Coatings, Vol. 16, Pages 34: Microstructure of Cobalt Alloy Coating Manufactured by LVOF Process: Spray Distance and Stoichiometric Gase Ratio Effect

Coatings doi: 10.3390/coatings16010034

Authors:
Fernando Juárez-López
Rubén Cuamatzi-Meléndez
Melquisedec Vicente-Mendoza
Ángel de Jesús Morales-Ramírez

This work presents a microstructural characterization methodology for Diamalloy 3001 metallic powders sprayed onto Inconel 718 substrates by flame combustion. Hence, two flame stoichiometric (acetylene/oxygen) rates and specified thermal spray distances were performed in order to study their effects on the developed microstructure of the sprayed coatings. The morphology and chemical composition of the developed coatings were evaluated with microscopy, and a comparison of microstructural quality was performed. The findings indicated that spray distance affected coating quality, which is composed of morphology-type lamellar with elongated features, while gravel-like morphologies related to semi-solid powder particles were observed. Moreover, X-ray diffraction analyses established that chemical content of phases rich in oxides increased proportionally with spray distance. Vickers hardness measures and three-point bending tests were correlated with the microstructure and spray distance. These characteristics show that cobalt-based coatings could be proposed for commercial applications requiring high mechanical resistance.

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