Processing–structure–property correlation and decarburization phenomenon in detonation sprayed WC–12Co coatings

• Published in: Acta materialia Vol. 56; no. 18; pp. 5012 - 5026
• Main Authors: Suresh Babu, P., Basu, Bikramjit, Sundararajan, G.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2008; Elsevier
• Subjects: Applied sciences; Cermet; Coatings; Correlation; Decarburization; Deposition; Detonation; Diagnostic systems; Diamond pyramid hardness; Exact sciences and technology; Hardness; High speed; Metals. Metallurgy; Nanoindentation; Production techniques; Surface treatment; Thermal spray; Decarburization; Coatings; Hardness; Cermet; Thermal spray; Hot spraying; Spray coating; Surface treatment
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2008.06.023

In this paper, we demonstrate how the microstructure evolution in terms of nature/extent of decomposition of WC as well as properties of WC–12wt.% Co coatings is critically dependent on variation of oxygen–fuel (OF) ratio. The coating deposition was carried out over a wide range of OF ratios using a detonation spray technique, and particle velocity was measured using a high-speed particle diagnostics system. The presence of free W and increased W 2C phase is observed under deposition at higher OF ratios of 1.5 or 2.0, and this has been confirmed using XRD, EBSD and SEM-EDS elemental mapping. In order to obtain representative hardness and modulus of the as-deposited coatings, careful measurements and analysis of indentation response (cross-section and surface) were carried out using nanoindentation and Vickers hardness testers. Based on our experimental results, a major emphasis has been put forward to establish a processing–structure–property correlation for detonation sprayed WC–12Co coatings.