Investigation and Optimization of Ni-P-Zn Electroless Alloy Coatings

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Kordijazi, Amir | 2012

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Type of Document: M.Sc. Thesis
Language: English
Document No: 43108 (57)
University: Sharif University of Technology, International Campus, Kish Island
Department: Science and Engineering
Advisor(s): karam, SaeedAllah; Dolati, Abolghasem
Abstract:
An optimization condition for obtaining Ni-Zn-P electroless alloy coating has been developed. The sulphate bath with sodium hypophosphate as a reducer and sodium citrate and ammonium chloride as complexing agents were used. The effect of variation in the pH level , temperature , time of deposition and reactants concentration on stability of bath, coating composition, microstructure, microhardness and corrosion resistance of coatings was investigated. The composition of coatings was obtained by using the EDAX analysis. To investigate coating morphology, SEM images were taken and to study the corrosion behavior of coatings potentidynamic polarization, Electrochemical Impedance Spectroscopy (EIS) and the salt spray technique were performed. The coating obtained at pH 10.5 and reducing agent concentration 10 g/l with 74 %wt Nickel, 7.56 %wt Zinc and 12.24 %wt Phosphorus exhibited the best corrosion resistance with corrosion rate 0.011 mm/year and corrosion potential -0.4 V
Keywords:
Alloy Coating ; Corrosion Resistance ; Acid Sulfate Bath ; Coating ; Electroless

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