Wood Electroless Nickel Plating And Electromagnetic Shielding Materials Made Of Nickel Plated Wood

To improve the wood surface decorate property, wooden material electricity conductive function and electromagnetic shielding property and to increase its utilization rate, the new functional wood and wooden composite material with electromagnetic shielding property are studied in this dissertation. The electroless plating is used in this dissertation. The basic theory of wood electroless nickel plating,solution composition and influencing factor are analyzed. The technology of nickel plating on wood veneers and particles are studied. Quantitative researches for electromagnetic shielding effectiveness of electromagnetic shielding wooden material made from nickel-plated veneers and particles are made. Organization structure of electroless nickel plating film are also studied.Research results are summed up as follows:1.The effect of plating solution composition and technology on wood electroless nickel plating depositing speed are studied .Under the conditions of main salt NiSO4 6 H2O is 50 g/L and reducing agent NaH2PO2 H2O is 60 g/L, Complexant mixture HOCOCH ( OH )2 CH2CO is 60 g/L and complexing agent HOCOCH2CH2COOH is 60 g/L, when pH is between 7.0 ~ 7.5, plating temperature is 80 癈, plating time is 20 min., we can get ideal metal deposition rate.2.Along with the increase of metal Nickel deposition, the surface resistivity of nickel-plated veneers decreases, while its conductivity increases and have anisotropy. The surface resistivity of parallel fiber direction is lower than that of perpendicular to fiber direction, in the scope of this laboratory measurements, the surface resistivity nickel-plated veneers of perpendicular to fiber direction is 1.34-- 3.45 times as high as that of parallel to fiber direction. The electromagnetic shielding effectiveness of nickel-plated poplar veneer can reach 31.8 decibels ~ 51.4 decibels. The electromagnetic shielding effectiveness of nickel-plated veneer is similar to plywood made from nickel-plated veneers.3.The extractive content from different tree species has great effect on electroless plating. The resin of Softwood and the tannic of hardwood cause plating liquid easily decompose. When extractive are excluded, wood electroless nickel plating can be done.4.Electroless nickel plating on Chinese Fir particles, make Chinese Fir particles have conductive function, the density of conductive particleboard made from nickel-plated particles changes between 0.57 g/cm3 ~ 1.12 g/cm3. When electromagnetic shielding material was produced using nickel-plated particles with smaller surface resistivity, it demonstrated smaller volume resistivity and better electromagnetic shielding effectiveness. A higher pressing pressure can improve electromagnetic shielding effectiveness of conductive particleboard to some extent. In experiments, electromagnetic shielding effectiveness can be measured in frequency 5 KHz -1500 MHz. It can reach 21.62 decibels -43.31 decibels.5.During plating nickel in wood, metal nickel not only deposit in wood surface, but also permeate into the cell wall and the cell cavity. In this experiment, the optical microscope was used to observe and analyze that nickel-plated veneer and we found Nickel depositing in the cell cavity, ray, pit, tracheae, and fiber of timber. When tree species are different, the route and structure that mental permeates into wood are also different.6.XRD has been used to study nickel-plated veneers and particles first time, the tendency of the relatively crystallization degree of cellulose of nickel-plated timber decreases, at the same time, XRD results show that Ni ( 111 ), Ni ( 200 )and Ni ( 220 ) diffraction summit exist in nickel-plated particles .The influence that structure of nickel-plated veneers and particles has on its properties is the result of timber micro structure and metal layer common role. In research, still discover that besides the factors such as main salt density, the density of reducing agent, temperature and pH value, the pretreatment course of timber matrix also affects structure of plating layer. Diffe...