The problem of selection of materials for the manufacture of contact devices of heatand mass-transfer units used in ammonia plants is very relevant. Such devices are made of carbon steel, stainless steels, ceramic materials, and, experimentally, unfilled pol~propylene. Devices made of these materials have significant drawbacks: those made of carbon steel break down rapidly because of its low corrosion resistance; those made of steel 12KhlSNIOT (in the form of Raschig rings or GIAP (State Scientific-Research and Design Institute of the Nitrogen Industry and Organic Synthesis) packing elements) are expensive (scarce nickel is consumed), and, in addition, they exert an unfavorable effect on the composition of the working solution; those made of ceramics are leached by the working solutions and fracture because of brittleness (fouling of the packing by the leaching products is possible); and those made of unfilled polypropylene are insufficiently heat-resistant and melt in contact with the working solutions.