What are advantages of zinc nickel alloy finish for custom screw fastenerWhat are advantages of zinc nickel alloy finish for custom screw fastener
The main advantage of zinc-nickel coating is that it provides superior corrosion protection independent of post-treatment. The protection of zinc or zinc-iron coatings largely depends on the post-treatment, the most important of which is the application of the sealing layer. Once the post-treatment layer is destroyed, the corrosion will accelerate and produce more white corrosion products.
Any mechanical shock during assembly or use may damage the post-treatment layer.
In addition to the low corrosion of Zn-Ni alloy, it also has the characteristics of high wear-resistant alloy, and its hardness is as high as 500HV-550HV (14%Ni).
High-strength fasteners with a tensile strength of 1000n/mm² (performance level 10.9 and above) have the risk of hydrogen embrittlement. As the tensile strength of fasteners increases, this is a key factor.
Long-term experience and scientific research have shown that the uniqueness of zinc-nickel alloy is that it greatly reduces the risk of hydrogen embrittlement. Pure zinc coatings or other zinc alloy coatings have a much higher risk of hydrogen embrittlement.
This characteristic of zinc-nickel alloy makes it the first choice to replace cadmium in the aviation industry, even on high-strength steel materials of 1400n/mm. Therefore, zinc-nickel alloy should always be considered when making high-strength fasteners.
The last important point: zinc-nickel coating is the preferred choice, because of the thermal resistance of the coating, even if it is subjected to high temperatures, it can still maintain corrosion protection.
This makes zinc-nickel coatings the first choice, for example: for automotive applications-brake parts or engine compartment parts.
In recent years, the application of zinc-nickel alloys has been increasing, especially in the automotive industry. This is obviously a lot of favorable factors for this coating:
(1) Very high corrosion resistance.
(2) High wear resistance.
(3) Compared with pure zinc or zinc iron, the risk of hydrogen embrittlement is significantly reduced.
(4) Excellent thermal stability.
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