Microstructure and corrosion properties of thick WC composite coating formed by plasma cladding

✍ Scribed by Xie Guozhi; Song Xiaolong; Zhang Dongjie; Wu Yuping; Lin Pinghua

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 773 KB
• Volume: 256
• Category: Article
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2010.04.016

✦ Synopsis

The thick Ni-coated WC coatings, in a matrix of Nickel-based alloys, were prepared on AISI 1045 steel using plasma cladding equipment. A pre-placed layer of uniform mixture, with different weight fractions of Ni-coated WC powder and Nickel-based alloy powder, on the steel substrate was melted at the high temperature of the plasma jet. The coating composition, microstructure and microhardness were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS) and microhardness testing. The experimental results show that the metallurgical bond was formed between the coating and substrate. The XRD results show that the coatings contain ␥-Ni, carbides (such as M 23 C 6 and M 7 C 3 ) and boride (such as Fe 2 B, Fe 3 B phases). SEM shows that all the coatings are crackfree with lower porosity (<1%). It is found that the microhardness and the electrochemical behavior of the coatings are depended on the content of Ni-coated WC powder. The corrosion mechanism for the coatings may be due to the microgalvance corrosion between the phases in the cladding coatings.