Use of scaling functions to determine mechanical properties of thin coatings from microindentation tests

The indentation of elastic-plastic coatings deposited on elastic substrates is studied in this work. The functional expressions that relate the load-i ndentation behaviour to coating and substrate material properties are deriv ed using dimensional analysis in conjunction with finite element simulation s. Based on these scaling functions, a method is proposed to determine the coating Young's modulus, yield strength and strain hardening properties fro m the microindentation tests. A method to obtain improved estimates of the material hardness is also discussed. While the analyses are based on a coni cal (i.e. Rockwell) indenter, the indenter angle used in the simulations wa s selected so that the results can also be used to extract mechanical prope rties from measurements using the pyramidal indenters such as Vickers and B erkovich types. (C) 2000 Elsevier Science Ltd. All rights reserved.