Analytical methods for surface coatings on electrical steel

Abstract

The invention discloses a method of analyzing surface coating of electrical steel and belongs to the technical field of analytical method. The method comprises the steps of 1) pretreating a sample ofsurface coating of electrical steel; 2) adjusting surface of the coating sample to a common focus point of electron beams and ion beams; 3) performing metal deposition on the surface of the coating sample; 4) using ion beams to pit front and rear areas to the coating sample; 5) subjecting the pitted coating to U-shape cutting, extracting is performed before welding; 6) thinning and polishing. Themethod of the invention has the advantages precision positioning is performed via focused ion beams to produce a transmission electron sample via focused ions, the microscopic morphology of the surface coating of electrical steel is analyzed in conjunction with the conventional transmission electron microscope, and the problems of the prior art with analyzing the microscopic morphology of the surface coating of electrical steel are solved.

Description

technical field [0001] The invention relates to the surface coating of electrical steel, belongs to the technical field of analysis methods, and in particular relates to an analysis method of the surface coating of electrical steel. Background technique [0002] The surface coating of electrical steel is usually divided into two layers, the bottom layer and the insulating coating layer; the bottom layer is a glass-like layer formed by the reaction of magnesium oxide coated on the surface of the steel plate after decarburization annealing and the silicon dioxide silicon-rich film on the surface of the steel plate under high temperature conditions. Magnesium silicate underlayer; insulating coating is a phosphate coating applied over a high temperature annealed magnesium silicate underlayer. The magnesium silicate bottom layer formed after high-temperature annealing of electrical steel not only has insulation and corrosion resistance, but also produces tensile stress in the ste...

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Problems solved by technology

[0005] 1) Scanning electron microscope or electron probe can only observe the morphology and micro-region composition of the coating, but the phase structure characteristic information of the coating cannot be obtained

[0006] 2) Since the resolving power of the scanning electron microscope or the electron probe is lower than that of the transmission electron microscope, it is impossible to observe the high-resolution image of the coating, and the electrical steel coating is generally composed of several parts, and the morphology and structure are different, and these information cannot be obtained. Obtain

[0007] 3) At present, there is no TEM sample preparation method for electrical steel coatings in China, which makes it impossible to observe electrical steel coatings with TEM

[0009] At present, there is no use of the precise positioning function of the focused ion beam to position and prepare the transmission electron microscope section sample of the surface coating of electrical steel

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