1.Timing Belt Pulleys Materials: Type Characteristics Aluminum suitable for moderate power transmission light weight / reduced rotational inertia moderate chemical and corrosion resistance standard material for stock pulleys Steel suitable for high power transmission durable limited chemical and corrosion resistance aesthetic material Stainless Steel suitable for high power transmission durable meets FDA regulations excellent chemical and corrosion resistance aesthetic material Delrin suitable for high power transmission excellent chemical and corrosion resistance nonmetallic stainless steel flanges recommended 2.Timing Belt Pulleys Surface Finishes: Type Available for Characteristics Anodized Aluminum Timing Belts Pulleys increased chemical and corrosion resistance available in natural, black, or colored limited increase of surface hardness aesthetic treatment Hard Anodized Aluminum Timing Belts Pulleys excellent chemical and corrosion resistance increased surface hardness for abrasive environments stainless steel flanges recommended Black Oxide Steel Timing Belts Pulleys increased chemical and corrosion resistance aesthetic treatment Zinc plated Steel Timing Belts Pulleys increased corrosion resistance Chromate Steel Timing Belts Pulleys increased chemical and corrosion resistance