Thin coatings are studied to protect polyimide films from atomic oxygen induced erosion. Both single and multiple layer coatings of Al, AlN and multilayered Al/AlN are studied in the thickness range of 5 to 60 nm. The exposures were performed both by a plasma asher and an atomic oxygen beam. The erosion craters were studied with optical and scanning electron microscopes. When comparing single-layer coatings Al and Al/AlN were found to be superior to plain AlN. The multiple layer scheme of separating the protective coatings by a spacing polyimide film was found to be effective in restricting the erosion crater growth only to the spacing polyimide.