Siliconization is an important process in the manufacture of modern ceramic matrix carbon fiber reinforced composites. These composites have superior material properties, such as high thermal stability, high thermal conductivity, low density and high abrasion resistance.
Due to their properties, C/C – SiC composites are therefore the material of choice in highly oxidizing atmospheres and very high temperatures. The material is used, for example, in jet vanes for missile rockets, brake pads for sport cars, bullet proof vests and nose caps for spacecrafts (reentry into earth atmosphere).
One major manufacturing process of these compounds is siliconization, more accurately the liquid silicon infiltration (LSI) of porous C/C. Compared to other processes like chemical vapor infiltration, LSI is a cost efficient and quick manufacturing process, which may be carried out in Carbolite Gero's HTBL GR vacuum furnace.
During heat treatment in the furnace, silicon is melted on top of the porous C/C material and diffuses into the pores of the material. This results in the reaction of the carbon matrix with silicon, which forms SiC and yields a dense material with C/C segments separated from each other by SiC.
The all-around accessibility of the HTBL furnace is very advantageous for this application. The automatic software control makes unattended operation possible and ensures a proper data logging.
Dwa piece HTBL 80 GR/22-1G podczas instalacji u klienta. Jeden piec jest używany do procesu pirolizy. Drugi piec jest używany do procesu silikonizacji.
Jednostka pompowa jest używana do osiągnięcia próżni doskonałej. Specjalna pompa olejowa jest używana podczas procesu odparowania lepiszcza (debinding) przy częściowym ciśnieniu. Pompa ta jest montowana jako jednostka wspierająca pracę niezależnie.
Vanes in original position before siliconization: Vanes perpendicular to the graphite rods. Graphite rods parallel to each other. The Same crucible after siliconization is shown in the next picture.