中文摘要：

微波加热高碳铬铁粉固相脱碳涉及高碳铬铁中铬铁碳化物相的分解和碳的固相迁移,固相脱碳的难易程度与高碳铬铁的金相组织和物相结构密切相关。本文采用金相分析、电子探针显微分析以及XRD物相分析对高碳铬铁的金相显微组织和物相结构进行了研究。高碳铬铁金相组织主要由富铬富碳相（Cr,Fe）7C3、富铁富硅相（Cr,Fe）23C6、富铁富硅相铬铁素体（CrFe）和少量石墨相组成,初生相（Cr,Fe）7C3以六方柱状自形、半自形粒状结构为主,占75%,晶粒粗大,晶形完整,碳固相迁移需要较大的能量;包晶相（Cr,Fe）23C6以包裹、熔蚀（Cr,Fe）7C3的包晶结构（Cr,Fe）23C6-（Cr,Fe）7C3为主,占1.5%,晶粒较小,且不完整,呈胡须状、熔蚀状分布在（Cr,Fe）7C3晶间,碳固相迁移需要的能量较小;共晶相（Cr,Fe）23C6-CrFe以细粒蠕虫状、桃仁状交织结构为主,占23%,填充在初生相之间,晶粒相对细小,晶界复杂,碳的固相迁移相对容易;石墨相以片状充填结构为主,占0.5%,呈细片状充填在（Cr,Fe）23C6-CrFe共晶相裂隙中,有利于碳的固相迁移。由于液态高碳铬铁边缘区域冷却速度较快,改变了热力学平衡态结晶顺序,物相由初生相/包晶相混晶区（Cr,Fe）7C3/（Cr,Fe）23C6-（Cr,Fe）7C3平衡态结晶顺序转变到初生相/包晶相/共晶相混晶区（Cr,Fe）7C3/（Cr,Fe）23C6/（Cr,Fe）23C6-CrFe非平衡态结晶顺序,在高碳铬铁边缘区域出现了低碳（Cr,Fe）23C6-CrFe共晶相,冷却速度造成的相选择为粉状高碳铬铁固相脱碳奠定了有利的相结构条件。

英文摘要：

Solid phase decarburization of high-carbon ferrochrome powders by microwave heating is involved with the decomposition of carbides and migration of carbon.The decarburization difficult degree is closely related to the microstructure and phase structure of high-carbon ferrochrome.The microstructure and phase structure of high-carbon ferrochrome were investigated by metalloscopy,electron probe microanalysis（EPMA） and X-ray diffraction（XRD）.Experimental results showed that metallography structure of high-carbon ferrochrome is mainly composed of chromium and carbon-rich phase（Cr,Fe）7C3,iron and silicon-rich phase（Cr,Fe）23C6,iron and silicon-rich ferrochrome ferrite phase（CrFe）,and a small amount of graphite phase.Primary phase（Cr,Fe）7C3（accounting for 75%）,which is of mainly idiomorphic and hypidiomorphic granular texture,contains mainly coarse grains and has a complete crystal form,requiring a great amount of energy to realize carbon migration in solid phase.Peritectic phase（Cr,Fe）23C6（accounting for 1.5%） is mainly of peritectic structure（Cr,Fe）23C6-（Cr,Fe）7C3 wrapped and corroded by（Cr,Fe）23C6,which contains mainly small grains and has a incomplete crystal form and beard like corroded wrapping around（Cr,Fe）7C3,requiring less energy for the migration of carbon in solid phase.Eutectic phase（Cr,Fe）23C6-CrFe（accounting for 23%） exists mainly wormlike of fine-grained and peachlike intertwined each other with relatively small grains,complex grain boundary and filling in the primary crystal phase,which is relatively easy for carbon migration in solid phase.The graphite（accounting for 0.5%） with mainly flakes-filling structure fills in the fissures of eutectic phase（Cr,Fe）23C6-CrFe,which is conductive to the migration of carbon in solid phase.Due to the fast cooling of high-carbon ferrochrome in fringing field,thermodynamic equilibrium crystallization sequence is changed,froming equilibrium crystallization sequence of mixed crystal of primary phase and pe