High Corrosion-Resistant and Long-Life-Span Electroless Nickel Process

摘要

Corrosion is one of the most severe problems faced by industry today. The economic impact of corrosion is significant and includes costs for equipment replacement, maintenance, excess capacity, increased inventory, greater technical support, and high investment. Electroless nickel (EN) has progressed because of its well-distributed thickness, good wear resistance, corrosion resistance (CR), no dependence on current intensity, etc. The electroless deposition of Ni-P alloys is widely used in diverse fields such as the aerospace, automation, electronics, nuclear, oil and gas production, and valve industries. The CR of EN is usually very good in 1 metal turn over (MTO). But with the plating process going on, the CR becomes rapidly worse. What's more, the life span of the EN solution (determined by the sediment of nickel phosphite or the decomposition of EN solution) is less than 6 MTOs. The higher the CR of the EN layer, the lower proportion of goods damaged and the lower the cost in the full life span of the products. How to select the formula for preparing the EN solution and properly control the plating process is the first question, when you want to produce a protective layer and put it into industrial production. The life span of the EN solution is measured by MTO, which is the ratio of the amount of nickel sulfate added to that at the beginning. The higher the life span of EN solution the higher utilization ratios of nickel sulfate and sodium hypophosphite, so the production cost is decreased, the productivity of harmful materials becomes less, and the environmental pollution is reduced.