Abstract: To investigate the performance evolution of silicon carbide castables in acidic environments,silica sol-bonded silicon carbide castables were prepared using silicon carbide,α-Al₂O₃ micropowder,and silica sol as the main raw materials.The physical properties,microstructure,and phase composition of the castables after immersion in nitric acid of different concentrations (0,5%,10%,15%,and 20%,by mass) were studied.The results show that:(1)the surface of the dried specimens after acid immersion remains intact,without pulverization,peeling,or corrosion;(2)with the increase of the nitric acid concentration,the strength of the specimens improves,while the linear shrinkage and mass loss rate increase;(3)after immersion with 20% nitric acid,the phase composition does not change significantly,the bonding between surface particles becomes tighter,and the morphology becomes more even and orderly.It can be concluded that the silicon carbide castables have excellent acid corrosion resistance and can be used stably for a long time in various industrial acidic environments.

Key words: silicon carbide castables, silica sol, acidic environment, nitric acid, strength

摘要： 为研究碳化硅浇注料在酸性环境下的性能演变规律,以碳化硅、α-Al₂O₃微粉和硅溶胶为主要原料,制备了硅溶胶结合碳化硅浇注料,研究了经过不同质量分数(0、5%、10%、15%、20%)的硝酸浸泡处理后浇注料的物理性能、显微结构和物相组成。结果表明:1)浸酸后干燥试样表面完整,并未出现粉化、脱落、侵蚀现象;2)随着硝酸质量分数的增加,试样的强度提高,线收缩率和质量损失率增加;3)与未酸浸试样相比,经20%(w)的硝酸浸泡后试样的物相组成并没有发生明显变化,表面颗粒之间结合更紧密,形貌更加平整有序。因此,碳化硅浇注料具有优异的耐酸侵蚀性,可在多种工业酸性环境中长期稳定使用。

关键词: 碳化硅浇注料, 硅溶胶, 酸性环境, 硝酸, 强度