METHOD FOR THE CHEMICAL VAPOR INFILTRATION OF REFRACTIVE SUBSTANCES

摘要

The invention relates to a method for the chemical vapor infiltration of refractive substances. A gas which contains at least one gaseous precursor flows through a porous structure in a reaction zone. The partial pressure of the precursor and the dwell time of the gas are set at a specified temperature such that a deposition reaction of the precursor occurs in the partial pressure range of the saturation adsorption in the porous structure, and the conversion of the precursor in each stage of the infiltration is limited such that no more than 50% of the precursor is deposited as a solid phase in the porous structure as the gas flows though the reaction zone. The flow through the porous structure occurs through annular vertical peripheral gaps (A, B) as well as through transverse gaps (C) which are open towards the peripheral gaps (A, B) in a stack of superimposed layers. The outer peripheral gap (A) is open both towards the inlet side as well as towards the outlet side of the reaction zone, whereas the inner peripheral gap (B) is closed towards the inlet side and the outlet side of the reaction zone and has a gap width which is greater than the outer gap (A).