纳米SiC颗粒强化7075铝合金在NaCl溶液中的电化学腐蚀行为  

Corrosion Characteristics of AA7075 Reinforced with Nano-SiC Particles in NaCl Solution

作　　者：李晓丹[1] 翟玉春[1] 邱峰[1] 刘涛涛[1] 

机构地区：[1]东北大学材料与冶金学院,沈阳110819

出　　处：《腐蚀科学与防护技术》2012年第2期139-143,共5页Corrosion Science and Protection Technology

基　　金：国家重点基础研究发展规划项目(2005CB623707);青年教师培养基金111(704015)资助

摘　　要：研究了纳米SiC颗粒强化7075铝合金(SiC_p/7075A1)经T6处理后在3.5%NaCl中性水溶液中的腐蚀特性及腐蚀机理.结果表明,适量纳米SiC颗粒的加入,可提高AA7075-T6的自腐蚀电位和击穿电位,降低腐蚀速率,增强其耐蚀性.SEM观察表明,SiC_p/7075Al-T6的腐蚀以点蚀为主,主要发生在晶界及近晶界区域,没有大的点蚀坑,而未经强化的AA7075-T6则呈现出严重的点蚀和晶间腐蚀的特征,这与EIS特征相符,浸泡实验也得到了同样的结果.TEM观察证实SiC颗粒在晶界的存在分割了η相;阻断了晶界阳极性的η相与其边缘合金组成的腐蚀电偶形成的活性通道;阻碍了蚀孔的长大,提高了腐蚀抗力.Corrosion characteristics of AA7075 reinforced with nano-SiC particles（SiC_p/7075Al） after T6 treatment were studied in 3.5%NaCl solutions and the corrosion mechanisms were further analyzed.The results show that in comparison with the bare 7075A1,the free corrosion potential of SiC_p/7075Al become much positive and its corrosion rate decreases,therewith its corrosion resistance enhances.The surface microstructure of the sample after corrosion text and then polished was analyzed by SEM,two distinct features were found：（1） micropitting corrosion occorred at grain boundary and the adjacent Al matrix in the SiC_p/7075Al-T6;（2） The number and the spread area of pits on the AA7075-T6 are significantly larger than that on the SiC_p/7075Al-T6; intergranular corrosion of AA7075-T6 is very serious,which are consistent with the EIS and immersion test.The SiC_p distributes discontinuously on the grain boundary was observed by TEM,theη（MgZn_2） phase and the active corrosion path resulting from theηphase and their adjacent Al matrix were destroyed by SiC_p,the corrosion resistance was then improved.

关 键 词：SiC_p/7075A1合金 耐蚀性能 极化曲线 电化学阻抗 

分 类 号：TG174[金属学及工艺—金属表面处理]