Microscopic analysis of overglaze green pigment on Chinese famille rose porcelain from the Imperial Palace.

Famille rose porcelain made in the imperial workshop was one of the symbols of the highest manufacturing techniques in ancient China. It was very precious and only owned by the royals for a long time. Because of its complex making technology, overglaze green pigment painted on famille rose porcelain shows many variations. In this work, selected porcelain shards that were excavated at the Forbidden City were analyzed by using microscopy observation, micro-Raman spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectrometer to obtain a deep understanding of overglaze green pigment technique on famille rose porcelain. The results revealed that four types of green pigment are used in the selected samples. With different recipes and combinative ways on green pigment and opaque white pigment, craftsmen can choose the using method of pigment to get the effect they want.

Emerging Approaches in Synchrotron Studies of Materials from Cultural and Natural History Collections.

Synchrotrons have provided significant methods and instruments to study ancient materials from cultural and natural heritages. New ways to visualise (surfacic or volumic) morphologies are developed on the basis of elemental, density and refraction contrasts. They now apply to a wide range of materials, from historic artefacts to paleontological specimens. The tunability of synchrotron beams owing to the high flux and high spectral resolution of photon sources is at the origin of the main chemical speciation capabilities of synchrotron-based techniques. Although, until recently, photon-based speciation was mainly applicable to inorganic materials, novel developments based, for instance, on STXM and deep UV photoluminescence bring new opportunities to study speciation in organic and hybrid materials, such as soaps and organometallics, at a submicrometric spatial resolution over large fields of view. Structural methods are also continuously improved and increasingly applied to hierarchically structured materials for which organisation results either from biological or manufacturing processes. High-definition (spectral) imaging appears as the main driving force of the current trend for new synchrotron techniques for research on cultural and natural heritage materials.

Learning from the past: rare ε-Fe2O3 in the ancient black-glazed Jian (Tenmoku) wares.

Ancient Jian wares are famous for their lustrous black glaze that exhibits unique colored patterns. Some striking examples include the brownish colored "Hare's Fur" (HF) strips and the silvery "Oil Spot" (OS) patterns. Herein, we investigated the glaze surface of HF and OS samples using a variety of characterization methods. Contrary to the commonly accepted theory, we identified the presence of ε-Fe2O3, a rare metastable polymorph of Fe2O3 with unique magnetic properties, in both HF and OS samples. We found that surface crystals of OS samples are up to several micrometers in size and exclusively made of ε-Fe2O3. Interestingly, these ε-Fe2O3 crystals on the OS sample surface are organized in a periodic two dimensional fashion. These results shed new lights on the actual mechanisms and kinetics of polymorphous transitions of Fe2O3. Deciphering technologies behind the fabrication of ancient Jian wares can thus potentially help researchers improve the ε-Fe2O3 synthesis.

Thermal expansion, polarization and phase diagrams of Ba(1-y)Bi(2y/3)Ti(1-x)Zr(x)O(3) and Ba(1-y)La(y)Ti(1-y/4)O(3) compounds.

The thermal expansion properties of the ceramic compositions Ba(1-y)La(y)Ti(1-y/4)O(3) (y = 0.0, 0.026, 0.036, 0.054) and Ba(1-y)Bi(2y/3)Ti(1-x)Zr(x)O(3) (y = 0.10; x = 0.0, 0.04, 0.05, 0.10, 0.15) were determined in the temperature range 120-700 K. We report the temperature-dependent measurements of the strain, thermal expansion coefficient and the magnitude of root mean square polarization. The results obtained are discussed together with the data on the structure and dielectric properties.

Heat capacity study of relaxors BaTi(0.65)Zr(0.35)O(3) and BaTi(0.60)Zr(0.40)O(3).

The heat capacity of two relaxors BaTi(1-x)Zr(x)O(3) (x = 0.35,0.40) was measured using adiabatic calorimetry in the temperature range 100-360 K. The C(p)(T) dependence of both compositions is characterized by the presence of two diffuse anomalies near the Burns temperature T(d) and the temperature of the maximum in permittivity T(m) in the temperature ranges 250-350 K and 120-200 K. The anomalous heat capacity near T(d) was analysed taking into account the distribution of Zr concentration in nanoregions leading to the distribution of their transition temperatures into the polar phase. Excess heat capacity near T(m) was discussed in the framework of the spherical random bond-random field model. The results are compared with the data obtained by the same procedures for PbMg(1/3)Nb(2/3)O(3) studied experimentally earlier.