Using Simultaneous Deposition and Rapid Growth to Produce Nanostructured Composite Films of AIN/TiN by Chemical Vapor Deposition

Abstract

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 (AlN/TiN) films produced by CVD. The AlN/TiN nanostructured composite films were synthesized by atmospheric‐pressure CVD (APCVD), using aluminum chloride (AlC13), titanium chloride (TiCl4), and ammonia (NH3) as reactant gases at temperatures ranging from 923 to 1123 K in a horizontal tubular 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 AlN/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.

Preparation and pyrolysis of a blended precursor possessing TiN and AlN bonds

“…[3][4][5] Ti-Al-N ceramic composites are usually prepared by traditional powder processing using TiN and AlN powders as starting materials. The chemical vapor deposition (CVD) process has been applied to the preparation of TiN-AlN composite films recently, 6 but it is difficult to apply it to largescale production and to coating preparation on substrates with complex shapes because of its largeequipment requirement.…”

Nanostructured Materials for Microstructural Control of Thermal Properties

“…Of these techniques, only thermal spray and MOCVD appear feasible for applications where cost-effectiveness, scalability, and field servicing are major concerns. Previous studies of MOCVD processing of nanocrystalline coatings of TiC, TIN, and SiC [25], and AIN/TiN [26] have established that several strategies can be employed in obtaining and stabilizing nanocrystalline microstructure via MOCVD processing. For example, Liu and co-workers [26] successfully used high speed deposition techniques to suppress relaxation processes believed to result in grain growth.…”

“…Previous studies of MOCVD processing of nanocrystalline coatings of TiC, TIN, and SiC [25], and AIN/TiN [26] have established that several strategies can be employed in obtaining and stabilizing nanocrystalline microstructure via MOCVD processing. For example, Liu and co-workers [26] successfully used high speed deposition techniques to suppress relaxation processes believed to result in grain growth. These same workers [26] also established that codepositing insoluble components to form a composite is an effective means of stabilizing a nanocrystalline microstructure.…”

“…Nanocrystalline thin films and coatings have been previously produced by several techniques including thermal spray [21,22], electrodeposition [23], sputter deposition [24], and MOCVD [25,26]. Of these techniques, only thermal spray and MOCVD appear feasible for applications where cost-effectiveness, scalability, and field servicing are major concerns.…”

“…For example, Liu and co-workers [26] successfully used high speed deposition techniques to suppress relaxation processes believed to result in grain growth. These same workers [26] also established that codepositing insoluble components to form a composite is an effective means of stabilizing a nanocrystalline microstructure.…”