Corrosion-resistant lacquer contg. zinc@ alloy pigment

摘要

A corrosion-resistant lacquer contains binder, solvent, thinner, pigment and various additives. The pigment contains corrosion-resistant, powdered Zn alloy. The alloy is a binary alloy, namely a Zn-Ni alloy contg. 5-15% Ni, a Zn-Fe alloy contg. 0.1-1.5% Fe, a Zn-Co alloy contg. 0.1-1.5% Co, or a ternary Zn-Co-Fe alloy contg. 0.1-1.5% Co and 0.1-1.5% Fe, and it may be used in a chromated form. Lacquer Zn-alloy content is 25-90 wt.%. In an example, two sections of a linear guide unit made of CK35 steel are coated with a lacquer of the following compsn. (in pts.wt.): water-soluble phenolic resin 120.0, butanol 80.0, butylene glycol 15.0, water 75.0, powdered Zn or Zn-alloy 700.0 and silica 10.0. One section is coated with lacquer contg. Zn, and the other with lacquer contg. a Zn-Fe alloy contg. 0.4% Fe, said coating being allowed to dry for 60 hrs. and being 35 microns thick in both cases. Both sections are subjected to a NaCl soln. spray test (DIN 50021), with visual evaluation of the tests showing the section coated with Zn-contg. lacquer withstanding 60 hrs. of spraying before rust spots appeared, and the section coated with Zn-Fe alloy contg. lacquer withstanding 200 hrs. of spraying.