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采用粉末冶金方法(机械合金化+真空热压烧结)制备了不同SrCO_3和Ag含量的NiCrW-Al_2O_3-SrCO_3-Ag金属陶瓷复合材料,利用UMT-3考察复合材料在室温至1000℃条件下的摩擦磨损性能,利用SEM、EDS、XRD等表征分析其显微组织、物相组成及其磨损机理.结果表明:热压烧结过程中,SrCO_3高温分解,并与Ti_3SiC_2反应生成SrAl_4O_7,同时生成了Cr_2O_3和NiCr_2O_4等新相.分别添加质量分数10%SrCO_3和Ag的复合材料在宽温域内的摩擦磨损性能最优,归因于在中高温阶段复合材料摩擦表面发生摩擦化学反应生成了SrCrO_4和NiO等润滑相,与复合材料中的Ag、NiCr_2O_4等润滑相形成协同润滑,使得复合材料在400~1000℃宽温域范围内具有优异的摩擦磨损性能.
NiCrW-Al_2O_3-SrCO_3-Ag cermet composites with different contents of SrCO 3 and Ag were prepared by powder metallurgy method (mechanical alloying + vacuum hot pressing sintering). The friction of the composites at room temperature to 1000 ℃ was investigated by UMT-3 The microstructure, phase composition and wear mechanism were analyzed by SEM, EDS and XRD.The results showed that during the hot-pressing sintering, SrCO_3 decomposed at high temperature and reacts with Ti_3SiC_2 to form SrAl_4O_7, while Cr_2O_3 and NiCr_2O_4, etc. The friction and wear properties of the composites with mass fraction of 10% SrCO 3 and Ag are best in the wide temperature range, respectively, which are attributed to the tribochemical reaction of the tribological surface of the composite at the mid-high temperature stage to produce lubricants such as SrCrO 4 and NiO Phase, and the composite material of Ag, NiCr_2O_4 and other lubrication phase to form a synergistic lubrication, making the composite material in the 400 ~ 1000 ℃ wide temperature range has excellent friction and wear properties.