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1、SiC陶瓷的高壓燒結工藝及性能材料專業(yè)本科畢業(yè)論文河摘要碳化硅陶瓷具有高溫強度高、抗氧化性強、耐磨損性好、熱膨脹系數(shù)小、硬度高、抗熱震和耐化學腐蝕等優(yōu)良特性,因此,在很多領域得到廣泛應用。然而,SiC是一種共價鍵性很強的化合物,其自擴散系數(shù)極小,可燒結性很差。在傳統(tǒng)的粉末冶金SiC燒結工藝條件下,如果不加入適當?shù)奶砑觿?純SiC是很難燒結致密化。采用超高壓燒結方法可以在較低溫度、較短時間、低燒結助劑添加量下獲得高致密度、高性能的陶瓷。本文利用高壓六面頂壓機對SiC陶瓷的高壓燒結,對SiC陶瓷的高壓
2、燒結工藝及性能進行了初步的研究,并進行了理論分析,探索了其顯微結構與性能之間的關系。通過對SiC復相陶瓷的相對密度和XRD譜的研究分析,發(fā)現(xiàn)高壓燒結的SiC陶瓷材料具有優(yōu)良的性能,主要體現(xiàn)在導熱性能和韌性在,有良好的應用前景。與常壓相比,高壓燒結可以有效的降低金屬陶瓷的燒結時間和燒結制度,增進致密化,進而達到改進性能的目的。六面頂高壓燒結技術是一種快速、高效的燒結技術,大大降低了燒結溫度和縮短了燒結時間,并且可制備出接近理論密度的復相陶瓷材料。采用超高壓燒結工藝可以燒結獲得無燒結助劑添加的高致密度
3、SiC陶瓷(致密度92%~100%)。燒結工藝對陶瓷的性能有明顯的影響,實驗結果表明:Al2O3是SiC燒結的有效燒結助劑,在低添加量下(約2wt%)即可實現(xiàn)陶瓷的全致密燒結。燒結工藝對添加了燒結助劑陶瓷性能的影響與純SiC的燒結類似,但獲得的陶瓷的致密度普遍較高。關鍵詞:SiC陶瓷高溫高壓技術燒結性能物相分析(XRD譜)IIISiC陶瓷的高壓燒結工藝及性能材料專業(yè)本科畢業(yè)論文河ABSTRACTSiCceramicsisagoodmaterialwithhightemperaturestrengt
4、h,oxidationresistance,wearresistance,thermalexpansioncoefficient,highhardness,thermalshockandchemicalresistanceandotherexcellentproperties,therefore,hasbeenwidelyusedinmanyfields.However,SiCisacovalentbondstrongcompound,theself-diffusioncoefficientise
5、xtremelysmall,thesinterabilityispoor.SiCsinteredintheconventionalpowdermetallurgyprocessconditions,withouttheinclusionofsuitableadditives,pureSiCdensificationisdifficult.Usingultra-highpressuresinteringmethodcanlowerthetemperature,theshorterthetime,th
6、elowsinteringadditivesaddedamountobtainedbyahigh-densityandhigh-performanceceramic.Inthispaper,basedonsixsideshigh-pressurejackingmachineofSiCceramicshighpressuresintering,highpressuresinteringprocessandtheperformanceofSiCceramicshascarriedontheprelim
7、inaryresearch,andhascarriedonthetheoreticalanalysis,toexploretherelationshipbetweenitsmicrostructureandproperties.ThroughtherelativedensityofSiCceramiccompoundphasespectrumandXRDanalysis,foundthathighpressuresinteringSiCceramicmaterialwithexcellentper
8、formance,mainlyreflectedintheperformanceofthermalconductivityandtoughnessin,hasthegoodapplicationprospect.Comparedwithnormalpressure,highpressuresinteringcaneffectivelyreducemetalsinteringtimeandsinteringtheceramicsystem,promotedensification,a