Dense mullite?zirconia?zirconium titanate ceramic composites by reaction sintering

N. RENDTORFF; M. GAUNA; S. GOMEZ; M.S. CONCONI; G.SUAREZ; E. AGLIETTI

CERAMICS INTERNATIONAL

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2015 vol. 42 p. 1563 - 1572

0272-8842

AbstractMaterials from the Al2O3?SiO2?ZrO2 and the Al2O3?SiO2?ZrO2?TiO2 systems have several high temperature applications because theypresent the good refractoriness, chemical inertness, adequate mechanical and thermo-mechanical behaviors with a relatively good cost:performance ratio. In this work stoichiometric (3:2:1) molar incompatible mixtures of alumina (Al2O3), zircon (ZrSiO4) and titania (TiO2) wereslip casted and sintered in a 1300?1500 1C temperature range in order to obtain mullite (3Al2O3 2SiO2), zirconia (ZrO2) and zirconium titanate(ZrTiO4) dense triple ceramic composite.Both sintering and reaction occurred after the thermal treatments. Reaction progress and densification evolutions were established. DenseTriplex composite materials were achieved after 1500 1C treatments. The reaction-sintering was followed by XRD, TG?DTA, and dilatometry.Densification started at 1100 1C and the chemical reactions only started above 1300 1C. Aluminum titanate (Al2TiO5) was found to be anintermediate of the reaction after 1400 1C treatments. Materials treated below 1300 1C presented a partial densification of the unreacted startingpowders. Resulting ceramic materials were characterized. The crystalline phases were evaluated, as well as the texture properties. The achievedmicrostructure consisted in interlocked multiphase ceramic with zirconia (monoclinic) grains. The achieved Hv and KIC reached 9 GPa and4.3 MPa m1/2 respectively. The dense and interlocked ceramic microstructure and relative high mechanical properties of the developed materialencourages several high temperature applications. Finally it can be pointed out that after 1500 1C treatments some detrimental grain growth wasobserved.& 2015 Elsevier Ltd and Techna Group S.r.l. All