Microstructural Characteristics of Glaze in Blackware due to Variations in Glaze Materials, Firing Temperature, and Firing Environment

Abstract

This study investigated the microstructural characteristics of glaze, building on the results of investigating the fundamental properties of existing color development. It identified the effect of the firing temperature, firing environment, and mixing ratios of glaze materials on the microstructural characteristics of glaze. Additionally, Mössbauer analysis was utilized to explore the phase changes in iron oxides formed during the firing process. Observations of the cross-sections of replicated specimens showed that the gradual addition of feldspar to glaze materials resulted in the formation of glaze with progressively uniform microstructural characteristics. Furthermore, the compositional analysis of glaze revealed minimal variation in the component content between the glaze surface and interior, indicating a trend toward a more homogeneous composition throughout glaze. Analysis of the crystalline structure revealed that specimens with added feldspar exhibited an increase in the amorphous peak area, while crystalline peak intensities tended to decrease. This suggests that the degree of vitrification is considerably influenced by the amount of feldspar added as a flux. TheMössbauer analysis of aggregated iron oxides revealed that under an oxidation environment, hematite was identified, whereas magnetite was observed under a reduction environment, depending on the firing environment. This indicates that microstructural differences within the glaze of blackware are affected by the materials used, firing temperature, and firing environment. Moreover, the study highlights that the formation of crystals and types of crystalline phases vary according to these parameters.