Zirconium salt conversion technology can be carried out at room temperature, treatment time is short, no surface adjustment and closure / passivation, the process of non-phosphorus-free heavy metals, Zirconium do not need to increase the cost of waste treatment, is a pollution-free environment-friendly surface treatment technology , Is expected to be one of the good solutions for alternative phosphating and chromating processes.
Pure zirconium salt conversion technology refers to the conversion of liquid in the film is the main salt containing zirconium, without the use of other properties of the compounds (such as cerium salt, silane, etc.) play a synergistic role.
(1) the choice of zirconium salt system;
(2) a method for preparing a zirconium salt conversion film;
(3) control of zirconium salt treatment parameters, film morphology and corrosion behavior;
(4) the adhesion of the conversion film to the subsequent coating and the corrosion resistance of the overall coating system.
Zirconium salt conversion film technology in recent years, Zirconium the rapid development of metal surface treatment technology, can effectively improve the corrosion resistance of steel and organic coating with the adhesion to the steel surface treatment industry has brought a significant impact. At present, the research on the transformation technology of pure zirconium salt has made great progress and fruitful results, Zirconium but there are still some problems such as insufficient mechanism of transformation, insufficient process stability and difficult practical industrial production. In the future research and development process, Zirconium the focus should be on:
(1) development and selection of low toxicity or non-toxic zirconium compounds;
(2) digging into the mechanism of in-depth study, using the new in situ research method to explore the film-forming process;
(3) to improve the stability of the conversion process to improve the practical application of adaptability;
(4) attention to the development of composite zirconium salt development direction, improve the zirconium salt conversion technology.
Zirconium and titanium chemical properties of lively, at high temperatures easily with the atmosphere of various gases react. In the welding, Zirconium the weld and heat affected area is easily polluted by hydrogen, oxygen, nitrogen and other gases in the air to produce hard and brittle compounds and produce brittle needle-like structure to increase the hardness and strength of the welded joint. , Toughness decreased, Zirconium corrosion resistance also dropped significantly. The activity of zirconium is higher than that of titanium, and the affinity of hydrogen, oxygen and nitrogen is stronger. The weld and heat affected zone and the backside in the welding bath and cooling are in the range of 350 ~ 400 ℃ or higher. under. Therefore, the weld, weld and heat affected area are fully protected to completely isolate the air.