The Fracture of Surface Coatings on a Strained Substrate

Abstract

The fracture of brittle coatings on a strained substrate is examined from two points of view. In the first case, the substrate deforms continuously and regularly spaced fractures occur in the coating. The spacing d at any strain ε is given by In ε/ε0 = (4g/d) (1−d/d0), where d0, ε0 are any convenient set of data points, and g is a parameter having the units of length. In the second case, the substrate deforms by crystallographic slip and fracture of the oxide may or may not occur at the slip step. The criteria for fracture are that the interface adhesive stresses be too large for the coating to sustain the necessary peel stress. Quantitative relations are given in terms of the coating thickness, fracture strain, and the orientation of the slip step with respect to the surface. The results for both cases are compared with experiment and found to be in essential agreement.

Durability of nanosized oxygen-barrier coatings on polymers

“…In their earlier work, Grosskreutz and McNeil [285] introduced a stress relaxation mechanism at the coating/substrate interface, in which Fig. 18.…”

Adhesion and Deadhesion

“…[4] [5] These fractures may then be the initiation points for fracture in the interface as well as cause degradation of other film properties. An example is the heating of a system where the film and substrate have different coefficient of expansions thus stressing the interface during thermal cycling and initiating flaws.…”

Effects of thickness and field strength of anodic oxide film on aluminum on its compressive rupture

“…For the investigation, abrasion (Bensalah, Elleuch, Feki, Wery, & Ayedi, 2007) and impingement (Akiyama, Stratmann, & Hassel, 2006;Hassel & Smith, 2007;Smith, Stratmann, & Hassel, 2006) of a second body, and external stress-induced deflection (Bensalah, Elleuch, Feki, Petris-wery, & Ayedi, 2009;Mohan, Hon, Idapalapati, & Seow, 2005) were often used. Mechanical properties and rupture behavior of anodic oxide films on aluminum substrates seemed to depend on the film thickness, electric field and stress applied in the film (Grosskreutz, 1969(Grosskreutz, , 1970Grosskreutz & Mcneil, 1969) . The film thickness particularly influences the rupturing mode of the anodic oxide film when the surface is strained.…”