Electrochemical synthesis of TiN precursors and their conversion to fine particles

Abstract

TiN precursors were synthesized at room temperature by galvanostatic electrolysis of a titanium plate andn-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 °C in vacuum. The solid samples were characterized by IR and ¹H NMR measurements, suggesting formation of butylamidotitanium.

The black solids were pyrolyzed both in vacuum and under an ammonia atmosphere at 200 to 1000 °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 °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 °C for 12 h and successively at a fixed temperature (600, 800 and 1000 °C) for 1 h, was found to be effective in reducing impurities and producing the TiN powders at temperatures as low as 600 °C.