Rear earth polyoxometallate silanization process for metal cathode before electrophoresis

Abstract

The invention discloses a rare earth polyoxometallate silanization process before metal cathode electrophoresis. By adopting a rare earth silanization treatment technique before cathode electrophoresis, namely the successful combination of polyoxometallate synthetic technique and silanization technique, the synthesized silicon molybdenum heteropolyacid rare earth lanthanite salt is hybridized with silane, and then a silane---silicon molybdenum heteropolyacid rare earth lanthanite hybridization film is formed on a metal surface. The hybridization film obtained in the process has the advantages of strong corrosion resistance, compactness and uniformity, low resistance, good adhesion, good self-repairing performance and the like.

Description

technical field [0001] The invention relates to the field of metal surface treatment, in particular to a polyoxometalate rare earth salt-silanization treatment process before metal cathodic electrophoresis. Background technique [0002] In metal surface treatment, the quality of substrate surface treatment directly affects the adhesion, appearance and corrosion resistance of the coating. Although traditional phosphate conversion and chromate passivation surface treatment technologies can achieve good results, the waste liquid discharged during the treatment process contains heavy metal ions such as zinc, manganese, nickel, chromium and carcinogens such as nitrite, which are harmful to the environment. Environmental pollution is very serious. The metal surface silanization treatment technology is considered to be expected to replace phosphate conversion treatment and chromate passivation treatment because it does not involve substances that are harmful to the environment, th...

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Problems solved by technology

[0004] The silane treatment of metal surfaces has broad application prospects, but the silane film formed by the existing technology has defects such as weak corrosion resistance, uneven film formation, no "self-repair" performance or poor "self-repair" performance, which limits its development

In cathodic electrophoretic coating, the requirements for various indicators of the pretreatment film layer are more stringent, such as alkali resistance performance requirements, because the alkalinity enhancement during the electrophoresis process will destroy the silane film layer, resulting in changes in the microstructure of the substrate surface, seriously affecting Overall Coating Properties