Sulfur-doping of nc-TiC/a-C films by reactive sputtering
2012 (English)In: Thirteenth International Conference on Plasma Surface Engineering, Garmisch-Partenkirchen, Germany, 10-14 September 2012, 2012Conference paper, Poster (Refereed)
Nanocomposite thin films with carbide grains in a matrix of amorphous carbon have been found interesting for various mechanical and electrical applications. An important advantage of these materials is the possibility to tune the properties by varying the composition and the microstructure. A well-known example is the nc-TiC/a-C system, which is interesting for its tribological as well as its electrical and chemically protective properties. One way to modify the material is doping with a third element. Usually, another metal or a p-element such as oxygen or nitrogen is considered. In this work, however, Ti-C films have been doped with sulfur. The doping was performed by introduction of increasing amounts of H2S to the chamber during DC magnetron sputtering from elemental Ti and C targets.
An increased flow of H2S during deposition leads to an increase in the S content of the films, as well as a slight decrease in the C:Ti ratio. Pure TiC/a-C films were proved by GI-XRD and XPS to contain crystalline TiC with the NaCl structure in a matrix of amorphous carbon. The introduction of S leads to a significant and gradual increase of the cell parameter of the carbide phase – from 4.3 Å up to more than 4.8 Å for coatings with approximately 20 at-% of S. This clearly indicates that the S atoms enter the carbide phase, forming a previously unknown Ti-C-S solid solution. The addition of S also affects the mechanical properties, such as the hardness which was seen to decrease from 8 GPa for pure TiC in an amorphous carbon matrix, to 5 GPa when doped with sulfur.
Thus, the introduction of S is shown to have effects on the chemistry as well as the properties of nc-TiC/a-C thin films. In the current work, the effect of S doping on the structure, chemical bonding and mechanical properties as well as tribological performance will be presented.
Place, publisher, year, edition, pages
Inorganic Chemistry Materials Chemistry Tribology
Research subject Chemistry with specialization in Inorganic Chemistry; Engineering Science with specialization in Tribo Materials; Engineering Science with specialization in Electronics; Engineering Science with specialization in Materials Science
IdentifiersURN: urn:nbn:se:uu:diva-182689OAI: oai:DiVA.org:uu-182689DiVA: diva2:560541
Thirteenth International Conference on Plasma Surface Engineering, Garmisch-Partenkirchen, Germany, 10-14 September 2012