Abstract: The present invention relates to a sol-gel process for the inexpensively and in large quantities agglomeration of silicon particles in a green body which is more suitable for industrial uses of silicon than the powder itself.

Abstract: Process for the preparation and the deposition of vitreous films on substrates comprising: the dissolution of one or more metal alkoxides in aprotic solvent, the hydrolysis of the resulting solution, the eventual removal of the formed alcohol, the deposition of the resulting sol on the substrate surface of interest and the final drying of the film.

Abstract: Process for the production of monoliths of glass by means of the sol-gel process, comprising the following steps: a) dispersion in water of an oxide prepared by the pyrogenic route, b) hydrolysis of an alkoxide in aqueous solution to form a hydrolysate, c) mixing of the hydrolysate of the alkoxide with the oxide prepared by the pyrogenic route to form a colloidal sol, d) optional removal of coarse contents from the colloidal sol, e) gelling of the colloidal sol in a mould, f) replacement of the water contained in the resulting aerogel by an organic solvent, g) drying of the aerogel, h) heat treatment of the dried aerogel.

Abstract: The present invention relates to glassy inorganic films, characterized by a high chemical stability and a high adhesion, containing, among the others, titanium dioxide, employable to coat metal surfaces characterized by the presence of oxides, particularly stainless steel sheets. The coated structures obtained thereby, which are the second object of the present invention, are used to build many articles such as pipes, reactors, exchangers, containers, and so on. With reference to the peculiar case of stainless steel structures coated by the above film, these ones can be used in the food industry since that film coated article shows specific and very high photobactericide properties.

Abstract: It is described a sol-gel process that allows to obtain dry gels, and possibly the corresponding dense glassy bodies, having higher dimensions compared to similar known processes.

Abstract: Glassy articles are prepared by subjecting to hydrolysis and policondensation a solution or suspension of a suitable precursor, mainly comprising a silicon alkoxide, and by drying the obtained gel in a pressure chamber, the gel solvent having been substituted by a non-protic solvent, mainly acetone, under nitrogen flowing, at temperature and pressure conditions lower than the gel solvent critical values. The dried gel is then densified by a thermal treatment.

Abstract: Particularly shaped articles constituted by silicon oxide, as such or with suitable additives, prepared by room temperature molding according to a process comprising: preparation of a sol starting from a silicon alcoxide, or from a silicon alcoxide and at least a precursor of at least one of the additional elements; hydrolysis of the sol obtained thereby; addition of colloidal silica; pouring the resulting mixture into the desired mould; sol gelling and fast removal of the solid product; gel drying; gel densification by means of a thermal treatment at temperature ranging from 900 ° C to 1500 ° C. The articles can be used as preforms for the optic fiber spinning.

Abstract: It is described a process based on sol-gel chemistry suitable to the production of nanocomposite materials being photoluminescent at ambient temperature, comprising silicon grains of dimension of nanometers embedded in a silica matrix.

Abstract: Sol-gel process for the production of optical fiber preforms or overcladdings by preparing a sol, gelling the sol, drying the wet gel to a dry porous gel and densifying the dry gel to fully dense glass, wherein during the calcination treatment from 350° C. to 900° C. to remove organic impurities in the dry gel, it is carried out at least one reduced-pressure phase at a pressure comprised between about 0.01 and 0.5 bar.