The Effect Of Ultrasonic On The Amorphous Ni-W-P And Ni-W-P/nano-ZrO₂ Electrodeposits

Metal matrix nano-composites (MMNCs) is one sort of the MMCs which keeps at least one dimension of its intensified phase into nano scale (0-100nm). These dispersed nano scale intensified materials could enhance the physical and mechanical properties of composite materials.Amorphous materials are order in long distance and out-of-order in short distance in its structure. So amorphous materials have several special properties due to their special structure, such as high hardness, corrosive-resistance, etc., and these make amorphous materials have a all-right applied prospect.In this paper, Ni-W-P amorphous alloy coating and Ni-W-P/nano-ZrO₂ composite coating were prepared by electroplating method under ultrasonic field. Seeing about the influences of different electrolyte particle-addition on plating-speed, micro-hardness and wearability, and compared with the coating prepared without ultrasonic field. SEM and XRD were adopted to show the surface morphology and inner structure, moreover, the influence of ultrasonic field to electroplating process was studied. In the meantime, the influences of annealing time and temperature to the structure and properties of coating were also studied.The results of XRD indicate, the adoption of ultrasonic could minish the size of crystal grain, the average crystal grain of Ni-W-P amorphous alloy prepared without ultrasonic field was 1.25nm, and after the adoption of ultrasonic field, Ni-W-P amorphous alloy with the average crystal grain size of 1.23nm was prepared. Further more, the Ni-W-P amorphous alloy prepared with ultrasonic field showed an improvement in corrosive-resistance when compared with the Ni-W-P amorphous alloy prepared without the ultrasonic field, and a slight fall in micro-hardness and plating-speed.The adoption of ultrasonic field could obviously improve the dispersing condition of nano-particles in the electrolyte, and hence minished the size of particles composited in the coating. The uniformly dispersed nano-particles resulted in a better corrosive-resistance of Ni-W-P/nano-ZrO₂ composite coating than the Ni-W-P/nano-ZrO₂ composite coating prepared without ultrasonic field, and a fall in micro-hardness and plating-speed. Moreover, no matter ultrasonic field was adopted or not, the Ni-W-P amorphous alloy had a better corrosive-resistance than the Ni-W-P/nano-ZrO₂ composite coating before anneal. After analyzed the component of the coating before and after the anneal, we found that the Ni3P new phase which separated out during the anneal and the oxidative film could enhance the micro-hardness and corrosive-resistance of the coating, respectively. The Ni-W-P/nano-ZrO₂ composite coating prepared with ultrasonic field had a better corrosive-resistance and oxidative-resistance than the Ni-W-P/nano-ZrO₂ composite coating prepared without ultrasonic field after anneal because of its well-dispersed nano-particles, whereas a lower micro-hardness than the Ni-W-P/nano-ZrO₂ composite coating prepared without ultrasonic field. No matter adopted ultrasonic field or not, all the properties of Ni-W-P/nano-ZrO₂ composite coating were better than the Ni-W-P alloy coating after anneal.