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

Abstract

In order to improve the corrosion resistance of the TiB 2 /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 TiB 2 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.

Microstructure and Wear Behavior of Laser Cladded Ni45 + High-Carbon Ferrochrome Composite Coatings

“…In this paper, high-carbon ferrochrome was added to the Ni45 alloy, and as a result more chromium carbides could form due to the high Cr content of high-carbon ferrochrome. After the laser cladding process, the carbides were usually found to be Cr 7 C 3 and Cr 23 C 6 [15][16][17]. Such hard phases are very brittle, making the matrix alloy less ductile and more susceptible to the high thermal stress imposed by the high thermal gradients and high solidification rates associated to the laser cladding process [18,19].…”