Please use this identifier to cite or link to this item:
Title: Refitting of zirconia toughening into open-cellular alumina foams by infiltration with zirconyl nitrate
Author(s): Betke, Ulf
Scheunemann, Marcel
Scheffler, Michael
Issue Date: 2019
Type: Article
Language: English
URN: urn:nbn:de:gbv:ma9:1-1981185920-367751
Subjects: Cellular ceramic
Ceramic foam
Reticulated porous ceramic (RPC)
Zirconia-toughened alumina (ZTA)
Metal salt infiltration
Abstract: The present work describes the combination of the well-established dispersion infiltration of the hollow struts in reticulated porous ceramics (RPCs) and the salt solution infiltration of the remaining strut porosity. This approach is applied on alumina foams, which are loaded subsequently with a dispersion of sub-micrometer alumina particles and a ZrO(NO3)2 solution. The zirconyl nitrate is converted into a ZrO2 transformation toughening phase during the final sintering step. As a consequence of the complex microstructure evolution during the consecutive infiltration cycles, the reinforcement phase concentrates selectively at the weak spots of RPC structures—namely, the hollow strut cavities and longitudinal cracks along the struts. As a consequence, a severe improvement of the compressive strength is observed: The average compressive strength, normalized to a porosity of 91.6 vol.%, is 1.47 MPa for the Al2O3/ZrO2 infiltrated foams, which is an improvement by 40% with respect to alumina-only loaded foams (1.05 MPa) or by 206% compared to uninfiltrated alumina RPCs (0.48 MPa). The compressive strength results are correlated to infiltration parameters and the properties of the infiltration fluids, for example the rheological behavior and the size of the Zr solute species in the respective ZrO(NO3)2 solution.
Open Access: Open access publication
License: (CC BY 4.0) Creative Commons Attribution 4.0(CC BY 4.0) Creative Commons Attribution 4.0
Sponsor/Funder: DFG-Publikationsfonds 2019
Journal Title: Materials
Publisher: MDPI
Publisher Place: Basel
Volume: 12
Issue: 12
Original Publication: 10.3390/ma12121886
Page Start: 1
Page End: 23
Appears in Collections:Fakultät für Maschinenbau (OA)

Files in This Item:
File Description SizeFormat 
Betke et al._Refitting_2019.pdfZweitveröffentlichung6.75 MBAdobe PDFThumbnail