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1、SiC陶瓷的高壓燒結(jié)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(qiáng)度高、抗氧化性強(qiáng)、耐磨損性好、熱膨脹系數(shù)小、硬度高、抗熱震和耐化學(xué)腐蝕等優(yōu)良特性,因此,在很多領(lǐng)域得到廣泛應(yīng)用。然而,SiC是一種共價(jià)鍵性很強(qiáng)的化合物,其自擴(kuò)散系數(shù)極小,可燒結(jié)性很差。在傳統(tǒng)的粉末冶金SiC燒結(jié)工藝條件下,如果不加入適當(dāng)?shù)奶砑觿?純SiC是很難燒結(jié)致密化。采用超高壓燒結(jié)方法可以在較低溫度、較短時(shí)間、低燒結(jié)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(jī)對(duì)SiC陶瓷的高壓燒結(jié)，對(duì)SiC陶瓷的高壓燒結(jié)工
2、藝及性能進(jìn)行了初步的研究，并進(jìn)行了理論分析，探索了其顯微結(jié)構(gòu)與性能之間的關(guān)系。通過對(duì)SiC復(fù)相陶瓷的相對(duì)密度和XRD譜的研究分析，發(fā)現(xiàn)高壓燒結(jié)的SiC陶瓷材料具有優(yōu)良的性能，主要體現(xiàn)在導(dǎo)熱性能和韌性在，有良好的應(yīng)用前景。與常壓相比，高壓燒結(jié)可以有效的降低金屬陶瓷的燒結(jié)時(shí)間和燒結(jié)制度，增進(jìn)致密化，進(jìn)而達(dá)到改進(jìn)性能的目的。六面頂高壓燒結(jié)技術(shù)是一種快速、高效的燒結(jié)技術(shù)，大大降低了燒結(jié)溫度和縮短了燒結(jié)時(shí)間，并且可制備出接近理論密度的復(fù)相陶瓷材料。采用超高壓燒結(jié)工藝可以燒結(jié)獲得無燒結(jié)助劑添加的高致密度SiC陶瓷(
3、致密度92%~100%)。燒結(jié)工藝對(duì)陶瓷的性能有明顯的影響，實(shí)驗(yàn)結(jié)果表明：Al2O3是SiC燒結(jié)的有效燒結(jié)助劑,在低添加量下(約2wt%)即可實(shí)現(xiàn)陶瓷的全致密燒結(jié)。燒結(jié)工藝對(duì)添加了燒結(jié)助劑陶瓷性能的影響與純SiC的燒結(jié)類似,但獲得的陶瓷的致密度普遍較高。關(guān)鍵詞：SiC陶瓷高溫高壓技術(shù)燒結(jié)性能物相分析（XRD譜)IIISiC陶瓷的高壓燒結(jié)工藝及性能材料專業(yè)本科畢業(yè)論文河ABSTRACTSiCceramicsisagoodmaterialwithhightemperaturestrength,oxidati
4、onresistance,wearresistance,thermalexpansioncoefficient,highhardness,thermalshockandchemicalresistanceandotherexcellentproperties,therefore,hasbeenwidelyusedinmanyfields.However,SiCisacovalentbondstrongcompound,theself-diffusioncoefficientisextremelysmal
5、l,thesinterabilityispoor.SiCsinteredintheconventionalpowdermetallurgyprocessconditions,withouttheinclusionofsuitableadditives,pureSiCdensificationisdifficult.Usingultra-highpressuresinteringmethodcanlowerthetemperature,theshorterthetime,thelowsinteringad
6、ditivesaddedamountobtainedbyahigh-densityandhigh-performanceceramic.Inthispaper,basedonsixsideshigh-pressurejackingmachineofSiCceramicshighpressuresintering,highpressuresinteringprocessandtheperformanceofSiCceramicshascarriedonthepreliminaryresearch,andh
7、ascarriedonthetheoreticalanalysis,toexploretherelationshipbetweenitsmicrostructureandproperties.ThroughtherelativedensityofSiCceramiccompoundphasespectrumandXRDanalysis,foundthathighpressuresinteringSiCceramicmaterialwithexcellentperformance,mainlyreflec
8、tedintheperformanceofthermalconductivityandtoughnessin,hasthegoodapplicationprospect.Comparedwithnormalpressure,highpressuresinteringcaneffectivelyreducemetalsinteringtimeandsinteringtheceramicsystem,promotedensification,a
