What are the properties and application characteristics of high temperature thermal barrier cermet composite powder

       The cermet type high temperature and thermal barrier composite powder is made by coating or agglomerating the high temperature alloy powder (or heat-resistant metal powder) into the coating or agglomerating composite powder. Coatings sprayed with this type of powder have properties such as expansion coefficient, thermal conductivity, bond strength and porosity, which are between the underlying metal coating and the surface ceramic material, and are often used as an intermediate transition between them. layer.



    This material mainly includes: nickel-coated zirconia (Ni/ZrO2) composite powder, self-bonding high temperature resistant thermal barrier mixed powder and nickel-chromium-aluminum-stabilized zirconia composite powder. Coatings are generally prepared by a plasma spray process.

    1) Nickel-coated zirconia Ni/ZrO2 composite powder

    This composite powder sprayed coating has good heat resistance, thermal shock resistance and chemical stability. It is mostly used for the intermediate transition layer of the high temperature resistant oxidation resistant coating and the high temperature resistant thermal barrier ceramic surface layer coating below 1000 ℃. The relative vapor pressure of zirconia is very low, so it is also very suitable as a heat-resistant coating for vacuum furnaces. For example, it is applied to the intermediate transition layer of thermal barrier ceramic coatings for aero-engine components.

    2) Self-bonding high temperature and thermal barrier mixed powder

    This is made of Ni/AI self-bonding composite powder or NiCr heat-resistant alloy powder, and ZrO2-based ceramic powder such as ZrO2 powder, MgO·ZrO2 powder, CaO·ZrO2 powder, CaO·ZrO2 powder, etc., which are mechanically mixed in a certain proportion. mixed powder. This kind of powder has both the good toughness and good bonding strength of self-adhesive alloy coating and the comprehensive performance of ZrO ceramics in high temperature resistance, heat insulation and thermal shock resistance. It is mainly used as the intermediate transition layer of ZrO2-based high temperature resistant thermal barrier ceramic surface coating, which contributes to the uniform transition of thermal expansion coefficient and thermal stress of high temperature resistant thermal barrier gradient coating system.

    3) Ni-Cr-Al and stabilized zirconia composite powder

    This is a cermet-type composite powder composed of high-temperature self-bonding nickel-chromium-aluminum (NiCrAI powder and stabilized zirconia (including CaO-ZrO2, MgO-ZrO2 and Y2O3-ZrO2) powder. The coating is combined with nickel-based superalloys. The bonding strength of the substrate is high, and it can directly withstand high temperature oxidation at 982 ° C. It is often used as the intermediate transition layer of the high temperature-resistant stabilized zirconia thermal barrier ceramic surface coating, and can also be directly used as a high-temperature resistant gas used at about 1000 ° C. Self-adhesive working coating for oxidation, sulfide corrosion and erosion, such as thermal barrier coating applied to high temperature end blad