。668· 北京科技大学学报 2006年第7期 Microstructure and properties of an MoSi2 heating element modified by ceramic compound FENG Peizhong",QU Xuanhui,DU Xueli2.CUI Dawei,TIAN Jianjun,ZANG Ruyu) 1)Materials Scierce and Engineering School,State Key Laboratory for Advanced M etals and Materials University of Science and Technobgy Beijing.Beijng 100083.China 2)School of Materials Science and Engineering.Tianin University of Technology.Tianjin 300191.China ABSTRACT An MoSi2 heating element was prepared by pow der metallurgy with MoSi2 pow der sy nthe- sized by self-propagating high temperature synthesis(SHS)and ceramic compound as the starting materi- als.Its microstructure and properties were tested by XRD and SEM with EDS.The results indicated that MoSi2 was the major phase accompanied by small fraction of MosSi3 and ceramic compound.Adding ceramic compound could obviously activate the sintering of MoSi2 and reduce its sintering temperature and retard the over growth of grains.The hardness and fracture toughness were also improved.A glass scale with high content SiO2 and less MgO,CaO,Na20,Al203 was produced by oxidation at high temperature of electric current. KEY WORDS ceramic;molybdenum disilicide;heating element;microstructure;properties (上接第624页) Porous flow mathematic models of multi-component foam drive ZHU Weiyoo,CHENGJiecheng,WUJuzheng,JU Yan 1)Civil and Envimnmental Engimering School.Uriversity of Science and Techmlogy Beijng.Beijing 10083.Chim 2)Daqing Petroleum Administration Burea of Petrobum China,Daqing 163100.China 3)Langfang Normal College.Langfang 065000.Chima ABSTRACT According to the main multi-component foam drive mechanism and various phy sicochemical phenomena taking place in the EOR method,such as phase change,rheological property of foam phase, and foam vertical shallow,a series of mathematical models for describing the parameters of multi-component foam drive were established on the basis of foam drive mechanism and experimental results.The foam flow- ing rules in porous media were described in these models.The mathematical description of this complicated flow for multi-component foam drive was resolved.Numerical simulation results proved that the models could reveal the physical essence of porous flow. KEY WORDS chemical agent;complex drive;mathematical model;flow ing mechanism;flow featureMicrostructure and properties of an MoSi2 heating element modified by ceramic compound FENG Peizhong 1) , QU Xuanhui 1) , DU Xueli 1, 2) , CUI Dawei 1) , TIAN Jianjun 1) , ZANG R uoyu 1) 1) Mat erials Science and Engineering School, St at e Key Laborat ory for Advanced M etals and Materials, University of Science and Technology Beijing, Beijing 100083, China 2) School of Mat erials Science and Engineering, Tianjin University of Technology, Tianjin 300191, China ABSTRACT An M oSi2 heating element w as prepared by pow der metallurgy w ith MoSi2 pow der sy nthe￾sized by self-propagating hig h temperature sy nthesis ( SHS) and ceramic compound as the starting materi￾als .Its microstructure and properties w ere tested by XRD and SEM w ith EDS .The results indicated that M oSi2 w as the major phase accompanied by small fraction of Mo5Si3 and ceramic compound .Adding ceramic compound could obviously activate the sintering of MoSi2 and reduce its sintering temperature and retard the over grow th of grains.The hardness and fracture toughness were also improved .A glass scale w ith high content SiO2 and less MgO, CaO, Na2O, Al2O3 was produced by oxidation at hig h temperature of electric current . KEY WORDS ceramic;molybdenum disilicide ;heating element ;microstructure ;properties ( 上接第 624 页) Porous flow mathematic models of multi-component foam drive ZHU Weiyao 1) , CHENG Jiecheng 2) , WU Juzheng, JU Y an 3) 1) Civil and Environment al Engineering S chool, Uni versit y of Science and Tech nology Beijing, Beijing 10083, C hina 2) Daqing Petroleum Administration Bureau of Petroleum China, Daqing 163100, China 3) Langf ang Normal College, Langfang 065000, C hina ABSTRACT According to the main multi-component foam drive mechanism and various phy sicochemical phenomena taking place in the EOR method, such as phase change, rheological property of foam phase, and foam vertical shallow, a series of mathematical modelsfor describing the parameters of multi-component foam drive w ere established on the basis of foam drive mechanism and experimental results .The foam flow￾ing rules in po rous media were described in these models .The mathematical description of this complicated flow for multi-component foam drive w as resolved .Numerical simulation results proved that the models could reveal the physical essence of porous flow . KEY WORDS chemical agent ;complex drive ;mathematical model ;flow ing mechanism ;flow feature · 668 · 北 京 科 技 大 学 学 报 2006 年第 7 期