Abstract
Crack networks and residual tensile stresses are general characteristics of electrodeposited hard chromium coatings. In this paper, crack-free hard chromium coatings with compressive stresses have been obtained by an electrodeposition process assisted by abrasive polishing. The deposited coatings had mirror-like smooth surfaces, values of hardness in the range 800–1000 HV and compressive stresses between 1000 and 1600 MPa. A model involving hydrogen disentanglement from the lattice is proposed to explain the effects of abrasive polishing on the complete elimination of cracks and the generation of a compressive stress. This explanation is discussed in terms of the variations in properties of the coating with the rotation speed of the cathode.
Funding
This work was supported by the National Natural Science Foundation of China under [grant number 50975143].