Chromium-free zinc-aluminum anticorrosive paint with phosphomolybdic acid hydrate as passivating agent

Abstract

The invention discloses a water-borne chromium-free zinc-aluminum anticorrosive paint with phosphomolybdic acid hydrate as a passivating agent. The water-borne chromium-free zinc-aluminum anticorrosive paint with the phosphomolybdic acid hydrate as the passivating agent includes the following components, by mass, 250-310 parts of zinc powder, 10-30 parts of aluminum powder, 3-10 parts of the phosphomolybdic acid hydrate, 110-150 parts of polyethylene glycol, 70-140 parts of a silane coupling agent, 3-8 parts of 2-ethoxyethyl acetate, 1-18 parts of a surfactant, 1-6 parts of a defoaming agent,10-60 parts of tetraisopropyl titanate, 10-18 parts of boric acid and 380-480 parts of deionized water. The polyethylene glycol and the silane coupling agent being 35-50% of the total amount of formula, the 2-ethoxyethyl acetate, the surfactant and the defoaming agent are stirred to be made into an A component; the deionized water, the phosphomolybdic acid hydrate and the silane coupling agent inthe weight ratio and being 50-65% of the total amount of the formula, the tetraisopropyl titanate and the boric acid are stirred to be made into a B component; before use, the A component and the B component are mixed and stirred uniformly according to the weight ratio of 1:1-1.4, and the finished paint is prepared. The thermal stability of the prepared product of the water-borne chromium-free zinc-aluminum anticorrosive paint with the phosphomolybdic acid hydrate as the passivating agent is improved, and a coating after coating conforms to the comprehensive performance requirements of a thincoating, high adhesive strength, good anticorrosive performance and the like required by an automobile fastener.

Description

technical field [0001] The invention belongs to the technical field of anti-corrosion coatings, in particular to a chromium-free zinc-aluminum anti-corrosion coating using phosphomolybdic acid as a passivating agent. Background technique [0002] Among the existing anti-corrosion coatings for metal substrates, zinc-chromium coating (also known as Dacromet coating) technology does not comply with the "Restriction on the use of certain substances in electronic and electrical equipment" because the coating contains hexavalent chromium Hazardous Components Directive (ie RoHS standard). The RoHS standard is a mandatory environmental protection standard formulated by the EU legislation, which is used to regulate the material and process standards of electronic and electrical products. At present, the standard has been extended to many fields related to people's livelihood and military products. Countries around the world have begun to take increasingly strict measures to limit t...

AI Technical Summary

Problems solved by technology

For water-based chromium-free zinc-aluminum coatings, metal oxide passivators have poor water solubility and incomplete dispersion; salt passivators have problems such as insufficient passivation and instability of zinc-aluminum powder. It can't meet the comprehensive performance requirements of thermal stability of coating, thin coating, high adhesion strength and stable anti-corrosion performance proposed by automotive fasteners.