Manufacturing of Reticulated Open‐Cellular Aluminum Nitride Ceramic Foams from Aqueous AlN Suspensions

Betke, Ulf; Friedrich, Alexandra; Scheffler, Franziska; Scheffler, Michael

doi:10.1002/adem.201600660

Cited by 23 publications

(28 citation statements)

References 40 publications

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“…Only the hollow strut cavities originating from the PU template are present; they contribute a porosity of 32 ± 3% w. r. t. the total strut volume. is value is in good agreement to alumina foams with a densely sintered strut material made from the same PU templates [36].…”

Section: Macrostructure Of Zno Ceramic Foamssupporting

confidence: 79%

Reticulated Open-Celled Zinc Oxide Ceramic Foams: Manufacturing, Microstructure, Mechanical, and Thermal Properties

Betke

Scheffler

2019

Advances in Materials Science and Engineering

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Open-celled zinc oxide ceramic foams were prepared by the polymer sponge replication (Schwartzwalder) technique from aqueous ZnO dispersions with Sb2O3 and Bi2O3 as sintering additives, and mechanically stable ZnO foams with an average porosity of 93.6% were obtained. Their microstructure consists of ZnO grains with a Bi-containing grain boundary phase together with a Zn-Sb-O secondary phase with spinel structure. The obtained ZnO ceramic foams were characterized with respect to their morphology by computed tomography; in addition, the compressive strength and the thermal conductivity were determined, and the data were applied for modelling of the mechanical and thermal properties of the bulk ZnO strut material.

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Section: Macrostructure Of Zno Ceramic Foamssupporting

confidence: 79%

Reticulated Open-Celled Zinc Oxide Ceramic Foams: Manufacturing, Microstructure, Mechanical, and Thermal Properties

Betke

Scheffler

2019

Advances in Materials Science and Engineering

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“…The presence of a strut porosity below the resolution limit of the CT data, which would falsify the CT results, can be excluded from previous investigations on alumina foams manufactured using the same slurry composition and sintering temperature regime. [40] These results demonstrate the potential and performance of the binarization threshold determination based on the analysis of the differential change of foam geometrical key parameters. In the present work, the benchmark indicator was set to the total porosity as its experimental validation is less complex.…”

Section: Full Papermentioning

confidence: 79%

Impact of Slurry Composition on Properties of Cellular Alumina: A Computed Tomographic Study

et al. 2017

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Fine-pored, 45 ppi (pores per linear inch) alumina foams are prepared from ceramic slurries with varying contents of additives (deflocculant, binder) and solid loading following a standardized procedure. Rheological key parameters (yield stress, high-shear viscosity) of the respective slurries are determined by approximation of the experimental flow curves with appropriate rheological models. The resulting ceramic foams are characterized by computed tomography (CT) followed by a morphometric analysis of the reconstruction volume data. The main scope of the work involves the development of a procedure to reliably define the binarization threshold during these morphometric calculations, which is based on the analysis of the differential course of the total porosity results from calculations performed at varying binarization threshold values ("differential thresholding"). A very good match of the CT porosity results with experimental data is achieved, despite the unfavorable CT voxel resolution to foam structure fineness relation. The CT evaluation results are finally correlated to the rheological properties of the respective slurries used in foam manufacturing. The dominant slurry composition parameters are the weight fraction of the ceramic powder and the binder concentration. Increasing binder and solid content result in an increased yield stress and viscosity of the respective dispersion and consequently in a decreased porosity and cell size of the finally manufactured cellular ceramic.

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“…water [28] AlN PVA water [29] Bioglass 1 PVA water [30] Ca 2 KNa(PO 4 ) 2 -water [31] Ca 5 (OH)(PO 4 ) 3 Acrylamide water [32] Ca 5 (OH)(PO 4 ) 3 Dextrin water [33] Ca 0.95 Sm 0.05 MnO 3 PVA water [34,35] CeO 2 PVA water [36] LZSA glass Bentonite water [37] LZSA glass Bentonite 2-propanol [38] Mullite/SiC CMC, bentonite water [39] Si 3 N 4 CMC water [25] Y 2 BaCuO 5 PVA water [40] a) Based on polyacrylate.…”

Section: Bindermentioning

confidence: 99%

Reticulated Replica Ceramic Foams: Processing, Functionalization, and Characterization

et al. 2017

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Reticulated ceramic foams are used in a wide range of applications such as filters, catalyst supports, lightweight materials, energy absorptions materials, or as scaffolds for tissue engineering as the most common ones. Based on gaseous foaming processes of polymers, a stochastic distribution of closed pores is obtained. By reticulation processing thin foam windows are removed between cells turning a closed cell into an open cell structure. These foams are used as template for porous ceramics manufacturing: With different processing approaches, for example, with dip coating of a ceramic slurry and a subsequent (multistep) thermal treatment ceramic reticulate foams are obtained. A variety of material properties strongly depend on the cell and strut size, as well on material composition. Functionalization of ceramic foam surfaces (outer surface functionalization), for example, with zeolites or nanosized aggregates lead to an increase of the specific surface area or provides catalytic or heat storage functionality. Filling of struts (inner surface functionalization) may lead to improved mechanical stability or may provide functionalities such as electric conductivity. The present work summarizes the processing steps from the template foam to the final cellular ceramic, functionalization strategies, and the most common characterization techniques.

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Manufacturing of Reticulated Open‐Cellular Aluminum Nitride Ceramic Foams from Aqueous AlN Suspensions

Cited by 23 publications

References 40 publications

Reticulated Open-Celled Zinc Oxide Ceramic Foams: Manufacturing, Microstructure, Mechanical, and Thermal Properties

Reticulated Open-Celled Zinc Oxide Ceramic Foams: Manufacturing, Microstructure, Mechanical, and Thermal Properties

Impact of Slurry Composition on Properties of Cellular Alumina: A Computed Tomographic Study

Reticulated Replica Ceramic Foams: Processing, Functionalization, and Characterization

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