Chemical nickeling liquid and its process

Abstract

The present invention discloses a chemical nickel bath that is composed of solvable nickel salt, complexing agent, buffer, pH regulator of alkali metal hydroxide, and stabilizer. The operation temperature of the bath is 50-55DEG C, and the pH value is 7.0-8.5. This invention is a mesothermal alkali chemical nickel plating process that has low energy consumption and stable bath. Furthermore, the pH value is nearly neural and not regulated by ammonia, which saves the cost and improves the work condition.

Description

technical field [0001] The invention relates to the field of electroless plating, in particular to an electroless nickel plating solution and process. Background technique [0002] Electroless plating is a process in which metal deposition is produced through a controllable redox reaction under the catalysis of metals. It is also known as autocatalytic plating or electroless plating. [0003] To achieve electroless plating, the following conditions should be met: (1) the potential of the reducing agent in the solution to be oxidized is significantly lower than the potential of the metal ion to be reduced, so that the metal may be deposited on the substrate; (2) the prepared The solution does not spontaneously decompose, and the metal deposition process occurs only when it is in contact with the catalytic surface; (3) When the pH and temperature of the solution are adjusted, the reduction rate of the metal can be controlled, that is, the plating speed can be adjusted; (4) It...

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Problems solved by technology

[0012] For example, in the Chinese patent application, the application number is 02815773.7, which discloses a kind of electroless nickel plating bath and its method, using sodium hypophosphite Sodium hypophosphite as reducing agent, alkali metal hydroxide, alkaline earth metal hydroxide, etc. as pH adjustment Although there is no need to use ammonia water, its process operation is very complicated. Since the operating temperature is about 80-90°C, and the chemical plating solution must be cooled to below 60°C before adjustment with alkali metal hydroxide, so in this application In technology, to adjust the pH value, first of all, part of the high-temperature plating solution should be regularly or continuously removed from the plating tank, cooled to below 60°C, the pH value of the part removed from the plating solution is detected, and a pH regulator is added to adjust the pH After the value is reached, this part of the plating solution is sent back to the plating tank, which not only increases the equipment cost, but also is not convenient for production operation