Modification of TiB₂/Fe coating by SMAW with high carbon ferrochrome

Abstract

In order to improve the corrosion resistance of the TiB₂/Fe composite coatings, high carbon ferrochromium powder was added to the precursor powders. This study evaluates the effect of high carbon ferrochrome added to the composite coating processed by shielded metal arc welding process. The phase composition and microstructure were investigated by X-ray diffraction analysis, scanning electron microscopy (SEM) and energy dispersive spectrum. Vickers hardness was measured from the top surface of the coatings using a Vickers hardness tester. Corrosion property was carried out by a potentiodynamic corrosion test. Thermodynamic analysis was used to make clear of the formation process. It is found that with the amounts of high carbon ferrochromium in the electrodes increasing, the TiB₂ reinforcements in the coatings are replaced progressively by TiC particles and iron boride phase and practically disappear at last. Both the hardness and corrosion resistance of the coatings modified with high carbon ferrochrome have been improved.

Keywords:

• SMAW
• TiB₂
• Corrosion
• Thermodynamic