Method for preparing magnesium-based lanthanum aluminate thermal barrier coating

Abstract

The invention relates to a preparation method of a magnesium-based lanthanum aluminate thermal barrier coating material, belonging to the field of materials. The characteristics are: according to the stoichiometric ratio of LaMgAl11O19, the ingredients are prepared. The preparation method: 1) Wet ball milling in a polyurethane ball mill tank with alumina balls as the grinding body, drying, and compression molding; 2) The molded body is pre-fired in a high-temperature furnace , to obtain a calcined block; 3) pulverizing the above calcined block, adding MgO fine powder to the pulverized calcined raw material; putting it into a polyurethane ball mill tank and carrying out wet ball milling with alumina balls to obtain a ceramic slurry; 4) drying the above ceramic slurry in a drying oven, granulating, and forming the granulated raw material by isostatic pressing; sintering the formed green body at 1550-1700° C. for 6-24 hours to obtain a high-purity magnesium-based lanthanum aluminate ceramic material; The ceramic material can be used as a target material for preparing a thermal barrier coating by the EB-PVD method.

Description

1. Technical field [0001] The invention relates to a preparation method of a magnesium-based lanthanum aluminate thermal barrier coating material, belonging to the field of materials. 2. Background technology [0002] With the development of the aerospace industry, the engine has a high thrust-to-weight ratio and a large driving force. The main measure adopted is to increase the inlet temperature of the turbine. This makes the original high-temperature alloy materials for manufacturing aero-engines unable to meet the requirements. In order to increase the service temperature of the engine, it is generally used at present to coat a transition alloy layer such as NiCrAlY on the surface of the turbine working blades, guide vanes, turbine disks, and hot end parts of the combustion chamber of the aeroengine and various gas turbines. Then apply a layer of 6-8% yttrium oxide (Y 2 o 3 ) partially stabilized zirconia (ZrO 2 ) (Y-PSZ) thermal barrier coating material to reduce the...

AI Technical Summary

Problems solved by technology

However, the Y-PSZ-based thermal barrier coating material has the following disadvantages: 1) When the service temperature is higher than 1100 ° C, the coating is easy to sinter, and the microcracks and micropores in the coating will heal, resulting in the densification of the ceramic coating. Cause the volume change of the coating material, exacerbate the stress mismatch between the coating and the substrate, and further lead to the generation of coating defects

2) When the service temperature exceeds 700°C, a large number of oxygen vacancies in the Y-PSZ thermal barrier coating will accelerate the transmission of oxygen ions and cause rapid oxidation of the metal bonding layer, increasing its volume and stress, and the final thermal barrier coating fail

However, when using the above process, it is difficult to prepare high-purity magnesium-based lanthanum aluminate ceramic materials due to the fluctuation of raw material components during the firing process.

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