A steel for a large bearing suitable for parts of a large-sized bearing which are excellent in resistance to breakage and rolling fatigue life characteristics, and having a chemical composition by mass percentage of 0. The method comprises etching a PZT ferroelectric layer with a high temperature BCl3 etch which provides substantial selectivity with respect to the hard mask. In stationary operation, this enables an optimized operating mode since the internal combustion engine is no longer heated and the exhaust heat of the fuel cell is fully available for heating purposes.