Sharif Digital Repository

In this study, the magnetite protective oxide layer was successfully formed on carbon steel substrate in an alkaline solution by an electrochemical method. The electroblackening was performed at a constant potential of 2 volts and in a 50 wt% solution at 75 ° C for 10 minutes. The properties of coating characterized using X-ray diffraction, field emission-scanning electron microscopy, polarization test and visible light spectrophotometery and porosity and thickness of oxide coating investigated. By adding 50 grams per liter of each of nitrate and chromate oxidizers, the porosity of oxide coating decreased from 24 percent to 14 percent and coating thickness increased from 1 micron to 3...