An apparatus for manufacturing hexagonal Si crystal includes: a reaction tube; a mixed source part placed on one side in the reaction tube, for receiving mixed source of silicon, aluminum, and gallium which are in a solid state; a halogenation reaction gas supply pipe for supplying a halogenation reaction gas to the mixed source part; a substrate mounting part placed on the other side in the reaction tube, for mounting a first substrate, wherein the first substrate is disposed such that a crystal growth surface of the first substrate faces downwards; a nitrification reaction gas supply pipe for supplying a nitrification reaction gas to the substrate mounting part; and a heater for heating the reaction tube. The heater heats the reaction tube in a temperature range of 1100-1300° C.

Methods for preparing single crystal silicon substrates for epitaxial growth are disclosed. The methods may involve control of the (i) a growth velocity, v, and/or (ii) an axial temperature gradient, G, during the growth of an ingot segment such that v/G is less than a critical v/G and/or is less than a value of v/G that depends on the boron concentration of the ingot. Methods for preparing epitaxial wafers are also disclosed.

A colloidal crystal having a diamond lattice structure, including: a first layer in which a first plurality of particles are arranged to form a plane of a face-centered cubic lattice structure; a second layer in which a second plurality of particles are arranged on the first layer in contact with the first particles; and a third layer in which a third plurality of particles are arranged on the second layer in contact with the second particles, wherein the colloidal crystal includes at least one layer of each of the first layer, the second layer and the third layer.

A colloidal crystal having a diamond lattice structure, including: a first layer in which a first plurality of particles are arranged to form a plane of a face-centered cubic lattice structure; a second layer in which a second plurality of particles are arranged on the first layer in contact with the first particles; and a third layer in which a third plurality of particles are arranged on the second layer in contact with the second particles, wherein the colloidal crystal includes at least one layer of each of the first layer, the second layer and the third layer.

A diamond powder comprising diamond particles having an average particle size of no more than 20 μm and a vacancy or impurity-vacancy point defect concentration of at least 1 ppm. At least 70% of the volume of diamond in the powder is formed from a single crystal growth sector. This leads to a substantially uniform concentration of vacancies or impurity-vacancy point defects in the diamond particles because the rate of impurity take-up during growth is heavily dependent on the growth sector, which in turn leads to a more uniform fluorescent response. There is also described a method for making such a powder.

A diamond powder comprising diamond particles having an average particle size of no more than 20 μm and a vacancy or impurity-vacancy point defect concentration of at least 1 ppm. At least 70% of the volume of diamond in the powder is formed from a single crystal growth sector. This leads to a substantially uniform concentration of vacancies or impurity-vacancy point defects in the diamond particles because the rate of impurity take-up during growth is heavily dependent on the growth sector, which in turn leads to a more uniform fluorescent response. There is also described a method for making such a powder.

A method is disclosed for manufacturing lab grown diamond material by plasma enhanced chemical vapour deposition (PECVD). A substrate is exposed to a plasma containing carbon species while supported within a recess in a holder, resulting in a single crystal diamond (SCD) growing on the substrate while polycrystalline diamond (PCD) is deposited on the substrate holder. The relative rate of growth of the single crystal diamond on the substrate and the polycrystalline diamond on the surface of the holder is set, by control of at least one of the applied energy, cooling of the substrate holder and the chemical composition of the process gases, such that the single crystal diamond grown on the substrate protrudes above the surface of the holder and is constrained not to increase or to reduce in cross sectional area with increased distance from the surface of the holder by simultaneous growth of a polycrystalline diamond layer on the surface of the holder.

A method is disclosed for manufacturing lab grown diamond material by plasma enhanced chemical vapour deposition (PECVD). A substrate is exposed to a plasma containing carbon species while supported within a recess in a holder, resulting in a single crystal diamond (SCD) growing on the substrate while polycrystalline diamond (PCD) is deposited on the substrate holder. The relative rate of growth of the single crystal diamond on the substrate and the polycrystalline diamond on the surface of the holder is set, by control of at least one of the applied energy, cooling of the substrate holder and the chemical composition of the process gases, such that the single crystal diamond grown on the substrate protrudes above the surface of the holder and is constrained not to increase or to reduce in cross sectional area with increased distance from the surface of the holder by simultaneous growth of a polycrystalline diamond layer on the surface of the holder.

The present invention provides a crystal comprising a plurality of silanol compounds of at least one selected from the group consisting of a hexamer represented by following formula (1), an octamer represented by following formula (2), and a decamer represented by following formula (3) and having an interaction via a hydrogen bond by at least one hydroxy group between the silanol compounds.

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Methods of manufacturing or repairing a turbine blade or vane are described. The airfoil portions of these turbine components are typically manufactured by casting in a ceramic mold, and a surface made up of the cast airfoil and at the least the ceramic core serves as a build surface for a subsequent process of additively manufacturing the tip portions. The build surface is created by removing a top portion of the airfoil and the core, or by placing an ultra-thin shim on top of the airfoil and the core. The overhang projected by the shim is subsequently removed. These methods are not limited to turbine engine applications, but can be applied to any metallic object that can benefit from casting and additive manufacturing processes. The present disclosure also relates to finished and intermediate products prepared by these methods.