A metal-based high-temperature insulating layer and its preparation method

Abstract

The invention discloses a metal-based high-temperature insulating layer and a preparation method thereof, belonging to the technical field of thin film materials. Including six-layer structure, from bottom to top are alloy substrate 1, NiCrAlY alloy transition layer 2, α-Al2O3 layer 3, crystalline YSZ layer 4, amorphous YSZ layer 5, Al2O3 layer 6, of which α-Al2O3 layer It is obtained by thermal oxidation, the crystalline YSZ layer and the amorphous YSZ layer are both obtained by sputtering, and the Al2O3 layer 6 is prepared by electron beam evaporation. The insulating layer of the present invention can ensure good electrical insulation between the functional layer of the thin film sensor and the metal substrate at least at 800°C, and after annealing in a high-temperature environment for a long time, the insulation resistance will not decrease, and has a tendency to increase , which can meet the normal work of thin film sensors in high temperature, high stress and other environments.

Description

technical field [0001] The invention belongs to the technical field of thin film materials, in particular to an insulating layer of a thin film sensor with a turbine engine blade as a base and a preparation method thereof. The normal operation of the sensor in the high temperature environment. Background technique [0002] In modern aero-engine technology, turbine blade technology is one of the most critical technologies. The turbine blades of the engine work in harsh environments such as high temperature, high heat flux density, high vibration, and strong airflow, which can easily damage the turbine blades and cause the entire engine to be scrapped. Therefore, it is a key technology to develop high-temperature-resistant thin-film sensors to measure blade operating temperature, blade stress and strain and other state parameters. Aeroengine blades are generally metal-based superalloys, and the thin-film sensor must be electrically insulated from the metal substrate to ensur...

AI Technical Summary

Problems solved by technology

This may be due to the SiO 2 -Al 2 o 3 The insulating layer of the structure, SiO 2 and Al 2 o 3 The modulus of elasticity and coefficient of thermal expansion are quite different. As the temperature rises, the stress of the film will increase, cracking or even falling off.

while electron beam evaporated Cr 3 C 2 (1μm)-Electron beam evaporated Al 2 o 3 (4μm) The use temperature is 950℃ on the stainless steel metal substrate, but the electron beam evaporates Cr 3 C 2 - E-beam evaporated Al 2 o 3 In the insulating layer structure, Cr 3 C 2 The resistance at 1100°C is 80×10- 6 Ω.cm, is a good conductor of electricity, and may be oxidized at high temperature, resulting in failure of the insulating layer

While electron beam evaporated YSZ (yttrium stabilized zirconia) (1μm)-electron beam evaporated Al 2 o 3 (4μm) structural insulating layer in Al 2 o 3 The insulation on the ceramic substrate has an effective service temperature of 1080°C, but it has poor adhesion on the stainless steel metal substrate, and it falls off directly before any data is measured, which may be due to electron beam evaporation YSZ-electron beam evaporation Al 2 o 3 In the structure of the insulating layer, the YSZ evaporated by the electron beam has an amorphous structure, and its thermal expansion coefficient is quite different from that of stainless steel. The adhesion on the stainless steel substrate is not strong, and it may fall off.

To sum up, the insulating layer currently prepared cannot meet the normal work of thin film sensors in harsh environments such as high temperature and high stress.

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