The characteristics of chemical plating are simple equipment, no need for electroplating power supply, uniform thickness of coating can be obtained for workpieces of various shapes, low aging treatment temperature, small deformation, etc. Electroplating uses electrical energy to reduce metal cations to metal and deposits on the cathode, while electroless plating uses chemical reduction methods to reduce nickel cations to metal nickel and deposit on the catalytic metal surface without DC power.
Since iron, nickel and other metals and alloys have catalytic effects, the above alloy materials can be used to deposit Ni-P alloys, and once started, due to the self-catalysis of nickel, this redox reaction will be uniform throughout the plating. Continue to go on, so as to obtain a certain thickness of Ni-P alloy coating.
When the phosphorus content of the coating is relatively high, generally 8% to 13.5%, the coating structure is amorphous. This structure has no structural defects such as grain boundaries and dislocations, and does not produce intergranular corrosion and stress corrosion. Provides better corrosion resistance than electroplated coatings. Due to the high hardness of Ni-P alloy coating, in the deposited state, the hardness of the coating is 500~600HV and 980~1100HV after heat treatment at 400°, so it has wear resistance equivalent to or better than that of hard chromium plating.
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