Relationship between Oxide Film Growth and Color Tone in Copper Alloys

Abstract

The relationship between oxidation-treated copper alloy (brass) and its color tone was investigated. The results showed that the color change of the copper alloy due to oxidation treatment was attributed to changes in surface morphology caused by dezincification, which led to a decrease in the L* value, which indicates the brightness or darkness of a color. Furthermore, copper hydroxide formed during the initial stage of treatment transitioned to copper oxide over time. This transition influenced the b* value, which represents the blue-yellow axis of a color, suggesting that the color tone can be controlled by adjusting the ratio of hydroxide to oxide.