摘要
纳米复合材料的腐蚀、腐蚀磨损以及干摩擦磨损行为非常复杂,受化学、物理和机械等多方面因素影响。采用机械球磨、冷压和热挤压技术制备Al/SiC纳米复合材料,研究纳米SiC含量对材料硬度、干滑动磨损、腐蚀和腐蚀磨损行为的影响。采用电化学极化测试研究了复合材料在3%NaCl溶液中的抗腐蚀性能。采用盘-销装置研究了复合材料的干滑动磨损和在3%NaCl溶液中腐蚀磨损性能。利用扫描电子显微镜研究了材料及磨损表面的显微组织。结果表明,随着SiC含量的增加,纳米复合材料的干滑动摩擦和抗腐蚀性能均得到提高。由于溶液的润滑作用,使材料软化的摩擦因数和摩擦生热均降低。与基体合金相比,纳米复合材料的强度和抗腐蚀性能提高,因此其抗腐蚀磨损性能也提高。对于未增强的基体合金,其磨损机理为黏着磨损,而对于Al/SiC纳米复合材料,磨损机理转变为磨粒磨损。
The corrosion, corrosive wear and dry sliding wear of nanocomposites, are extremely complicated and involve various chemical, physical anbd mechanical factors. The aim of this work is to investigate the effects of nanosized SiC content on the hardness, dry sliding wear, corrosion and corrosive wear of Al/SiC nanocomposites synthesized by mechanical milling cold pressing and hot extrusion. The corrosion resistance of these composites in 3%NaCl solution was investigated by electrochemical polarization testing and their dry sliding as well as corrosive wear resistance in the same solution was evaluated using a pin-on-disc tester. The microstructures of the samples and their worn surfaces were examined using scanning electron microscopy. It was shown that the dry sliding wear and corrosion resistance of these nanocomposites were improved with the increase of SiC content. It was concluded that due to the lubrication effect of the solution, both the friction coefficient and frictional heat that might soften the material were reduced. In addition, the improved strength of the nanocomposites combined with their better corrosion resistance contributed to their increased corrosive wear resistance, compared with the base alloy. The prominent wear mechanism in the unreinforced alloy was adhesive wear, in the Al/SiC nanocomposites, the wear mechanism changed to abrasive.
基金
Iranian Nanotechnology Initiative (INI) for finical support of the research work
