Al-C, Cr-C, Al-Cr and Al-Cr-C thin film coatings were sputtered onto Ni-201 substrates. Samples were deposited with 1.0 ± 0.3 mg cm −2 Na 2 SO 4 and exposed to dry air/2 ppm SO 2 gas atmosphere, at 700 • C for 250 hours. Coated samples had reduced corrosion rates relative to uncoated samples. Al-C and Cr-C coatings were not effective since NiO was the only compound detected on the surfaces; in contrast Cr-Al and Cr-Al-C developed protective layers of Al 2 O 3 and Cr 2 O 3 with Cr-Al-C coated samples having the least corrosion rate.