氮化硼/二硼化锆对氧化镁-氧 化铝-碳材料性能影响

以电熔镁砂、用后镁碳砖、α-氧化铝和石墨为原料，引入复合添加剂氮化硼/二硼化锆（BN/ZrB2），经共磨、加酚醛树脂结合剂混炼、成型及热处理工艺制备氧化镁-氧化铝-碳耐火材料，研究复合添加剂BN/ZrB2及煅烧温度对烧后试样烧结性、抗氧化性、显微结构和矿物相组成的影响。结果表明： BN/ZrB2添加剂在氧化镁-氧化铝-碳耐火材料中的优先氧化顺序为二硼化锆>氮化硼>碳，添加剂BN/ZrB2氧化生成三氧化二硼，三氧化二硼与基质中电熔镁砂及用后镁碳砖中的氧化镁反应生成低熔点相Mg3B2O6，液相Mg3B2O6有利于提高氧化镁-氧化铝-碳耐火材料的烧结性和抗氧化性。烧后试样矿物相组成为方镁石、镁铝尖晶石和少量Mg3B2O6相。

Effect of BN/ZrB2 on property of MgO-Al2O3-C materials

MgO-Al2O3-C refractories were prepared with fused magnesia，used MC brick，α-Al2O3 and graphite as raw materials，with BN/ZrB2 as the compound additive，through the process of co-grinding，mixing with phenolic resin as the bonder，forming and heat treatment.The effects of BN/ZrB2 additive and sintering temperature on the sintering property， oxidation resistance，microstructure，and mineral composition of the sintered specimens were investigated.Results indicated that the preferential oxidation，in the MgO-Al2O3-C refractories with BN/ZrB2 as the compound additive，was ordered by ZrB2>BN>C，and BN/ZrB2 was oxidated to B2O3.It was shown that Mg3B2O6 with low melting point was generated with B2O3 reacted with MgO from fused magnesia and used magnesia-carbon brick in the experiment.The sintering property and oxidation resistance of MgO-Al2O3-C refractories were contributed by the liquid Mg3B2O6 generation.The mineral composition included periclase，MA spinel and a small amount of Mg3B2O6.