陶瓷材料的实际烧结及其计算机仿真研究

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1、摘要陶瓷材料在烧成过程中通常会发生晶粒和气孔的数量、大小和形状的变化。本文采用传统的固相反应法制备BaTi03和PZT陶瓷，获得陶瓷微观形貌的SEM照片和陶瓷宏观形状的CCD照片，以及气孔率和收缩率的定量数据，表明烧结体随着气孔减少而收缩；使用IPP软件对SEM照片进行图像处理，获得晶粒生长动力学因子和晶界分维值，表明在陶瓷烧结初期晶粒生长动力学因子为0---2，后期为3--一4；分维值随着保温时间的延长而减小；采用HP4284A测量仪测量不同气孔率样品的电容率，表明在气孔率减小的同时电容率逐渐变大。结合实际陶瓷的烧结过程，在原有仿真工作基

2、础上，根据MonteCarlo仿真方法建立AB03型陶瓷晶粒生长的三维仿真模型，并用MicrosoftVisualC++和OpenGL开发的仿真软件，进一步将陶瓷烧结理论应用于计算机模拟仿真。仿真中将气孔引入到晶粒生长过程中，获得仿真过程晶粒和气孔的系列演化图片及相应的晶粒生长动力学因子和分维值，并在气孔率减小的同时呈现烧结体的收缩，实现宏观与微观的结合。最后采用Okazaki和Banno模型对陶瓷烧结过程电容率的变化进行初步仿真预测，把仿真结果与实际烧结陶瓷的结果相对比，两者具有较好的一致性。关键词：陶瓷仿真；晶粒生长；气孔率；收缩率Ab

3、stractDuringthefningprocessofceramics，threemajorchangescommonlyoccur：thenumber,sizeandshapeofgrainandpore．Inthisthesis，BaTi03andPZTceramicswerepreparedviatheconventionalsolid-statereactionmethod．MicrostructureofSEMphoto，MacrostructureofCCDphotoandthedataofporosityandshrink

4、agewereobtained．Theresultshowedthatthesamplesshrunkastheporositydecreased．SEMphotoweredealedwithIPPsoftware．Boththegraingrowthkineticsexponent(about0～2intheearlystageand3～4inthelatestageofgraingrowthlandthefi'actaldimension(decreasedastimeincressed)weregot．Dielectricproper

5、tiesofthesampleswithdifferentporosityweremeasuredbyHP4284Aprecisionmeter．Theresultsshowedthatadecreaseintheporosityledtolargerdielectricconstant．Onthebasisoftheformersimulationprogram(thatwas，athree-dimedsionalmodelWasproposedforthecomputersimulationofgraingrowthinceramics

6、withAB03structure，whichwasdeveloped谢tllMicrosoftVisualC++andOpenGL．)，谢t11thesinteringprocessofpracticalceramics，sinteringtheorywerefurtherappliedtocomputersimulation．Poreswereintroducedtotheprocessofgraingrowth．Thefractaldimensionsofgrainboundariesandkineticexponentsofgrai

7、ngrowthwereobtained．Seriesofdataresultedfromthesimulationofporeswereappliedforthesimulationofsinteringshrinkage．BasedtheBannoandOkazakimodel，theeffectofporosityondielectricconstantwaspredictedundercertainconditions．Meanwhile，thesimulatedresultswerealsocomparedwiththeonesof

8、practicalceramicsintering，anditwasingoodagreementwiththeexperimentalresultofpracticalcera