Лако-красочные материалы — производство

This is a widely used optical technique for measuring film thicknesses. The technique uses polarized light at oblique incidence and yields information on the optical constants of materials and the thickness of overlayers. The signal is generated by interference of the components of the primary beam, which are reflected at phase boundaries between the substrate and the film. Best results are obtained when the films are no thicker than only a few multiples of the wavelength of the light. Discontinuous or island film structures can also be studied. An ellipsometric analysis gives two numbers delta and psi (A and Ф), which together define the so-called complex reflection ratio p of the reflection coefficient in the directions parallel and perpendicular to the plane of incidence. More information on the principles can be found in the literature. There is a wealth of literature on the subject [88-91], both concise introductions and more comprehensive discussions or conference proceedings.

For applications in adhesive bonding research or technology, ellipsometry is useful for the quantitative determination of film thicknesses. Especially aluminum is a metal that has been studied extensively. It lends itself well to oxide thickness measurements because Al2O3 is transparent, which is a requirement. The thickness of the oxide formed in certain media can be determined [92]. Other studies reported on the use of ellipsometry to inves­tigate the corrosion or rate of oxide film dissolution in certain environments in situ. As the film dissolves, the formation of pores and differences between the densities of different layers in the oxide film can be distinguished and related to the conditions of the anodizing process [93].