电解法测定化学钝化镀锡板表面铬量

Determination of chromium on the surface of chemical passivation tinplate by electrolytic method

应用电解法测定化学钝化镀锡板表面铬量，在50μA／cm^2电流密度下，采用中性磷酸盐作为电解液，采集电位-时间（u-t]曲线，再用微分处理得到微分曲线（du／dt-t），根据微分曲线特征值进行化学钝化镀锡板表面铬量电解法测定的终点判断，并采用比色法对电解法测定值标定，根据标定系数和电解时间可以得到表面铬量。对镀锡板不大于2mg／m^2的表面铬量，电解法与比色法测定值偏差小于0．2mg／m^2，经t检验两方法间无显著性差异。

Determination of chromium on the surface of chemical passivation tinplate by electrolytic method under the current density of 50μA/cm^2, using neutral phosphate as electrolyte, and collect potential - time （u - t） curve. Then differential curve （du/dt - t） was obtained by differential treatment. The electrolytic end point was judged according to the differential curve characteristic value for determination of chromium on the surface of chemical passivation tinplate. Determination of chromium by electrolytic method is calibrated by the colorimetric method. The surface chromium content is determined according to the calibration coefficient and electrolytic time. No greater than 2 mg/m^2 for tinplate surface chromium content, the deviation of the electrolytic method and the eolorimetric method were less than 0.2 mg/m^2. There was no significant difference for the determination values of the two methods.