DEPOSITION OF HARD MATERIAL COATINGS USING AN ORGANOMETALLIC PRECURSOR

The deposition of titanium or zirconium carbonitride films is possible using organometallic precursors as starting material. In the temperat ure range from 550 to 850 K in combination with a d.c. plasma-assisted chemical vapour deposition process, golden-bronze or grey coatings we re obtained depending on the gas-phase composition. The layers have be en characterized regarding composition, morphology and microstructure and show differences in some properties (microhardness and structure) from plasma-assisted samples, using TiCl4-N2-H-2-Ar as starting compou nds. The C, N and O contents respectively are dependent on temperature , gas phase composition and plasma power. Scanning electron microscopy and transmission electron microscopy investigations revealed a small grain size (5-8 nm) in the initial stage followed by a typical columna r growth. By secondary-electron mass spectrometry investigations, frag ments or crack products of the organometallic starting materials can b e detected and they influence the hard material properties unfavourabl y. Thermodynamic calculations for the Ti-N-C-H system with regard to o rganometallic starting material were made and discussed in comparison with experiments.