Evolution of interface in pulsed electrode deposited titanium diboride on copper and steel

Pulsed electrode surfacing (PES) is a microwelding surfacing process for the successful deposition of ultrahard wear and erosion resistant ceramic coatings on metals. The present study investigates titanium diboride deposition on oxygen free high conductivity Cu. A thin and irregular coating with cracks was obtained on the Cu substrate, with the ceramic/metal interface distinct in TiB2 deposited on Cu leading to decohesion at the interface. The present work has been compared with an earlier study on TiB2 coatings deposited on 1018 steel using the PES technique. The difference in nature of the interfaces has been related to wettability, and the role of copper and iron as binders for TiB2 ceramics has been addressed. Iron acts as an excellent binder for TiB2, providing a crack free coating and a strong interface, whereas Cu is a poor binder, leading to a weak ceramic/metal interface. (C) 1999 IoM Communications Ltd.