采用明度法确定高速电镀锌工艺参数

Confirmation of technological parameters in high-speed electro-galvanizing by means of lightness

为了快速、准确的研究高速电镀锌工艺 ,确定电解液流速、硫酸锌浓度和电流密度与电镀锌层表面质量的关系 ,采用白度颜色测定仪测定镀层表观明度值 (L)的方法 ,评价高速电镀锌镀层的表面质量 ,同时利用明度法研究了在硫酸盐电解液中不同电流密度下的高速电镀锌工艺 .研究结果表明 :采用明度评价镀锌板表面质量的方法简单、方便 ,当镀层明度值L≥ 75时镀层均具有合格的外观 ,当L≥ 82时 ,镀层具有优良的外观 ;电流密度在 5 0 15 0A·dm-2 区间时 ,在不同的硫酸锌浓度 (2 5 0 35 0 g/L)和高流速 (3 4m/s)下均能得到外观质量合格的镀锌层 ,而当电流密度为 190A·dm-2 时 ,只有在高硫酸锌浓度 (35 0 45 0g/L)和高流速(34m/s)

To confirm the relationship between surface appearance of zinc deposits and the electrolyte flowrate the concentration of zinc sulfate and current density, a whiteness and color meter was used for measuring the surface lightness(L) of deposits and evaluating the surface quality of zinc plate deposited from high speed electrogalvanizing process. Results show that the lightness method is found to be brief and convenient for the evaluation of surface quality of zinc plates. When the plate surface lightness value is greater than the lower limit of 75, the plate has a qualified surface appearance. Furthermore, excellent appearance was observed on the plate surface when the lightness value is higher than 82. By means of lightness method, the relationship among technological parameters (electrolyte flowrate, concentration of zinc sulfate and current density) in high speed electro galvanizing system was obtained. It was confirmed that good deposits at relative low current density (50 to 150 A·dm -2 ) can be obtained in the whole range of concentration of zinc sulfate (250 g/L to 450 g/L) and high electrolyte flowrate(3 to 4 m/s). But at high current density (190 A·dm -2 ), the deposit with good appearance only can be obtained at high concentration of zinc sulfate (350 g/L to 450 g/L) and high electrolyte fowerate(3 to 4 m/s).