Thermal stability of the CoWO4 layer formed on ferritic stainless steel

This study focuses on the temperature capability of CoWO4 as the oxidation protection layer of ferritic stainless steel (FSS). The thermogravimetric-differential thermal analysis revealed that until CoWO4 started to melt at 1297 °C, little mass change was observed. In addition, the coefficient of thermal expansion of CoWO4 was 11.5 ± 0.2 (×10−6 K−1), which was similar to that of FSS, evidencing its good thermal stability and compatibility for the protection of FSS. The oxidation test of the Co–W coated specimens at 700 °C – 1000 °C in air confirmed effectiveness of the CoWO4 layer at T ≤ 850 °C.