Electroless Plating Ni-W-P Alloy On Piezoelectic Ceramic

In order to meet some special requirements for the using of the piezoelectric ,such as electric conductivity ,corrosion resistance ,sonic property and etc ,electroless plating Ni-W-P was studied in this paper .With the help of the perpendicular design methods ,the approximate bath was got and finally be actually revised by analysed the effect of bath components on the film's ability of anti-corrosion ,the deposition rate and the adhesive strength in detail. The film's composition, structure and crystal transformation was confirmed by XPS , XRD and DTA. Some electrochemistry equipments also(were used to get the polarization curves and AC impedance of the film. And the spectrophotometer was first used to analyse the film's composition .The film's component in different depths were investigated by using x-ray photoelectron and sputtering with Ar+. The result showed that the inner layer are dominatingly composed of Ni ,W, P and WO2, but the outer layer are mostly composed of oxides .XRD analysis indicated that the film's structure was determined by the P's content and was independent of the W's.The heat treatment experiment prove that the tungsten was useful to the stability of heat treatment, but adverse to the inner tensile strength .The heat treatment below 300 helpful to reduce the internal tensile strength, so the resistance to corrosionwere risen. But has fallen above 400 degree. The film starts to crystallize at 362 degree and all were crystallized at 407 degree. Then the amorphous is not exit again and the resistance to corrosion is worsen. This intend also can be gained from the polarization curve AC impedance and the metallurgic photographs of the films after heated at different temperature .The film have excellent corrosion resistance in the seawater ,the vitriol ,waste water of the oilfield and the hydrochloric acid ,so it can meets the requirement of applying .Palladium test indicated that the bath also has distinguish stability .