Why is the zinc-nickel alloy coating of the ball valve suitable for marine and corrosive harsh working conditions?

The reason why the zinc-nickel alloy coating of the ball valve can adapt to marine and corrosive harsh working conditions is mainly due to its unique corrosion resistance and long-term stability. The zinc-nickel alloy coating usually contains 12%-15% nickel, and it performs better in electrochemical protection than ordinary galvanized coating. On the one hand, zinc corrodes preferentially as a sacrificial anode, protecting the substrate from erosion; on the other hand, the addition of nickel promotes the formation of a dense passivation film on the surface of the coating, which greatly reduces the corrosion rate, especially in the chloride ion-rich seawater environment. This dual protection mechanism enables the zinc-nickel alloy coating to maintain long-term protection under harsh working conditions.

In the salt spray test, the performance of the zinc-nickel alloy coating far exceeds that of the ordinary galvanized coating. The zinc-nickel alloy coating of the ball valve can pass the salt spray test for more than 1,000 hours, while ordinary galvanizing can usually only last for 72-240 hours. In the marine environment, the corrosion rate of zinc-nickel alloy is only 1/5 to 1/10 of that of ordinary galvanizing, which means that it can withstand high-salt and high-humidity environments for a long time and effectively avoid the generation of red rust. This excellent salt spray resistance makes it particularly suitable for harsh application scenarios such as ships and offshore platforms.

The chemical corrosion resistance of zinc-nickel alloy coating enables it to cope with a variety of harsh working conditions. It can effectively resist the erosion of corrosive media such as seawater, acid rain, hydrogen sulfide and carbon dioxide, so it performs outstandingly in environments such as offshore oil platforms and chemical pipelines. In addition, the addition of nickel inhibits the excessive dissolution of zinc and extends the service life of the coating. At the same time, the zinc-nickel alloy coating has a higher hardness, far exceeding the ordinary galvanized layer, making it more resistant to wear and erosion under high pressure or particle-containing media. Its wide temperature adaptability also ensures that the coating will not fail due to oxidation or embrittlement in extreme temperature environments.

Compared with other surface treatment methods, zinc-nickel alloy coating has obvious advantages in corrosion resistance and comprehensive performance. Ordinary galvanizing has a short salt spray test time and is prone to white rust or red rust; although chrome plating has good corrosion resistance, it has environmental restrictions and brittleness problems; Dacromet coating is resistant to high temperatures but lacks mechanical strength. In contrast, zinc-nickel alloy coatings are balanced in terms of salt spray resistance, chemical corrosion resistance, mechanical strength and temperature adaptability. Although the cost is higher, it is more economical in long-term use.

The excellent performance of zinc-nickel alloy coatings makes it widely used in many industrial fields. In marine engineering, it is used in ship pipelines and offshore oil platforms, and can effectively resist high salt spray environments; in the energy and chemical industry, it is suitable for acidic oil and gas pipelines and refining equipment, and resists the corrosion of hydrogen sulfide and carbon dioxide; in the field of heavy machinery, its high hardness and high pressure resistance make it an ideal choice for hydraulic systems.