Study on Electrodeposition of Ni-W-P Alloy Coating on Q235 carbon steel from Pyrophosphate Bath and Its Corrosion Resistance

Ni-W-P alloy coatings were prepared at 40 degrees C and 8 A dm(-2) circuit density by DC electrodeposition in pyrophosphate bath, and the coatings with nanocrystalline and amorphous structures were selected for heat treatment and performance tested. The results show that W and P are deposited into the Ni lattice in the form of solid solution, the increase of H3PO3 mainly promotes the deposition of W, and the microhardness of Ni-W-P alloys with nanocrystalline and amorphous structures after heat treatment is higher, all above 1100 HV, the microhardness of amorphous Ni-W-P alloy is higher, up to 1139 HV. The polarization curve of Ni-W-P alloy is shifted positively, the corrosion potential is more positive, the corrosion current density is smaller, the corrosion resistance is good, and the corrosion resistance of the alloy is improved after heat treatment. The surface of the alloy is oxidized violently at 600 degrees C, and the R-ct value of the amorphous Ni-W-P alloy increases to 47963 Omega cm(2), and the corrosion resistance is the best.