Study of properties of cobalt-tungsten binary alloy deposit as copper barrier

Abstract

铜和铜合金饰品表面需镀金 ,由于铜扩散至镀金层表面 ,引起金层变色。本文提出以电镀钴钨二元合金镀层作为防铜渗层。实验表明 ,随着镀液中钨离子浓度的不同和电流密度的改变 ,钴钨合金镀层组成不同。当镀液中钨离子含量低 ,电流密度低时 ,镀层为晶态结构 ;当镀液中钨离子含量高 ,电流密度大时 ,镀层呈非晶态或混合微晶态结构。同时比较了在 40 0～ 80 0℃下 ,钴钨合金镀层与镍层、钴层的防铜渗能力。当温度低于 5 0 0℃时 ,钴钨合金镀层的防铜渗性能优于后二者。 Gold electrodeposit as top coating of artificial jewelry made of copper and copper alloy tarnished because of copper diffusion to gold top deposit. Cobalt-tungsten electrodeposit as copper barrier was presented in the paper. Composition of cobalt-tungsten deposit was changed with the change of tungsten concentration and current density in plating solution. Crystalline deposit obtained in low concentration of tungsten and current density, and amorphous or mixture microcrystal deposit obtained in high concentration of tungsten and current density. Meanwhile, properties of cobalt-tungsten, nickel, cobalt deposit as copper barrier at temperature between 400℃ and 800℃ were compared. Results showed cobalt-tungsten deposit as copper barrier at temperature of 500℃ and below was superior to nickel, cobalt deposit.