机加工过程中切削液对航空铝合金零件的腐蚀机理研究

Corrosion mechanism of aviation aluminum alloy during machining process

机加工过程中航空铝合金零件的腐蚀是一个普遍而又难以解决的问题,这与切削液的长期浸泡有直接关系。文章通过浸泡实验模拟机加工过程中切削液对航空铝合金零件的腐蚀现象,再结合其他实验分析机加工过程中航空铝合金的腐蚀机理。航空铝合金腐蚀区域Al、Mg、Zn和Cu元素含量明显降低;腐蚀区域C和O元素大幅增加,而这些变化与现场液杂质相关。含量较高的Cl-对航空铝合金具有非常强的腐蚀性,含量较高的Ca2+、Mg2+、Na+可以间接加速航空铝合金零件的腐蚀。阳离子杂质一方面提高切削液电导率,加速航空铝合金的电化学腐蚀;另一方面消耗缓蚀剂含量,削弱缓蚀剂的保护作用。文章为机加工过程中航空铝合金零件的保护和切削液缓蚀剂的研究提供一定理论依据。

Corrosion of aviation aluminum alloy parts during machining is a common and difficult problem,which is directly related to long-term immersion in cutting fluid.In this paper,immersion experiments with cutting fluid were applied to simulate the corrosion phenomenon of aviation aluminum alloy parts in the machining process.Taking other auxiliary experiments into account,the corrosion mechanism of aviation aluminum alloy parts in machining process was analyzed.The content of Al,Mg,Zn,and Cu elements in corrosion area decreased significantly,the content of C and O elements increased significantly.In detail,the dissolution of aluminum matrix and alloy elements was related to the impurity composition of cutting fluid.A high content of chloride ion(Cl-)in used cutting fluid was highly corrosive to aviation aluminum alloy parts.A high content of calcium ion(Ca^(2+)),magnesium ion(Mg^(2+))and sodium ion(Na+)in used cutting fluid can indirectly accelerate the corrosion of aviation aluminum alloy.In addition,these impurity ions improved the conductivity of used cutting fluid,thus accelerating the electrochemical corrosion of aviation aluminum alloy.Meanwhile,corrosion inhibitor in used cutting fluid could be consumed by the impurity ions,thus weakening protective effect of corrosion inhibitor.This paper provided a theoretical basis for protection of aviation aluminum alloy parts in machining process,research of cutting fluid corrosion inhibitor.