A kind of electroplating solution used for hard chrome plating by nickel-cobalt tungsten sulfide nanocrystalline alloy electroplating for piston ring and its production process

Abstract

The invention relates to an electroplating liquid adopting nickel-cobalt tungsten sulfide nanocrystalline alloy electroplating for piston rings instead of hard chrome plating. The electroplating liquid comprises the following components according to the ratio: 100-165 g / l of nickel sulfate, 80-136g / l of cobaltous sulfate, 40-50 g / l of boric acid, 3-9 g / l of potassium chloride, 5-38 g / l of nano tungsten disulfide plating pulp, 3-5 g / l of a brightening agent and saccharin, 0.3-0.7 g / l of a wetting agent (lauryl sodium sulfate), and 20 g / l of sodium citrate. A production process of the electroplating liquid adopting nickel-cobalt tungsten sulfide nanocrystalline alloy electroplating for piston rings instead of hard chrome plating comprises the following steps: (1) checking before plating, (2) product hanging, (3) high-temperature degreasing, (4) electrolytic degreasing, (5) washing with deionized water, (6) activation with weak acid, (7) nickel preplating, (8) electroplating, (9) washing and recycling, and (10) heat treatment for removing hydrogen. Through the adoption of the electroplating liquid adopting nickel-cobalt tungsten sulfide nanocrystalline alloy electroplating for piston rings instead of hard chrome plating, and the production process of the electroplating liquid, which are provided by the invention, the overall performance and the life cycle of an electroplated layer can completely exceed those of the existing hard chrome plated layer, the environment is protected, and the energy is saved.

Description

technical field [0001] The invention relates to the technical field of electrochemistry and metal surface treatment, in particular to an electroplating solution used for electroplating a piston ring with a nickel-cobalt-tungsten sulfide nanocrystalline alloy instead of hard chrome plating and a production process thereof. technical background [0002] Wear-resistant and pressure-resistant coatings are required in the automotive, mechanical, and electronic industries. At present, hard chromium plating, vapor deposition, and composite plating are mostly used for processing, and some even directly use polished blanks. Among the main paired friction pairs of internal combustion engine cylinder liner / piston ring, crankshaft / bearing bush, camshaft / tappet, valve / valve seat, plunger pair, etc., the working condition of the cylinder liner / piston ring pair is the worst, and the wear is also the worst. Seriously, it directly affects the service life of the internal combustion engine. ...

AI Technical Summary

Problems solved by technology

[0003] The surface of electroplated hard chromium is extremely brittle, and it is easy to break and fall off. The hard particles that fall off will aggravate the wear of the cylinder, and the hardness will decrease with the increase of temperature. There are microcracks in the chrome plating layer, which inevitably produces penetrating cracks, resulting The corrosive medium penetrates from the surface to the interface and corrodes the substrate, causing rust spots or even peeling off on the surface of the coating; the deposition speed of the electroplating process is slow, and it often takes 2 to 3 shifts to plate a coating with a thickness of 0.2-0.3 mm, which is not conducive to the application of thick coatings

In addition, the hard chromium electroplating process consumes a lot of power and is extremely toxic. The chromic acid solution used in the chromium plating process will produce chromic acid mist and waste water. Even if corresponding measures are taken, it will be poisonous to the human body and pollute the environment. , electroplating hard chromium has been basically banned abroad, and this process is gradually canceled in China

Images