METHOD FOR CHEMICAL VAPOUR INFILTRATION OF REFRACTORY SUBSTANCES, ESPECIALLY CARBON AND SILICON CARBIDE

摘要

Disclosed is a method for chemical vapour infiltration (CVI) of refractory substances, especially an isothermic, isobaric method of CVI, especially of carbon (C) and silicon carbide (SiC), based on diffusion in a porous structure, whereby the pressure of the gas or partial pressure of an educt gas contained in the gas and the dwell time of the gas in the reaction zone are set at a given temperature in the reaction zone so that a separation reaction occurs in the porous structure in the area of pressure or partial pressure of the saturation adsorption of the gaseous and volatile compounds forming the solid phase. Saturation adsorption means that the separation speed remains substantially constant at an increased pressure of the gas or the partial pressure of the educt gas and the reaction of the educt gas is limited in such a way that no more than 50 % of the elements supplied in the educt gas forming the solid phase as it flows through the reaction zone are separated as a solid phase in the porous structure. The flow through the porous structure occurs in a straight line from bottom to top via slits substantially similar in width, ranging from 1-50 mm.