Berkovich indentation of diamondlike carbon coatings on silicon substrates

Abstract

The deformation behavior of diamondlike carbon (DLC) coatings on silicon substrates induced by Berkovich indentation has been investigated. DLC coatings deposited by a plasma-assisted chemical vapor deposition technique were subjected to nanoindentation with a Berkovich indenter over a range of maximum loads from 100 to 300 mN. Distinct pop-ins were observed for loads greater than 150 mN. However, no pop-out was observed for the loads studied. The top surface of the indents showed annular cracks with associated fragmented material. The cross sections showed up to 20% localized reduction in thickness of the DLC coating beneath the indenter tip. Cracking, {111} slip, stacking faults, and localized phase transformations were observed in the silicon substrate. The discontinuities in the load–displacement curves at low loads are attributed to plastic deformation of the silicon substrate, whereas at higher loads they are attributed to plastic deformation as well as phase transformation.

Development of DLC coating architectures for demanding functional surface applications through nano- and micro-mechanical testing

“…Investigation of the data reported in XTEM studies by Haq and co-workers clearly shows that the influence of indenter geometry is greater than that of coating thickness [38][39][40][41]. In the micro-scratch test the indenter radius was 25 m so compressive strain in the coating should be minimal.…”

“…m spherical indenter the localised compressive plastic strain determined by cross-sectional transmission electron microscopic analysis (XTEM) is relatively low (~4%) compared to that induced by Berkovich indentation to the same load [38]. Investigation of the data reported in XTEM studies by Haq and co-workers clearly shows that the influence of indenter geometry is greater than that of coating thickness [38][39][40][41].…”

Contact damage of tetrahedral amorphous carbon thin films on silicon substrates

“…Also evident in the P-h curves are steps or discontinuities during loading (pop-ins) and unloading (pop-outs), both in coated and uncoated samples. Pop-ins and pop-outs in brittle materials are typically related to fracture events [18][19][20][21][27][28][29] or to phase transformations in the case of silicon. 30,31 The number of pop-ins in coated systems seems to be higher than in the uncoated substrate, and also to increase with increasing film thickness.…”

Correlation of nanoindentation-induced deformation microstructures in diamondlike carbon coatings on silicon substrates with simulation studies

“…The experimental procedure used for deposition of the coating, nanoindentation studies, and the characterization of the coatings following indentation has been discussed in detail in earlier publications. [20][21][22][23] A. Parameters for simulation…”

“…[16][17][18][19] Cross-sectional transmission electron microscopy (XTEM) studies of diamondlike carbon (DLC) coatings on silicon substrates [20][21][22][23] have shown that the presence of the coating alters the deformation behavior in the substrate so that, at lower loads of indentation, only slip is observed in the substrate, without any phase transformation being evident. Therefore, in such systems the initial deformation mechanism responsible for pop-ins changes from phase transformation to dislocation nucleation in the silicon substrate.…”