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Structure characterization of spark plasma sintered alumina by positron annihilation lifetime spectroscopy
Author(s) -
Djourelov Nikolay,
Aman Yann,
Berovski Kalin,
Nédélec Patrick,
Charvin Nicolas,
Garnier Vincent,
Djurado Elisabeth
Publication year - 2011
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201026474
Subject(s) - spark plasma sintering , materials science , annealing (glass) , positronium , intergranular corrosion , analytical chemistry (journal) , grain boundary , sintering , porosity , plasma , spectral line , annihilation , spectroscopy , positron , composite material , microstructure , nuclear physics , chemistry , electron , quantum mechanics , physics , astronomy , chromatography
Positron annihilation lifetime spectroscopy (PALS) measurements were performed to study the influence of the sintering temperature, heating rate and dwell time on the porosity and on the defect concentration on series of spark plasma sintered alumina samples. Two long‐lived components were found in the PALS spectra and were associated to pick‐off annihilation of ortho‐positronium localized in two types of pores. The same spectra were analysed in the frame of the three‐state‐trapping model and information for the intragranular and at grain boundary defect concentration was extracted. At sintering temperatures below 1200 °C the regime of the high (600 °C/min) heating rate leaded to more efficient defect annealing compared to the regime of the low (8 °C/min) heating rate, while at higher temperatures this difference disappeared. The low heating rate at high temperatures leaded to more compact samples compared to these sintered at the high heating rate as a result of intergranular pore concentration decrease.