铝酸钙水泥对氧化镁系包埋料性能的影响

Influence of CA cement on properties of MgO-based investment materials

以铝酸钙水泥作为结合剂、电熔氧化镁和电熔白刚玉作为原料以及刚玉球作为混磨介质,在聚氨酯滚筒中混磨2 h后制得氧化镁系包埋料,研究结合剂铝酸钙水泥含量对氧化镁系包埋料性能的影响。结果表明,随着铝酸钙水泥含量的增加,氧化镁系包埋料的初凝时间缩短,流动性变差;对比110℃热处理试样,经900℃热处理试样显气孔率上升,体积密度下降。当铝酸钙水泥含量大于20%时,铝酸钙水泥的加入可明显地提高氧化镁系包埋料的耐压强度。

To prepare MgO-based investment materials, CA cement as binder, MgO and Al2O3 as raw materials were mixed for 2 h in polyurethane pots using alumina balls. The influence of CA cement on the properties of MgO-based investment materials was studied. The results show that, with the in- crease in CA cement content, the fluidity of MgO-based investment materials decreases and so does the initial setting time. The apparent porosity of the specimen heated at 900℃ increases and the bulk density decreases, as compared with the specimen heated at 110 ℃. When CA cement content is more than twenty percent, the compressive strength of the investment increases with the increase of CA cement content.