The Study On The Controllable Property Of The Microstructure Of Electroless Nickel-boron Films

The Electroless nickel films have many excellent properties, such as uniformity, hardness, wear resistance and corrosion resistance. Now this technology in material surface treatment field has attracted many attentions. The electroless nickel-boron alloy films have been widely used in aviation, automotive, light industrial machinery and electronic technology owing to its good comprehensive performances. In the process of the nickel-boron alloy, it's still a tough task to control the microstructure of the coatings according to actual production needs. Therefore, this research analyzes the single factor which can influence the creation of the coating; at the same time the orthogonal experiment is designed, and the optimization of the coating is prepared; the third element is added to prepare ternary alloy plating; in the chemical plating process the auxiliary energy field is included. The microstructure of the coating is researched to sum up the control measures.The results of the study show that, each bath component of the solution and operating conditions of the plating will affect the plating speed and the stability of solution, it was found that the main factors are the reducing agent, complexing agent, plating temperature and pH value.In the electroless nickel plating process, the dosage of the nickel salt, complexing agent and reductant, decided the structure of the coating.The optimal method for preparation by this research is: NiCl2 (30 g/L), ethylenediamine (40 mL/L), NaBH4 (0.15 g/L), and the method for plating was repeated for several times.This research also studies the three elements coating preparation technology, and the results show that the addition of the third element Mo can affect the coating organization form, and the dosage must be controlled in appropriate range. The dosage of Na2MoO4 according to the result of research is about 4 g/L.Electroless in the condition of the ultrasonic wave and current are also studied. The results showed that ultrasonic has a positive effect on the formation of crystalline coatings, while the effect of the current condition is poorer.The coatings obtained by the optimization of process, have a good performance in hardness, adhesion, corrosion resistance and so on.