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Improved microstructure and strength of dry-pressed advanced ceramics by controlled slurry destabilization and ultrasonic atomization

  • Spray drying of ceramic slurries aims for soft and free-flowing granules with homogenous microstructure neither containing voids nor hard shells suitable for uniaxial and isostatic pressing. The controlled destabilization of the slurries was introduced, since the unwanted formation of hard granules with voids donut-like shape could be drastically reduced. Spray drying of such modified slurries resulted in soft granules and finally leaded to sintered bodies with improved microstructure, density and strength. Optimized slurries were atomized in a laboratory spray dryer (Hi-Tec, Niro, Denmark) both with a commercial two stream nozzle and an adapted ultra sound atomization unit. Potential advantages of the ultra sound nebulization are investigated for model systems of alumina, zirconia and a ZTA composite while focusing on solids content of slurries, yield, and granule properties (size distribution, flowability, shape, microstructure, pressability) as well as the final sinter bodySpray drying of ceramic slurries aims for soft and free-flowing granules with homogenous microstructure neither containing voids nor hard shells suitable for uniaxial and isostatic pressing. The controlled destabilization of the slurries was introduced, since the unwanted formation of hard granules with voids donut-like shape could be drastically reduced. Spray drying of such modified slurries resulted in soft granules and finally leaded to sintered bodies with improved microstructure, density and strength. Optimized slurries were atomized in a laboratory spray dryer (Hi-Tec, Niro, Denmark) both with a commercial two stream nozzle and an adapted ultra sound atomization unit. Potential advantages of the ultra sound nebulization are investigated for model systems of alumina, zirconia and a ZTA composite while focusing on solids content of slurries, yield, and granule properties (size distribution, flowability, shape, microstructure, pressability) as well as the final sinter body properties (density, microstructure, strength). Using ultrasound nozzles in spray drying of identical slurries, as before tested and optimized for a two stream nozzle atomization process, resulted in a more suitable size distribution for dry pressing (less particles below 20 µm), a better flowability and a higher yield. Furthermore the sinter bodies produced of the ultra sound granules have higher sintered density, more homogenous microstructure without large pores and higher strength.zeige mehrzeige weniger

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Metadaten
Autoren/innen:Torsten Rabe
Koautoren/innen:Patrick Höhne, Petra Kuchenbecker, Wolfgang Güther
Dokumenttyp:Vortrag
Veröffentlichungsform:Präsentation
Sprache:Englisch
Jahr der Erstveröffentlichung:2017
Organisationseinheit der BAM:5 Werkstofftechnik
5 Werkstofftechnik / 5.5 Technische Keramik
DDC-Klassifikation:Naturwissenschaften und Mathematik / Chemie / Analytische Chemie
Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten
Freie Schlagwörter:Dry-pressing; Granulation; Slurry; Ultrasonic atomization
Themenfelder/Aktivitätsfelder der BAM:Material
Analytical Sciences
Veranstaltung:EUROMAT, European Congress and Exhibition on Advanced Materials and Processes
Veranstaltungsort:Thessaloniki, Greece
Beginndatum der Veranstaltung:17.09.2017
Enddatum der Veranstaltung:22.09.2017
Verfügbarkeit des Volltexts:Volltext-PDF im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:04.10.2017
Referierte Publikation:Nein