Abstract: The invention relates to a method for producing nanoparticles of at least one oxide of a transition metal selected from Ti, Zr, Hf, V, Nb and Ta, which are coated with amorphous carbon, wherein said method includes the following successive steps: (i) a liquid mixture containing as precursors at least one alkoxyde of the transition metal, an alcohol, and an acetic acid relative to the transition metal is prepared and diluted in water in order to form an aqueous solution, the precursors being present in the solution according to a molar ratio such that it prevents or sufficiently limits the formation of a sol so that the aqueous solution can be freeze-dried, and such that the transition metal, the carbon and the oxygen are present in a stoichiometric ratio according to which they are included in the nanoparticles; (ii) the aqueous solution is freeze-dried; (ii) the freeze-dried product obtained during the preceding step is submitted to pyrolysis under vacuum or in an inert atmosphere in order to obtain the nano

Abstract: The invention relates to a method for producing nanoparticles of at least one oxide of a transition metal selected from Ti, Zr, Hf, V, Nb and Ta, which are coated with amorphous carbon, wherein said method includes the following successive steps: (i) a liquid mixture containing as precursors at least one alkoxyde of the transition metal, an alcohol, and an acetic acid relative to the transition metal is prepared and diluted in water in order to form an aqueous solution, the precursors being present in the solution according to a molar ratio such that it prevents or sufficiently limits the formation of a sol so that the aqueous solution can be freeze-dried, and such that the transition metal, the carbon and the oxygen are present in a stoichiometric ratio according to which they are included in the nanoparticles; (ii) the aqueous solution is freeze-dried; (ii) the freeze-dried product obtained during the preceding step is submitted to pyrolysis under vacuum or in an inert atmosphere in order to obtain the nano

Abstract: The invention relates to a method for preparing a transparent ceramic material based on an intermetallic oxide, comprising the following steps: (A) particles (p) based on said intermetallic oxide are synthesised by oxidising calcination of particles (p0) containing a homogeneous mixture of organic salts of different metallic cations of the intermetallic oxide; (B) a moulded material (M) is produced from the particles (p) obtained in this way, using a filtering pressing technique; and (C) the moulded material (M) is thermally processed (sintered). The invention also relates to the materials based on transparent oxides obtained according to said method, especially the transparent ceramic materials based on Y3A15012 (YAG) doped by lanthanides such as neodymium, and to the uses of said materials, especially for laser amplification.