Combined effect of electrolytic composition and type of polarization current on the protective properties of chromic coatings

Single-layered chromic coatings are often used to increase the wear and corrosion resistance of steel in mining atmospheres saturated with coal dust and gases. In this investigation the authors studied the influence of aluminum-ion additives in a Cr (III) aqueousdimethyl electrolyte on the internal stress. The protective properties of the coating were evaluated by measuring the corrosion current with the P-5035 corrosion meter in a 10% solution of NaC1. Transferring to a pulsed current in an electrolyte without aluminum ions is shown to be more effective than the addition of ions at a constant current. The combined use of these two inhibitive processes improves the protective properties of the chromium coating by 1.5-10 times.