自発的浸透による粒子強化型マグネシウム複合材料の作製と浸透プロセス解析
1995 年 45 巻 6 号 p. 321-326
詳細
1995 年 45 巻 6 号 p. 321-326
The fabrication method of particulate reinforced magnesium matrix composites using spontaneous infiltration phenomenon was developed. By pre-mixing the infiltration agent to reinforcement powder, magnesium melt infiltrated into the powder spontaneously even under pure argon gas atmosphere at 973K. In this work, fundamental experiments were carried out to find out the conditions that the spontaneous infiltration can occur in the pure Mg-SiCp system, using SiO2 powder as an infiltration agent. Microstructure observation and XRD analysis were also carried out to make clear the infiltration mechanism. The spontaneous infiltration depends both on SiCp diameter and on SiO2 content. The threshold SiO2 content decreases with increasing SiCp diameter. Microstructure observation revealed no uninfiltrated part and the formation of two kinds of reaction products. In the composites MgO, Mg2Si and no SiO2 were detected by XRD analysis. Since the reaction for producing MgO and Mg2Si from magnesium and SiO2 is exothermic (thermit reaction), it is predicted that the temperature becomes higher in the infiltration front than in other part, as temperature rise was actually confirmed during infiltration. It is predicted that the spontaneous infiltration is caused by the temperature rise due to the thermit reaction and/or the contribution of good wettability of magnesium to SiO2.
