Effect of high-temperature oxidation on the surface properties as applied to quenching of high-temperature bodies

Abstract

This paper contains the results of studying the surface properties before and after high-temperature oxidation. For this, the plate zirconium samples with chromium, gold and silver coatings were prepared. Cut profiles of the samples were obtained to study the structure of coatings and the thickness of the oxide layer. The measurements of contact angles were carried out. The results showed that a porous heterogeneous oxide layer was formed on the samples after high-temperature oxidation. At the same time, the wettability of the samples was improved. The thickness of the oxide layer on the chrome-coated zirconium sample was the smallest. Using of electroplated silver coating for experiments involving heating to high temperatures seems inappropriate because it was damaged after the oxidation tests. It is assumed that the main factor which influence on the rise of the transition temperature to the intensive cooling regime during quenching is the appearance of the oxide layer, rather than the improved wettability and wickability. High-temperature oxidation leads to the simultaneous formation of an oxide layer with a low thermal effusivity and to an improvement in wettability, therefore the contribution of each of these two effects on quenching can be confused or overestimated.