EVALUATION OF PHYSICAL AND CHEMICAL PROPERTIES OF ELECTRODEPOSITED Ni–W–P OBTAINED IN HULL CELL

Química Nova

Silva, Paulo S. G.¹  Universidade Federal Rural do Semi-Árido, Mossoró, Brasil¹  Oliveira, José A. M.¹  Santos, Andarair G.¹  Universidade Federal de Campina Grande, Cuité, Brasil¹  Silva, Gecílio P.¹  Cunha, Ricardo de S.¹ 

关键词:  electrodeposition;    Hull cell;    corrosion;   

DOI  :  10.5935/0100-4042.20150144

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

Ni–W–P electrodeposits were synthesized in a Hull cell in order to simulate the obtainment under industrial conditions. Complete coverage of panels was accomplished by applying total currents of 1.0 and 2.0 A. Panels obtained with a current of 1.0 A appeared brighter. The best compositional uniformities, as determined by Energy Dispersive Spectrometer (EDS) occurred in the current density ranges of 0.6 to 3.0 A dm−2 and 1.6 to 6.0 A dm−2 obtained with 1.0 and 2.0 A, respectively. However, the best morphological characteristics, as determined by Scanning Electro Microscope (SEM), were observed in those obtained with a total current of 1.0 A. Analysis of corrosion resistance by Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic Linear Polarization (PLP) in NaCl have shown significant variations in the amount of corrosion potential, polarization resistance, and even total impedance. The alloys exhibited amorphous character (XRD) and crystallized above 400 °C to Ni and Ni3P phases, and possibly Ni–W, with a subsequent increase in hardness. The results suggest that under industrial conditions, current density variations due to the large and complex geometric shapes of substrates lead to formation of distinct alloys. Furthermore, these materials are potential substitutes for chromium deposits in many applications.

【 授权许可】

Unknown