还原气氛下ZrO_2-Al材料在加热过程中的组成和结构演变

Evolution of phase composition and microstructure of ZrO_2-Al materials in reducing atmosphere

为了解决加入金属Al粉的含锆耐火制品在高温下易产生裂纹、开裂的问题,以单斜Zr O_2粉、金属Al粉、复合稳定剂Mg CO_3·Mg(OH)_2·6H_2O和Y(NO_3)_3·6H_2O为主要原料,研究了加入不同量Al粉的Zr O_2-Al材料在埋炭条件下于1 000、1 200、1 400和1 500℃加热过程中性能、物相组成和显微结构的演变。结果表明:当Al粉加入量超过1%(w)时,热处理后试样产生较多裂纹,导致试样强度急剧降低。在加热过程中,Al与气氛中的O_2、CO和N_2反应生成Al_2O_3和Al N,生成的Al_2O_3再与试样中的稳定剂Mg O发生反应生成Mg Al_2O_4导致Zr O_2失稳,而Zr O_2失稳导致的体积效应以及生成Mg Al_2O_4和Al N产生的膨胀导致试样产生裂纹。因此,在锆碳和铝锆碳材料中添加金属Al时,其加入量不宜太多,以不超过1%(w)为宜。

In order to solve the cracking and spalling at high temperatures of Zr02 containing refractories when metal Al powder is added, m-Zr〇2 powder, metal Al powder’ stabilized agents MgC03· Mg（OH）2 · 6H20 和 Y（N03） 3· 6H20 were used as starting materials to prepare Zr02-Al materials. Evolution of properties,phase composition and microstructure of Zr02-Al materials during heating at 1 000,1 200,1 400 and 1 500 ℃ in reducing atmosphere was studied. The results show：there are many cracks in specimens with Al addition 〉1 mass%,which leads to sharp decrease of strength;during heating,Al reacts with 02, CO and N2 forming Al203 and AIN,the formed Al203 further reacts with MgO from stabilized agent forming MgAI204,causing instability of Zr02. The expansion caused by the formation of MgAI204,AIN and the insta-bility of Zr02 leads to cracks. So,when Al is added into Zr02-C or Zr02-Al203-C materials,the optimum amount shall be ≤1 mass%.