Al-Si复合Al_2O_3-β-SiAlON-C材料加热过程中性能、相组成和显微结构的变化

Change of properties,phase composition and microstructure of Al_2O_3-β-SiAlON-C material with Al-Si during heating

以电熔白刚玉(≤0.5、≤0.088和≤0.045mm)、熔融石英(≤0.5mm)、鳞片石墨(≤0.15mm)、矾土基β-SiAlON(≤0.088mm)、Al粉(≤0.074mm)和Si粉(≤0.074mm)为主要原料,以热固性酚醛树脂为结合剂,制成25mm×25mm×125mm的Al-Si复合Al2O3-β-SiAlON-C试样,经200℃固化24h后,分别在800、1000、1200、1400和1600℃下埋炭(石墨)保温3h,冷却后测定其体积密度、显气孔率、常温耐压强度、常温抗折强度、高温抗折强度和抗热震性,并进行XRD和SEM分析。结果表明:1)随着热处理温度的升高,Al-Si复合Al2O3-β-SiAlON-C试样的显气孔率均下降,体积密度、常温耐压强度、常温抗折强度、高温抗折强度、热震后残余抗折强度均逐渐提高,但其抗折强度保持率在经1000℃热处理后最高,随后逐渐降低;2)在高温还原气氛的热处理过程中,试样中的Al、Si与C(CO)或N2反应,原位生成了AlN、β-SiC、Al4C3和β-SiAlON等非氧化物,对试样具有填充气孔及增强增韧的作用。

Using fused white alumina （≤0.5, ≤0. 088 and ≤0. 045 mm） ,fused quartz （ ≤0.5 mm） ,flake graphite （≤0.1.5 mm）,bauxite based β-SiAlON（ ≤0.088 mm）,AI powder（ ≤0. 074 mm）,and Si powder（ ≤0. 074 mm）as main starting materials,and hot set phenolic resin as binder,the specimens of Al2O3-β-SiAlON - C material with Al-Si were prepared with the size of 25 mm×25 mm ×125 mm,cured at 200℃for 24 h, and then carbon（ graphite）-embedded fired at 800, 1 000, 1200, 1 400 and 1 600 ℃ for 3 h, respectively. After cooling ,the bulk density, apparent porosity, cold crushing strength ,cold modulus of rupture, hot modulus of rupture and thermal shock resistance were determined,and the specimens were analyzed with XRD and SEM. The results show that： （1）With temperature rising,AP decreases, BD,CCS,CMOR,HMOR and residual strength after thermal shock increase, but the conservation rate of modulus of rupture reaches the highest at 1 000 ℃,then decreases gradually; （2）During firing at high temperature in reduction atmosphere,Al ,Si in the specimen react with C（CO） or N2 in-situ forming non-oxides,such as AlN,β-SiC,Al4C3 and β-SiAlON,which have the effects of filling the pores,toughening and reinforcing.