PYROLYSIS-GAS CHROMATOGRAPHY OF CARBONATE APATITES USED FOR SINTERING

Gas chromatography was employed to quasi-continuously determine the am ount of carbon dioxide that evolved from carbonate apatite specimens d uring sintering. Assuming that the carbonate in the specimens decompos ed to carbon dioxide on a mole-for-mole basis, the determination of th e carbon dioxide evolved allowed for the determination of the amount o f carbonate that remained in the specimens during different stages of sintering. Previously, this measurement could be carried out only afte r sintering was completed. Comparison of data obtained from specimens compacted isostatically at 600 MPa for sintering with powder specimens indicated that the amount of carbonate remaining in the sintered apat ite mass strongly depended on heating rates, heating temperatures, and holding-time intervals. (C) 1995 John Wiley & Sons, Inc.