Chromium-free Passivation & Eco-coloring Standards
无铬钝化与环保着色新规范
标签：无铬钝化, REACH, 环保, BTA, 法规, 封护
欧盟 REACH 与国内 GB/T 新规收紧六价铬，户外铜件着色封护转向铬-free 体系：BTA 或噻二唑衍生物 0.5–1 wt%、60–70 °C 浸 5–10 min 成膜，盐雾 72–96 h；配合硅烷偶联剂（KH-560，2% 乙醇液）可再提升 30% 耐蚀。旧铬酸盐着色液废弃前需用亚硫酸钠还原至 Cr(III) 方可排放，新体系废水只需 pH 中和。
REACH and newer Chinese standards restrict hexavalent chrome, so outdoor copper finishing has shifted to chromium-free systems: BTA or thiadiazole derivatives at 0.5–1 wt%, 60–70 °C for 5–10 min, passing 72–96 h salt spray; adding 2% KH-560 silane in ethanol improves corrosion resistance another 30%. Old chromate baths need reduction to Cr(III) with sodium sulfite before disposal; the new baths need only pH neutralization. ---