Abstract: To develop Si-free antioxidants for the body of submerged entry nozzles (SENs),alumina-carbon (Al₂O₃-C) refractories were prepared using tabular corundum,flake graphite,α-Al₂O₃ powder,Ti(C,N) composite powder and silicon powder as raw materials,phenolic resin as the binder,and industrial alcohol as the solvent.The prepared samples were cured at 200 ℃ for 24 h,followed by heat treatment at 1 000 ℃ for 3 h under an argon atmosphere.The effects of the Ti(C,N) composite powder or Si powder addition (mass fractions of 0,0.5%,0.75%,1.0%,1.25% and 1.5%) on the mechanical properties,thermal shock resistance and oxidation resistance of the materials were investigated.The results show that with the increasing addition of Ti(C,N) composite powder or Si powder,the apparent porosity,bulk density and cold modulus of rupture of the heat-treated samples have no obvious change.Nevertheless,Ti(C,N) composite powder can significantly improve the cold crushing strength,with the maximum achieved at a Ti(C,N) addition of 0.75%.The hot modulus of rupture of the samples first increases and then decreases with the rising addition of either Si powder or Ti(C,N) composite powder.The MOR retention ratio of the samples increases gradually with the increasing Si addition,while a decreasing trend is observed with the increasing Ti(C,N) addition.The sample with 0.75% Ti(C,N) composite powder exhibits the optimal oxidation resistance.This is mainly because TiN and TiC possess lower Gibbs free energy of oxidation reaction,and their oxidation products TiO₂ and Al₂TiO₅ have superior volume expansion effects,which can pre-ferentially form a dense protective layer to block internal pores.In summary,the sample with 0.75% Ti(C,N) composite powder delivers excellent comprehensive performance,showing promising application potential to replace silicon-containing antioxidants.

Key words: submerged entry nozzles, Ti(C,N) composite powder, Si powder, mechanical properties, oxidation resistance

摘要： 为开发浸入式水口本体用无Si抗氧化剂,以板状刚玉、鳞片石墨、α-Al₂O₃粉、Ti(C,N)复合粉及单质Si粉为原料,酚醛树脂粉为结合剂,工业酒精为溶剂,先经200 ℃保温24 h固化,再于氩气气氛下1 000 ℃保温 3 h 热处理,制备铝碳耐火材料。研究Ti(C,N)复合粉或Si粉的不同添加量(质量分数分别为0、0.5%、0.75%、1.0%、1.25%、1.5%)对材料力学性能、抗热震性及抗氧化性的影响。结果表明:随着Ti(C,N)复合粉或Si粉添加量的增加,热处理后试样的显气孔率、体积密度和常温抗折强度均无明显变化,但Ti(C,N)复合粉可显著提升常温耐压强度,其添加量为0.75%(w)时耐压强度最高;随着Si粉或Ti(C,N)复合粉添加量的增加,试样的高温抗折强度均先升高后降低;添加Si粉试样的抗折强度保持率随其添加量的增加而逐渐提高,而添加Ti(C,N)复合粉的试样则呈下降趋势;添加0.75%(w)的Ti(C,N)复合粉的试样表现出最佳的抗氧化性能,这主要归因于TiN和TiC具有更低的氧化反应吉布斯自由能以及产物TiO₂和Al₂TiO₅具有更大的体积膨胀效应,可优先形成更致密保护层堵塞气孔。综合来看,添加0.75%(w)的Ti(C,N)复合粉的试样整体性能较优,具备替代含硅抗氧化剂的应用潜力。

关键词: 浸入式水口, Ti(C,N)复合粉体, Si粉, 力学性能, 抗氧化性能