Phosphating solution and preparation method thereof

Abstract

The invention provides a phosphating solution and a preparation method thereof. The phosphating solution is made from the following raw materials, by weight, 15%-20% of phosphoric acid, 6%-10% of zinc oxide, 20%-25% of zinc nitrate, 1%-5% of ethylenediamine tetraacetic acid, 0.5%-2% of citric acid and the balance water. According to the normal-temperature and quick phosphating solution, the time of a phosphating film copper sulfate droplet test reaches 45 sec, the time of a neutral salt spray test reaches 4 hours, paint film adhesive force reaches 0 stage, meanwhile, the phosphating solution has the characteristics that the phosphating time is short and the using temperature is low, the production efficiency is improved, and a great deal of energy is saved.

Description

technical field [0001] The invention relates to the technical field of phosphating solution, in particular to a normal-temperature fast phosphating solution and a preparation method thereof. Background technique [0002] With the rapid development of the metal processing industry, the phosphating process is widely used in metal surface treatment, especially in the pre-treatment of painting (or spray painting). Most of the phosphating solutions currently used are medium and high temperature phosphating solutions (use temperature 55°C-95°C). Unfavorable factors such as large investment in chemical equipment, high energy consumption, large acid mist, poor solution stability, many sediments, cumbersome adjustments, and high pressure on environmental protection. [0003] Chinese patent CN 102703889A discloses a low-temperature one-component zinc-based phosphating solution and its preparation method. The components and their contents in the low-temperature one-component zinc-base...

AI Technical Summary

Problems solved by technology

However, this patent has the following disadvantages: (1) When preparing the low-temperature one-component zinc-based phosphating solution, the nitric acid added produces a large amount of yellow toxic and harmful smoke, which greatly endangers the health of production personnel

At the same time, nitric acid is highly corrosive, which increases the risk factor of production personnel

(2) Sodium chlorate in this patented formula is a strong oxidizing substance, while hydroxylamine sulfate is a strong reducing substance, and the two will produce violent explosive reactions

At the same time, the effectiveness of the composite accelerator is greatly reduced, and it may even cause yellowing and unevenness of the phosphating film due to insufficient accelerator.