Study On Gold Nanoparticles In Electroless Plating On Nonmetal Materials

With the development of science and technology, produce of new material, the study on metallized non-metallic material is extensive. On the basic of its properties, the material has the properties of conductivity, magnetic permeability, impact resistance, high temperature antioxidation capacity and electrocatalysis due to surface metallization. Non-metallic material is regarded as the hard electroless plating material because of no catalytic activity. Therefore, a strict pretreatment process prior was needed before plating. The purpose of pretreatment is to generate more active points for the metal atoms to deposit on. As we all know, nanoparticles are full of large surface area and have a great number of atomic on surface. They also have a lot of dandling bonds because of the unsaturation of surface atomic coordination. Therefore, a strong chemical activity and adsorption capacity are shown. Compare with other nanoparticles, gold nanoparticles are easy to prepare and stable relatively. In this thesis, gold nanoparticles were applied to activation processes for the pretreatment process prior electroless plating on plastic and ceramic. Electroless copper coating and nickel coating with excellent performance were prepared.Under the protection of sodium oleate, gold nanoparticles solution was prepared with chemical reduction method. Gold nanoparticles were characterized by ultraviolet-visible spectrometry and transmission electron microscope. The results showed that the gold nanoparticles we prepared were spherical, and the mean particle size is about 50nm with narrow distribution. The concentration of gold nanoparticles solution is 3.3×10-4mol/L. It is convenient, economic and can be used as activation solution for plastic and ceramic repeatedly.In the etching stage, non-polluting H2O2/H2SO4 solution was used to obtain a coarsening surface of ABS plastic. Then the gold nanoparticles were used as the activating agent. Compared to the palladium activation, pre-treatment process had been simplified, and the steps were reduced from the three-step to a two-step. All steps were carried out at room temperature. In the meantime, it overcame the precious waste of Cr6+and palladium and saved energy, thereby the environment pollution could be avoided. X-ray photoelectron spectroscopy (XPS) was used to test the substrate that had been activated. The results indicated that golc nanoparticles were adsorbed on the ABS surface successfully. Using the deposition rate as the evaluation index, the optimal technology parameters of electroless plating copper were obtained by the orthogonal experiments. The deposition rate was 5.027μm/h. The coating wa(?) smooth, uniform and had metallic luster. The scanning electron microscope (SEM), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS) were applied to detect th(?) surface morphology, crystal structure and component of the copper coating. The result(?) showed that the copper coating was uniform and dense. The product was indicated to be pun copper with crystal structural. The scratch test showed that the adhesion strength between tr(?) substrate and coating was excellent. The experimental results indicate that, the gol(?) nanoparticles have very strong catalytic properties, and adsorb on ABS plastic surface to forn a large amount of active centers to provide nucleation centers for the deposition of coppe atoms.The ceramic substrate was coarsened by NaOH and H2SO4/HF solution to increas(?) surface micro roughness. The "locking latch effect" which provided an essential foundation fo the formation of active center and coating was realized. Gold nanoparticle solution was use(?) for activation, and the nanoparticles were adsorbed on the surface of ceramic to provid nucleation centers for the electroless plating copper and nickel. By controlling th concentration of components in plating solution, temperature and loading capacity, we studie(?) the effect of technology parameters on the deposition rate of electroless copper and electroles nickel. The optimal technology parameters of electroless plating on ceramic were obtained b the single factor experiments. The coating was characterized by SEM, XRD, EDS, XPS an adhesion test. In contrast with the technology of palladium activation, the surface morpholog of coating which was prepared in the manner of gold nanoparticle activation was uniform dense and the adhesion strength was well. The SEM indicated that the particle size O electroless nickel coating is smaller and more uniform. The surface of coating showed n cracks and the adhesion strength was excellent after heat treated at 400℃for an hour. Th XRD analysis indicated that the electroless nickel coating was with the structure of amorphou Ni and Ni3P crystal structure appeared after the process of heat treatment.