Metallographic Evaluation and Process Correlation of Thermally Sprayed Coatings

Abstract

Thermal sprayed coatings are widely used for industrial applications. One of the main characteristics that have to be evaluated in a coating is its microstructure that finally determines the coating performance. Several techniques and processes are available for coatings deposition and new materials have been incorporated in the long list of the available ones. Therefore, since microstructure is a key factor to be evaluated, its preparation has to follow some rules in order to inhibit incorrect statements that can arise from wrong interpretation of an incorrect sample preparation. In this work, a series of distinctive materials are thermally sprayed onto low carbon steel substrates. The metallographic preparation of samples for the different coatings is presented and the effects of correct or wrong sample preparation are discussed and correlated to coating microstructure and process characteristics. The coatings were applied by Air Plasma Spray (APS) and Electric Arc Spray.

Behavior of Thermally Sprayed WC-Co Layers on 5086 Aluminum Alloy and 304 L Stainless Steel

“…The coatings quality and performance depend strongly on the substrate-coating pair, the coating applications parameters and environmental conditions [11][12]. Several methods are used to evaluate the adhesion force of thermally sprayed coating layers, including the standard tensile test (EN582), indentation testing and fracture toughness tests on fracture mechanics specimen [13].…”