Study On Preparation Technology Of Electroless Nickel Plating On Acrylic Resin Microspheres

The electroless nickel plating technology on some matrix which have autocatalytic nature, such as copper, iron, and steel, was ripe, and it has been widely used so far. However, the electroless nickel plating on hard substrates like the polymer powder materials, magnesium alloy and aluminum alloy, still have many issues that need to break through, such as adhesion, coating density, electrical conductivity, wear resistance, heat resistance, etc. Polymer powder composites, also known as core-shell material, one of which is polymer material for the shell and metal material as a core, and the other is a metallic material coated on a polymer core. In the past decades, the former received more attention, which mainly used in biological medicine. The latter received extensive attention in recent years. After metallization process, polymer powder materials can be obtained conductivity, magnetic, catalytic materials, such as metal, and can also have lightweight, plasticity, and good color retention as polymer materials. It can be applied into all aspects of the military, medical, electronics, chemicals, etc. And get a lot of attention in recent study of composite materials. Currently, the use of chemical plating method to metalized plastic powder have been reported in many studies, but the in-depth studies on the chemical plating roughened condition is still relatively little.In this study, chemical plating process in an acrylic resin microsphere surface coated with a layer of nickel is to obtain a light absorbing coating material. Since the non-metallic does not have the self-catalytic activity in chemical nickel plating solution, substrate surface must be special treatment in order to obtain the non-metallic substrate with a good coating surface. The acrylic resin microspheres get some hydrophilic under aqueous conditions by oil, such as surface roughening or treatment, and then obtain nickel clad in the nickel plating solution successfully. And the surface of the microspheres and coating were analyzed by infrared spectroscopy, scanning electron microscopy, spectrum analysis.The results show that the use of potassium dichromate in concentrated sulfuric acid to the base of the experiment, the optimum coarsening temperature is 70℃, the coarsening time is 60-90mins, there is little or no chemical modification of the remaining material. Meanwhile, the results of electroless nickel plating on acrylic resin microspheres after pretreatment show that electroless nickel can occur at a reaction temperature which greater than 30℃. With rising of the plating temperature and the extension of etching time, the starting time of microspheres’plating speed up, and surface defects on acrylic resin microspheres increasing, becoming small, and the distributing more uniform. Meantime, the particle size of nickel deposited on the surface of microspheres decreases, the electroless plating layer is smoother, higher density, the adhesion between the substrate and the coating enhanced, obtaining more thick nickel plating layer within the same time. When the temperature is higher than plating 60℃, producing large amounts of free nickel powder bath in the bath stability which will be destroyed. Under alkaline conditions, the optimum temperature for nickel plating is 40～50℃.