Micro-structural and compositional study: ε-Fe2O3 crystals in the Hare’s Fur Jian Ware

The Jian kilns in the present-day Jianyang county of Fujian province are well-known as their thick and lustrous black-glazed porcelain production. The hare’s fur (HF) glazed Jian wares characterized by radial fur-like strips, as one of the most typical representatives of black-glazed tea bowls, are originated from phase separation of glaze melt and crystallization of iron oxides. In this work, various techniques were performed on the yellowish-brown HF samples, including portable energy-dispersive X-ray fluorescence (PXRF), synchrotron X-ray absorption near-edge spectroscopy (XANES), optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy (RS). The objective of this study was to well understand the microstructure characteristics and chemical compositions of glaze patterns. Results showed that the main constituents of the ceramic glaze were alumina (10.61-16.43 wt.%), silica (62.20-77.07 wt.%), calcium (3.85-6.97 wt.%) and iron oxide (4.10-8.35 wt.%). The studies evidenced that the presence of metastable epsilon-hematite crystals (ε-Fe2O3) formed on the brownish yellow glazed surface. Microstructural analysis revealed that there were three types of crystal structures in the glaze surface, one consisted of well-grown leaf-like or dendritic-like structure with highly ordered branches at micrometers scales, one was comprised of flower-like clusters accompanied by branches radiating from the center, petals growing along the branches and needles on both sides of the petals, and the last embraced a honeycomb structure tightly packed with plentiful spherical or irregular-shaped particles. In addition, ε-Fe2O3 crystals in the cross-section of glaze showed a gradient distribution.

The application of LIBS and other techniques on Chinese low temperature glaze

ABSTRACT The focus of this paper is on analysis, comparison and research on the colorful low-temperature, lead-containing overglazes on glazed porcelain body and on the enamel glazes on the metal body of the Qing Dynasty by adopting several analytical methods. Analysis and tests on the element, boron in overglaze on glazed porcelain body and enamel glaze on metal body, were performed using laser induced breakdown spectroscopy (LIBS), and the results showed that Cloisonné enamel, painted enamel and Falangcai samples contained boron, while Famille Rose (Fencai) samples did not contain boron. Meanwhile, such analysis methods as laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), energy dispersive X-ray spectroscopy (EDXRF), Micro-Raman, stereomicroscope and Confocal laser scanning microscopy (CLSM) were used to test and observe the element composition, crystal composition and microstructure of the samples. The results illustrated that matrix glaze of Cloisonné enamel, painted enamel and Falangcai was the same. The yellow glaze was a lead-alkali glass and other color glazes were boron-lead-alkali glass, while all color glazes of Famille Rose were lead-alkali glass. Colorful low-temperature overglaze on glazed porcelain body and enamel glaze on metal body had a common practice and technology in the use of opacifiers and colorants. Compared to painted enamel, the painting technique of Famille Rose was more complicated, and effect was apparently praised as being superior.

Titania (TiO2) as Antibacterial Material in Ceramic Tiles: Effect of Composition

Titania (TiO2) is one of a common and favorable material use in the manufacturing industry due to its uniqueness and functional performances to human and environment. The study was focused on the performance of glaze added TiO2 (anatase phase) in the application of porcelain tiles. Anatase powder in micro size was used (varies at 5 wt%, 10 wt % and 15 wt%) to observe their performance as antibacterial materials. The anatase powders were mix into the glaze composition and apply to the porcelain tile through dip coating. The viscosity of each composition was observed to study their effect. Characterization used to observe the properties of anatase mixed glazed porcelain tile were X-ray diffraction (XRD), Scanning electron microscopy (SEM) and antibacterial test. The results shown that higher composition of anatase powder, viscosity of the mixed glaze is higher and a rougher surface of glazed tiles was formed. XRD result shows that the higher the composition is more the intensity of TiO2 on the glaze coating surface, supported by SEM results. Antibacterial testing towards E.Coli was observed by counting the colonies of bacterial growth in 0 hr, 2 hrs, 4 hrs and 8hrs. The antibacterial properties increase when the composition of anatase increases.