Ion Plating Chrome Coatings in Tubes

摘要

A hollow cathode discharge(HCD) source has been developed for use in ion plating of high melting temperature metals. The HCD source has been operated under varying power levels and pressures and is predictable and reproducible. Chromium films with thicknesses up to 1 mil have been deposited in iron and copper tubes having a length to diameter ratio of 7. Rutherford backscattering analysis has shown that a large (APPROX.= 1 um) graded coating-substrate interface exists which is instrumental in obtaining the excellent adhesion characteristic of ion plated films. Plating rates of 1 um/min per cm of tube length have been achieved which makes the process feasible for the ion plating of erosion protective coatings inside gun tubes.