Microstructural development and electrical behavior during crystalization of iron-rich glass-ceramics obtained from mill scale

Autor(es)

Klegues Montedo, Oscar Rubem ; Faller, Cristian Arnaldo ; Bertan, Fernando Marco ; Jiusti, Jeanini ; Piva, Roger Honorato ; Piva, Diogenes Honorato

• Tipo de documento: Artigo Científico
• Fonte: CERAMICS INTERNATIONAL; v. 43, n. 15, p. 11864-11873, OCT 15 2017.
• Citações Web of Science: 3

Resumo

Mill scale is one of the most hazardous waste generated from the steelmaking industry. In 2014, around 16.4-32.8 million t of mill scale was generated all over the world. In this paper, we present recent results about the effect of the structure and microstructure of iron-rich glass-ceramics obtained from mill scale on their electrical behavior. Five iron-rich glass compositions were investigated. The crystalline phases of the crystallized (glass ceramic) materials were identified by X-ray diffractometry, and phase content quantifications were performed by the Rietveld method. The crystallinity and porosity were also related to the electrical behavior of the glass ceramics, which was determined by impedance spectroscopy, and the hardness, measured by the Vickers indentation method. Albite, andradite, anorthite, clinopyroxene, franklinite, nepheline, and spinel were shown to be the main crystalline phases present in the investigated compositions. The conductivity showed an increasing trend with the degree of crystallinity. This behavior was attributed to a decrease in porosity, an increase in the concentration of charge carriers in the glass phase (iron, Li+, and Na+), and an increase in the number of conduction paths through the glassy phase/crystalline phase interfaces. The relationship between hardness and crystallinity could not be verified due to the structural complexity of the glass-ceramics studied. However, a nearly linear relationship was found between the effect of porosity and hardness. The G2Z composition exhibited a hardness of 6.1 +/- 0.5 GPa at 850 degrees C, which is a value in very good agreement with other iron-rich glass-ceramics studied. (AU)

• Processo FAPESP: 13/14189-8 - Revestimentos de zircônia codopada com Nb2O5/Ta2O5 + Sc2O3 como barreira térmica para aplicação em turbinas
• Beneficiário: Roger Honorato Piva
• Modalidade de apoio: Bolsas no Brasil - Doutorado