A kind of electroless plating method based on reducing water-based solution bath preheating

Abstract

The invention discloses a novel chemical plating method based on reductive water base solution bath preheating. The method comprises three main steps of surface adjustment, reductive water base solution bath preheating and chemical plating. Bath liquid is 0.25-100.0 g / L sodium hypophosphite water base solution; and the relation between the temperature Tph of the bath solution for preheating and the temperature TEP of chemical plating liquid is that Tph is in an interval of TEP-30 DEG C-TEP+20 DEG C. The method has such characteristics as good protection effect on workpieces in preheating period and in transfer process after preheating, short deposition induction period in chemical plating and high and stable plating layer quality. The method is specifically suitable for high-quality and high-efficiency chemical plating of difficult-plated materials, high-chemical-activity materials and products thereof.

Description

technical field [0001] The invention belongs to the technical fields of material surface processing engineering, material corrosion and protection engineering, and remanufacturing engineering, and in particular relates to a new chemical plating method based on preheating of a reducing water-based solution bath. Background technique [0002] As a low-temperature liquid phase forming technology characterized by "stack forming and layered manufacturing", electroless plating not only has mild conditions, but also has a wide range of processing objects, strong throwing and deep plating capabilities, good profiling effect, simple process, energy saving, and Material saving, environmental protection, and the coating is firmly bonded to the substrate, which can significantly improve the corrosion resistance, hardness and wear resistance, weldability, electrical conductivity, decoration and anti-fouling properties of the material. Therefore, the electroless plating technology has bee...

AI Technical Summary

Problems solved by technology

[0004] Although the above-mentioned conventional practice simplifies the process, there are at least two major defects in two aspects: one, before entering the plating solution, the workpiece is either directly exposed to the air, or only covers a non-protective thin liquid film, and is actually in an unprotected state. Therefore, it is inevitable to be subjected to atmospheric corrosion, and the surface rapidly and spontaneously forms oxide films that are fatal to the induction of electroless plating deposition reactions, the bonding force of the coating / substrate, and the uniformity and density of the coating.

However, there are also deficiencies, mainly including: because hot water or water-based alkaline dilute solution is used as the working medium, the working medium and its liquid film cannot provide effective protection for the workpiece substrate. During or after the transfer, it even promotes the corrosion dissolution or passivation of the substrate, such as the oxidation of magnesium and magnesium alloys with high chemical activity in hot water, the oxidation of aluminum, zinc and other metals and their alloys in lye, and the oxidation of iron-based Passivation of materials in alkaline media, etc., is not conducive to normal plating or leads to deterioration of coating quality

In addition, the "catalytic effect" of hot water or water-based alkaline dilute solution on the plating process is only based on the comprehensive effect of the heat storage of the workpiece before plating, the heat release of acid-base neutralization, and the increase in the pH value of the micro-area plating solution. It is not beneficial for the workpiece / plating solution to quickly adapt to each other after the workpiece enters the tank (including but not limited to the wetting process of the plating solution on the surface of the workpiece and the process of important components of the deposition reaction such as mass transfer and adsorption of reducing agents), so it will affect the quality of the coating. The improvement effect is limited