High-temperature ceramic base film thermocouple and manufacturing method thereof

Abstract

The invention discloses a high-temperature ceramic base film thermocouple and a manufacturing method of the high-temperature ceramic base film thermocouple, and belongs to the field of sensor manufacturing technologies and high temperature measurement technologies. The high-temperature ceramic base film thermocouple sequentially comprises a ceramic base 1, a SiO2 layer 2, a first A12O3 layer 3, an interlayer 4, a second A12O3 layer 5, a thermocouple layer 6 and a third A12O3 layer 7. The high-temperature ceramic base film thermocouple has the advantages that (1) the SiO2 transition layer is adopted, so that binding force on the interface between an insulating layer and the ceramic base is enhanced; (2) the A12O3-Si3N4/A1N-A12O3 composite insulating layer is adopted, the excellent insulating performance is possessed, oxygen can be prevented from entering the high-temperature ceramic base film thermocouple, oxidization of a film on an inner layer is eliminated, and good dynamic response of a sensor is guaranteed; (3) thermal stress of the film caused by thermal loads is effectively reduced, and film forming quality and stability of the film are guaranteed.

Description

technical field [0001] The invention belongs to the field of sensor preparation technology and high-temperature temperature measurement technology. Specifically, it is a thin-film thermocouple for high-temperature ceramic substrates and a manufacturing method thereof. Background technique [0002] In aero-engine design and verification experiments, in order to verify the combustion efficiency of the engine and the design of the cooling system, it is necessary to accurately test the temperature of the engine turbine blade surface, the inner wall of the combustion chamber and other parts. Thin film thermocouples (TFTCs, thin film thermocouples) have the characteristics of small heat capacity, small size, fast response speed, small damage to the parts to be tested, and little interference to the test environment, so they are more suitable for surface transient temperature measurement. The surface temperature distribution of hot-end components can be accurately understood throu...

AI Technical Summary

Problems solved by technology

NASA conducted a lot of research in the early days, and the insulating layer material prepared by depositing Al on the surface of the substrate 2 o 3 , but due to the direct preparation of Al 2 o 3 The film is loose and porous, resulting in poor insulation and affecting the performance of the sensor, so the method of increasing the thickness of the insulating layer and performing high-temperature heat treatment is usually used to make up for structural defects

The problem with this method is that Al 2 o 3 The thermal conductivity itself is low (25W / m·k), which affects the dynamic response of the sensor; at the same time, the internal stress of the film increases with the increase of thickness, which is easy to cause device failure and damage

However, the aero-engine works in a high-temperature oxidizing environment, and AlN will undergo a strong oxidation reaction to form Al 2 o 3 , when the temperature is higher than 1200℃, Al 2 o 3 The crystal transformation begins to occur, when the amorphous film is completely transformed into α-phase Al 2 o 3 14.3% volume shrinkage will occur, which will easily cause the film on the surface to peel off, break or separate the film from the substrate

[0004] It can be seen from the above background technology that the existing insulating layer film has the following defects: Al 2 o 3 The low thermal conductivity of the film and the poor insulation caused by structural defects limit its application. Although AlN has high thermal conductivity, its stability in high-temperature oxidizing environments is not high, so it will affect the performance of the sensor. have an impact

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