George Douglas Vaughn

SCRATCH INDENTATION, A SIMPLE ADHESION TEST METHOD FOR THIN FILMS ON POLYMERIC SUPPORTS

We have utilized scratch indentation as a test method for evaluating the strength and adhesion of polymeric substrates coated with metal and diamond-like carbon (DLC) films. Metallized films were prepared by coating poly(ethylene terephthalate) with copper, using a proprietary electroless deposition process. The copper adhesion was evaluated using a standard tape-pull test, a special inverse peel test in addition to scratch indentation, and a good correlation was observed among the methods. The most critical experimental parameter in the scratch indentation method was the stylus radius. Good differentiation of adhesion among samples was much more evident using an 800 μm tip radius as opposed to 200 μm. We concluded that a simple reliable measurement of practical adhesion could be based on commercially available scratch indentation equipment. The DLC coatings are hard and brittle compared to the ductile copper. The scratch indentation tests were quite sensitive to the strength of the DLC coatings. Adhesion...