Invar alloy corrosive liquid and application thereof

Abstract

The invention relates to an invar alloy corrosive liquid and application thereof. The corrosive liquid comprises, by weight, 10-20% of glycerol, 10-20% of hydrochloric acid, 20-40% of ferric chloride, 5-10% of copper chloride, and the balance of water. The application comprises the following steps: grinding and polishing a cut invar alloy sample, carrying out ultrasonic oscillation for 10-15 seconds, and immersing the sample into the corrosive liquid to complete corrosion. The corrosion inhibitor can be applied to corrosion of invar alloy, and is simple in formula, long in preservation time, simple in overall use method, free of special requirements on experimenters and free of security threats.

Description

technical field [0001] The invention relates to the technical field of a corrosion method for Invar alloys, in particular to a formula and a method of use of a corrosion solution for Invar alloys, which can be applied to the corrosion of macro and cellular substructures of cast Invar alloys Observations provide corresponding data support for the further development and utilization of Invar alloys. Background technique [0002] Invar Alloy (Invar Alloy) is an alloy with a very low expansion coefficient, that is, an alloy whose volume does not change or changes very little with temperature. Due to the low expansion characteristics of Invar alloy, it is widely used in precision balances, laser instruments, long-distance power transmission, laser gyroscopes, liquid cargo tanks of natural gas (LNG) carriers, and composite molds for aerospace. Although Invar alloy has a strong application background, its strength and toughness are not high. Because of the inhomogeneous dislocati...

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Problems solved by technology

However, it is difficult to carry out the corrosion work before the microstructure observation, especially the corrosion of the cellular substructure

[0003] In the existing technology, generally aqua regia (HCl:HNO 3 =3:1) directly corrodes Invar alloy, but because aqua regia is highly corrosive, the corrosion process is difficult to control, and the cellular substructure cannot be well displayed. It has high requirements on the operating ability, and at the same time, aqua regia is not easy to store and needs to be reconfigured every time it is used, so it is not used frequently; in addition, 30% or supersaturated ferric chloride aqueous solution is used for direct corrosion, but because ferric chloride is in The surface of the sample is easy to crystallize and covers the surface of the sample, which greatly affects the observation of the sample. At the same time, the aqueous solution of ferric chloride will have different degrees of precipitation during storage, resulting in the failure of the corrosion solution; Electrolytic polishing liquid and electrolytic polishing method of tile alloy (patent No. CN 108505108 B), although the electrolytic polishing technology is efficient, it is difficult to obtain suitable polishing liquid and process parameters, and only the grain boundaries of Invar alloy can be corroded. The cellular substructure cannot be displayed; although the smelting process can be directly displayed through the ultra-high temperature laser confocal microscope simulation, the requirements for samples and personnel are high, the cost is expensive, and the grain boundaries are etched out during the heating process, which will be lost with time. When the temperature rises, a "twin grain boundary" (caused by grain growth) is generated, causing misjudgment

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