The invention relates to a process for preparing silicon-containing composite particles in a fluidized bed. Porous conductive particles having a defined particle size and pore structure are combined with a particulate additive having defined particle size, density and BET surface area. The combined porous conductive particles and particulate additive are subjected to chemical vapour infiltration in a fluidised bed to cause deposition of silicon in the pores of the porous conductive particles.

A method for producing a hollow part made of a ceramic matrix composite material. The method includes shaping a hollow fibrous preform. A core of oxidizable material is housed or inserted into the preform. The method also includes consolidating the preform and extracting the core by oxidising the core.

Crystal pulling systems having composite polycrystalline silicon feed tubes, methods for forming such tubes, and methods for forming a single crystal silicon ingot with use of such tubes. The composite polycrystalline silicon feed tubes include quartz and at least one dopant. The composite polycrystalline silicon feed tube may be made by a slip cast method.

Antiballistic armour plate includes a ceramic body including a hard material, provided, on its inner face, with a back energy-dissipating coating. The ceramic body is monolithic. The constituent material of the ceramic body includes grains of ceramic material having a Vickers hardness that is higher than 15 GPa, and a matrix binding the grains, the matrix including a silicon nitride phase and/or a silicon oxynitride phase, the matrix representing between 5 and 40% by weight of the constituent material of the ceramic body. The maximum equivalent diameter of the grains of ceramic material is smaller than or equal to 800 micrometres. The constituent material of the ceramic body has an open porosity that is higher than 5% and lower than 14%. The metallic silicon content in the material, expressed per mm of thickness of the body, is lower than 0.5% by weight.

A barrier coating resin formulation comprising at least one polycarbosilane preceramic polymer, at least one organically modified silicon dioxide preceramic polymer, at least one filler, and at least one solvent. A barrier coating comprising a reaction product of the at least one polycarbosilane preceramic polymer and the at least one organically modified silicon dioxide preceramic polymer and the at least one filler is also disclosed, as are articles comprising the barrier coating, rocket motors comprising the barrier coating, and methods of forming the articles.

The present disclosure provides a boron carbide composite material having a novel composition with excellent mechanical properties, and a production method therefor. The boron carbide composite material has high fracture toughness and may be applied as a lightweight bulletproof ceramic material. The boron carbide composite material is a boron carbide/silicon carbide/titanium boride/graphite (B.sub.4C—SiC—TiB.sub.2—C) composite material. The composite material may overcome a technical limitation on increasing the fracture toughness of the boron carbide composite material, and may be produced as a high-density boron carbide composite material using a reactive hot-pressing sintering process at a relatively low temperature. The boron carbide composite material having excellent mechanical properties may be applied to general industrial wear-resistant parts and nuclear-power-related industrial parts, and particularly, may be actively used as a lightweight bulletproof material for personal use and for military aircraft including helicopters.

A dielectric composition includes a main phase and a Ca—Si—P—O segregation phase. The main phase includes a main component expressed by ABO.sub.3. “A” includes at least one selected from calcium and strontium. “B” includes at least one selected from zirconium, titanium, hafnium, and manganese. The Ca—Si—P—O segregation phase includes at least calcium, silicon, and phosphorus.

A Cr—Si sintered body contains Cr and Si. The Cr—Si sintered body contains a crystalline CrSi.sub.2 phase and a crystalline Si phase. A content of the Si phase in the Cr—Si sintered body is 40% by mass or more. A relative density of the Cr—Si sintered body relative to a true density of the Cr—Si sintered body is 95% or more. The CrSi.sub.2 phase has an average crystal grain size of 40 μm or less, and the Si phase has an average crystal grain size of 30 μm or less. A total content of impurities in the Cr—Si sintered body is 200 ppm by mass or less, and the impurities are composed of at least one element selected from the group consisting of Mn, Fe, Mg, Ca, Sr, and Ba.

Provided is an article that includes silicon carbide as a main component and that has sufficient mechanical strength while manufactured by a three-dimensional shaping technology. The article that includes silicon carbide as a main component includes: silicon carbide; a metal boride having a melting point lower than a sublimation point of silicon carbide; and metal silicon.

A method for producing an article containing silicon carbide as the main constituent includes a plurality of sets of steps of forming a layer of a raw material powder and irradiating the layer with laser light according to three-dimensional model data. The low material powder is a mixture of silicon carbide powder, metallic silicon powder, and carbon powder. The laser light used in the step of irradiation with laser light has a spatial laser power density of 11 J/mm.sup.3 to 50 J/mm.sup.3.