PHOSPHATING OF STEEL IN LOW-TEMPERATURE SOLUTION

At present, the research in the field of energy and resource-saving phosphating technologies is being continued, including the processes of applying adhesive and anticorrosive phosphate layers. The phosphating used in the industry is energy-intensive due to the high operating temperatures of the processes, which is necessary to obtain high-quality coatings in a technologically acceptable time. In addition, traditional zinc phosphate solution phosphating processes operating at moderate to low operating temperatures typically use sodium nitrite salts as an accelerating agent. In the course of the studies, we have found that the introduction of an ecologically safe nitrogen-containing accelerator into the phosphating electrolyte makes it possible to reduce the temperature of the phosphating process down to room temperature and to abandon toxic nitrate and nitrite compounds. We have carried out studies of the low-temperature sedimentation process of crystalline phosphate coatings, which allows to obtain phosphate layers with an increased protective ability (PA). We have developed low-temperature phosphating solutions, operating at a temperature of 20-27 ºC, allowing to obtain adhesive phosphate coatings with a specific weight of 3.0 g/m 2 , suitable as an underlayer for paint and varnish coatings, and anticorrosive coatings with a specific weight of 7.5 g/m 2 . It was revealed that phosphate layers of various thicknesses are formed from the same solution at different temperatures. They can be used to form anticorrosive layers for oiling with a specific gravity of up to 8.0 g/m 2 and adhesion layers for coloring with a specific gravity of up to 5.0 g/m 2 . surface treatment.