本文選題：β-SiC + 無壓燒結　； 參考：《西安科技大學》2015年碩士論文

【摘要】：碳化硅陶瓷以其優(yōu)異的性能廣泛應用于國防、機械、冶金、電子等工業(yè)領域。在眾多的陶瓷材料中,碳化硅由于其硬度高、耐高溫、熱穩(wěn)定性好、熱膨脹系數(shù)低以及優(yōu)良的熱傳導性能,一直是材料科學研究的熱點。本文采用固相燒結法(無壓燒結和熱壓燒結)成功制備了高致密度的碳化硅陶瓷。主要研究了燒結溫度、保溫時間、熱壓壓力對碳化硅陶瓷性能的影響并確定了最佳工藝參數(shù),用水靜力天平、萬能拉伸實驗機、維氏硬度儀、SEM和XRD對其性能與顯微結構做了測試與表征。實驗結果表明,無壓燒結最佳工藝參數(shù):燒結溫度2010℃,保溫時間45min,Si C陶瓷體積密度高達3.1261g/cm3,斷裂韌性達4.46MPam1/2,抗彎強度達379MPa;熱壓燒結最佳工藝參數(shù):燒結溫度1900℃,保溫時間60min,熱壓壓力50MPa,Si C陶瓷體積密度達3.1756g/cm3,斷裂韌性達5.12MPam1/2,抗彎強度達596MPa。本文在本課題組前人研究成果的基礎上,采用同粒徑(1μm)的β-Si C和α-Si C做為實驗原料,系統(tǒng)地研究了β-Si C添加量對Si C陶瓷力學性能的影響。研究結果表明,無壓燒結和熱壓燒結β-Si C最優(yōu)添加量分別為5%和10%,β-Si C燒結后晶粒呈長柱狀,添加β-Si C后Si C陶瓷的斷裂韌性有較大的提高,相比純α-Si C制備的陶瓷,無壓燒結提高了0.52MPam1/2,熱壓燒結提高了0.21MPam1/2;無壓燒結抗彎強度從341MPa提高到379MPa,熱壓燒結抗彎強度從527MPa提高到596MPa。本文研究了研磨介質球的制備工藝(滾制成型和冷等靜壓成型)對研磨介質球密度的影響。滾制成型的球坯燒結密度為2.930g/cm3,1mm、2mm、3mm、4mm、5mm研磨介質球分別在36.8MPa、32.1MPa、29.9MPa、16.1 MPa、13.8MPa的壓力環(huán)境下壓碎值都小于2.08%。1mm~5mm研磨介質球磨損率都小于0.95g/kg·h,其中3mm研磨球的磨損率最低為0.27g/kg·h。球坯冷等靜壓成型是用石蠟作為密封材料包裹球坯。冷等靜壓成型球坯的燒結密度能提高到2.958g/cm~3。
[Abstract]:Silicon carbide ceramics are widely used in national defense, machinery, metallurgy, electronics and other industries due to their excellent properties. Among many ceramic materials, silicon carbide has been a hot spot in material science because of its high hardness, high temperature resistance, good thermal stability, low thermal expansion coefficient and excellent thermal conductivity. High density silicon carbide ceramics were prepared by solid state sintering (pressureless sintering and hot pressing sintering). The effects of sintering temperature, holding time, hot pressing pressure on the properties of sic ceramics were studied and the optimum process parameters were determined, such as water static balance, universal tensile tester, The properties and microstructure of Vickers hardness tester were characterized by SEM and XRD. The experimental results show that the optimum process parameters of pressureless sintering are sintering temperature 2010 鈩，

本文編號：2004376