1. Different functions
1. Nickel electroplating is mainly used as a protective decorative coating.
2. The performance of the electroless nickel plating layer has the following functions
(1) The electroless nickel plating process using sodium hypophosphite as the reducing agent obtains Ni-P alloy, which controls the plating layer. The phosphorus content in Ni-P amorphous structure coating can be obtained. The coating is dense, has low porosity, and has better corrosion resistance than electroplated nickel.
(2) The as-plated hardness of the electroless nickel plating layer is 450~600HV. After reasonable heat treatment, it can reach 1000-1100HV. In some cases, it can even be used instead of hard chromium.
(3) Depending on the phosphorus content in the coating, the coating can be controlled to be magnetic or non-magnetic.
(4) The friction coefficient of the coating is low, it can achieve oil-free lubrication, and its lubricity and metal wear resistance are also better than electroplating.
(5) Low phosphorus coating has good solderability.
2. Different principles
1. Nickel electroplating is a method of depositing a layer of nickel on the surface of ferrous or non-ferrous metal parts through electrochemical action.
2. The principle of electroless nickel plating is that under the catalytic action of the catalyst Fe, the hypophosphite in the solution catalytically dehydrogenates on the catalytic surface to form active hydride, which is oxidized into phosphite; active hydrogenation The substance reacts with the nickel ions in the solution to deposit nickel, which itself is oxidized into hydrogen.
3. Different uses
1. Electroplated nickel can be used as surface coating, but it is mainly used for chrome plating as a base to prevent corrosion and increase wear resistance, gloss and appearance. Widely used in manufacturing industries such as machines, instruments, meters, medical equipment, and household appliances. The product is used as a cathode and a pure nickel plate is used as an anode, and is hung into an electrolyte made of nickel sulfate, sodium chloride and boric acid for electroplating.
2. Since the electroless nickel plating layer has excellent comprehensive physical and chemical properties such as uniformity, hardness, wear resistance and corrosion resistance, this technology has been widely used. It is almost difficult to find an industry that does not use chemical plating. Nickel plating technology.
According to reports, the proportion of electroless nickel plating used in various industries is roughly as follows: aerospace industry: 9, automobile industry: 5, electronic computer industry: 15, food industry: 5, machinery industry: 15, Nuclear industry: 2, petroleum industry: 10, plastic industry: 5, power transmission industry: 3, printing industry: 3, pump manufacturing industry: 5, valve manufacturing industry: 17, others: 6.
Reference materials: Baidu Encyclopedia - Electroless Nickel Plating
Baidu Encyclopedia - Electroless Nickel Plating