Abstract: The sulfidation resistance of a silver-base material coating is further improved by making a concentration gradient of silver, oxygen and of one or more oxidizable alloying elements that may be present in the material, from the free surface of the coating up to a depth comprised between 10 nm and 1 ?m and more particularly between 100 nm and 1 ?m. Thus, the coating comprises a stack of one main layer made from silver-base material and of one oxidized thin film. The thin film, with a thickness comprised between 10 nm and 1 ?m, thus presents a decreasing silver concentration gradient from the interface between the thin film and the main layer to the free surface of the thin film. Deposition of the coating on a support can be achieved by two successive physical vapor deposition steps, and more particularly by magnetron cathode sputtering.

Abstract: The method enables metallurgical silicon to be purified by directional solidification to obtain solar or photovoltaic grade silicone. A crystallization step uses at least one silicon seed, preference of solar grade or even microelectronic grade, having for example a purity substantially equal to or greater than a predetermined purity of the solar-grade silicon. The silicon seed which covers the bottom of the crucible can come from a previous crystallization or be formed by a silicon wafer. The use of a single-crystal or textured multi-crystal seed enables crystallographic orientation of the solar-grade silicon. An intermediate layer of solid metallurgical silicon can be arranged on the silicon seed and a metallurgical silicon feedstock is arranged on the intermediate layer.

Abstract: Wafers of semi-conducting material are formed by moulding and directional crystallization from a liquid mass of this material. A seed, situated at the bottom of the crucible, presents an orientation along non-dense crystallographic planes. The mould is filled with the molten semi-conducting material by means of a piston or by creation of a pressure difference in the device. The mould is preferably coated with a non-wettable anti-adhesive deposit.

Abstract: The device for producing a block of crystalline material from a bath of molten material comprises a crucible having a bottom and heat extraction means arranged under the crucible. It also comprises means for modulating the thermal conductivity fitted between the bottom of the crucible and the heat extraction means. The means for modulating the thermal conductivity comprise a plurality of plates made from thermally conducting material of low emissivity, parallel to the bottom of the crucible, and means for moving said plates closer to and away from one another.

Abstract: Wafers of semi-conducting material are formed by moulding and directional crystallization from a liquid mass of this material. A seed, situated at the bottom of the crucible, presents an orientation along non-dense crystallographic planes. The mould is filled with the molten semi-conducting material by means of a piston or by creation of a pressure difference in the device. The mould is preferably coated with a non-wettable anti-adhesive deposit.

Abstract: The sulfidation resistance of a silver-base material coating is further improved by making a concentration gradient of silver, oxygen and of one or more oxidizable alloying elements that may be present in the material, from the free surface of the coating up to a depth comprised between 10 nm and 1 ?m and more particularly between 100 nm and 1 ?m. Thus, the coating comprises a stack of one main layer made from silver-base material and of one oxidized thin film. The thin film, with a thickness comprised between 10 nm and 1 ?m, thus presents a decreasing silver concentration gradient from the interface between the thin film and the main layer to the free surface of the thin film. Deposition of the coating on a support can be achieved by two successive physical vapor deposition steps, and more particularly by magnetron cathode sputtering.