Analysis of Two Bronze Mirrors With Tin-rich Surface

"black lacquer " and “silver lacquer”are very special categories of ancient chinese bronze mirrors, and the cause of the formation of lacquer surface has attracted much attention. In this paper, metallographic microscope, scanning electron microscope are used to analyze one "black lacquer " and one “silver lacquer”bronze mirror. The matrix of the two mirrors is copper-tin alloy with lead and the metallographic structure is as cast. The tin-rich layer with uneven thickness exists on the surface of the 2 mirrors. Based on the analysis of tin-rich layer, it is concluded that the“silver lacquer” is intentionally artificial, and its surface is treated with lead-tin amalgam, which is composed of mechanical combination and micro-metallurgy. The "black paint" was formed by natural corrosion in the underground environment.