Metal-base film thermocouple and preparation method thereof

Abstract

The invention belongs to a metal-base film thermocouple and a preparation method thereof. The thermocouple comprises a metal substrate to be tested and a NiCrAlY alloy transitional layer arranged on the top face of the metal substrate, wherein a metal aluminum layer, an AlN layer, an AlN ceramic insulation layer, a thermocouple film electrode assembly and an aluminum oxide protective layer are formed on the transitional layer in turn. The production method comprises: processing the metal substrate to be tested; preparing a composite substrate with the NiCrAlY alloy transitional layer; precipitating metal aluminum; nitriding the aluminum; sputtering and depositing the AlN insulation layer; and setting the film thermocouple group and covering the aluminum oxide protective layer. In the invention, the AlN ceramic material with high coefficient of heat conductivity and high insulating performance is used as the insulation layer, so the temperature difference between the metal substrate and the surface of the insulation layer and the thickness of the insulation layer are reduced considerably; and thus, the metal-base film thermocouple has the characteristics of effectively reducing measurement error, improving the consistency between the temperature measured by the thermocouple and the actual temperature of the metal substrate to be tested, improving reliability, providing accurate and reliable basis for the design of turbine engines, and the like.

Description

technical field [0001] The invention belongs to the field of sensor production technology and measurement technology for turbine blades, in particular to a thin-film thermocouple made of turbine engine blades to be measured as a substrate (material) and a production method thereof. This type of thermocouple can be widely used in Measure the surface temperature distribution of turbine engine blades, combustion chambers, etc., and provide corresponding basic data basis for the design of turbine engines. Background technique [0002] In modern aero-engine technology, the harsh gas environment such as high temperature and high pressure generated by gas combustion will cause the surface temperature of the turbine blade and the combustion chamber to rise sharply, and at the same time generate a large thermal strain, while the temperature of the turbine blade and the surface of the combustion chamber The distribution and thermal strain have a great influence on the performance and ...

AI Technical Summary

Problems solved by technology

This kind of thin-film thermocouple uses alumina ceramics as the insulating layer, which has the following problems: the insulating performance of the alumina ceramic layer is relatively poor, and the texture is loose. In order to ensure sufficient insulation, it is usually necessary to use thicker (about 20 μm) alumina. Ceramics are used as an insulating layer; what is more unfavorable is the thermal conductivity of alumina ceramic materials {The thermal conductivity refers to the temperature difference between the two sides of a 1m thick material is 1 degree (K, ℃) under stable heat transfer conditions, in 1 second The heat transferred through an area of ​​1 square meter within the bell, the unit is w (watt) / m K or ℃ (meter degree)} is low, only about 10W / m K, resulting in a gap between the surface temperature of the heat insulating layer and the substrate There is a large difference in the actual temperature, resulting in a large measurement error, which affects the accuracy of the measurement and the parameters provided as the basis for the design; Affect measurement accuracy

Therefore, due to the poor thermal conductivity and insulation of alumina ceramics and the large thickness of the required insulating layer in the above-mentioned background technology, there is a large difference between the actual temperature of the metal substrate and the surface temperature of the insulating layer and poor measurement accuracy in actual measurement, resulting in The consistency and reliability of the temperature measured by the thermocouple and the actual temperature of the metal substrate to be tested are poor, and the accuracy of using it as a design parameter is poor and other defects

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