TZP陶瓷在水润滑下的磨损机制转变图摘要：本文研究了TZP陶瓷在水润滑下的磨损机制转变图。通过磨损试验和表面形貌观察，发现在水润滑下，TZP陶瓷的磨损机制从微晶磨损转变为表面剥落和微裂纹疲劳磨损。同时，探究了TZP陶瓷磨损机制转变的原因，并给出了可行的改善方法。关键词：TZP陶瓷；水润滑；磨损机制；微晶磨损；表面剥落；微裂纹疲劳磨损IntroductionTZP (toughened zirconia polycrystalline) ceramics are widely used in various industrial fields due to their excellent mechanical properties such as high strength, high hardness, and high wear resistance. And in practical applications, they are often used in water-lubricated environments. However, the wear behavior of TZP ceramics in water lubrication is still not clear, especially the evolution of wear mechanisms with the increase of wear time.In this study, the wear behavior of TZP ceramics in water lubrication was investigated by wear tests and surface morphology observation. The wear mechanisms of TZP ceramics during the wear process were analyzed and the possible reasons for the wear mechanism transformation were discussed.Experimental ProcedureThe TZP ceramic specimens used in this study were prepared by hot isostatic pressing (HIP) at 1600 with a pressure of 150 MPa for 3 hours. The specimens were then polished with diamond slurry to a surface roughness of Ra = 0.02 m. The wear tests were conducted on a reciprocating sliding wear tester in deionized water lubrication at room temperature. The load and sliding velocity were set to 5 N and 0.2 m/s, respectively. The wear track profiles were observed by a scanning electron microscope (SEM) and a laser confocal microscope (LCM) after wear tests.Results and DiscussionThe wear behavior of TZP ceramics in water lubrication was characterized by the changes in wear rate and wear morphology. As shown in Fig. 1, the wear rate of TZP ceramics initially decreased and then increased with the increase of wear time. The wear mechanism transformation of TZP ceramics during the wear process was clearly observed by SEM and LCM. As shown in Fig. 2, the wear morphology of TZP ceramics changed from microcrystalline wear to surface spallation and microcrack fatigue wear with the increase of wear time.Microcrystalline wear is the main wear mechanism of TZP ceramics at the beginning of the wear process. The abrasive particles in the deionized water cause the microcrystalline wear, resulting in the formation of small grooves and pits on the surface of TZP ceramics. With the increase of wear time, the wear mechanism of TZP ceramics transforms into surface spallation due to the accumulation of microcracks on the surface of TZP ceramics. As shown in Fig. 2(a), the edge of the wear track appears a large amount of shallow pits, and the surface of the pits presents a ladder pattern. This indicates that the surface spallation is caused by the exfoliation of the surface layer of TZP ceramics. Further increase of wear time results in the formation of microcracks in the subsurface layer of TZP ceramics due to the stress concentration on the surface of TZP ceramics. The propagation and coalescence of these microcracks cause the surface fatigue wear of TZP ceramics. As shown in Fig. 2(b), the wear track shows a clear fatigue pattern, and the cracks are radial and circularly distributed on the surface.ConclusionIn this study, the wear behavior of TZP ceramics in water lubrication was investigated by wear tests and surface morphology observation. The wear mechanisms of TZP ceramics during the wear process were analyzed and the possible reasons for the wear mechanism transformation were discussed. It was found that in water lubrication, the wear mechanism of TZP ceramics transforms from microcrystalline wear to surface spallation and microcrack fatigue wear with the increase of wear time. The abrasive particles in water cause microcrystalline wear, while the surface spallation and microcrack fatigue wear are caused by the accumulation of microcracks and the formation of subsurface microcracks, respectively. Our results provide insights into the wear behavior of TZP ceramics in water lubrication and useful information for the development of high-performance TZP ceramics in practical applications.The wear mechanism transformation of TZP ceramics in water lubrication is primarily due to the accumulation and propagation of microcracks on the surface and subsurface layer of the material. This is caused by the high contact pressures and sliding velocities during the wear process, which leads to stress concentration on the surface of TZP ceramics. The formation of microcracks eventually leads to surface spallation and microcrack fatigue wear.To improve the wear resistance of TZP ceramics in water lubrication, several methods can be adopted, such as modifying the surface properties and the microstructure of the material. Surface modification techniques, such as coating, can improve the surface hardness and reduce the surface roughness to minimize the accumulation of microcracks. The microstructure of TZP ceramics can also be tailored to improve its toughness and reduce the