Quantitative evaluation of the decarburization and microstructure evolution of WC–Co during plasma spraying
Qing Zhan, Ligen Yu, Fuxing Ye, Qunji Xue, Hua Li
Surface & Coatings Technology
abstract
The major hurdle that limits extensive applic ation of thermal sprayed WC –Co coatings is the undes irable phase changes from WC to W2C or even W due to loss of carbon. This study investigated quantitatively the decarburizatio n of WC in both in- flight and coating formation stages durin g atmospheric plasma spray ing.The microstructur e evolution of WC particles accompanyi ng the decarburization was also investigated. Re-sults showed that decomposition and oxidation of WC to W2C predominantly occu rred in the in-flight stage (75.82%), while remnant 24.18% occurred during the coating formation stage. Further carbon loss dur-ing the coating forma tion stage of WC-Co droplets is dependent signi fi cantly on the temperature of the sub-strate/pre-co ating. Most of the irregular WC particles turned into rounded morphology with a signi fi cant decrease in size. W2C precipitated from the liquid matrix showed eit her columnar growth or epitaxial growth on WC sub strate.
keywords: WC–Co,Decarburization,Plasma spraying,Microstructure evolution,Quantitative analysis
参考文献 略
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