Low Temperature Nano-Tribological Study on a Functionally Graded Tribological Coating Using Nanoscratch Tests

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Colleges, School and Institutes


Previous studies on low temperature tribological investigations were limited to macro-scale studies because of the lack of suitable instrumentation. This limitation has been overcome using a newly developed low temperature nanoscratch tester capable of characterizing the scratch resistance of coatings down to -30 A degrees C. The scratch resistance and mechanical properties of a functionally graded a-C:H(Ti)/TiCN/TiN/Ti coating have been investigated for temperatures ranging from 25 to -30 A degrees C. It has been found that the a-C:H(Ti)/TiCN/TiN/Ti coating failed at high loads by cracking and spallation during the room-temperature scratch tests. Fractography suggests that these failures originate from or close to the interface between the top a-C:H(Ti) and the TiCN layers. Decreasing the test temperature from 25 to 0 A degrees C resulted in increased values in H, H/E (r) and H (3) /E (r) (2) , consistent with improved crack- and wear resistances, with further smaller improvements being achieved on further decreasing the temperature to -30 A degrees C.


Original languageEnglish
Pages (from-to)351-360
Number of pages10
JournalTribology Letters
Issue number3
Publication statusPublished - 1 Sep 2011


  • Low temperature, Carbon, Nanotribology, Contact mechanics, Hardness, Coatings