What are the advantages of chemical plating compared to electroplating process

Electroplating is a process in which the metal ions in the plating solution are reduced and deposited as metal at the cathode (workpiece) under the action of an applied current, which is the process of obtaining electrons. This metal deposition is characterized by getting electrons from an external power source. Chemical plating is no external power supply metal ions to provide the electrons required for the reduction, but by the chemical reaction in the solution to provide, to be precise, by one of the chemical reaction - the reducing agent to provide.

Chemical plating has the following characteristics compared with electroplating process:

(1) The thickness of the plated layer is very uniform, the dispersion of the chemical plating solution is close to 100%, there is no obvious edge effect, almost a replica of the shape of the substrate (workpiece), so it is especially suitable for plating on surfaces of complex shapes, cavities, deep holes, and the inner walls of tubes and pipes. Electroplating method is difficult to do due to the limitations of uneven distribution of power lines. Due to the uniform thickness of chemical plating, and easy to control, the surface is clean and smooth, generally do not need post-plating processing, suitable for workpiece repair and selective plating;

(2) through the sensitization, activation and other pre-treatment, chemical plating can be carried out on the surface of non-metallic (non-conductors) such as plastic, glass, ceramics and semiconductor materials, while electroplating can only be applied to the surface of the conductor, so the chemical plating process is a non-metallic surface metallization. Therefore, chemical plating process is a common method of metallization of non-metallic surfaces, but also non-conductor materials plating before the conductive layer of the method;

(3) process equipment is simple, does not require a power supply, power transmission system and auxiliary electrodes, the operation of the workpiece can be correctly suspended in the plating solution;

(4) chemical plating is based on the substrate's autocatalytic activity in order to start plating, and its bonding is generally better than the electroplating. The plating layer has bright or semi-bright appearance, fine grain, dense, low porosity, some chemical plating layer also has special physical and chemical properties.

However, the electroplating process also has its own advantages that can not be replaced by chemical plating, first of all, can be deposited metal and alloy varieties far more than chemical plating, and secondly, the price is much lower than the chemical plating, the process is mature, and the plating solution is simple and easy to control.

Since the electroplating method can not do things chemical plating process can be completed, just because the chemical plating method has these obvious advantages and make its use more and more widely, at present in the industry has been mature and commonly used chemical plating species are mainly nickel and copper, especially the former.

Chemical nickel plating compared to electroless nickel plating has the advantage of:

(1) with hypophosphite or boride as a reducing agent of the plating bath obtained by plating Ni-P or Ni-B alloys, control the amount of phosphorus obtained by the Ni-P amorphous structure of the plating layer dense, non-porous, corrosion resistance is far superior to the electroless nickel plating, and in some cases even replace the stainless steel can be used;

(2) Chemical nickel plating layer is not only high hardness, but also can be adjusted through heat treatment to improve, so good wear resistance. Therefore, in some cases can even replace the use of hard chrome, more rare is the chemical nickel plating layer both good corrosion resistance and wear resistance;

(3) according to the amount of phosphorus in the plating layer can be controlled for magnetic or non-magnetic;

(4) brazing performance is good;

(5) has some special physicochemical properties.