Abstract
The results for joints obtained by dynamic diffusion bonding of a 90MnCrV8 high strength steel coated with WC-Co are shown in the present work. This high strength steel substrate was coated with WC-Co, sprayed by HVOF technique (Diamond Jet Hybrid DJH-2700) using propylene as fuel gas at different conditions. The dynamic diffusion bonding was carried out in a high frequency furnace, all joints were made in air. Before doing the joints, the steel was coated with Ni and Cu by electrochemical processes in order to obtain a soft 20 m interlayer of Ni30Cu alloy. Microstructure and reacted zones in the joints were investigated by means of Scanning Electron Microscopy (SEM) and Dispersive X Ray Spectrometry (EDX). In all joints different reacted zones can be distinguished, caused by diffusion processes which take place during the joint tests. The mechanical properties of the joints were quantified in a tensile machine, using a constant load of 0.1 MPa·s-1. All joints broke by the WC-Co coating zone by delamination processes. The fracture surface was studied by SEM-EDX in order to know the fracture mechanism of the joints. The maximum tensile strength obtained confirm a very promising technology for industrial applications.
