钛酸铝复相陶瓷的制备及其抗热震性能的研究

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1、中文摘要钦酸铝是目前所知唯一集低膨胀和耐高温于一体的结构材料。它在8500C-1280℃时会分解成A120:和Ti02，并且其强度也很低，这两个弱点严重制约了它的使用范围。本文首先以无机盐为原料，合成钦酸铝(AT)粉，以此和琼脂为原料，采用凝胶注模成型方式，制备出结构均匀的A〕陶瓷，研究了琼脂加入量、钦酸铝含量对料浆流动性和材料结构的影响;通过加入各种添加剂并采用合理的工艺制备出两个系列综合性能好的材料。较系统地研究了Mg0.Ce021Si3N;晶须、铿辉石各种添加剂对钦酸铝的烧结性能、机械性能、热稳定性、热膨胀性及抗热震性的影响规律。得到两种材料强度高，热稳定性好，热膨胀系数小，抗

2、热震性好材料。M90-CeO2-Si3N4,,-AT体系的强度达70.6MPa，抗热震温差达1200'C，经900℃循环20次而均无表面破损;铿辉石一MgO-AT体系的强度也达24.6MPa，热膨胀系数达到1.04x10'6/0C，且热处理过程中会逐步降低，使其具有较好的抗热震性能。研究了烧成工艺与材料性能的关系。初步确定了最佳工艺参数。通过对氧化物添加剂、晶须和矿物粉料对材料的吸水率体积密度、力学性能、显微结构、热膨胀系数、抗热震温差等性能的影响，综合研究钦酸铝复相陶瓷的组成一结构一性能之间的关系，制备出综合性能好的抗热震材料，探讨了Al，材料抗热震机理。关键词:钦酸铝、凝胶注模、

3、晶须、热分解率、热膨胀系数、抗热震性AbstractAluminiumtitanateisamaterialwhichhaslow-thermalexpansionandcanbeusedathightemperature.ButitcannotbeusedatsomeconditionbecauseitwillbedecomposedandbecomesA1203andTi02，andithaslowstrength.Atfirstthegood-structureceramicspreparedbygel-casting,usingagaroseandaluminiumtitan

4、atepowderswerepreparedbyinorganicsalt.TheefectsofcontentofagaroseandaluminiumtitanatepowdersonviscosityofATceramicssuspensionandstrustureofceramicswereinvestigated.Somefactorsthatmayafectpreparation,andperformanceofmaterialsincludingdensity,thermaldecomposition,thermalexpansion,thermalshockresi

5、stanceetcwerediscussedsystematically.TwokindsofATmaterialhavebothhigh-strengthandlow-thermalexpansioncoefficient.ThebendingstrengthofMgO-CeO2-Si3N4w-ATseriesreached70.6MPa,itstemperaturediferencebythennalshockis1200'Candthesamplewasnotfracturedafterthermallytreatedat400℃for20times.Thebendingstr

6、en沙ofspoundume-MgO-ATreached24.6MPa,itsthermalexpansioncoeficientis1.04X10"6/0Candbecomessmallerwhenitisusedathightemperature.Therelationshipbetweenperformanceandsinteringconditionswasalsostudied.Propersinteringtemperatureandtimeweredeterminedessentially.Bymeasuringtherelevantpropertiesofmateri

7、alsuchaswaterabsorption,density,SEM,thermalexpansioncoefficient,thermalshocktemperature,andsoon,therelationshipofcomposing-structure-performanceofATceramicswasstudiedcomprehensively.GoodqualitiesofATceramicswereprepared.Thermalsho