Capacitive strain sensor and preparation method therefor

Abstract

The invention provides a capacitive strain sensor and a preparation method therefor, and belongs to the technical field of sensor design and production. The sensor is sequentially provided with a substrate, a first barium strontium titanate dielectric film layer, a PdCr electrode layer, a second barium strontium titanate dielectric film layer and an Al2O3 protection layer from the bottom to the top, wherein the PdCr electrode layer is in an interdigital electrode structure. The sensor employs an interdigital capacitive plane structure, takes barium strontium titanate (Ba0.5Sr0.5TiO3) as a dielectric material, takes PdCr as an electrode material, and achieves a purpose of stable operation under bigger strain (2500 mu*epsilon) and higher temperature (500 DEG C) employs a preparation technology combining magnetron sputtering coating with the photoetching technology.

Description

technical field [0001] The invention belongs to the technical field of sensor design and production, and in particular relates to a capacitive strain sensor and a preparation method thereof. Background technique [0002] Strain sensors play an important role in the study of mechanical properties and mechanical behavior of various components. At present, there are many types of strain sensors such as wire type, foil type, thin film type, metal, semiconductor, etc., most of which are based on the piezoresistive effect, that is, the resistance changes proportionally with the change of strain. Due to the high temperature requirements of the engine, nuclear power and other fields, the shortcomings of the application of resistive strain sensors at high temperatures are becoming more and more obvious, and the errors and reliability problems caused by high temperatures have become a huge challenge. The capacitive strain sensor is based on the change of the capacitance of the device...

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Problems solved by technology

K.I.Arshak et al. (K.I.Arshak, D.McDonagh, M.A.Durcan, Development of new capacitance strain sensors based on thick film polymer and cermet technologies, Sens.Actuators A: Phys.79(2000) 102-114) lead zirconate titanate ( PZT) and polyvinylidene fluoride (PVDF) have been prepared as dielectric materials for capacitive strain sensors, which have the following defects: the strain and temperature that can be tolerated are low, the maximum strain that can be tolerated is 350με, and the maximum operating temperature is 85°C; The dielectric material is prepared by screen printing method, so that the film thickness is too large, and it is easy to fall off when the internal stress is too large at high temperature; the electrode uses Heraeus conductor C12121S, which limits the application of the strain sensor at high temperature; the structure of the sensor is The parallel plate capacitor structure is not conducive to controlling the quality of the dielectric material, making the dielectric loss too large and the process complicated

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