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ID:37291500
大小:1.44 MB
页数:5页
时间:2019-05-20
《先驱体浸渍-裂解法制备高密度再结晶碳化硅》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、硅酸盐学报第38卷第8期Vol.38,No.82010年8月JOURNALOFTHECHINESECERAMICSOCIETYAugust,2010先驱体浸渍–裂解法制备高密度再结晶碳化硅郭文明,肖汉宁,雷海波,谢文(湖南大学材料科学与工程学院,长沙410082)摘要:分别采用聚碳硅烷(polycarbosilane,PCS)/二甲苯(xylene)溶液和SiC/PCS/xylene浆料浸渍–裂解(precursorimpregnationandpyrolysis,PIP)法制备高密度再结晶碳化硅(recrystall
2、izedSiC,RSiC)。测量了RSiC的体积密度和抗弯强度。用扫描电镜观察了RSiC样品的显微结构。结果表明:采用33PCS/xylene溶液浸渍的裂解产物均匀分布在RSiC的孔隙中,经6次PIP循环后,RSiC的密度从2.74g/cm提高到约2.90g/cm,抗弯强度与初始样品相比提高了28.1%。采用SiC/PCS/xylene浆料浸渍后的产物在基体中呈梯度分布,基体表层孔隙填充致密,有利于提高RSiC的抗氧化能力。仅33次PIP循环后,RSiC的密度就可达2.90g/cm,抗弯强度也可提高37.0%。关键词:
3、再结晶碳化硅;浸渍–裂解法;聚碳硅烷;致密化中图分类号:O482.3文献标志码:A文章编号:0454–5648(2010)08–1514–05DENSIFICATIONOFRECRYSTALLIZEDSILICONCARBIDEPREPAREDBYPRECURSORIMPREGNATIONANDPYROLYSISPROCESSGUOWenming,XIAOHanning,LEIHaibo,XIEWen(CollegeofMaterialScienceandEngineering,HunanUniversity,Chan
4、gsha410082,China)Abstract:ThedenserecrystallizedSiC(RSiC)materialswerepreparedbyaprecursorimpregnationandpyrolysis(PIP)processus-ingpolycarbosilane(PCS)/xylenesolutionandSiC/PCS/xyleneslurryasimpregnatedagents,respectively.ThedensityandbendingstrengthofRSiCwerem
5、easured,anditsmicrostructureswereobservedbyscanningelectronmicroscopy.TheresultsshowthatthepyrolysisproductsviaPCS/xylenesolutionaredistributedhomogeneouslyintheporesofRSiC,andwith6PIPcyclesitsdensity33increasesfromtheoriginaldensityof2.74g/cmtoabout2.90g/cm,asa
6、result,itsbendingstrengthincreasesby28.1%comparedtothatoforiginalRSiC.However,thepyrolysisproductsviaSiC/PCS/xyleneslurryhaveagradientdistribution,namelycondensationinexteriorandloosedistributionininterior,whichmightimprovetheoxidationresistanceofRSiC.Withonly3P
7、IPcyclesviaSiC/3PCS/xyleneslurry,thedensityofceramicreachesto2.90g/cm,anditsbendingstrengthshouldbeincreasedby37.0%accordingly.Keywords:recrystallizedsiliconcarbide;precursorimpregnationandpyrolysis;polycarbosilane;densification再结晶碳化硅(recrystallizedSiC,RSiC)由于其法
8、获得的RSiC的密度最大,也仅为其理论密度的纯度高、不含有晶界杂质相而具有优异的高温强度85%左右,且绝大部分气孔为开口气孔。RSiC高的保持能力、抗氧化性、高热导率以及较小的热膨胀气孔率,致使其室温强度仅为80~100MPa,高温系数,因此广泛用作高温结构材料,尤其是在1500强度为120~130MPa,热导率仅20~30W/(
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