Protective coating for zinc - is obtd. by dipping into an oxygen-saturated calcium hydroxide soln.

摘要

Zn (alloy) surfaces are provided with a corrosion resistant coating by dipping into an aq. alkaline Ca(OH)2 soln. or slurry which is satd. with O. The thickness of the coating depends on the treatment time, and the colour depends on the chemical compsns. of the Zn alloy. The method can be applied to rolled sheet or strip without a pretreatment, and the concn. of the coating medium remains approx. constant eliminating measures for controlling or adjusting the concn.