.668 北京科技大学学报 2006年第7期 Microstructure and properties of an MoSiz heating element modified by ceramic compound FENG Peizhong,QU Xuanhui),DU Xueli),CUI Dawei,TIAN Jianjun),ZANG Ruoyu) 1)Materials Science and Engineering School,State Key Laboratory for Advanced Metals and Materials.University of Science and Technology Beijing.Beijing 100083.China 2)School of Materials Science and Engineering.Tianjin University of Technology.Tianjin 300191.China ABSTRACT An MoSiz heating element was prepared by powder metallurgy with MoSiz powder synthe- 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 MoSiz was the major phase accompanied by small fraction of MosSis and ceramic compound.Adding ceramic compound could obviously activate the sintering of MoSiz 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 SiOz and less MgO,CaO,Na2O,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 Weiyao,CHENG Jiecheng2,WU Juzheng.JU Yan 1)Civil and Environmental Engineering School,University of Science and Technology Beijing.Beijing 10083.China 2)Daqing Petroleum Administration Bureau of Petroleum China.Daqing 163100.China 3)Langfang Normal College.Langfang 065000.China ABSTRACI According to the main multi-component foam drive mechanism and various physicochemical 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;flowing mechanism:flow featureMicrostructure and properties of an MoSi2 heating element modified by ceramic compound FENG Peiz hong 1）‚QU Xuanhui 1）‚DU Xueli 1‚2）‚CUI Dawei 1）‚TIA N Jianjun 1）‚ZA NG Ruoyu 1） 1） Materials Science and Engineering School‚State Key Laboratory for Advanced Metals and Materials‚University of Science and Technology Beijing‚Beijing100083‚China 2） School of Materials Science and Engineering‚Tianjin University of Technology‚Tianjin300191‚China ABSTRACT An MoSi2 heating element was prepared by powder metallurgy with MoSi2 powder synthe￾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 Mo5Si3and ceramic compound．Adding ceramic compound could obviously activate the sintering of MoSi2and 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 SiO2and less MgO‚CaO‚Na2O‚Al2O3 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 mult-i component foam drive ZHU Weiyao 1）‚CHENG Jiecheng 2）‚W U Juz heng‚JU Y an 3） 1） Civil and Environmental Engineering School‚University of Science and Technology Beijing‚Beijing10083‚China 2） Daqing Petroleum Administration Bureau of Petroleum China‚Daqing163100‚China 3） Langfang Normal College‚Langfang065000‚China ABSTRACT According to the main mult-i component foam drive mechanism and various physicochemical 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 mult-i 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 mult-i 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；flowing mechanism；flow feature ·668· 北 京 科 技 大 学 学 报 2006年第7期