Wear and Corrosion of Components under Stress and Subjected to Motion.
Interim rept. 14 Sep 79-14 Sep 81,
IIT RESEARCH INST CHICAGO IL
Pagination or Media Count:
A Dynamic Corrosion-Wear Cell was developed to study the effects of both electrochemical and mechanical factors on the material degradation of bearing components applicable to Navy aircraft. Electrode polarization technique was used to evaluate corrosion behavior of the materials under stress and motion. M2 steel, 52100 steel, Armco iron, and 304 SS were evaluated in various electrolytes containing NaC1 with corrosion inhibitors such as dichromates and molybdates. Corrosion current density, open-circuit potential, and wear loss were analyzed both statistically and phenomenologically. The effect of continuous wear on the corrosion process was very significant when a passive film was formed in air or in solution, but almost negligible otherwise. Generation of active metal surface by disruption of passive film under wear was mainly responsible for increase in corrosion current and the open-circuit potential shift. However, a small increase in corrosion current and negligible shift in the open-circuit potential were observed from surface roughening and structural deformation by frictional wear. Analytical scanning electron microscopy was used for metallugrical examination of the corrosion-wear surface morphology. Elemental maps of the materials passivated in NaC1 solutions with Na2Cr207 and Na2MoO4 showed that deposition of Cr and Mo was higher in the activated wear debris that at general wear scar areas. Surface roughness was measured to obtain additional insight into the observed phenomena. Wear appears to control the anodic polarization process significantly, but not the cathodic polarization process.
- Physical Chemistry
- Machinery and Tools