Enhanced high-temperature electrical response of hydroxyapatite upon grain size refinement. (January 2015)

• Record Type: Journal Article
• Authors: Lukić, Miodrag J.; Jovalekić, Čedomir; Marković, Smilja; Uskoković, Dragan
• Is Part Of: Materials research bulletin. Volume 61(2015:Jan.)
• Page Start: 534
• Page End: 538
• Publication Date: 2015-01
• Subjects: Materials -- Periodicals; Crystal growth -- Periodicals; Matériaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Crystal growth; Materials; Periodicals; 620.11
• DOI: 10.1016/j.materresbull.2014.10.072
• Languages: English
• ISSNs: 0025-5408

Abstract

Graphical abstract: Highlights: Grain size decrease to nanometer level influences electrical response of dense HA. Grain interior and grain boundary contributions were separated. Nanostructured HA possessed enhanced grain interior conductivity (Ea∼2.4 eV). Grain boundary conductivity was similar for all microstructures (Ea∼2.0 eV). An improvement should be correlated with dehydroxylation during sintering. Abstract: Correlation between high-temperature electrical response and microstructural properties of dense hydroxyapatite with average grain size from micrometer to nanometer level in heating/cooling cycle was investigated. Grain interior and grain boundary contributions to overall conductivity were determined. Nanostructured hydroxyapatite exhibited enhanced grain interior conductivity, with significantly higher activation energy (∼2.4 eV) than that of coarsed microstructures (∼1.7 eV). This difference in activation energies is explained by the possible influence of dehydroxylation during materials fabrication procedure, which affected the amount of OH − ions as the main charge carriers. Grain boundary conductivity was similar for all microstructures, with activation energy above ∼2 eV, implying the OH − ions migration across grain boundaries. Electrical response in cooling cycle confirmed the trends found during heating.