40 Surface Treatment Services for Others-Namely, Refining, Coating and Hardening of Metals, Metal Alloys, Ceramics, Plastic and Composite Substances, and Technical Consulting Services for Others in the Field of Surface Treatment of Metals, Metal Alloys, Metal Graphite, Ceramics, Ceramic-Metal Mixtures, Oxides, Silicides, Carbides, Nitrides, Plastics and Composite Substances