Modification of Porous Alumina Ceramics with Bioinert and Bioactive Glass Coatings

Porous biomaterials including porous bioceramics play important roles for hard tissue replacement and regeneration. I this paper, porous alumina (with and without zirconia addition) ceramics were produced via coating polyurethane (PU) foams with Al2O3 (ZrO2) slurries, followed by drying at room temperature and sintering at 1300 oC. The advantage of the PU foam method was the achieved high pore interconnectivity, but the mechanical properties of the porous ceramics were rather poor due to the high macroporosity and the high microporosity. To remove the microporosity and strengthen the porous alumina ceramics, a lanthanum-modified aluminosilicate (LAS) glass was used to infiltrate the alumina struts. Nevertheless, the resulting LAS-modified macroporous alumina ceramics would have no ability to bond to bone tissues. To impart a bioactivity (i.e. the ability of bone bonding) to the bioinert porous ceramics, a bioactive glass layer was applied by dipping with the bioactive glass slurry and sintering at 1200 oC. The twice coated porous alumina ceramics would exhibit high compressive strengths, allow bone tissue ingrowth, and form strong bonematerial integration. A biodegradable filler – calcium phosphate cement was also incorporated. A possible application of the porous bioceramics would be for the maxillofacial reconstruction.

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Alumina ceramics prepared with new pore-forming agents

Processing and Application of Ceramics ◽

10.2298/pac0801001z ◽

2008 ◽

Vol 2 (1) ◽

pp. 1-8 ◽

Cited By ~ 23

Author(s):

Zuzana Zivcová ◽

Eva Gregorová ◽

Willi Pabst

Keyword(s):

Thermal Analysis ◽

Porous Alumina ◽

Slip Casting ◽

Porous Ceramics ◽

Rice Starch ◽

Alumina Ceramics ◽

Poppy Seed ◽

Biological Origin ◽

Filtration Membranes ◽

Wide Range

Porous ceramics have a wide range of applications at all length scales, ranging from filtration membranes and catalyst supports to biomaterials (scaffolds for bone ingrowths) and thermally or acoustically insulating bulk materials or coating layers. Organic pore-forming agents (PFAs) of biological origin can be used to control porosity, pore size and pore shape. This work concerns the characterization and testing of several less common pore-forming agents (lycopodium, coffee, fl our and semolina, poppy seed), which are of potential interest from the viewpoint of size, shape or availability. The performance of these new PFAs is compared to that of starch, which has become a rather popular PFA for ceramics during the last decade. The PFAs investigated in this work are in the size range from 5 ?m (rice starch) to approximately 1 mm (poppy seed), all with more or less isometric shape. The burnout behavior of PFAs is studied by thermal analysis, i.e. thermogravimetry and differential thermal analysis. For the preparation of porous alumina ceramics from alumina suspensions containing PFAs traditional slip casting (into plaster molds) and starch consolidation casting (using metal molds) are used in this work. The resulting microstructures are investigated using optical microscopy, combined with image analysis, as well as other methods (Archimedes method of double-weighing in water, mercury intrusion porosimetry).

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Modification of Porous Alumina Ceramics with Bioinert and Bioactive Glass Coatings

Frontiers in Materials Science and Technology - Advanced Materials Research ◽

10.4028/0-87849-475-8.211 ◽

2008 ◽

pp. 211-214 ◽

Cited By ~ 1

Author(s):

X. Miao

Keyword(s):

Bioactive Glass ◽

Porous Alumina ◽

Alumina Ceramics

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High-strength porous alumina ceramics prepared from stable wet foams

Journal of Advanced Ceramics ◽

10.1007/s40145-021-0479-9 ◽

2021 ◽

Author(s):

Linying Wang ◽

Liqiong An ◽

Jin Zhao ◽

Shunzo Shimai ◽

Xiaojian Mao ◽

...

Keyword(s):

Heat Insulation ◽

Porous Alumina ◽

High Strength ◽

Porous Ceramics ◽

High Porosity ◽

Alumina Ceramics ◽

Direct Foaming ◽

Catalyst Carrier ◽

Average Grain Size ◽

Direct Foaming Method

AbstractPorous ceramics have been widely used in heat insulation, filtration, and as a catalyst carrier. Ceramics with high porosity and high strength are desired; however, this high porosity commonly results in low strength materials. In this study, porous alumina with high porosity and high strength was prepared by a popular direct foaming method based on particle-stabilized wet foam that used ammonium polyacrylate (PAA) and dodecyl trimethyl ammonium chloride (DTAC) as the dispersant and hydrophobic modifier, respectively. The effects of the dispersant and surfactant contents on the rheological properties of alumina slurries, stability of wet foams, and microstructure and mechanical properties of sintered ceramics were investigated. The microstructure of porous ceramics was regulated using wet foams to achieve high strength. For a given PAA content, the wet foams exhibited increasing stability with increasing DTAC content. The most stable wet foam was successfully obtained with 0.40 wt% PAA and 0.02 wt% DTAC. The corresponding porous alumina ceramics had a porosity of 82%, an average grain size of 0.7 µm, and a compressive strength of 39 MPa. However, for a given DTAC content, the wet foams had decreasing stability with increasing PAA content. A possible mechanism to explain these results is analyzed.

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