Effect of Heating in Air or Vacuum on the Delamination Strength of WC-Co Coating Deposited by High-Velocity Flame Spraying

Dongkun ZHANG, Masahiko KATO, Keijiro NAKASA, Keiichiro TASAKA
1999 Journal of the Society of Materials Science Japan  
High-velocity flame spraying of WC-Co cermet was applied on a tool steel substrate (JIS: SKD5). After the specimens were heated in air or vacuum, edge-indentation tests of the specimens were carried out to examine the change of delamination energy. For the specimens heated at 773K in air or vacuum within 144ks, delamination load did not change. When the heating temperature was 873K and hold time was longer than 144ks, the delamination load decreased. Delamination area decreased when the hold
more » ... e exceeded 3.6ks. Delamination energy Ed of the specimen heated at 773K increased with increasing hold time within 144ks without decreasing hardness of coating and substrate, and the Ed was larger for the specimen heated in air than in vacuum. The Ed of the specimen heated at 873K in air increased with increasing hold time, but the hardness of coating and substrate decreased. The increase in delamination energy by heating was due to the diffusion of Fe and Co elements across the interface between coating and substrate.
doi:10.2472/jsms.48.1065 fatcat:bu3awmefszhhrffgxljzfkemvi