Metallographic erosion method of nickel-aluminum bronze crystal boundary

Abstract

A metallographic erosion method of a nickel-aluminum bronze crystal boundary is provided. The method includes polishing the nickel-aluminum bronze by waterproof abrasive papers with granularity of 80, 280, 400, 600 and 800 in order, polishing the nickel-aluminum bronze by a lint and a 1 [mu]m diamond polishing slurry in order, adding nitric acid into hydrochloric acid, stirring the mixture uniformly, allowing the mixture to stand for 2 min to prepare a corrosive agent which has a preparation ratio according to every 30 ml hydrochloric acid in every 3-5 ml nitric acid, dipping the corrosive agent by an absorbent cotton clamped by a plastic tweezer, wiping the surface of the nickel-aluminum bronze for 5-15 s until the color of the surface of the nickel-aluminum bronze turns grey, washing the surface of the nickel-aluminum bronze by clear water, flushing the surface of the nickel-aluminum bronze by absolute ethyl alcohol, blow-drying the surface of the nickel-aluminum bronze by a electric hair drier, and putting the blow-dried nickel-aluminum bronze by the electric hair drier to a metallographic microscope to obtain a crystal boundary photograph of the nickel-aluminum bronze. The etching time is only 5-10 s, the crystal boundary not a K phase of the nickel-aluminum bronze can be preferentially etched, and the crystal boundary of the nickel-aluminum bronze is clear and intact.

Description

technical field [0001] The invention belongs to the technical field of metallographic inspection of metal materials, and in particular relates to a metallographic corrosion method of nickel-aluminum-bronze grain boundaries. Background technique [0002] Nickel-aluminum bronze has good corrosion resistance and mechanical properties, so it is widely used in marine environments, such as ship propeller blades, pumps, seawater valves and offshore drilling platform equipment. [0003] The nickel-aluminum bronze currently used is generally cast, and its typical metallographic structure is α (Cu) matrix + various K phases {K Ⅰ 、K Ⅱ 、K Ⅲ 、K Ⅳ}, in terms of the composition of its metallographic structure, the complex K phase microstructure is easy to cause electrochemical corrosion between each phase and reduce its corrosion resistance, and the grain size of the α (Cu) matrix will affect the nickel aluminum The level of mechanical properties of bronze. In order to make better use...

AI Technical Summary

Problems solved by technology

[0006] In order to solve the problem that there is no suitable corrosion method for nickel-aluminum-bronze grain boundaries, the present invention provides a metallographic corrosion method for nickel-aluminum-bronze grain boundaries. Simple and effective features

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