电熔锆莫来石对Al_2O_3-Cr_2O_3耐火材料抗热震性能的影响

Effect of fused zirconia mullite on thermal shock resistance of Al_2O_3-Cr_2O_3 refractories

为研究添加电熔锆莫来石颗粒对Al_2O_3-Cr_2O_3耐火材料抗热震性能的影响,以电熔刚玉、电熔氧化铬、氧化铬绿和煅烧α-Al_2O_3粉等为主要原料,分别添加10%(w)的电熔锆莫来石颗粒和3%(w)的m-ZrO_2微粉,对试样进行水冷法抗热震试验、模拟开停车热震试验(2001 600℃)和常温物理性能检测,并重点研究了电熔锆莫来石颗粒对试样抗热震性能的影响机制。结果表明:添加电熔锆莫来石颗粒和m-ZrO_2微粉没有对烧后试样的常温物理性能和显微结构造成较大影响;添加电熔锆莫来石颗粒可以显著提高Al_2O_3-Cr_2O_3试样抗热震性能,效果与添加m-ZrO_2微粉试样的相同;电熔锆莫来石颗粒在烧成过程中析出的SiO_2相,增强了电熔锆莫来石颗粒与基质的结合程度,引导裂纹向电熔锆莫来石颗粒内部扩展,且电熔锆莫来石的共晶及多裂纹结构对裂纹的扩展起"分裂"和"吸收"等作用,从而使得添加电熔锆莫来石的试样获得优异的抗热震性能。

Fused corundum,fused chrome oxide,chrome oxide green and Calcined α-Al2O3 powder as main raw materials,and 10% fused zirconia mullite particles and 3% m-ZrO= micropowder were added,respectively,in order to research fused zirconia mullite particles on thermal shock resistance of Al2O3-Cr2O3 refractories. The water quenching thermal shock tests and the simulated start-up and shut-down thermal shock tests （200←→1 600 ℃） were carried out. The physical properties of the specimens were determined. The results show that adding fused zirconia mullite particles and m-ZrO2 micropowder doesn＇t have obvious influence on physical properties and microstructure of the fired specimens. Both fused zirconia mullite particles and m-ZrO2 micropowder can improve thermal shock resistance of Al2O3-Cr2O3 specimens. SiO2 phase precipitates from fused zirconia mullite particles during the firing, strengthens the bonding degree between fused zirconia mullite particles and the matrix, guides the cracks to expand towards the particle inside;the eutectic and multi-crack structure of fused zirconia mullite plays ＂splitting＂ and ＂absorbing＂ role in the crack development, so the specimens added by fused zirconia mullite have excellent thermal shock resistance.