Use of the 56Fe(p,n)56Co Reaction in Erosive Wear Measurements

A well defined surface layer of 56Co can be produced in steel samples by means of the 56Fe (p,n)56Co reaction at proton energies greater than 5.45 MeV. Erosive wear from the steel surface is then measured by detecting the loss of the radioisotope 56Co. A detailed calibration curve relating the loss of 56Co activity to the amount of surface material removed has been measured. The method has a precision of ± 0.1 ¿m, can be performed in a short time, in-situ, and without surface cleaning. Three experiments in which erosive wear has been measured from steel surfaces exposed to burning propellants will be discussed. In the first, a land on a 20 mm barrel was activated and the wear measured under several different firing conditions. In the second, wear was measured from an activated plug inserted into a land of the 20 mm barrel. In the third, steel erosion nozzles were exposed to several different propellants and wear losses as well as mass losses were measured. Possible applications of this method to a variety of wear measurement experiments are discussed.