Search

Iron‐rich porcelains generally embrace relatively high iron concentration in the glaze and body, which have an important position in the history of ancient Chinese high‐temperature ceramics. The colour and lustre of glaze patterns are closely related to the orientation and order of crystallisation. In this work, three representative types of iron‐rich porcelains (persimmon red‐glazed sample, oil spot‐glazed sample and mirror black‐glazed sample) were analysed by portable energy‐dispersive X‐ray fluorescence (PXRF), optical coherence tomography (OCT), optical microscopy (OM), scanning electron microscopy (SEM), X‐ray diffraction (XRD) and laser Raman spectroscopy (RS) to determine the morphology, chemical composition and microstructure. Results showed that layered structure was observed in both persimmon red and oil spot glazes, however with respective thickness. Besides, iron‐enriched crystals mostly precipitated on glaze surface. For the persimmon red sample, multilayer microstructure consisting of three sublayers beneath glaze surface was identified. Crystals and dark red substrates were all made of ε‐Fe2O3, implying that it was fired at a strong reducing atmosphere. But for the oil spot sample, large‐scale leaf‐shaped crystals were well characteristic of ε‐Fe2O3, while small snowflake‐shaped crystals were assigned to α‐Fe2O3, indicating that the firing environment was partially reduced. In addition, there was no crystalline layer existing on surface of mirror black‐glazed porcelain, and plain black glaze layer was featured by a glassy matrix. The Jian kiln is a famous ancient folk kiln in the southern China that is currently located in Jianyang county of Fujian province. Its production of black‐glazed porcelain began in the Tang dynasty (618–907 AD), became prosperous in the Southern Song dynasty (1127–1279 AD), and declined and ended in the Yuan dynasty (1271–1368 AD). Black‐glazed Jian tea bowls were perfect for highlighting the rich white tea decoction. The thick and lustrous black glaze of Jian bowls sometimes were featured by streaked or mottled patterns, usually recognised by 'hare's fur (HF)', 'oil spot (OS)', 'partridge spot (PS)' and so on, which were the crystalline markings of iron oxide precipitated during firing in the dragon kiln. Iron oxide acted as a colorant for black‐glazed porcelain and, thus, was called as iron‐rich porcelain. The unique patterns originated from local iron‐enrichment raw materials and firing process, and the locally iron‐enriched areas generated due to the supersaturated crystallisation of different iron oxide in the cooling period. It was generally believed that research studies on the crystallographic nature and growth mechanism of surface crystals would provide help for the manufacturing of ancient Chinese glazes. With this aim, three types of iron‐rich porcelain excavated from the Jian kiln were selected to further study the forming cause and growth process of glaze patterns using a series of characterisation methods, like portable energy‐dispersive X‐ray fluorescence (PXRF), optical coherence tomography (OCT), optical microscopy (OM), scanning electron microscopy (SEM), X‐ray diffraction (XRD) and laser Raman spectroscopy (RS). [ABSTRACT FROM AUTHOR]

Jian tea bowls are greatly appreciated not only due to their thick and lustrous black glazes, but also their exquisite streaked and mottled patterns. Researches on the firing process and colouring mechanism of typical hare's fur and oil spot Jian glazes have continuously been carried out in the past decades; however, there are few reports about other scarce types of black-glazed porcelains excavated from the Jian kiln site. In this work, we report on a multi-technique analysis of the surface and cross-sectional structure, phase, morphology and chemical composition of three rare types of Jian tea bowls (tea-dust-glazed ware, grey-glazed ware and pearl-glazed ware) combining optical and spectroscopic methods such as optical coherence tomography (OCT), optical microscopy (OM), Portable energy dispersive X-ray fluorescence spectrometry (XRF), laser-Raman spectroscopy (LRS) and scanning electron microscopy coupled with an X-ray energy dispersive spectrometer (SEM-EDS). Results revealed that the tea dust glaze was one high-temperature iron-based crystalline glaze, and its glaze was characterized by a transparent glass matrix; irregular pits completely or partially filled by TiO2; and that ε-Fe2O3 and residual quartz were randomly distributed all over the surface, which produced the appearance of tea-dust. The grey-glazed porcelain was fired at a lower temperature in the dragon kiln than that of the traditional hare's fur and oil spot samples, its glaze contained some residual quartz, and anorthite crystals showed a serried distribution along the thickness. The pearl-glazed porcelain was fired through a secondary glazing process via artificial stippling quartz powder. This work provides guidance for the firing process of three rare types of Jian wares and has not only scientific but also cultural profound significance, which reveals the features of their historical heritage. [ABSTRACT FROM AUTHOR]

The Jian kilns in the present-day Jianyang County of Fujian Province are well known for 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, originate from phase separation of glaze melt and crystallization of iron oxides. In this study, 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 provided evidence that metastable epsilon-iron oxide 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; another comprised flower-like clusters accompanied by branches radiating from the center, petals growing along the branches, and needles on both sides of the petals; the last type involved a honeycomb structure tightly packed with plentiful spherical or irregular-shaped particles. In addition, ε-Fe2O3 crystals in the cross-section of the glaze showed a gradient distribution. [ABSTRACT FROM AUTHOR]

Sepia pharaonis (cuttlefish) has a narrow salinity adaptation range, therefore, it is highly sensitive to changes in salinity. This limits breeding practices for Sepia pharaonis. The aim of this study was to explore effects of low salinity concentrations on gills of cuttlefish. Larvae were randomly categorized into two groups and acclimatized to 2 different salinity conditions (22 psu and 29 psu). Salinity was adjusted by diluting salinity water (29 psu) with fresh water then aeration was carried out overnight. Observation of gills under light and electron microscopy showed that cuttlefish survived up to 22 psu salinity levels. Further, light and transmission electron microscopic examination showed that gills exposed to low salinity stress (22 psu) showed significant pathological changes compared with the control group (29 psu). Biochemical and molecular analyses showed that Na+/K+‐ATPase, Ca2+/Mg2+‐ATPase, TIP4‐1 and Zfand4 were involved in regulation of osmotic pressure in S. pharaonis. [ABSTRACT FROM AUTHOR]