Electroless nickel plating is the fastest growing kind of electroless plating. The plating bath generally uses nickel sulfate, nickel acetate, etc. as the main salt, hypophosphite, sodium borohydride, borane, hydrazine, etc. as reducing agents, and various additives are added. Work in an acidic solution at 90°C or a neutral solution or alkaline solution close to room temperature. It can be divided into two categories: electroless nickel-phosphorus plating and electroless nickel-boron plating based on the difference of reducing agent used. The coating shows superiority in uniformity, corrosion resistance, hardness, solderability, magnetism, and decoration.