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Compressor Instability with Integral Methods Episode 2 Part 2

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Tham khảo tài liệu 'compressor instability with integral methods episode 2 part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Chapter 5 Substrate and Coating Erosion 5.1 Introduction The basic process of blast cleaning is the impingement of individual abrasive particles under different conditions on the target material. In the reference literature this process is often referred to as solid particle erosion. The system coating -interfacial layer - substrate is illustrated in Fig. 5.1. This complete system responds by the following two mechanisms to the impingement of solid particles erosion of the coating material cohesive mode debonding of the coating material adhesive mode . These mechanisms are illustrated in Fig. 5.2 and they will be discussed in detail in the subsequent sections. Erosion occurs usually either if the coating is rather thick or if the adhesion of the coating to the substrate is very good. The erosive response of bulk coating materials can be subdivided into elastic response brittle and elastic-plastic response ductile . These modes of response are illustrated in Fig. 5.3 in terms of scratching images of organic coatings. Debonding and delamination in the interface between substrate and coating are alternative coating removal mechanisms and they occur at rather small coating thickness or if the adhesion is low. 5.2 Mechanical Properties of Oxides and Organic Coatings 5.2.1 Relevant Mechanical Properties The material to be considered for blast cleaning is rather a material system composed of the three following parts substrate interfacial layer layer coating oxide . A. Momber Blast Cleaning Technology 167 Springer 2008 168 5 Substrate and Coating Erosion Fig. 5.1 System substrate aluminium - interface - coating epoxy . Photographs Zhang et al. 2003 . Left deteriorated adhesion Right good adhesion a Fig. 5.2 Basic types of coating response to solid particle impingement Strojny et al. 2000 . a Buckling and debonding b Brittle response with bulk material erosion Fig. 5.3 Basic types of organic coating response to scratching Randall 2006 . a PVC-based hardcoat finish elastic