On the condensation and preferred orientation of TiC nanocrystals — effects of electric field, substrate temperature and second phase

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 276; no. 1; pp. 99 - 107
• Main Authors: Kuo, Li-Ying, Shen, Pouyan
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.01.2000; Elsevier
• Subjects: Brownian rotation–coalescence; Condensation; Cross-disciplinary physics: materials science; rheology; Crystallographic orientation; Exact sciences and technology; Growth from vapor; Materials science; Methods of crystal growth; physics of crystal growth; Nanoscale materials and structures: fabrication and characterization; Physics; Transmission electron microscopy; Crystallographic orientation; Brownian rotation–coalescence; Transmission electron microscopy; Condensation; Crystal orientation; Vapor condensation; Crystal growth from vapors; XRD; Experimental study; Preferred orientation; Substrates; Deposition process; Orientation relation; Titanium carbides; TEM; Nanocrystal; Lattice image
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/S0921-5093(99)00504-3

The condensates formed by reacting Ti plasma with C 2H 2 gas (75 sccm) under relatively low vacuum (1×10 −3 Torr) and collected on carbon-coated collodion film were characterized by transmission electron microscopy to be TiC nanocrystals in random crystallographic orientation. The TiC condensates showed preferred orientation (200) when assembled on polycrystalline and amorphous substrates at ca. 150°C, and changed further into (111) when the substrate was subject to voltage bias (−120 V) with or without preheating to 450°C. The α-Ti co-deposited, with the TiC at a relatively low flow rate of C 2H 2 (25 sccm), followed the crystallographic relationship: (0001) α-Ti//(111) TiC; [112̄0] α-Ti//[11̄0] TiC, in accordance with the TiC (111) preferred orientation. On the other hand, the amorphous carbon formed at a high flow rate of C 2H 2 (250 sccm) hindered the preferred orientation (111) of TiC. The effects of applied electric field, substrate temperature and second phase on the accumulation and reorientation of the TiC condensates in the coating can be rationalized by surface charge of the TiC crystallites, Brownian rotation–coalescence of the crystallites, and atom configuration specification at the interphase interface, respectively.