Mechanical properties of metallic films

Effect of substrate hardness and film structure on indentation depth criteria for film hardness testing

“…Figure 2 demonstrates the dependence of h c /t on H f /H s for all investigated coating/substrate systems. The data [2,3] for metallic films on metal and glass substrates are also included. The obtained critical indentation depth values for 0.01 0.1…”

“…Figure 2. Normalized critical indentation depth as a function of the ratio of coating/substrate hardness ( ) polycrystalline coatings, ( ) polycrystalline coatings [3], (•) amorphous films, (⊕) low melting point metal films, ( ) multilayer and ( ) epitaxial films or large-grained coatings. The dotted line shows the results of kinematic calculations [5].…”

“…Understanding the indentation behaviour of thin film structures is important in a variety of scientific and technological applications. A key problem in the film hardness testing is to measure the film properties independent of the properties of the underlying substrate [1][2][3][4][5][6]. If some critical indentation depth is surpassed, the measured apparent hardness includes contributions of both substrate and coating.…”

“…However, it is well established that the one-tenth rule is not a universal law. The relative critical indentation depth (h c /t) (where h c is the critical indentation depth and t is the film thickness) strongly depends on the ratio of film/substrate hardness (H f /H s ) [1][2][3][4][5][6] and varies with the indenter geometry, plastic pile-up, film/substrate adhesion, elastic properties of the film and substrate and the friction between the indenter and film [5,[10][11][12][13]. The predictions of the mechanical response of coatings under indentation still remain controversial.…”

“…The first systematic studies of the indentation depth criteria for coated systems were performed by Palatnik and Iljinski [2,3]. Indentation tests on metal films were conducted at a constant load and the values of t/ h c were obtained by a variation of the film thickness.…”