Research of Color and Discoloration Resistance of 18K Rosy Gold for Ornaments
75Au25Cu was the basic rosy gold alloy for jewelry, but it had no good brightness and was prone to tarnish and darken. This paper modified this basic alloy through multiple elements and less (micro) alloying, and measured its color and discoloration-resistance. The results showed that small amounts of zinc plus trace of silicon and cerium helped to improve the color and discoloration-resistance of the alloy, the initial colorimetric values fell in between 5N-18 standard alloy and 75Au25Cu basic alloy, while the brightness reached nearly 86, implying that the color was superior to the requirements of EN28654:1993 and ISO8654:1997. Moreover, the test alloy had better preferable resistance to darkening, discoloration and oxidation. All these performances indicated that the test alloy could meet the color requirement of rosy gold for ornaments such as clocks & watches and jewelries.
Zhong Cao, Xueqiang Cao, Lixian Sun, Yinghe He
J. P. Yuan et al., "Research of Color and Discoloration Resistance of 18K Rosy Gold for Ornaments", Advanced Materials Research, Vols. 239-242, pp. 3284-3289, 2011