Nondestructive thickness measuring method for nickel coat on Fe substrate

Abstract

The invention discloses a non-destructive thickness measuring method of nickel coating on iron base metal; the method is to setting samples of known thickness of nickel coating on iron base metal, by detecting the nickel coated surface of samples through eddy current sensor installed with exciting coils and magnetic test coils, the exciting coils send out pumping signals, obtain eddy current testing data corresponding to the thickness of nickel coating on iron base metal after managing the eddy current induction signal the magnetic test coils obtained, so as to establish a thickness model of nickel coating on iron base metal, in the actual measurement, with the help of this model, the thickness of nickel coating on iron base metal can be tested using the same method. The method is nondestructive, suitable for testing the thickness of all nickel coating on iron base metal, has the advantages of low cost, easy to carry with testing equipment, simple to operate, intuitive and detect fast, can immediate get the testing results at the scene with accurate results.

Description

technical field [0001] The invention relates to a method for detecting the thickness of a nickel coating, in particular to a method for measuring the thickness of a nickel coating on an iron substrate by using eddy current detection technology. Background technique [0002] Nickel is a silvery white ferromagnetic metal. Density 8.9 g / cm 3 , melting point 1455°C. It is ferromagnetic and ductile, and can conduct electricity and heat. Nickel also has good oxidation resistance. At room temperature, nickel forms a dense oxide film on the surface in humid air, which can not only prevent further oxidation, but also resist corrosion by alkali and salt solutions. Experiments have proved that nickel with a purity of 99% will not rust within 20 years. Nickel has strong corrosion resistance, especially to caustic soda. In 50% boiling caustic soda solution, the annual corrosion rate of nickel does not exceed 25 microns. The strength and plasticity of nickel are also very good, and i...

AI Technical Summary

Problems solved by technology

In order to know the thickness of the nickel coating, it is usually necessary to measure the thickness of the nickel coating on the iron substrate. The existing thickness measurement method generally adopts the "microscopic measurement method of the thickness of the metal and oxide coating cross-section", which cuts the measured object , so that the cross-section of the object to be tested is exposed, and then the cross-section of the object is measured through a microscope to obtain the thickness of the nickel coating on the iron substrate in the object. However, this measurement method is likely to cause damage to the object. For example, it is necessary to measure When the thickness of the nickel coating on the iron base body of the engine block, it is necessary to cut off a part of the engine block, so that the block of the engine is destroyed. Therefore, the existing method is not suitable for all nickel-coated iron Substrate objects for thickness measurement of nickel coating