Conversion coating concentrate for coating aluminum and its alloys by immersion or spray processes. BONDERITE M-CR 12 (ALUTECH 12) is a liquid conversion coating concentrate for coating aluminum and its alloys by immersion or spray processes. It controls the rate of coating of aluminum and is an iridescent, golden colored chromate-type coating that is decorative and resists corrosion. On cast aluminum alloys the color varies from yellow to brown. Please note: BONDERITE M products are used in the surface modification of metals and usually applied in a multi-stage process. The performance of these surface treatments depends on various factors such as the preceding cleaning or etching steps (BONDERITE C portfolio), line design or process parameters.