Chromium-free passivator

Abstract

The invention discloses a chromium-free passivator. Every 1 l of the chromium-free passivator is prepared from components by mass including 50% of amino silane or/and epoxy silane, 2% of polyacrylic acid, 5% of tetraethoxysilane, 5% of starch, 5% of sodium phenylacetate, 2% of polyurethane, 8% of melamine, 1% of cold-drawn polypropylene fibers, 4% of phosphorus-containing polyalcohol, 3% of polyamide polyethylene glycol, 1% of sodium bicarbonate, 3% of starch phosphate, 2% of isopropanol, 5% of polyurethane, 3% of liquid paraffin, 2% of iron oxide yellow, 1% of rare earth ions, 1% of barium dioxide nano-particles and the balance water. According to the passivator, as multiple kinds of organic phosphoric acid, multiple kinds of metal ions and multiple kinds of nano-particles are chelated todifferent degrees, on one hand, the thickness and the density of a passivation film can be enhanced; and meanwhile the passivation film (inorganic film) obtained after chelating is completed can display colors to a certain degree on the surface of an aluminum alloy.

Description

technical field [0001] The invention relates to a passivator which does not contain chromium and manganese elements. Background technique [0002] Aluminum alloy workpieces such as aluminum profiles or aluminum wheels usually need surface treatment before painting to enhance the adhesion between the metal and the paint. At present, the aluminum alloy surface treatment technology before painting mostly adopts hexavalent chromium passivation treatment process . However, this treatment method contains heavy metal ions of hexavalent chromium, which is highly toxic and seriously pollutes the environment. The implementation of the EU RoHS environmental protection directive has put forward clear restrictions on harmful substances such as hexavalent chromium. Therefore, in recent years, the research on the chromium-free technology of aluminum alloy surface treatment has been a hot spot at home and abroad. [0003] At present, as a chromium-free passivation technology that can repl...

AI Technical Summary

Problems solved by technology

However, there is a certain gap between the passivation effect of these chromium-free passivation technologies and the hexavalent chromium technology.

In addition, the traditional hexavalent chromium passivation agent can show a certain color on the film layer formed on the aluminum alloy surface, which is convenient for the operator to judge the reaction process, while the current chromium-free passivation technology forms the film layer on the aluminum alloy surface. It is colorless, which makes it difficult for field operators to judge whether a film is formed