·276· 北京科技大学学报 2004年第3期 2001,45:1099 14 Wagner C.Reaktionstypen bei der oxydation von leg 13 Wagner C.Formation of composite scales consisting of ierungen [J].Z Elektrochem,1959,63:772 oxidation of different metals [J].J Electrochem Soc,1956, 11:627 High-temperature Corrosion Behavior of Cr5Mo Steel with Micro-crystalline Aluminide Coating by Vibratile Electro-pulse Deposition SONG Hongjian,MA Jing2 HE Yedong 1)SINOPEC Jinling Petrochemical Corporation,Nanjing 210037,China 2)Beijing Key Laboratory for Corrosion,Erosion and Surface Technology,University of Science and Technology Beijing,Beijing 100083,China 3)School of Materials,Hebei University of Science and Technology,Shijiazhuang0054,China ABSTRACT A micro-crystalline aluminide coating of 100 um thick was obtained by vibratile electro-pulse de- position on Cr5Mo steel.An Fe-Al intermetallic compound layer forms due to high temperature during instant dis- charging between alumimum electrodes and specimens,micro-crystalline structure is achieved due to the high cool- ing rate during deposition,and the coating bonds with the substrate firmly.The experimential results of oxidation in air for 200h at 600C and sulfuration in flowing 99.98%SO2 for 50 h at 600'C and the analysis of SEM and XRD show that the high temperature oxidation and sulfuration resistances of Cr5Mo steel with aluminide coating are gre- atly improved. KEY WORDS electro-pulse deposition;aluminide coating;Cr5Mo (上接第259页) Numerical Simulation for Thixotropic Filling Process and Filling Pressure Behav- ior during Metal Material Forming YANG Maosheng",LI Shiqi,XU Hong,MAO Weimin,ZHONG Xueyou 1)Metallurgical and Ecological Engineering School,University of Science and Technology Beijing,Beijing 100083,China 2)Materials Science and Engineering School,University of Science and Technology Beijing,Beijing 100083,China ABSTRACT Based on the behavior of filling pressure during semisolid alloy slurry filling process,a mathematic model of slurry flow coupled with apparent viscosity was established.The filling process and filling pressure of thixotropic Al alloys and steel were simulated.It is demonstrated that the filling pressure gradually increases with the course of the filling,in response to flow resistance and gravity and with a range of 0.12 MPa.Semisolid alloy slurry flows in a stable and laminar-type manner within the range of filling velocity.Compared with thixotropic Al alloys,the high melting point of steel leads to the decrease of filling temperature easily,so the increase of apparent viscosity results in casting defects.The simulation results of filling pressure and the experimental results of semiso- lid brake pump casting show that semisolid casting filled along the radial presents good forming quality. KEY WORDS thixotropic filling;filling pressure;numerical simulation北 京 科 技 大 学 学 报 年 第 期 ， 刀 ， ， 研 ， ， 一 权 一 一 口刀 儿 ’ 澎几助叼 五” ， ， ， ， ， 俪 ， ， ， ， 价 ， 一 林 一 一 ， 一 ， 江 狂 迁 一 切 上接第 页 们 入 弃匆 ，礼 ，乙 “ 心礼」创 口 肠 毛 刀口刀召 即 山 ， ， ， 州 们 ， ， ， ， 田了 ， 一 ， ， 切