Surfaces of plastics are studied by RF sputter etching process. The surface texture of PTFE changes from initial submicron hillocks to larger cones and finally to needle like texture during sputter etching. These surface textures are formed by sputter etching in other plastics, provided that they have the same characteristic of tending to decompose thermally to their monomer gas. It is proposed that such a surface texture can be formed because a repolymerization process of the sputtered monomer gas occurs in parallel with the ion etching process.
A Microscope has been designed and const-ructed for the purpose of direct observation of the real area of contact between two bodies. The technique used for this attempt is the inter-nal reflection method developed earlier in So-viet Russia. By using this microscope the area of contact has been measu red between a steel roller and an optically flat surface of glass prism. The experimental results indicate that the heights of surface asperities have a great influence on the area of contact. When great surface asperities remain on the surface of roller, the area of contact is amaller than the Hertz area of contact.