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以镁砂为主要原料,以硅灰为结合剂,研究了不同氮化硅加入量对镁质浇注料的常温物理性能和高温力学性能的影响,用X射线衍射仪、扫描电镜等对浇注料的物相和显微结构等进行了分析。结果表明:经110℃,24h烘干的浇注料的常温抗压和抗折强度随着氮化硅加入量的增加而降低;经1200℃,3h烧结后的浇注料的常温抗压和抗折强度随着氮化硅加入量的增加先升高后降低,并在氮化硅加入量为3%(质量分数,下同)时达到极值点;经高温(1500℃,3h)烧结后的浇注料的常温抗压和抗折强度随着氮化硅加入量的增加而降低;;烘干后的浇注料的高温(1400℃)抗折强度在氮化硅加入量为3%时达到最大。在加热过程中氮化硅的作用包括两方面:一方面能部分氧化成二氧化硅,进而形成纤维状的镁橄榄石,增大浇注料的强度;另一方面氮化硅保留下来妨碍烧结,导致浇注料的强度降低。
Magnesia as the main raw material, with silica fume as binding agent, studied the different amount of silicon nitride on the magnesia castables at room temperature physical properties and high temperature mechanical properties, X-ray diffraction, scanning electron microscopy of castables The phase and microstructure were analyzed. The results show that the compressive strength and flexural strength at room temperature of castables dried at 110 ℃ and 24h decrease with the addition of silicon nitride. After being sintered at 1200 ℃ and 3h, the compressive strength and flexural strength The strength increases first and then decreases with the addition of silicon nitride, and reaches the extreme point when the silicon nitride content is 3% (mass fraction, the same below). After the sintering at 1500 ℃ for 3h The compressive strength and flexural strength of castable at room temperature decrease with the increasing of silicon nitride addition. The high temperature (1400 ℃) flexural strength of the castable after drying reaches the maximum at the silicon nitride loading of 3% . The role of silicon nitride in the heating process includes two aspects: on the one hand can be partially oxidized into silica, and then form fibrous forsterite, increasing the strength of castable; the other hand, silicon nitride retained to prevent sintering, Resulting in a decrease in the strength of the castable.