柱状莫来石弥散钇稳定四方氧化锆多晶陶瓷摩擦磨损性能研究

研究了柱状莫来石弥散四方氧化锆多晶陶瓷(MDZ)在含质量分数2％SiO2磨粒的5％NaOH溶液中的摩擦磨损性能．结果表明：在100～500N载荷范围内,莫来石质量分数为15％的15MDZ的耐磨性明显优于莫来石质量分数为20％的20MDZ;含莫来石弥散相的Y-TZP的力学性能有所降低,但15MDZ陶瓷在500N载荷下的耐磨性能优于Y-TZP;MDZ复合陶瓷主要呈现擦伤和塑性变形特征,而3Y-TZP陶瓷在相同试验条件下主要呈现塑性变形和断裂特征;柱状莫来石可阻碍裂纹扩展、阻止晶界滑移、抑制ZrO2晶粒异常长大、提高MDZ陶瓷的致密度,从而改善MDZ复会陶瓷的抗磨性能。

Friction and Wear Behavior of Rod-Like Mullite Dispersed Yttria-Stabilized Tetragonal Zirconia Polycrystal Ceramics

The friction and wear of rod-like mullite dispersed yttria stabilized tetragonal zirconia polycrystals (MDZ) sliding against a high-chromium cast iron in 5%NaOH solution containing 2wt%SiO_2 as the abrasive particles was investigated on an MM-200 test rig in a block-on-ring configuration. The worn surface morphologies were observed on a scanning electron microscope, and the effect of the sliding on the tetragonal-to-monolithic phase transformation of ZrO_2 and on the wear resistance of the composite ceramics was discussed, based on analyses of the original surface and worn surface of the composite ceramics by means of energy dispersive spectrometry and X-ray diffraction. It was found that the Y-TZP incorporated with mullite had better wear resistance than the one without the mullite dispersive phase, though the inclusion of the mullite led to damage to the mechanical strengths of the composite ceramics. The improvement in the wear resistance of the composite ceramics by the inclusion of the mullite was mainly attributed to the actions of the rod-like mullite particulates to restrain the crack propagation and grain boundary slippage, and to densify the ceramics as well. The MDZ ceramics was characterized by scuffing and plastic deformation as they slid against the cast iron at a relatively larger load, while the Y-TZP was dominated by plastic deformation and fracture under the same test conditions.