PROTECTIVE COATING FOR INNER SURFACE OF STEEL PIPES Russian patent published in 2019 - IPC C03C3/112 C03C8/04 C03C3/93 C03C3/87 

FIELD: chemistry.

SUBSTANCE: invention relates to compositions of protective coatings for low-carbon and medium-carbon steels and can be used for protection of internal surface of pipeline transport operating under conditions of chemically aggressive and abrasive-active media. Protective coating comprises the following components, wt.%: SiO₂ – 45.0–48.0; Na₂O – 18.0–22.0; Al₂O₃ – 1.5–4.5; CoO or NiO – 0.5–0.9; CaO – 6.0–9.0; ZnO – 2.0–4.0; MgO – 3.0–6.0; Fe₂O₃ – 0.1–0.9; B₂O₃ – 11.6–15.0; F – 0.5–1.5. At that coefficient of linear thermal expansion of protective coating is 10.315–10.918⋅10^-6 deg^-1. Temperature of the protective coating boiling is 1,120–1,160 °C, and firing temperature during its application 920–930 °C.

EFFECT: high strength of adhesion of the protective coating to steel, low temperature and time of boiling the coating, temperature and time of application of the protective coating on the inner surface of steel pipes, obtaining a solid, non-porous, monolithic and uniform coating.

1 cl, 2 tbl