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Effect of Sintering Temperature on Flexural Properties of Alumina Fiber‐Reinforced, Alumina‐Based Ceramics Prepared by Tape Casting Technique
Author(s) -
Tanimoto Yasuhiro,
Nemoto Kimiya
Publication year - 2006
Publication title -
journal of prosthodontics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.902
H-Index - 60
eISSN - 1532-849X
pISSN - 1059-941X
DOI - 10.1111/j.1532-849x.2006.00133.x
Subject(s) - materials science , sintering , flexural strength , composite material , composite number , tape casting , fiber , ceramic , scanning electron microscope , casting , flexural modulus
Purpose : The purpose of this study was to investigate the effect of sintering temperature on flexural properties of an alumina fiber‐reinforced, alumina‐based ceramic (alumina‐fiber/alumina composite) prepared by a tape casting technique.Materials and Methods : The alumina‐based ceramic used a matrix consisting of 60 wt% Al 2 O 3 powder and 40 wt% SiO 2 ‐B 2 O 3 glass powder with the following composition in terms of wt%: 33 SiO 2 , 32 B 2 O 3 , 20 CaO, and 15 MgO. Prepreg sheets of alumina‐fiber/alumina composite in which uniaxial aligned alumina fibers were infiltrated with the alumina‐based matrix were fabricated continuously using a tape casting technique employing a doctor blade system. Four sintering temperatures were investigated: 900°C, 1000°C, 1100°C, and 1200°C, all for 4 hours under atmospheric pressure in a furnace. The surface of the alumina‐fiber/alumina composite after sintering was observed with a field‐emission scanning electron microscope (FE‐SEM). A three‐point bending test was carried out to measure the flexural strength and modulus of alumina‐fiber/alumina composite specimens. In addition, sintered alumina fiber was characterized by X‐ray diffraction (XRD).Results : FE‐SEM observation showed that alumina‐fiber/alumina composite was confirmed to be densely sintered for all sintering temperatures. Three‐point bending measurement revealed that alumina‐fiber/alumina composite produced at sintering temperatures of 1100°C and 1200°C exhibit flexural strengths lower than those of alumina‐fiber/alumina composite produced at sintering temperatures of 900°C and 1000°C; alumina‐fiber/alumina composite produced at sintering temperatures of 1100°C and 1200°C exhibit flexural moduli lower than that of alumina‐fiber/alumina composite produced at a sintering temperature of 1000°C. Additional XRD pattern of alumina fiber indicated that with increasing sintering temperature, the crystallographic structure of γ‐alumina transformed to mullite.Conclusions : There were significant differences in the flexural properties between the alumina‐fiber/alumina composite sintered at the four temperatures. This indicates that the choice of optimum sintering temperature is an important factor for successful dental applications of alumina‐fiber/alumina composite developed by the tape casting system.