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Microstructure and properties of thermally sprayed functionally graded coatings for polymeric substrates
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Ivosevic, M. Palmese, G. R. Sutter, J. K. Knight, R. Kalidindi, S. R. |
| Copyright Year | 2003 |
| Description | The use of polymer matrix composites (PMCs) in the gas flow path of advanced turbine engines offers significant benefits for aircraft engine performance but their useful lifetime is limited by their poor erosion resistance. High velocity oxy-fuel (HVOF) sprayed polymer/cermet functionally graded (FGM) coatings are being investigated as a method to address this technology gap by providing erosion and oxidation protection to polymer matrix composites. The FGM coating structures are based on a polyimide matrix filled with varying volume fractions of WC-Co. The graded coating architecture was produced using a combination of internal and external feedstock injection, via two computer-controlled powder feeders and controlled substrate preheating. Porosity, coating thickness and volume fraction of the WC-Co filler retained in the coatings were determined using standard metallographic techniques and computer image analysis. The pull-off strength (often referred to as the adhesive strength) of the coatings was evaluated according to the ASTM D 4541 standard test method, which measured the greatest normal tensile force that the coating could withstand. Adhesive/cohesive strengths were determined for three different types of coating structures and compared based on the maximum indicated load and the surface area loaded. The nature and locus of the fractures were characterized according to the percent of adhesive and/or cohesive failure, and the tested interfaces and layers involved were analyzed by Scanning Electron Microscopy. |
| File Size | 1455933 |
| Page Count | 12 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20030032481 |
| Archival Resource Key | ark:/13960/t3130tv3j |
| Language | English |
| Publisher Date | 2003-03-01 |
| Access Restriction | Open |
| Subject Keyword | Mechanical Engineering Sprayed Coatings Scanning Electron Microscopy Polymer Matrix Composites Hvof Thermal Spraying Metallography Aircraft Engines Adhesion Substrates Image Analysis Cermets Polyimides Functionally Gradient Materials Microstructure Turbine Engines Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
