Heißkorrosion im Brennergas bei 1200 °C

Hot Corrosion in Burner Gas at 1200°C . The lifetime of a material at high temperatures is controlled by its hot corrosion behaviour against the components (ashes, salts, sulfur) of the burner gas. In this paper Na₂SO₄, Na₂CO₃, NaCl, NaF and V₂O₅ as well as H₂S, SO₂ and HCl were used for the experiments. It could be shown that the hot corrosion behaviour of MoSi₂ coated Nb-and Ta-alloy is excellent against acid additives (NaCl, NaF, V₂O₅) to the burner gas while alcalic melts (Na₂SO₄, Na₂CO₅) corrode the silizide. The solubility of the MoSi₂ is caused by the transport rate of molecular oxygen through the glasses formed by oxidation on the surface of the materials. It can be shown, that the lifetime of sintered MoSi₂ coatings on refractory metals is more than 10 times longer as by NiAl coated superalloys in hot corrosion test.