ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Reinforcement with yttria stabilized zirconia (YSZ) is an alternative to improvemechanical strength of hydroxyapatite (HAp) ceramic. However, calcium may react with zirconiumto form calcium zirconate. In addition, decomposition of HAp to tricalcium phosphate (TCP) occurswith water loss inhibiting ceramic densification. In order to minimize the formation of thesecompounds, two synthesis routes were compared in this work: coprecipitation of hydrous yttriastabilized zirconia in a calcium phosphate gel medium and powder mixture of individual calcinedpowders. Composite nominal compositions were fixed at 90 and 95 HAp wt%. Calcium, zirconiumand yttrium chlorides and ammonium hydrogen phosphate were the employed precursors.Ammonium hydroxide was the selected precipitation agent. Calcination was performed at 800oC for1 hour and pellets were sintered in the range of 1150 and 1350oC for 1, 3 and 5 hours. Ceramicsamples were characterized by scanning electron microscopy and apparent density measurements.Crystalline phases were quantified by Rietveld analysis of X-ray diffraction patterns. Resultsindicate that powders prepared by coprecipitation can cause porosity formation due to the higherchemical reactivity during synthesis process
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/19/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.591-593.722.pdf
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