加入Si粉对低碳铝镁碳材料性能的影响

Effect of Si powder addition on properties of low carbon Al2O3-MgO-C refractories

以82%（质量分数,下同）的电熔白刚玉（3-0.088mm）、10%的镁铝尖晶石（≤0.088mm）、5%的氧化铝微粉（d50=2.4μm）、3%的电熔镁砂（≤0.088mm）以及占总粉体质量5%的酚醛树脂结合剂为基础配方,分别用2%、4%、6%的Si粉（≤0.088mm）取代等量的白刚玉,分别于1400℃3h和1600℃3h埋炭烧成后制备了不同Si粉含量的低碳铝镁碳材料,对材料的显气孔率、体积密度、强度、抗热震性、抗氧化性及抗渣性进行了检测,并借助XRD、SEM和EDAX研究了材料的物相组成和显微结构。结果表明：随着Si粉加入量的增加,经1400℃3h和1600℃3h埋炭烧成后,材料的体积密度逐渐降低,显气孔率增大,耐压强度明显提高（但Si粉加入量超过4%后材料的耐压强度有所降低）,高温抗折强度（1400℃）逐渐提高,抗热震性得到改善,抗氧化性能增强,抗渣性能明显提高。材料性能的这种变化主要同材料中酚醛树脂的残碳与Si粉原位生成β-SiC,以及材料气孔中有Mg-Si-Al-O-N物相生成相关。

The basic specimen was prepared with 82% white fused corundum （3 -0. 088 mm）, 10% spinel （ ≤0.088 mm） ,5% micropowder of α-Al2O3（ d50 =2.4μm）,3% fused magnesia （ ≤0. 088 mm） and phenolic resin （5% of total powder quantity） as the basic formula. Based on the above formula,2% ,4% and 6% Si powders （≤0.088 mm） respectively replaced the same quantity of white fused corundum for preparing other specimens. The specimens embeded in carbon were fired at t 400 ℃ and t 600 ℃ for 3 h respectively. The effects of Si powder addition on physical properties, oxidation resistance and slag resistance were researched. Phase composition and microstructure were analyzed by XRD, SEM and EDAX. The results showed that.For the specimens fired at 1 400 ℃ and 1 600 ℃ for 3 h,the bulk density decreased,apparent porosity increased ,crushing strength increased obviously （it decreased when the addition of Si powder is more than 4% ）,hot modulus of rupture （1 400 ℃） gradually increased,thermal shock resistance,oxidation resistance and slag resistance were enhanced with the increase of Si powder addition. The changes of properties had relationship with the formation of in-situ 15-SIC and Mg -Si-Al-O -N phase in pore.