Plating Prepared By Si <sub> 3 </ Sub> N <sub> 4 </ Sub> - Co Composite Nano Powder

The objective of the paper is to get nano SisN^Co composite powder of high quality by electroless plating at normal temperature. The rules were researched that the composition of electroless plating solution and reaction condition had an influence on the reaction of electroless plating of nano-Si3N4 with ultrasonic wave. The best composition of electroless plating solution was obtained. Mostly tasks as follows:It was realized that electroless cobalt plating of nano-Sis^ at normal temperature with ultrasonic wave. The problem of dispersion of the nano-powder was solved.The morphologies of powder were observed by using high-resolution transmission electron microscopy(HRTEM); X-ray diffraction (XRD) pattern was used to analyze the phases of the powder; Energy dispersive X-ray spectroscopy(EDX) was used to analyze the component of composite powder.Through parallel experiments, the rules were studied more that the composition of electroless plating solution and reaction condition affected on the reaction of electroless cobalt plating of nano-SiaN4 with ultrasonic wave, such as " induction period", the speed of reaction, appearance and morphology of composite powder, the component and phases of the plating et al."induction period" was reflected the quality of electroless plating solution ,and affected the efficiency of electroless plating, "induction period" was shortened with the increase of the concentration of NaH2?O2 ?I-hO and CoSO4. It was shortened by increasing the PH and the loading of powder.The speed of electroless plating was the result of the added weight divided by the "plating time". The experiments showed that these factors could increase the plating rate which the concentration of NaH2?O2 't^O, the PH and the temperature of electroless plating had been risen. The speed of electroless plating was increased with the increase of concentration of CoSCU. When the concentration of CoSC>4 was 30g/l, the plating rate was max. With the increasing of KNaC4H4O6 * 4H2O and NaaCeHsO? ?2H2O, the speed of plating was increasing when the concentration of them was low. However, when the concentration of them was enough higher, theinif.plating rate was decreasing.Phosphorus was more in composite powder with the decreasing of the PH of solution, it is also more when the concentration of Nal-^POa ?I-bO is increased. If Phosphorus was adequacy in composite powder, Co-P alloy coating becomes non-crystalline.The quality of composite powder was better, and the stabilization of solution is improved with the increase of the PH from 9.5 to 11.0. The cladding of composite powder was of higher uniformity and dispersion with the increase of the concentration of NaH2P02 ?H20(20~40g/l) and CoS04(18~40g/l).When the bath loading is lower than 10g/l , the metal covered was full and composite powder was thin and disperse well. The Co-P alloy coating of powder was more and thickness of plate was incrassate with the decreasing of the loading.When the nano-Si3N4 was thinner and drier, and the effect of activation was better, the speed of plating was increased and "induction period" was shortened.The best composition of electroless plating solution and reaction condition was optimized by comparison experiment. The composite power was analyzed by EDX , XRD , TEM. The result indicated that the cladding of composite powder was of high uniformity and dispersion .