Characterization of microstructure and mechanical behavior of sputter deposited Ti-containing amorphous carbon coatings.
We report on the characterization of microstructure and mechanical properties of sputter deposited Ti-containing amorphous carbon (Ti-aC) coatings as a function of Ti composition. Ti-aC coatings have been deposited by unbalanced magnetron sputter deposition, in an industrial-scale four-target coating deposition system. The composition and microstructure of the Ti-aC coatings have been characterized in detail by combining the techniques of Rutherford backscattering spectrometry (RBS) and hydrogen elastic recoil detection (ERD), transmission electron microscopy (TEM), X-ray absorption near edge structure (XANES) spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. At Ti compositions <4at.%, Ti atoms dissolve in an amorphous carbon (a-C) matrix. The dissolution limit of Ti atoms in an a-C matrix is determined to be between 4 and 8 at.%. At Ti compositions >8 at.%, XANES and EXAFS data indicate that the average Ti atomic bonding environment in Ti-aC coatings resembles that in cubic B1-TiC, consistent with TEM observation of precipitation of TiC nanocrystallites in the a-C matrix. Beyond the Ti dissolution limit, the Ti-aC coatings are nanocomposites with nanocrystalline TiC clusters embedded in an a-C matrix. A large scale, quasi one-dimensional composition modulation in the Ti-aC coatings was observed due to the particular coating deposition geometry. Elastic stiffness and hardness of the Ti-aC coatings were measured by instrumented nanoindentation and found to vary systematically as a function of Ti composition. Unlubricated friction coefficient of Ti-aC coatings against WC-Co balls was found to increase as the Ti composition increases. As Ti composition increases, the overall mechanical behavior of the Ti-aC coatings becomes more TiC-like.
- Research Organization:
- Argonne National Laboratory (ANL)
- Sponsoring Organization:
- SC; OUS
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 949561
- Report Number(s):
- ANL/MSD/JA-42010
- Journal Information:
- Surf. Coat. Technol., Journal Name: Surf. Coat. Technol. Journal Issue: 2-3 ; Dec. 3, 2001 Vol. 148; ISSN 0257-8972; ISSN SCTEEJ
- Country of Publication:
- United States
- Language:
- ENGLISH
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