Some recent findings on the use of SEM-EDS in microstructural characterisation of as-sprayed and thermally aged porous coatings: a short review

Abstract

Microstructural analysis by electron microscopy techniques is a powerful tool for determining the basic and functional properties of materials and their relationship with the processing parameters, thus giving useful keys to designers and producers for optimizing performance and durability of the related components. Materials and coatings produced by thermal spraying of powder-based raw materials exhibit unique physical, thermal and mechanical properties, resulting from the thermal effects associated to their processing. These properties can be tailored depending on the application the components are addressed to. Moreover, they can change during operation because of any aging mechanisms promoted by oxidation, corrosion, thermal exposure and wear, that can be responsible of reduced performance, degradation and damage, thus affecting their durability and service lifetime. In this work, the potentiality of scanning electron microscopy (SEM) is investigated with the purpose to analyze in detail the complex microstructure and some aging effects in metallic, ceramic and composite coatings, such as formation of oxide scales, grain growth, sintering, and so on. The analysis can be successfully expanded to a wide variety of materials as well as to the study of complex mechanisms of degradation occurring during service.

Keywords

• microstructure
• scanning electron microscopy
• aging
• coatings
• plasma spray