The fundamental difference between electroless nickel plating and electroplating nickel is that their principles are different

The fundamental difference between electroless nickel plating and electroplating nickel is that their principles are different

Electroplating requires additional current and anode, while chemical nickel plating relies on the self catalytic reaction generated on the metal surface.

2. Different electroplating speeds

Electroplating is faster than chemical plating due to the additional current; Electroplating is faster than chemical plating for nickel plating layers of the same thickness.

3. Different environmental performance

The majority of preservatives used in electroless nickel plating are food grade and do not use harmful substances such as lead, cadmium, cyanide, etc. Therefore, electroless nickel plating is more environmentally friendly than electroplating nickel.

4. The plating ability varies

If the plating solution can be soaked and the solute exchange is sufficient, the chemical nickel plating layer will be very uniform, basically achieving the effect of imitation; However, electroplating nickel has a weaker uniform plating ability than chemical nickel plating due to the influence of current density.

5. The deep plating ability varies in height

Chemical nickel plating can theoretically carry out full surface coating on all types of workpieces, but electroplating nickel cannot effectively carry out full surface coating on some complex workpieces.

6. Differences in coating adhesion

The bonding strength of chemically plated nickel layers is generally higher than that of electroplated nickel layers.

)The process is cumbersome and the cost is high. Compared to traditional processes, modern processes have made significant progress, but there are too many steps - mechanical polishing, alkaline oil removal, acid etching, activation, pre impregnation of intermediate layers, plating, etc. Many intermediate layers also need to be sensitized, activated, reduced, etc. again, which will inevitably increase costs and bring many adverse effects to subsequent processes.

2) Severe pollution and unsatisfactory coating quality. At present, the traditional chromium and fluorine containing processes are gradually shifting towards the development of chromium and fluorine free processes. However, the existing chromium and fluorine free processes are not yet mature, and the adhesion and corrosion resistance of the prepared nickel phosphorus coating cannot meet the requirements, making it difficult to carry out large-scale production.

3) The uniformity of the process is poor, and it is necessary to further improve the repeatability and controllability of the pre-treatment process to promote large-scale production.

4) Weak universality. Currently, most reports are on AZ91D The pre-treatment process of AZ31 magnesium alloy has different compositions and poor applicability for different grades of magnesium alloys. Based on the mechanism of processing technology and the correlation between different grades of magnesium alloys, a universal processing technology is designed and explored. Regular modifications and implementation are carried out for different grades of magnesium alloys, which is worth looking forward to.

In summary, based on the mechanism of pre-treatment technology and the characteristics of different grades of magnesium alloys, developing low-cost processes with simple processes, excellent coating performance, strong controllability, environmental friendliness, and strong versatility will be the research direction and development trend of chemical nickel plating pre-treatment for magnesium alloys.

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