Gas-dynamic zinc spraying

The gas dynamic spraying technology involves feeding of finely dispersed zinc particles (0.01-50 microns) through a supersonic nozzle (600-700 m/s) and heating the compressed air to 400-600°C. As a result, a zinc layer is formed on the metal surface, which has high adhesion (40-100 N/mm2) and low porosity (1-3%).

Zinc coating or galvanizing is the best protection against corrosion for metal and welding joints. Zinc forms a thick protective film during oxidation (if there is access to air and humidity). The resulting shell prevents the penetration of oxygen and moisture, thereby stopping further corrosion. At the same time, zinc absorbs the entire impact of corrosion. In addition, zinc and iron create a galvanic pair where metal (Fe) is the less active metal, as a result, the zinc in the composition of the coating enters into corrosion reactions first, and the base Fe remains almost untouched. The thickness of the zinc layer depends on the temperature and duration of the galvanizing process and varies from 6 microns for galvanizing to 1.5 mm.

The technology of spraying became a technological breakthrough in the metal system repairing and restoration. The coatings that are formed in the process of spraying have significant advantages:

  • when applying the coatings, the temperature of the substrate does not exceed 150 ° C;
  • coatings have high adhesion (40-100 N/mm2) and low porosity (1-3%);
  • it is possible to spray layers of almost any thickness;
  • light alloys can be sprayed: zinc, aluminum, silver.

Relative articles