화학공학소재연구정보센터
Thin Solid Films, Vol.355-356, 263-269, 1999
Determination of coating mechanical properties using spherical indenters
In recent years, various forms of indentation testing have been increasingly used to determine the material properties of specimens. This technique, particularly the nano-indentation method, has been extended to the testing of coating systems in order to calculate the individual properties of the thin coatings and the substrates. However, thr: interpretation of the test data to achieve this is complex and continues to be a widely studied subject. Based on the finite element analysis (FEA) of coated surfaces indented by a spherical indenter, this paper describes methods for combining FEA and experimental indentation testing to determine coating modulus and hardness independent of substrate effects. An indentation test on a coated specimen is first carried out using a spherical indenter. The combined contact modulus of the coated surface is determined from the elastic portion of the experimental load/displacement curve. The modulus of the coating alone is then computed from a function derived by a parametric finite element analysis of indentation behaviour. The hardness of the coating alone is determined by comparing the experimentally determined mean contact pressure with parametric finite element results for the same contact geometry and known hardness ratios. Using this proposed methodology, the properties of the substrate are fully taken into consideration, hence providing a more universal and accurate measurement of coating elastic modulus and hardness.