铸态中铬硅铸铁价电子结构与M7C3体积分数.pdfVIP

第l5卷 第6期 材 料 科 学 与 工 艺 V01．15 n 6 2 0 0 7年l2月 MA rERIALS SCIENCE rECHNOLOGY Dec．．2oo7 铸态中铬硅铸铁价电子结构与M7 C3体积分数 李 卫，胡世涛 (暨南大学材料科学与工程系，广东广州510632，E-mail：1wx~n@sohu．com) 摘 要：为提高中铬铸铁共晶碳化物中M c，比例，研究了中铬硅铸铁(290Cr8Si2)．建立了铸态中铬硅铸铁 基体的价电子结构，运用固体与分子经验电子理论(EET)分析了中铬硅铸铁中si的作用．分析和实验结果 表明，中铬硅铸铁基体含c、cr、si的 一Fe晶胞中，C原子与Si原子的结合力强于c原子与Cr原子的结合 力，较高的含si量降低了铸铁基体的含cr量，提高了共晶碳化物的含cr量，进而提高了共晶碳化物中M C 的比例．耐磨损中铬硅铸铁(290Cr8Si2)共晶碳化物(M，c，+M，c)中M C 占94．2％(体积分数)，明显高于 中铬铸铁(290Cr8Sil)共晶碳化物中的M c 的71．7％(体积分数)． 关键词：中铬铸铁；固体与分子经验电子理论；碳化物；价电子结构；硅 中图分类号：TG143文献标识码：A 文章编号：1005—0299(2007)06—0805—04 Valence electron structure of cast m um chrome．silicon cast iron and volume percentage of eutectic carbide M7 C3 LI Wei，HU Shi-tao (Dept．of Materials Science and Engineering，Jinan University，Guangzhou 510632，China，E．mail：1wx~n@sohu．com) Abstract：The medium chrome-silicon cast iron(290Cr8Si2)is studied for increasing the M7 C3content in eutectic carbide in medium chrome cast iron．The valence electron structure of cast medium chrome．sili． con cast iron matrix was set up and the effect of Si was analyzed by empirical electron theory of solids and molecules(EET)．The analysis and experimental results show．、that the affinity between C and Si is stron- ger than that between C and Cr in 一Fe lattice of medium chrome-silicon cast iron matrix containing C， Cr and Si．The higher content of Si reduces the content of Cr in cast iron matrix and improves the content of C r in eutectic carbide，therefore，the volume percent of M7 C 3 in eutectic carbide is improved．The M7C3content in eutectic carbide(M7C3+M3C)is 94．2％ (volume percent)in the wear-resistant medi- um chrome—silicon cast iron(290 C r8 Si2)，which is obviously higher than that(7 1．7％)in medium chrome cast iron(