Method for characterizing microstructure of nano-structure thermal barrier coating by adopting terahertz nondestructive testing technology

Abstract

The invention provides a method for characterizing the microstructure of a nano-structure thermal barrier coating by adopting a terahertz nondestructive testing technology, which comprises the following steps: preparing different microstructure coatings by adopting an adjusting process, and determining the microstructure characteristics of the coatings by adopting metallographic analysis; carrying out terahertz nondestructive testing to obtain the real refractive index of the ceramic coating; constructing a linear relation between the real refractive index and the coating microstructure characteristics; and based on the linear relation, constructing the range comparison relation between the real refractive index and the coating microstructure characteristics, wherein the coating microstructure characteristics of coatings prepared by different processes can be qualitatively or semi-quantitatively analyzed through terahertz nondestructive testing by utilizing the range comparison relation. The method has the characteristics of no damage, high efficiency, convenience in operation and high detection precision. Meanwhile, the data result of the method shows the characteristics that the data parameter rule guidance is clear, the data characterization method is simple, convenient, efficient and scientific, and powerful support can be provided for controlling the coating quality or providing rapid and effective nondestructive testing for process optimization.

Description

technical field [0001] The present invention relates to the technical field of terahertz non-destructive testing, especially the non-destructive testing technology for the microstructure of nanostructured thermal barrier coatings; specifically, it mainly relates to qualitative or semi-quantitative testing of ceramic coatings (porosity and unfused particle content) Signal characterization means and methods. Background technique [0002] The high-pressure turbine blades of aero-engines are covered with a thermal barrier coating (TBC) that is resistant to high temperature, corrosion and high heat insulation, which directly determines the overall quality and performance of aero-engines, and is also the core bottleneck technology restricting the development of the industry. Nano-structured thermal barrier coatings take advantage of the refinement of nano-ceramic grains to greatly improve toughness, strength and superplasticity, and have the characteristics of excellent thermal in...

AI Technical Summary

Problems solved by technology

However, so far, there is no qualitative or semi-quantitative analysis method for the correlation characterization of the microstructure information (mainly porosity and unfused particles) of nanostructured thermal barrier coatings by terahertz nondestructive testing technology.

[0007] Therefore, it can be seen from the above that the traditional destructive testing method (quantitative metallographic method) has certain advantages for the detection method of the porosity and unfused particles of the nanostructured thermal barrier coating. Some non-destructive testing technologies (ultrasonic testing technology, infrared thermal wave testing technology, etc.) will be limited by testing conditions and testing accuracy due to problems such as destructiveness, irreparability, low efficiency, and long testing cycle

Although, relatively speaking, advanced terahertz non-destructive testing has the advantages of non-destructive, non-contact, non-polluting, high safety, efficient and convenient operation, etc., it is currently effective for characterizing the porosity and unfused particles of nanostructured thermal barrier coatings. There are very few methods, and because the nanostructure thermal barrier coating has a variety of microstructural parameters, the influence of multiple parameters on the signal (especially the material parameters) cannot be effectively separated from each other

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