增强体SiCP对SiCP/Al复合材料腐蚀行为的影响

通过周期浸润腐蚀实验研究了不同SiC颗粒尺寸(70、90、140、220μm)和不同SiC颗粒体积分数(42%、49%、55%)的SiC_P/Al复合材料在酸性环境中的腐蚀行为。采用失重法、金相显微镜、X射线衍射仪以及扫描电镜分别计算腐蚀速率、观测微观组织、分析腐蚀产物的物相组成以及观察表面形貌。结果表明：腐蚀前期，SiC_P/Al复合材料的耐腐蚀性能随着颗粒尺寸的减小而降低，腐蚀中后期，耐蚀性能随着颗粒尺寸的减小反而有一定程度的提高；SiC颗粒的存在一方面促进了点蚀的成核，另一方面又打断了基体的连续性，改变了点蚀的生长方式，抑制了点蚀的进一步扩展；SiC_P/Al复合材料的耐腐蚀性能随着颗粒体积分数的提高而降低，其腐蚀产物主要为氧化铝和非晶态硫酸铝化合物。

Influence of SiC_P reinforcement on corrosion behaviour of SiC_P/Al composites

The corrosion behavior of SiC_p/Al composites with different SiC_p sizes(220, 140, 90, 70 μm)and different SiC_p volume fractions(42%, 49%, 55%)was investigated by the alternate immersion test. Mass loss was used to evaluate the corrosion rate. The microstructure of composites was observed by the optical microscope (OM). The phase and surface photography of corrosion products were analyzed by the X-ray diffraction(XRD)and scanning electron microscope(SEM). Experimental results show that the corrosion resistance of the SiC_p/Al composites decreases with decreasing the particle size in the initial stage of corrosion, but increases with decreasing the particle size in the corrosion latter stage. SiC_p accelerates the nucleation of pit, also interrupts the continuity of the matrix channels, alters the growth way and suppresses the further expansion. The corrosion resistance of the SiC_p/AI composites decreases with the increasing the particle content, of which the main corrosion products are Al_2O_3 and Al_xSO_(4y)OH_z.