Stelliting is the process of coating wearing parts with stellites. For sliding surfaces on seal faces and shaft protection sleeves the choice falls mostly on Stellite No. 6^® (1.1 % C, 27 % Cr; 4.5 % W; < 2 % Fe; the rest Co), which is applied in one or more layers to the substrate by the TIG method. Use of stellited seal faces and stationary seats in mechanical seals is on the decrease since harder face materials with greater wear and corrosion resistance have become available and/or are less expensive.