Improvements in MMC Coatings – Influence of Powder Preparation (Mixture or Ball Milling) and Powder Size on the Coating Behavior

In the present work, a mechanical alloying (ball milling) method was developed to synthesize NiCrBSi-WC composite powders for HVOF spraying. Coating properties and microstructure are shown to vary with composition and initial powder size prior to ball-milling. With nanometric particles, metallic and carbide powders appear to be intimately linked with WC, forming a highly protective layer. Conversely, with micrometric powders, ball-milled particles appear more fractured and regularly dispersed inside the matrix.