What are the properties and application characteristics of magnesium oxide-based ceramic composite powders

       This type of powder mainly includes forsterite (2MgO·SiO2) powder, magnesium oxide chromium oxide (MgO-Cr2O3) powder and magnesia + converter slag powder.



     1) Forsterite (2MgO·SiO2) powder

     The melting point of forsterite is 1890℃, the softening temperature under load is 1895℃~1650℃, the refractoriness is 1830℃~1880℃, the thermal expansion coefficient is 12x10-6K-1 (100℃~1100℃), and it has good high temperature oxidation resistance. , There is no crystalline transformation from room temperature to melting, and the performance is stable. Resistant to various metal melts and alkaline slags. Its thermal expansion has anisotropy, so the thermal shock resistance is poor. Mainly used for repairing basic refractory materials in steelmaking furnaces, high temperature oxidation protective coatings for heat exchanger water tanks, etc.

    Coatings can be prepared by water-stabilized plasma spraying, supersonic flame spraying, explosive spraying and powder flame spraying (accelerated with compressed air).

    2) Magnesium oxide----chromium oxide (MgO-Cr2O3 powder

    A certain amount of chromium oxide is added to the magnesium oxide crystal to obtain a chromium-magnesium spinel structure (MgCr2O4). The chrome-magnesium spinel coating is black, has high refractoriness, is resistant to corrosion by molten steel and alkaline slag, and has good thermal stability. Mainly used for oxygen lance gun body, thermocouple sleeve and protection for steel-making furnace, basic refractory lining repair of steel-making blast furnace body, etc.

    Coatings can be prepared by gas-stabilized plasma spraying, supersonic flame spraying, explosive spraying or powder flame spraying (accelerated with compressed air).

    3) Magnesite + converter slag powder

    The addition of converter slag can greatly reduce the vapor pressure of magnesia, and obtain a dense coating with good thermal stability and strong bonding with the substrate, and it is inexpensive. Its refractoriness is greater than 1820 ℃, and the coating has good resistance to high temperature oxidation and high temperature gas erosion. Mainly used in the protective coating of high-temperature air ducts, exhaust pipes of internal combustion engines, and fume pipes.

    Coatings can be prepared by powder flame spraying or supersonic flame spraying.