HIGH-TEMPERATURE PROTECTIVE COATING Russian patent published in 1997 - IPC

FIELD: protective materials. SUBSTANCE: coating has sublayer of nichrome of the following properties: porosity is 5%, not above, thickness is 50-100 mcm and roughness is R_z-40--100. Two-layer coating is made on the indicated sublayer lower layer of that has, wt.-%: SiO₂ 42-46; B₂O₃ 2-4; BaO 15-17; CaO 7.8-8.0; MgO 1.5-2.5; Al₂O₃ 8.5-10.5; Na₂O 0.5-1.0; F₂ 1-2; Cr₂O₃ 9-10; MoO₃ 1.5-2.25; CO₂O₃ 1.5-2.0; MnO₂ 1.5-2.0. Upper coating layer has, wt.-%: SiO₂ 31.5-35.5; B₂O₃ 4-6; BaO 30.5-31.5; CaO 2-3; Al₂O₃ 1.5-2.5; TiO₂ 1-2; Cr₂O₃ 22.0-23.5; MoO₃ 0.75-1.0; CO₂O₃ 0.5-0.75, and MnO₂ 0.5-0.75. Property: 57 thermocycles at soldering at 1250 C. Coating is used for protection from gaseous corrosion. EFFECT: improved quality and property.