Fabrication, characterization and fracture study of a machinable hydroxyapatite ceramic.
In this study the preparation of a machinable hydroxyapatite from mixtures of a fine, submicrometer powder and either a coarse powder composed of porous aggregates up to 50 microns or a medium powder composed of dense particles of 3 microns median size is described. These were characterized using X-ray diffraction, transmission and scanning electron microscopy and infra-red spectroscopy. Test-pieces were formed by powder pressing and slip casting mixtures of various combinations of the fine, medium and coarse powders. The fired test-pieces were subjected to measurements of firing shrinkage, porosity, bulk density, tensile strength and fracture toughness. The microstructure and composition were examined using scanning electron microscopy and X-ray diffraction. For both processing methods, a uniform interconnected microporous structure was produced of a high-purity hydroxyapatite. The maximum tensile strength and fracture toughness that could be attained while retaining machinability were 37 MPa and 0.8 MPa m1/2 respectively.
Department of Engineering Materials, University of Sheffield, UK.
M Y
MY
Shareef
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PF
Messer
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R
van Noort
D001672:Biocompatible Materials; D002516:Ceramics; D017886:Durapatite; D006882:Hydroxyapatites; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011208:Powders; D013055:Spectrophotometry, Infrared; D013314:Stress, Mechanical; D013718:Tensile Strength; D014961:X-Ray Diffraction
D001672:Biocompatible Materials; D006882:Hydroxyapatites; D011208:Powders; D017886:Durapatite