Tin coating passivator

Abstract

The invention discloses a tin coating passivator which comprises the following raw materials in parts by weight: 50-70 parts of trisodium phosphate, 2-5 parts of sodium tartrate, 2-5 parts of sodium molybdate, 2-5 parts of sodium citrate, 5-10 parts of cobaltous sulfate, 15-25 parts of phytic acid, 5-10 parts of oxalic acid, 10-20 parts of octadecylamine, 2-5 parts of nonylphenol polyoxyethylene ether, 4-7 parts of Tween-20, 5-10 parts of triethanolamine, 2-6 parts of 2,6-di-tert-butyl-4-methylphenol and 1-3 parts of N,N'-bis(1-methylpropyl)-1,4-phenylenediamine. The tin coating passivator provided by the invention does not contain high-valence chromium, does not cause environmental pollution or generate harm to a human body and has the advantages of corrosion resistance and oxidation resistance.

Description

technical field [0001] The invention relates to the technical field of passivating agents, in particular to a passivating agent for tin plating. Background technique [0002] In recent years, with the rapid development of the electronics industry, the demand for solderable tin coatings in electronic components and printed circuit boards has become higher and higher. At the same time, due to the stability of tin to organic acids and its harmlessness to the human body, Tin plating is widely used in the food industry. For a long time, the corrosion resistance of tin coating has been a special concern of manufacturers. [0003] In order to improve the oxidation resistance, corrosion resistance, sulfide blackening resistance, and the bonding force with the paint film of the tin plating layer, it is necessary to passivate the tin plating layer. The most commonly used passivation treatment method is to use 6-valent Chromium chromate cathodic passivation treatment. Chromate passi...