Two palettes, characteristic of the production of the Sèvres Factory (Manufacture Nationale de Sèvres), and representative of ancient glazing techniques, were studied. One was made with coloured glazes/enamels on Bisque (1050 • C) and the other one was composed of Moufle (880 • C) painting colours. Spectra specific to the white (opacifiers), yellow (including Naples yellow), green, pink, 'brown-red' and black coatings/paintings were considered. Emphasis was placed on the different Raman peaks arising from coloured coatings specific to ancient artefacts: greens obtained with dissolved Cu ions or from chromium pigments (Victoria green garnets), Naples yellows (Pb 2 Sb 2 O 7 pyrochlore), green and black spinels and pink sphene. Attention was paid to the effect of pigment grain size on the Raman spectrum. To illustrate the capability of the method, we analysed some old artefacts from the eighteenth and nineteenth centuries.

No abstract

No abstract

No abstract

No abstract

No abstract

Two crystalline phases of silicon: Si 111 (BCC) and Si IV (hexagonal diamond) are known to be metastable at ambient. Pure, single phase, microcrystalline samples of both varieties may be prepared by high-pressure synthesis above 18 GPa at 300 K. We report on high-resolution electron microscopy, kinetics of the temperature driven phase-change from Si 111 to Si IV, and Raman scattering measurements performed on these samples. Results are compared with those obtained by other characterisation methods and/or published in earlier works.

No abstract