Properties of nanocrystalline Cr coatings prepared by cathode plasma electrolytic deposition from trivalent chromium electrolyte

Pure Cr coatings were prepared directly from trivalent chromium sulfate electrolyte by cathode plasma electrolytic deposition (CPED). Composition and microstructure of the coatings were investigated by EDS, XRD, SEM and TEM. The deposited Cr coatings are crack-free with the thickness up to approximately 30μm, and exhibit nanocrystalline structure, high hardness, excellent adhesion and corrosion resistance with the stainless steels. The quality of Cr coatings prepared by CPED is improved significantly compared with that prepared by traditional chromium electroplating. It indicates that cathode plasma electrolytic deposition is an effective way to prepare high quality Cr coatings. •Cathode plasma electrolysis deposition was used to prepare Cr coatings.•Pure Cr coatings have been deposited from trivalent chromium electrolyte.•The coating is nanocrystalline structure and the grain size is only 10–20nm.•The coating is crack-free with the thickness up to 30μm and shows high hardness.•The coating exhibits excellent adhesion and corrosion resistance with steels.