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Tribological Characterization of WC–Co Plasma Sprayed Coatings
Author(s) -
Di Girolamo Giovanni,
Pilloni Luciano,
Pulci Giovanni,
Marra Francesco
Publication year - 2009
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2009.03023.x
Subject(s) - materials science , decarburization , microstructure , cermet , coating , thermal spraying , metallurgy , tribology , scanning electron microscope , atmospheric pressure plasma , toughness , oxidizing agent , dissolution , brittleness , composite material , plasma , chemical engineering , ceramic , chemistry , physics , organic chemistry , quantum mechanics , engineering
Atmospheric plasma spraying of WC coatings is typically characterized by increased decarburization, with a consequent reduction of their wear resistance. Indeed, high temperature and oxidizing atmosphere promote the appearance of brittle crystalline and amorphous phases. However, by using a high helium flow rate in a process gas mixture, plasma spraying may easily be optimized by increasing the velocity of sprayed particles and by reducing the degree of WC dissolution. To this purpose, a comparative study was performed at different spray conditions. Both WC–Co powder and coating phases were characterized by X‐ray difraction. Their microstructure was investigated by scanning electron microscopy. Mechanical, dry sliding friction, and wear tests were also performed. The wear resistance was highly related to both microstructural and mechanical properties. The experimental data confirmed that high‐quality cermet coatings could be manufactured by using optimized Ar–He mixtures. Their enhanced hardness, toughness, and wear resistance resulted in coatings comparable to those sprayed by high velocity oxygen‐fuel.