A kind of anti-oxidation composite protective layer for high temperature film sensor and its manufacturing method

Abstract

An anti-oxidation composite protective layer for high-temperature thin-film sensors and a preparation method thereof belong to the technical field of thin-film sensors. The anti-oxidation composite protective layer consists of BN insulating layer, ZrB2-based composite ceramic layer, and Al2O3 covering layer from bottom to top, wherein, the BN insulating layer, ZrB2-based composite ceramic layer and Al2O3 covering layer are sequentially deposited by methods such as evaporation or sputtering on the sensitive functional layer of the film sensor. The anti-oxidation composite protective layer for high-temperature thin-film sensors of the present invention can meet the anti-oxidation protection requirements of high-temperature thin-film sensors of aeroengines under high-temperature conditions of 1000-1700°C, and effectively improve the stability and reliability of thin-film sensors in high-temperature, high-pressure harsh environments and longevity.

Description

technical field [0001] The invention belongs to the technical field of thin-film sensors, in particular to the high-temperature protection technology of thin-film sensors used for testing the surface state parameters of hot-end parts of aero-engines. Accurate testing of state parameters such as , strain, etc. provides technical support for engine design, verification, and optimization. Background technique [0002] Aeroengines are known as the heart of aviation vehicles. When modern aero-engines are working, because the turbine blades and the combustion chamber are in harsh environments such as high temperature and high pressure, the surface temperature of the turbine blades and the combustion chamber rises sharply, and a large thermal strain is generated at the same time, while the temperature distribution of the turbine blades and the combustion chamber surface And the strain has a great impact on the performance and life of the turbine engine, and the local hot spots on ...

AI Technical Summary

Problems solved by technology

But this method has the following shortcomings: First, Al 2 o 3 The protective layer can isolate the oxygen in the external environment from diffusing into the film to a certain extent, and greatly reduce the oxidation rate of the sensitive functional layer, but in Al 2 o 3 Crystal defects inevitably exist in thin films, and Al 2 o 3 Oxygen in the protective layer or the external environment can slowly diffuse to the sensitive functional layer through these defects, causing the functional layer to be gradually oxidized at high temperature, thereby affecting the performance of the thin film sensor; secondly, due to the harsh working environment of the thin film sensor, Al 2 o 3 The chemical stability of the protective layer is not enough to resist the corrosive environment of aero-engine high-temperature gas for a long time; in addition, in the process of film preparation or under the harsh thermal shock working environment of aero-engine, Al 2 o 3 The protective layer may induce microcracks due to stress, and the cracks become oxygen diffusion channels, making the dispersion coefficient of the protective layer's oxidation resistance large, reducing reliability, and leading to device failure

However, this high-temperature protective film group still has shortcomings: under the high temperature condition above 1400°C, the resistivity of silicon carbide is already very small and has conductivity. The measurement of sensor electrical signals; in addition, at high temperatures, the diffusion of oxygen atoms in the protective layer of aluminum oxide film to the sensitive functional layer is more serious, which limits its application temperature range and cannot meet the anti-oxidation protection requirements under higher temperature conditions

Images