Formation of translucent hydroxyapatite ceramics by sintering in carbon dioxide atmospheres

• Published in: Journal of materials science 2003-10, Vol.38 (19), p.3979-3993
• Main Authors: BARRALET, E, FLEMING, G. J. P, CAMPION, C, HARRIS, J. J, WRIGHT, A. J
• Format: Article
• Language: English
• Subjects: Apatite; Applied sciences; Atmospheres; Biological and medical sciences; Biomedical materials; Building materials. Ceramics. Glasses; Carbon dioxide; Ceramic industries; Ceramic powders; Ceramics; Chemical industry and chemicals; Chemical precipitation; Exact sciences and technology; Gels; Hydroxyapatite; Materials science; Medical sciences; Miscellaneous; Partial pressure; Powder compacts; Pressure effects; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Sintering; Sintering (powder metallurgy); Soft tissues; Sol-gel processes; Surgical implants; Technical ceramics; Technology. Biomaterials. Equipments. Material. Instrumentation
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1023/A:1026258515285

Hydroxyapatite is used in a variety of clinical applications as a result of the apparent adherence to and mild reaction of bone and soft tissue to it owing to its structural similarity with bone mineral. Transparent hydroxyapatite has previously been fabricated by either or both of two methods; namely the application of pressure during sintering and/or the use of fine particle sized apatite prepared by either a sol-gel process or aqueous precipitation. Recently it has been shown that translucent carbonate hydroxyapatite may be formed by sintering nanocrystalline gels of carbonate hydroxyapatite in a wet carbon dioxide atmosphere. In this study we report for the first time that this atmosphere can be used to sinter microcrystalline powder compacts of hydroxyapatite to form translucent ceramics at ambient pressure. The effect of water partial pressure and sintering time at 1300°C on the optical transmission and microstructure of the ceramic was investigated. It was found that translucent ceramics were formed in all carbon dioxide atmospheres and that optical transmission varied with sintering time. Maximum transmission (∼13%) of 2 mm thick ceramic was obtained in materials sintered for four hours at 1300°C in a mixture of carbon dioxide containing water at a partial pressure of 4.6 kPa.