Electrochemical synthesis of TiN precursors and their conversion to fine particles

TiN precursors were synthesized at room temperature by galvanostatic electrolysis of a titanium plate and n-butylamine. The resulting liquid was black in color, and was converted to viscous liquid by polymerization, then to black solids by heat treatment at 200 degrees C in vacuum. The solid samples were characterized by IR and H-1 NMR measurements, suggesting formation of butylamidotitanium. The black solids were pyrolyzed both in vacuum and under an ammonia atmosphere at 200 to 1000 degrees C. The samples were characterized by XRD, TEM, and chemical analysis. Fine TiN crystallites of up to 30 nm in size were produced with the retention of free carbon and/or hydrocarbons at 800 to 1000 degrees C in vacuum. These impurities were drastically reduced by increasing the TiN content by pyrolysis in ammonia. Two step pyrolysis, consisting of heating at 400 degrees C for 12 h and successively at a fixed temperature (600, 800 and 1000 degrees C) for 1 h, was found to be effective in reducing impurities and producing the TiN powders at temperatures as low as 600 degrees C.