Hall Cell Test for Electroplating of Electric Heating Tubes to Check the Basic Properties of Brighteners

Hall Cell Test for Electroplating of Electric Heating Tubes to Check the Basic Properties of Brighteners

By combining various commercially available carrier brighteners, main brighteners, and auxiliary brighteners appropriately, high-performance alkaline zincate zinc plating brighteners or cyanide zinc plating brighteners can be prepared. It should be noted that there are many incompatibilities among carrier brighteners, main brighteners, and auxiliary brighteners, and sometimes they cannot be mixed at all; Sometimes it is feasible to add them separately to the tank solution, but it is not feasible to prepare them as brighteners (which may cause turbidity, precipitation, or performance degradation when combined). Nowadays, alkaline zincate zinc plating additives are often classified into several categories, such as cylinder opening agents, brighteners, and moving agents.

Discrimination of Basic Properties of 2 Alkaline Zinc Salt Zinc Plating Brighteners

2.1 Checking the basic performance of brighteners using Hall cell test

Zinc plating base solution ZnO8-12g/L, NaOH120-140g/L. Add various brighteners and additives according to the upper and middle limits of the process, and then conduct Hall cell experiments. Electroplating at a temperature of 20-30 ℃ without stirring, after IA, 5 and n, the Hall cell test piece should emit light with a mass fraction of 0.5% HNO3, and the entire piece should have uniform luster, no stripes, no missed plating, and no dark areas; If the low current density area of IA, 5, and n test pieces is gray or with obvious stripes and uneven luster after being exposed to light, then such brighteners should be used with caution. However, the Hall cell test for alkaline zincate zinc plating is different from that for potassium chloride zinc plating. In potassium chloride zinc plating, the appearance of IA, 5 and n Hall groove specimens is often slightly worse than that of IA, 10 and n specimens; However, some brighteners with poor performance in alkaline zincate zinc plating have better IA, 5, and n Hall cell specimens than IA, and 10 minute specimens. Such brighteners often encounter problems in industrial production, greatly increasing the difficulty of maintaining the plating solution. A brightener with good performance, IA, 10 and n test pieces should be better than IA, 5 and n test pieces. After the light is emitted, the entire piece should have uniform brightness, and there should be no gray in the low current density area; There is no whitening (fog) or obvious streaks in the medium and high current density areas. Therefore, for alkaline zincate zinc plating brighteners, at least IA, 10 and n Hall cell tests should be conducted to verify the basic performance of the brightener.

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