Morphological, chemical and mechanical characteristics of an anodic coating on stainless steel

Abstract

Anodic interference films were grown on stainless steel by an electrochemical process in a 70 g L 21 CrO 3 z500 g L 21 H 2 SO 4 solution at temperatures of 25-75uC. The aim of this research was to assess the influence of temperature on characteristics of this coating. The morphology of the films was assessed through atomic force microscopy, the chemical composition was assessed by X-ray photoelectron spectroscopy, while the mechanical characteristics were assessed by resistance to abrasion wear and nanohardness. The roughness of the films grown at 25uC is less than that of the other temperatures. No significant difference regarding the porosity of the films was detected. A chromium hydroxide was observed on the top of the oxide layer grown on stainless steel. The steel coloured at 75uC presented a lesser hardness compared to the samples grown at 25, 35 and 55uC. The wear resistance increased as the temperature of the film's growth rose, which was inversely proportional to the hardness.

Interference film grown on stainless steel by pulsed current process using chromium free vanadate solution

“…Alternating pulsed current with 0.1 Ad m −2 density having a square wave form was applied by means of a potenciostat/galvonastat PGSTAT302 from EchoChimie. The time for the electrodeposition of the interference films was controlled by duration in seconds of the anodic/cathodic pulse in 4/1ratio [11]. The colored specimens were fabricated with the same bronze color, ensuring that these interference colored films have identical thicknesses.…”