Study Of Technology And Mechanics On Colored Electroless Plating

Ingredients of the bath processing parameter and coloration method are studied deeply with respect to colored electroless Nickle plating on 45steel.Ammonium molybdate and sodium hypophosphite are the chief formulation of coloring agent. Coloration after electroless Ni-P plating and color change after heat treatment are adopted. By means of multiple experiment ,optimum range of each ingredient consistency, tem- perature and mixing speed are deter- mined : 0.25-0.30 g/L ammonium molybdate, 80-0.90g/L sodium hypophosphite,temperature: 85-90℃, revolution of agitator: 50- 75r/min.Under the condition of the formulation and crafts, blue yellow purple skyblue and iridescent colour are got. Colored coating also can get color or chang color throu gh heat treatment of 240℃ 360℃ .But experiments approve that means of get color by the way of heat treatment is subjected to the temperature time influence, very unsteady and more difficult control.Wear resistance corrosion resistance composition and change are studied with the help of equipments,such as optical microscope ,M-2000 abrasion machine X-ray di-ffractometer ,on the coating of Ni-P and colored fore and after heat treatment. Performance and structure are compared between colored coatings and normal Ni-P coatings.The results of abrasion tests show that, under the condition of oil-free lubrication, after heat treament colored coating is more wear-resisting; Whether heat treament is carried out or not.,wear resistance of colored coating and Ni-P coating are equivalent.New phases are finded by X-ray diffractometer. Results of phase analysis display them to be Mo-Ni and Mo-P compound. It indicates that,in the course of coloration, complex chemical reaction is carried out in the bath. Particularly, Mo enter into the compound. Elementary explanation is done for color formation.The results of neutral salt spray tests show that,after heat treatment of 240℃, corro- sion resistance of normal Ni-P coating descends sharply ,but colored coating is a bit strengthened. However, if temperature of heat treatment is above 300℃, corrosion resistance will be descended.