碳化硅颗粒增强铝基复合材料的无压浸渗反应机理探讨

Investigation on Reaction Mechanism of SiC Particulate Reinforced Aluminum Matrix Composite Prepared by Pressureless Infiltration

为探讨 Si CP/ Al基复合材料无压浸渗反应机理 ,利用 XPS鉴定了 Si C预制体浸渗前沿界面上的反应产物结构 ,采用 HRTEM研究了 Si CP/ Al基复合材料的界面结构。结果表明 ,浸渗与未浸渗部分之间的界面上存在 Mg O,Al2 O3和 Zn O诸化合物 ,没有发现氮的化合物。在 Si C相与铝相的界面上仅存在 Mg Al2 O4相 ,Mg Al2 O4相几乎连续地包敷在 Si C颗粒上。这表明 ,高温下 Si C与熔 Al合金接触后 ,Si C颗粒表面上的 Si O2 与 Al,Mg,Zn诸元素发生了放热反应 ,从而降低了表面张力 ,提高了湿润性 。

In order to investigate the pressureless infiltration reaction mechanism for a SiC/Al composite , the reaction products structures at the front interface of the SiC preform were identified by means of XPS and TEM The results of the XPS analysis show that the compounds such as MgO, Al 2O 3 and ZnO are present at the interfacial region between the infiltrated and uninfiltrated parts of the SiC preform and no nitrogen compound is found The HRTEM shows that there is only a MgAl 2O 4 phase existing at the interface between SiC phase and aluminum alloy matrix phase and the MgAl 2O 4 phase covers almost the whole SiC particulate surface It is suggested that the exothermic reactions take place between the SiO 2 on the surface of SiC particulate and the Al, Mg and Zn elements after the contact of the molten Al with the SiC particulate Hence the surface tension is decreased, the wettability is increased and the spontaneous infiltration is promoted