Reaction Path Study Of Preparation Ti₃SiC₂/SiC Compound Materials By TiC/Si Solid Reaction

The application in plasticity and pliability of traditional ceramic materials is usually confined for their brittleness. A new type structure ceramic material is studied dedicatedly by some specialists in recent years, that is the ternary carbide Ti3 SiC2 material, which combines many of the best attributes of both metals and ceramics. For the comprehensive mechanical property of this material, it is deemed as one of the most developing perspective new ceramic materials. However, it is very harsh in the technological condition of preparing pure Ti3SiC2 phase, it is very difficult to obtain the large grain of Ti3SiC2 material. Ti3SiC2ISiC composite material combines the best attributes of both Ti3S1C2 and SiC materials. Therefore we prepareTi3 SiC2 IS1C composite materials as one method of studying and using T13SiC2 materials. Because the solid state displacement in-situ reaction route is simple in fabrication and low in price, so it becomes the main approach of preparing Ti3 SiC2 IS1C composite materials.In this dissertation, the solid replacement in-situ synthesizing reaction path between TiC/Si, the vacuum hot pressing of TiC~ Si and graphite powder have been researched in preparing Ti3SiC2/S1C composite materials. The mechanism of solid state replacement in-situ has been studied, the solid state reaction path has been analyzed, and the mechanical property of composite materials has been tested. The main research topics and results are as follows:(1)The Ti-Si-C ternary equilibrium phase diagrams are important methods that we analyze quantificationally the TiC/Si solid state replacement in-situ reaction path. We use the Ti-Si-C ternary equilibrium phase diagrams and thermodynamic dates of some known materials at 1000 ~C 1100 .0 1200 C 1250 ~C respectively, estimate the unknown thermodynamic dates of some carbides and silicates of this system in using three different estimated methods. According to the conditions of thermodynamics phase equilibrium, calculated the stabilized chemical potential of Ti-Si-C ternary system at different temperature. The constituent stabilized chemical potential at 10000 110000 1200C 1250 ~C have been obtained and the constituent stabilized chemical potential diagrams have been plotted. The constituent stabilized chemical potential diagrams are one of theoretic analytic foundations in differentiating the reaction path of forming carbide Ti3SiC2/SiC composite materials.(2)According to the building of the BC/A interface diffusion reaction model, analyzed the special case at x1 in TiC~/Si solid diffusion reaction. We discussed the possible macrostructure of this diffusion reaction model and suggested the thermodynamic discussion,Which rationdhed the sbole layer to and describo the hability in shailar tempditheion couPle. The twle layer ot has been obtaind frOm the TiC/Si ditheioncouPle exPeriInent at l200'C temPeratUre annaling 50h. The exPetw results validatedthe tentative model. Accotheg to the ShaUr comParability of Ti,SiC, and TiC and theatomic rePlacemen charadristic of Ti,SiC, wt, analyzed the possible atondcrePlacemen path in TiC/Si ditheion rendon Process. The praCtial ditheion retalon pathat at l200C temneratri annwting 50ti are given:Ti: TiCrnC (insideblDck) island (Ti,SiC,+T-Si) -- (Ti,SiC,lpe) --SiCesiSi: SediC-- (Ti,SiC,larer) apC (insideblOck) island (Ti,SiC,+Ti-Si) enCC: TiCenC (hadeblock) islandTi,sic, (Ti,siqlayer) --siCsi(3) The thennodyntalc edyses in PreParin TbSiCYSiC coniposite materials havbeeV suggested: The Gibbs energy0 clhage is becomin redUCing the the indreasing of thecontent of Si and C in four equations tha we discussed. Tha is to sny the increasing of thecontent of Si and C was an aid to the Proceeding of reaction. At the sam tiIn it accoatdfor the feasibility of PreParin Ti,siCz/SiC comosite materials using the variety of si and Cand the contrOI1ability of the comPosite InateaIs pdriance.(4) The diffhaion reaction Parabolic d~c cOnStan of Si atom hav been calculatedaccordin to exPeriIn...