Electroless deposition of the NiP-ZrO2 composite coatings
Lucjan L. Duda, Alicja Turkiewicz-Głęboki Politechnika Wrocławska, Instytut Chemii Nieorganicznej i Metalurgii Pierwiastków Rzadkich, ul. Smoluchowskiego 23, 50-372 Wrocław
Annals 3 No. 6, 2003 pages 35-38
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abstract Nickel-composite coatings were deposited by electroless method and zirconium oxide was used as a dispersing agent. The bath composition was nickel (II) salt, KH2PO2 as a reducing agent, aminoacetic acid as a complexing agent, HCOONa as a buffor and Pb(NO3)2 to stabilize the bath. The obtained coating adheredwell to the base metal, was of uniform thickness over the entire surface, and the ZrO2 grains were completely enclosed in the nickel matrix which has been proved by microscopic photographs. The effect of temperature and zirconium oxide content in the bath solution on the deposition rate was investigated. The zirconium oxide content in the obtained composite layers was determined in relation to the conditions of the deposition process, and the microhardness of the obtained coatings was measured. It was found that the rate of building the NiP-ZrO2 coating rises as the temperature increases, and it is also dependent on the zirconium oxide content in the bath solution. The highest rate of the coating growth was observed at the ZrO2 concentration from 10 to 15 g/dcm3. The zirconium oxide content in the coating being formed is closely related to its deposition rate. The higher rate of coating growth, the higher ZrO2 content in the obtained coating. Key words: composite layers, electroless deposition, nickel, ZrO2