Study On Electroless Plating Nickel-Phosphorus- Nano Particles Composite Coating On Wood Surface

Wood is a natural and renewable biomaterial and often used for decoration due to its sound insulation, temperature and humidity-controlling properties. However, dry wood is a poor conductor, which limits its application in EMI shielding field. Electroless plating is one of the effective approaches to make wood surface with metal modification. Electroless nickel alloys deposition has become more popular for many industrial systems because of their stability, easy operation and low cost. However, Ni-P alloy is easily corroded in wet condition, which limits the application of materials for a long time. Therefore, it’s the main research content to improve the corrosion resistance of plated veneers. In this work, Ni-P-nanoparticle composite coatings were preparated by adding the nanoparticles (Al2O3, SiO2 and SiC) to the plating solution. The birch veneers were used as substrate and the surface resistivity was used as reference value to obtain the ptimal surfactant and nanoparticles concentration of plating solution. In addition, the structure, composition and properties of the composite coatings were analyzed and characterized. The results of the study are as follows:In the plating solution that preparation of the wood-based Ni-P-nano Al2O3 composite materials, when the concentration of PEG-4000 and Al2O3 nanoparticles were 0.5 g/L and 1 g/L, respectively, the plated veneer showed high electrical conductivity with surface resistivity of 75.45 mΩ/cm2. In the plating solution that preparation of the wood-based Ni-P-nano SiO2 composite materials, when the concentration of PEG-4000 and SiO2 nanoparticles were 0.5 g/L and 2 g/L. respectively, the plated veneer exhibited high electrical conductivity with surface resistivity of 116.12 mΩ/cm2. In the plating solution that preparation of the wood-based Ni-P-nano SiC composite materials, when the concentration of PEG-4000 and SiC nanoparticles were 0.5 g/L and 1 g/L, respectively, the plated veneer showed high electrical conductivity with surface resistivity of 134.12 mΩ/cm2.EDS analysis results determined that the three types of Ni-P-nanoparticle composite coatings containing nanoparticles. XRD analysis results demonstrated that the three kinds of composite coatings obtained from this experiment were all nano-crystalline. SEM images showed that the surface of birch veneer was completely covered with continuous and uniform coatings, and the special structure of wood still existed.Wettability test results demonstrated that birch veneers plated with three kinds of Ni-P-nanoparticle composite coatings exhibited good hydrophobic property with the water contact angle of over 125°. Tensile test results showd that three kinds of composite coatings firmly adhered to the wood surfaces and the bonding strength was greater than 1.2 MPa. EMS test results showd that electromagnetic shielding effectiveness of three kinds of composite coatings was over 50 dB in frequencies ranging from 9 KHz to 1.0 GHz. Corrosion resistance test results found that in 3.5% NaCl corrosion solution, the corrosion resistance of three kinds of composite coatings were higher than that of Ni-P plated veneer. In all composite coatings, Ni-P-nano Al2O3 composite coatings showed the best corrosion resistance with a polarization resistance of over 3 kd/cm2.The wood-based composites with electromagnetic shielding effectiveness and corrosion resistance were obtained by using electroless Ni-P-nanoparticles plating on wood surface. This method provides a new way for wood functional improvement, and plays a positive role for the development of wood industry.