This work is focused on the study of macroscopic and microscopic properties of traditional sanitary-ware vitreous bodies as a function of feldspar flux and firing time-temperature profile, using a fixed slip formulation (50 wt.% clay, 25 wt.% quartz and 25 wt.% feldspar). Two flux particle sizes (45 and 75 μm), three flux compositions (Na-based feldspar, K-based feldspar and a mix of them) and three firing cycles with the same soaking temperature (i.e. 1240 C) have been combined to evaluate their effects on the relevant industrial properties of water absorption and thermal expansion. The micro-scale observables, phase composition and micro-morphology, have also been investigated. Despite a general similarity exhibited by the ceramic samples, qualitative and quantitative differences in terms of feldspar dissociation temperature, phase-composition and densification trends have been observed. In particular, for a fixed firing cycle, the combination of the sodium based feldspar with the smallest flux particle size leads systematically to a water absorption value that is below the 0.5 target value and to a glass amount that approaches 70 wt.%. Thermal expansion coefficients below the quartz α-β transition are found in the 6.2-6.9×10-6 C-1 range; the highest values seem to be favoured by incorporation of potassium based.

Feldspar and firing cycle effects on the evolution of sanitary-ware vitreous body / A. Bernasconi, N. Marinoni, A. Pavese, F. Francescon, K. Young. - In: CERAMICS INTERNATIONAL. - ISSN 0272-8842. - 40:5(2014 Jun), pp. 6389-6398.

Feldspar and firing cycle effects on the evolution of sanitary-ware vitreous body

A. Bernasconi;N. Marinoni
Secondo
;
A. Pavese;
2014

Abstract

This work is focused on the study of macroscopic and microscopic properties of traditional sanitary-ware vitreous bodies as a function of feldspar flux and firing time-temperature profile, using a fixed slip formulation (50 wt.% clay, 25 wt.% quartz and 25 wt.% feldspar). Two flux particle sizes (45 and 75 μm), three flux compositions (Na-based feldspar, K-based feldspar and a mix of them) and three firing cycles with the same soaking temperature (i.e. 1240 C) have been combined to evaluate their effects on the relevant industrial properties of water absorption and thermal expansion. The micro-scale observables, phase composition and micro-morphology, have also been investigated. Despite a general similarity exhibited by the ceramic samples, qualitative and quantitative differences in terms of feldspar dissociation temperature, phase-composition and densification trends have been observed. In particular, for a fixed firing cycle, the combination of the sodium based feldspar with the smallest flux particle size leads systematically to a water absorption value that is below the 0.5 target value and to a glass amount that approaches 70 wt.%. Thermal expansion coefficients below the quartz α-β transition are found in the 6.2-6.9×10-6 C-1 range; the highest values seem to be favoured by incorporation of potassium based.
B. X-ray methods; D. Traditional ceramics; Fluxes; Particle size; Water absorption
Settore GEO/06 - Mineralogia
giu-2014
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/235288
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