CHROMIUM-PLATING METHOD OF STEEL PRODUCTS IN MUFFLE FURNACES WITH AIR ATMOSPHERE Russian patent published in 2010 - IPC C23C10/40 

FIELD: metallurgy.

SUBSTANCE: there is prepared saturated mixture, containing powder, received b prereduction of aluminothermic compound, containing Al 20-25 wt % and Cr₂O₃ 75-80 wt %, granules of size not more than 1-1.5 mm, received with usage of binding agent from liquid glass or aqueous sugar syrup from aluminothermic compound, containing Al 25 wt % and Cr₂O₃ 75 wt %, sal ammonia in the capacity of activating agent and waste charge for chromium-plating at following components ratio, wt part: powder 20-40, granules 20-40, NH₄Cl 1,5, waste charge for chromium-plating is the rest. Parts are packed into muffle with gate and is thermal treated at temperature 950-980°C with isolation in furnace during 2-3 hours with implementation in granules of exoergic reaction of reduction of chrome oxide by aluminium.

EFFECT: increasing of service durability of products and production accessories from structural steels in machine building, instrument making, food and chemical industries, it is reduced time for receiving of plating, allowing high corrosion stability.