Abstract: A method for isothermic, isobaric chemical vapor infiltration (CVI) of refractory substances, 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 deposition reaction occurs in the porous structure in the area of pressure or partial pressure of the saturation adsorption of the gaseous compounds forming the solid phase, saturation adsorption meaning that the deposition speed remains substantially constant at increased pressure of the gas or partial pressure of the educt gas. The reaction of the educt gas is limited in such a way that no more than 50% of the elements in the educt gas as it flows through the reaction zone are deposited as a solid phase in the porous structure.