2.3.5, 2.3.9
Methods of Determining Surface Roughness. M. K. Testerman. Univ. Fayetteville, Arkansas. U. S. Wright Air Development Center, Technical Rept. 58-230, June, 1958, 48 pp.
Twelve techniques for investigating the microscopic surface roughness of continuous surfaces are cited as background. (WADC TR 56-233 in a critique of known methods for measuring surface roughness.) Of these the method of capacitance measurements was chosen for experimental investigation. Measurements of permanent capacitance were made upon specimens coated with mono-molecular films and were found not to be reproducible. Measurements of polarization capacitance made in aqueous electrolyte solutions were reproducible. Two methods of measuring polarization capacitance were tested namely, the charging curve method, and the bridge method for copper, nickel and steel surfaces. Investigations with formamide and acetonitrile revealed that these non-aqueous solvents were not satisfactory for polarization capacitance measurements. Experimentation was begun to establish a radioactive method for measuring surface roughness. Results were...
