【摘要】 采用固气法对铸铁铬硅共渗渗层的组织特征和形成机制进行了分析和探讨。显微分析表明，渗层由ａ相和Ｃｒ＿７Ｃ＿３、Ｃｒ＿２３Ｃ＿６等碳化物组成，其外表面富集的铬含量可达３０％以上，不含石墨。渗层下面为含大量珠光体的过渡区，靠近表面的渗层里，可观察到包围石墨的白亮环区。该环区很可能是因共渗过程中Ｃｒ、Ｓｉ原子在石墨周围局部聚集而形成的。保温时间延长，环内石墨消失，但仍保留环区特征。这种组织结构提高了铸铁的抗蚀能力及抗高温氧化能力。更多还原

【Abstract】 The microstructure feature and its forming mechanism of chromized-siliconized layer for cast iron by solid-gas diffusion methed were in vestigated,The microanalysis showed that the surface layer of chromized-siliconized specimen consists of a phase and some carbides Cr₇C₃ and Cr₂3C₆.The chromium content in the area near surface of spocimen is more than 3 0 wt%and graphite was not obeerved.Under the laver there is a transition region,contain ing large amount of porlite ,where some a phase zone,surrounding graphite,was fou nded; Forming of a phase zone likely is caused by local gathering of atoms of Cr and Si close to the srapmte,With prolonged holding at the temperature for chromizing-siliconizing,undissolved graphite containing in the phase zone,can be dissolved in austenite,but its feature will be remained after cooling of specimen,This microstructure in the surface layer of cast iron after chromizing-siliconizing greatly im proves its corrosion resistance and high temperature oxidation resistance.更多还原