SciELO - Scientific Electronic Library Online

 
vol.38 issue10SYNTHESIS AND DETERMINATION OF THE RELATIVE STEREOCHEMISTRY OF A NEW EPOXIDE ALDEHYDE CYCLOPENTANE MONOTERPENOID author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand

Journal

Article

Indicators

Related links

Share


Química Nova

Print version ISSN 0100-4042On-line version ISSN 1678-7064

Abstract

SILVA, Gecílio P. et al. EVALUATION OF PHYSICAL AND CHEMICAL PROPERTIES OF ELECTRODEPOSITED Ni–W–P OBTAINED IN HULL CELL. Quím. Nova [online]. 2015, vol.38, n.10, pp.1253-1259. ISSN 1678-7064.  https://doi.org/10.5935/0100-4042.20150144.

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.

Keywords : electrodeposition; Hull cell; corrosion.

        · text in Portuguese     · Portuguese ( pdf )