【摘要】 4Cr9Si2和5Cr21Mn9Ni4N两种常用气门钢经氮碳共渗-氧化复合处理,其表面可获得深5～10μm、高硬度、高耐磨的氮化物层;最外表面渗层为深3～5μm、外观漂亮、致密的Fe₃O₄耐蚀氧化膜。研究发现,OH^-对形成氧化膜起催化作用。经电镜成分分析和金相观察发现,5Cr21Mn9Ni4N钢渗层仅有层次分明的双层氧化物层,而无氮碳扩散的过渡区。找出了4Cr9Si2钢在不同湿度下的氮碳共渗层深度随处理时间的变化规律。更多还原

【Abstract】 The samples made of two grades of commonly used valve steel 4Cr9Si2 and 5Cr 21MngNi4 Nare compositely treated by carbonitriding-oxidation, and both get an extremly hard and excellently wear resisting nitride layer each with thickness of 5-10μm on their surfaces. The most outside of the layer with a thickness of 3-5μm is a fine appearance, dense and anticorrosive Fe₃O₄ film. It is discovered through the investigation that OH- pocesses the catalyzing effect on forming the oxide film. Based on the compositionanalysis and metallographical examination by electromicroscope, it has been found that the treated surface of steel 5Cr21MngNi4N has only double-layer of distinctly stratified oxide, but no nitrogen and carbon diffusion transition region. Finally the rule of thickness variation of carbonitriding layer of steel 4Cr9Si2 with treating time under different temperatures is also found.更多还原