Using simultaneous deposition and rapid growth to produce nanostructured composite films of AIN/TiN by chemical vapor deposition

Brittleness has been the major obstacle in using ceramics, Previous research has shown, however, that ceramic materials that have small grain size show plasticity, We therefore propose two methods to produce nanostructured ceramic films by chemical vapor deposition (CVD): (1) high-speed deposition and (2) simultaneous deposition of insoluble materials (contained in a mixture of insoluble solids), These methods were successfully applied to aluminum nitride/ titanium nitride (AIN/TiN) films produced by CVD, The AIN/TiN nanostructured composite films were synthesized by atmospheric-pressure CVD (APCVD), using aluminum chloride (AlCl3), titanium chloride (TiCl4), and ammonia (NH3) as reactant gases at temperatures ranging from 923 to 1123 K in a horizontal tabular reactor, For the highspeed deposition strategy, we obtained growth rates as high as 1.2 mm/h. Using either method, we were able to attain AIN/TiN composite films that had a grain size of 8 nm (AlN crystals) and 6 nm (TiN crystals), showing that these methods are effective in producing nanostructured composite films by CVD. Measurements of the fracture toughness of the prepared materials indicated that these strategies can be used to improve the ductility of ceramics.