High-temperature insulating layer for engine blade film sensor and preparation method of high-temperature insulating layer

Abstract

The invention discloses a high-temperature insulating layer for an engine blade film sensor and a preparation method of the high-temperature insulating layer. The high-temperature insulating layer comprises a blade substrate layer, a high-temperature oxide layer, an Al2O3 film layer, a Ta2O5 film layer and a Si3N4 film layer which are sequentially arranged from bottom to top. The preparation method comprises the steps of vacuum heat treatment and high-temperature oxidation, preparation of the Al2O3 film layer, preparation of the Ta2O5 film layer, preparation of the Si3N4 film layer and high-temperature heat treatment. The high-temperature insulating layer is compact in film, few in defect and capable of reducing leakage current caused by film defects at high temperature, and the preparation method is simple, easy to implement and low in cost.

Description

technical field [0001] The invention belongs to the technical field of thin-film sensors, and in particular relates to a high-temperature insulating layer for engine blade thin-film sensors and a preparation method thereof. Background technique [0002] With the improvement of the thrust ratio of modern aero-engines and the improvement of the power of heavy-duty gas turbines, the speed and operating temperature of the turbine blades of the units are getting higher and higher, and the measurement of blade operating parameters (temperature, strain, heat flow, etc.) has become necessary for blade design verification. Basic test content. In order to solve the problem of measuring high-temperature working parameters of high-rotation curved blades, my country can only use high-temperature glue to paste sensors (such as thermocouple wires) on the blades for temperature measurement. Since the pasted sensors protrude from the surface of the blades, it interferes with the heat flow an...

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Problems solved by technology

However, the disadvantages of this technical method are: (1) The film layer structure is complex, resulting in high temperature stress, easy film peeling, and poor high temperature resistance. The thermal expansion coefficient of BN in the film layer structure is 41ppm / °C, while the thermal expansion of alumina The coefficient is about 8ppm / °C. The combination of these two thin film materials will inevitably lead to excessive stress and cracking at high temperature; (2) The thin film preparation process mostly uses evaporation and magnetron sputtering, and the prepared thin film has poor density. It is easy to generate leakage current at high temperature, which leads to the conduction between the thin film sensor and the blade base and introduces a large measurement error

The disadvantage of this method is that the prepared Al 2 o 3 The film density is poor, and it is easy to generate leakage current at high temperature, which reduces the high temperature insulation performance of the film

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