Abstract: The present invention relates to a process for preparing coating compositions which comprises condensing a mixture containing (A) at least one silicone resin containing Si-bonded alkoxy groups and, if desired, silanol groups and/or at least one silane and/or siloxane which contains Si-bonded alkoxy groups and, if desired, silanol groups to form a silicone resin, (B) a basic condensation catalyst in an amount sufficient to render this mixture basic, (C) optionally water and (D) optionally an organic solvent.The resultant coating compositions are preferably employed in the form of a solution, emulsion or dispersion.

Abstract: A novel material can be obtained by chemical reaction from elemental or alloyed silicon powder, to which fillers are optionally added. The novel material, which can be worked mechanically, can be further refined by means of subsequent heat treatment and/or surface coating, and can in many cases be used instead of polycrystalline or sintered silicon.

Abstract: A method for lowering the risk of contamination during comminution of solid silicon fragments produces in a first step a temperature gradient in the solid silicon fragments. This temperature gradient results from the action of heat applied from the outside. A second temperature gradient is then produced, whose direction is rapidly at least partly reversed in a second step. This treatment effects a decompacting which makes it possible to use, in a subsequent mechanical comminution step, tools whose contact surfaces are composed of silicon or of hard materials, for example, based on nitride or carbide. The product obtained is remarkable for its uniform grain size distribution and also for its high purity in fine grain size categories. In addition, the low forces required for the comminution makes possible a longer service life for the tools used.

Abstract: A process for the purification of silicon by the action of one or several acids, wherein silicon is established as a stationary phase and one or several acids are caused to form mobile phases for traversing the stationary phase under pressure and absorbing the impurities from the silicon during the passage, leaving behind the silicon with a higher degree of purity.

Abstract: Process for the determination of the boron content of pure halogensilanes pecially silicon tetrachloride and trichlorosilane, which contain up to 0.1% of atoms of acceptors and donors, which comprises the steps of converting the halogen silanes into the gaseous state in a testing apparatus by contacting said halogensilanes with an evaporator surface heated to a temperature ranging from 80.degree. C to 350.degree. C, passing the generated gases to a support heated to the decomposition temperature of the gases whereby the released silicon is deposited on the support, removing the support and the deposit thereon from the testing apparatus and determining the boron content by calculation from the measured value of the specific resistance of the support plus the deposited silicon. It should be understood that all parts of the testing apparatus which come into contact with the generated gas, with the exception of the support heated to the required deposition temperature, should be at the temperature above 80.