Paper 4: Adhesion of Metals in Hot Oxidizing Gases

Abstract

Metals in contact at high temperature in oxidizing gases have been found to adhere together. This ‘static adhesion’ can have a considerable effect on the forces required to operate mechanisms after dwell periods. Tests have been carried out to measure the adhesion of several different materials in carbon dioxide and air at temperatures up to 600°C. Apart from those which were corrosion resistant at the test temperature, most steels were found to adhere at temperatures above 300°C. The forces necessary to pull adhered surfaces apart or to slide them were measured. The probability of adhesion increased with increasing temperature but was relatively insensitive to the normal loading on the surface. The use of dry lubrication, pre-corroding, chromizing, and grit blasting of surfaces to prevent adhesion has been studied.