Research Progress of Electroless Nickel-boron Coating
Electroless nickel-boron coating is a kind of nickel-boron alloy layer deposited on the surface of the substrate by electroless plating surface treatment. Its excellent hardness, wear resistance, corrosion resistance, electrical conductivity and excellent process operability make it used in many fields.In this paper, statistics were made on the publication of articles on electroless plating and nickel-boron coating in the past 20 years. Since the 21st century, with the improvement of material properties in industry, nickel-boron coating has gradually attracted the attention of the scientific community, and the number of articles published on nickel-boron coating in the academic field has increased significantly in the past 20 years. The proportion of articles about nickel-boron coating in the whole field of electroless plating has increased significantly.In this paper, the deposition process of nickel-boron electroless plating and the mechanism of plating with borohydride and boron-nitrogen compound were described by introducing the different morphological characteristics of the substrate at different deposition times and the typical surface morphology of cauliflower. The advantages and disadvantages of Ni-B coating prepared with the above two different reducing agents and the effect of the concentration of reducing agents and the change of boron content on the properties of Ni-B coating were discussed. After a wave of research on nickel-boron coating, in recent years, researchers have replaced the original heavy metal stabilizer by using new environmentally friendly stabilizers or giving up the use of stabilizers to achieve the purpose of green environmental protection. In the use of accelerators and new surfactants, further consideration was also given to how they could be used without causing harm to the environment and life forms. In addition to the use of ultrasonic assistance by technical means, the more suitable plasma nitriding post-treatment method could also replace the traditional heat treatment method to reduce the damage to the coating. The research of complex coating such as multilayer coating, ternary alloy coating and composite coating provided many researchers with good ideas, which not only improved the performance of coating to a certain extent, but also opened up innovative and attractive new development direction.Of all electroless nickel plating, the hardness of nickel-boron coating is by far the highest, and it has been reported that the hardness of nickel-boron coating containing 8wt.％ B is as high as 872HV100. The Taber wear index (TWI) of nickel-boron coating is between 1.2 and 2, and the wear resistance is the best when the temperature is about 300 ℃ . The electrochemical properties of nickel-boron coating have been discovered and widely used in recent years, and the electrochemical properties of nickel-boron/nickel-phosphorus double coating are more excellent. In addition, nickel-boron coating also has unexpected high reflectivity, low resistivity and excellent magnetic properties, and the resistivity of nickel-boron coating is generally in the range of 10-200 μΩ·cm, which increases with the increase of boron content in the coating.In this paper, the basic theory research, process research, properties and applications of electroless nickel-boron coating are reviewed, the research progress of nickel-boron coating is described, and the difficulties in the large-scale industrialization of nickel-boron coating and the replenishment of plating solution are pointed out. Similarly, the development of new non-toxic and pollution-free compounds, the improvement of coating thickness performance and the possible impact of cost fluctuations are some opportunities and challenges that will be encountered in the future in terms of environmental protection and cost. Finally, the idea of further research and new exploration of nickel-boron coating is conveyed, and the focus, future prospect, development trend and important value of nickel-boron coating research in the future are prospected.
国家科技期刊平台
NSTL
万方数据
