Si addition. With an optimal Si content of 0.4, Ti3Al0.6Si0.4C2 presents the lowest coefficient of friction (COF), which is only approximately 0.27, showing the best lubricating and anti-wear performance.