Mullite coatings on ceramic substrates: Stabilisation of Al2O3–SiO2 suspensions for spray drying of composite granules suitable for reactive plasma spraying
| Autor: | Geoffroy Lumay, Frédéric Boschini, Nicolas Vandewalle, Sophie Andre, Bénédicte Vertruyen, Rudi Cloots, Audrey Schrijnemakers |
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| Rok vydání: | 2009 |
| Předmět: |
Materials science
Composite number technology industry and agriculture Mullite engineering.material equipment and supplies Dispersant Suspension (chemistry) Coating visual_art Spray drying Materials Chemistry Ceramics and Composites visual_art.visual_art_medium Zeta potential engineering Ceramic Composite material |
| Zdroj: | Journal of the European Ceramic Society. 29:2169-2175 |
| ISSN: | 0955-2219 |
| DOI: | 10.1016/j.jeurceramsoc.2009.01.031 |
| Popis: | The present work deals with the preparation of stable alumina + silica suspensions with high solid loading for the production of spray-dried composite powders. These composite powders are to be used for reactive plasma spraying whereby the formation of mullite and the coating on a ceramic substrate are achieved in a single step process. Electrostatic stabilisation of alumina and silica suspensions has been studied as a function of pH. Silica suspensions are most stable at basic pH whereas alumina suspensions are stable at acidic pH. The addition of ammonium polymethacrylate (APMA) makes it possible to stabilise alumina and prepare a stable 50 wt% alumina + silica suspension at pH 10. The optimum amounts of dispersant and binder have been determined by zeta potential, viscosity and sedimentation measurements. Spray drying of the suspension yields composite powders whose morphology, size distribution and flowability have been characterized before realizing reactive plasma spraying tests. |
| Databáze: | OpenAIRE |
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