Study On Ni-Cr Co-deposition On Polyurethane Foam

The effects of pH, current density, temperature and time on thickness of nickel, Cr(III) and Cr(VI) coatings produced by a electroplating process on polyurethane foam were studied. The effects of pH, temperature, current density, CrCl3·6H2O concentration and coordination agent/Cr3+ mole ratio on thickness, deposition rate and chrome content of coating produced by a electroplating process on polyurethane foam were studied with orthogonal test. Surface and cross-section morphologies and composition of the alloy deposit were examined by optical microscopy, scanning electron microscope and EDS.Experiment results show that the optimized plating conditions to obtain a bright, uniform and flawless nickel coating with a thickness of 95μm were at pH=4.2,9.6 A/dm2,60℃and 1 h. The optimized trivalent chromium electroplating conditions to obtain a bright, uniform coating with a thickness of 3.65μm were at 20℃, pH= 2.8,15 A/dm2 and 1 h, and the deposition rate reduce with electroplating time increase. And the optimized conditions to obtain a thickness of 16.50μm chromium VI coating were at 20℃, pH=2.8,15 A/dm2 and 1h.Experiment on the Ni-Cr co-deposition results show that Ni-Cr co-deposition rate and chrome content of coating were affected most by current density and CrCl3·6H2O concentration. A uniform, bright and flawless Ni80.86～75.57Cr19.14-24.43 alloy coatings with a thickness of 32～34μm was obtained at CrCl3·6H2O concentration was125～130g/L, temperature was 20℃, pH=1.5, current density was 28 A/dm2 and 1 h.