Accurate measurement of thin film mechanical properties using nanoindentation

Abstract

For decades, nanoindentation has been used for measuring mechanical properties of films with the widely used assumption that if the indentation depth does not exceed 10% of the film thickness, the substrate influence is negligible. The 10% rule was originally deduced for much thicker metallic films on steel substrates and involved only the hardness measurement. Thus, the boundaries of usability for measuring thin film elastic modulus may differ. Two known material systems of Mo and MoTa thin films on Si substrates are examined with nanoindentation and numerical modeling to show the limitations in measuring elastic moduli. An assessment of the hardness and elastic modulus as a function of contact depth and accurate modeling of the film/substrate deformation confirms the 10% rule for hardness measurements. For elastic modulus, the indentation depths should be much smaller. Results provide a recommended testing protocol for accurate assessment of thin film elastic modulus using nanoindentation. Graphical abstract

MoVN-Cu Coatings for In Situ Tribocatalytic Formation of Carbon-Rich Tribofilms in Low-Viscosity Fuels

“…Although the MoVN-Cu coating contains hard ceramic particles which provide wear resistance, the mechanical properties of thin films are highly influenced by the properties of the substrate material the film is adhered to, particularly in terms of stiffness properties. 53 As the MoVN-Cu coating is only 600 nm in thickness, its mechanical properties mirror that of the AISI 52100 steel that the coating was deposited onto. 19 There is, however, a contrast between the coating and steel mechanical properties in terms of the gradient of values present.…”

“…For both the steel and coating surfaces, the majority of indentations revealed S 2 / P values from 3000–4000 GPa. Although the MoVN-Cu coating contains hard ceramic particles which provide wear resistance, the mechanical properties of thin films are highly influenced by the properties of the substrate material the film is adhered to, particularly in terms of stiffness properties . As the MoVN-Cu coating is only 600 nm in thickness, its mechanical properties mirror that of the AISI 52100 steel that the coating was deposited onto .…”

Hot pressed PEEK/Graphite thin film laminate composites: Thermal properties and mechanical behavior

“…The hardness and Young's modulus of PEEK, PGP, and (PG) 2 P were measured using a nanoindentation technique, which has been shown to be effective in measuring the surface mechanical properties of thin lms [33]. Load-displacement curves were obtained from 24 nanoindentations of three samples at a maximum load of 5 mN (Figs.…”

“…A slight scatter can be observed in the measured Young's modulus pro les due to the friction between the indenter and samples. Thus, the values above the penetration depth of 820 nm and below 520 nm were not considered to avoid an error during the indentation tests [33]. Figures 7-9 show that the (PG) 2 P thin lm has a decrease in hardness compared to PGP and PEEK, as demonstrated by the shift of the experimental load-depth curves to higher depth values in (PG) 2 P compared to the other two materials.…”

Effect of Equibiaxial Pre-Stress on Mechanical Properties Evaluated Using Depth-Sensing Indentation with a Point-Sharp Indenter

“…Thus, indentation is often required to evaluate the mechanical properties of films and coatings on substrates. There are many studies on the evaluation of the mechanical properties of films/coatings on a substrate using the depth-sensing indentation method [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. In these previous studies, the transitional change in the P–h curve, where the hardness and Young’s modulus varied from those of films/coatings to those of a substrate, was often discussed as a weight function of the maximum penetration depth, h m , which depends on the difference in the E, H, and Y between the film/coating and the substrate [ 3 , 9 , 14 ].…”