As for the composition of plating solution
Electroplating method:
The plating solution mainly consists of the main salt (providing metal ions, such as nickel sulfate, ammonium nickel sulfonate), anode activator (such as nickel chloride, sodium chloride), buffer (boric acid) and wetting agent (sodium dodecyl sulfate) and so on.
Chemical plating method:
The plating solution usually contains metal salts (e.g. nickel sulfate, nickel chloride), reducing agents (sodium hypophosphite, formaldehyde, borohydride, etc.), complexing agents (sodium succinate, etc.), stabilizers (thiourea), and pH adjusters (NaOH, HCl, etc.).
Process Characteristics
Electroplating method
Electricity and onductive treatment are required:
an external power supply is needed to provide electrical energy to drive the reaction, and since diamond itself is an insulator, a conductive film or special treatment is usually required to make the surface conductive before electroplating.
Relatively fast deposition speed:
under the appropriate current density and other conditions, the metal ions are deposited relatively quickly, and a certain thickness of coating can be obtained in a relatively short period of time.
Limited uniformity of plating layer:
The uniformity of plating layer is not good, and it is easy to pile up the plating layer in the sharp corners and other parts of the diamond, which affects the dispersion of diamond particles.
Chemical plating method
No need to energize: No external power supply is required during operation, relying on the driving force of the chemical reaction itself to realize the deposition of metal.
Slower deposition speed: the chemical reaction rate is relatively slow, the plating speed is usually slower than the electroplating method, and it takes longer time for mass production.
Good plating uniformity: It can uniformly wrap the diamond particles, and even the complex shape of the diamond, including fine pores, grooves and other parts of the diamond can be uniformly plated, and the plating layer has good denseness.
Cost and environmental protection
Electroplating method
Higher equipment cost: It needs to be equipped with power supply, plating tank and other equipment, so the equipment investment cost is relatively high.
Relatively little environmental pollution: waste water such as degreasing and pickling can be polluted if not handled properly, but compared to chemical plating, there is no pollution problem caused by a large number of chemicals.
Chemical plating method
Higher material cost: the cost of chemicals such as reducing agent in plating solution is higher, and the stability of plating solution is poor, short life, and easy to fail due to the accumulation of side reactions after several times of use, resulting in the comprehensive cost may be higher.
Higher environmental pollution: improper handling of chemicals such as reductants will cause higher environmental pollution, and the subsequent waste water treatment is more complicated.
Combining force and performance
Electroplating method: metal ions are deposited through the action of electric field, and the bonding force with diamond is mainly metal bonding, after appropriate pretreatment and process control, it can also obtain better bonding strength, but there may be local uneven bonding force.
Chemical plating method: the deposition of metal atoms on the surface of diamond is carried out through chemical reaction, the combination at the atomic level is more uniform, the bonding strength between the formed plating layer and diamond is more uniform, which can better improve the bonding performance between diamond and the base material.
