青铜生锈过程中铜元素的扩散──CuCl的作用

The Diffusion of Element Cu in Bronze Powder Corrosion──The Key Action of CuCl

采用扫描电镜（ＳＥＭ）、电子探针微区分析（ＥＰＭＡ）、微区Ｘ射线衍射（Ｍｉｃｒｏ－ＸＲＤ）及Ｘ光荧光光谱（ＸＦＳ）等仪器分析手段，对一块被粉状锈（主要成分为Ｃｕ＿２（ＯＨ）＿３Ｃｌ）严重腐蚀的东汉青铜镜残片进行元素和结构的分区分析。剖面分析表明，青铜合金在浇铸过程中的偏析作用是造成其电化学腐蚀的内在因素；铜锈的生成是分步进行的；氯元素对合金的侵蚀由表面直至基体深部；生锈过程中铜元素从合金内部向表面外扩散．运用相平衡理论、电化学腐蚀原理及化学热力学对青铜器生锈各阶段的化学反应过程进行了探讨．

Methods of SEM, EPM, Micro-XRD and XFS are employed to detect the composition and structure of micro-regions in a piece of sereously corroded bronze mirror which was made in the East-Han Dynasty of China. The analysis of section indicates that:(1) the segregation of the bronze alloy during casting is the internal reason of its electro-chemical corrosion; (2) the copper corrosion forms step by step; (3) element Cl corrodes the alloy from the surface to the deep part of the matrix; (4) during corroding element Cu diffuses from the internal alloy to outside. In the present work,the process of chemical reactions at each stage of bronze corrosion is investigated,and simulated experiments are performed. The theory of phase-equilibrium,the principle of electro-chemical corrosion and the chemical thermodynamics are applied. The results of the work provide some reference for the corrosion of alloyes,and for the protection of the ancient bronze relics.