Beryllium bronze grain size display method and etching agent combination

Abstract

The invention discloses a beryllium bronze grain size display method and an etchant combination, and the method is characterized by comprising the following steps: sample preparation: grinding and polishing an inspection surface of a beryllium bronze sample to obtain a mirror surface, and cleaning the mirror surface; primary corrosion: wiping and corroding the inspection surface by using a first corrosive agent; primary cleaning: cleaning off the first corrosive agent on the inspection surface; secondary corrosion: wiping and corroding the inspection surface by using a second corrosive agent; secondary cleaning: cleaning off the second corrosive agent on the inspection surface; drying: drying the inspection surface for observation; wherein the first corrosive agent is a ferric chloride hydrochloric acid water solution, and the second corrosive agent is a cupric chloride ammonia water solution. The method is safe, environment-friendly, simple and convenient to operate, good in display effect, high in consistency, low in cost and easy to popularize.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metal material metallographic detection, and particularly relates to a chemical etchant for displaying beryllium bronze grain size and a display method thereof. BACKGROUND

[0002] Beryllium bronze has the advantages of small elastic hysteresis, high fatigue strength, good elastic stability, etc., and is an important high-elasticity and high-strength structural and functional material in the fields of aviation, electrical and electronic manufacturing, etc. Grain size is a key indicator for measuring the performance of beryllium bronze material, and its size directly determines the mechanical properties of the material. Therefore, during production and use, the grain size of beryllium bronze must be accurately detected.

[0003] However, due to the high grain boundary strength and large energy of beryllium bronze, it is very difficult to display its grain boundary. At present, the existing technology mainly uses 1% chromic acid (CrO3) aqueous solution for electrolytic corrosion to display the grain size of beryllium bronze. This method has many defects: first, it needs to rely on a constant voltage DC power supply, which is complex to operate and has potential electrical safety hazards; second, the consistency of the display effect is poor, and over-corrosion or insufficient corrosion is easily caused by improper control, resulting in low success rate and large workload for repeated sample preparation; most importantly, chromic acid is a highly toxic substance with strong carcinogenicity, and produces irritating harmful gases during electrolysis, which is extremely harmful to the health of the operator. At the same time, the treatment of chromium-containing waste liquid is difficult and costly, and if not properly disposed of, it will seriously pollute the environment and not meet the modern green and environmentally friendly production concept.

[0004] Therefore, it is urgent to develop a beryllium bronze grain size display method that is simple to operate, has good display effect, is non-toxic and environmentally friendly. SUMMARY

[0005] The purpose of the present application is to overcome the above-mentioned defects of the prior art, and to provide a beryllium bronze grain size display method and a dedicated etchant combination that is simple to operate, clean and environmentally friendly, and has clear and consistent display effect.

[0006] The above technical problems of the present application are mainly solved by the following technical scheme: a beryllium bronze grain size display method, characterized by comprising the following steps: S1, sample preparation: grinding and polishing the inspection surface of the beryllium bronze sample to obtain a mirror surface and clean it.

[0007] S2, first etching: using a first etchant to wipe and etch the inspection surface.

[0008] S3, first cleaning: cleaning the first etchant on the inspection surface.

[0009] S4, second etching: using a second etchant to wipe and etch the inspection surface.

[0010] S5, secondary cleaning: cleaning the second etchant on the inspection surface.

[0011] S6, drying: drying the inspection surface for observation.

[0012] The first etchant is a ferric chloride hydrochloric acid aqueous solution, and the second etchant is a copper dichloride aqueous ammonia solution.

[0013] In the foregoing beryllium bronze grain size display method, preferably, after the S5 secondary cleaning step and before the S6 drying step, a repeating step is further included, which is repeating the execution of the first etching to the secondary cleaning at least once. To obtain the best grain boundary contrast.

[0014] In the foregoing beryllium bronze grain size display method, preferably, the configuration of the first etchant includes 5g of ferric chloride, 10ml of hydrochloric acid, and 100ml of water.

[0015] In the foregoing beryllium bronze grain size display method, preferably, the configuration of the second etchant includes 8g-20g of copper dichloride and 8ml-100ml of aqueous ammonia.

[0016] In the foregoing beryllium bronze grain size display method, preferably, the configuration of the second etchant includes 10g of copper dichloride and 100ml of aqueous ammonia.

[0017] In the foregoing beryllium bronze grain size display method, preferably, the configuration of the second etchant includes 20g of copper dichloride and 100ml of aqueous ammonia.

[0018] In the foregoing beryllium bronze grain size display method, preferably, the duration of the first etching and the second etching is independently 1-4 seconds.

[0019] In the foregoing beryllium bronze grain size display method, preferably, the wiping etching is performed using degreasing cotton dipped in the corresponding etchant.

[0020] In the foregoing beryllium bronze grain size display method, preferably, the drying process includes using anhydrous ethanol to rinse and then using an electric hair dryer to dry.

[0021] A beryllium bronze grain size etchant combination for the foregoing method, characterized by being composed of a first etchant and a second etchant; wherein the first etchant is a ferric chloride hydrochloric acid aqueous solution; and the second etchant is a copper dichloride aqueous ammonia solution.

[0022] Compared with the prior art, the present application has the following significant advantages: 1. Safe and environmentally friendly: It completely abandons the highly toxic chromium anhydride and uses ferric chloride and copper dichloride, which are less polluting and basically harmless to the human body, as the main corrosive components, which greatly reduces the health hazards to operators and the pollution to the environment, and meets the requirements of green chemistry and safe production.

[0023] 2. Simple operation: This invention uses a chemical wiping method, which eliminates the need for a constant voltage DC power supply and complex electrolysis equipment, simplifying the operation process, reducing equipment costs and operational difficulty, and also eliminating potential electrical safety hazards.

[0024] 3. Excellent display effect and strong consistency: Through the synergistic effect of the two etchants, the grain boundaries of beryllium bronze can be clearly displayed with good grain contrast. This method has good repeatability and a high first-pass success rate, effectively reducing the number of reverse sample copies required due to poor etching effect and improving detection efficiency.

[0025] 4. Low cost and easy to promote: The chemical reagents used are common and readily available, resulting in low cost. The entire etching process requires small quantities, causing minimal pollution to the workplace. The containers are simple, making it very suitable for widespread application in conventional metallographic laboratories.

[0026] 5. Application potential: This method is not only applicable to beryllium bronzes of grades such as QBe2.0 and QBe1.9, but after adaptive adjustments, it is also expected to be used for grain size indication of other bronzes and copper alloys. Attached Figure Description

[0027] Figure 1 This is a grain size display image of QBe2.0 beryllium bronze after processing using the method of Embodiment 1 of the present invention.

[0028] Figure 2 The image shows the grain size of QBe1.9 beryllium bronze after processing using the method of Embodiment 2 of the present invention. Detailed Implementation

[0029] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0030] Example 1: This embodiment demonstrates a method for grain size indication of QBe2.0 beryllium bronze, the steps of which are as follows: 1. Preparation of etching agent: (1) Preparation of the first corrosive agent: accurately weigh 5g of ferric chloride (FeCl3), measure 10ml of concentrated hydrochloric acid and 100ml of deionized water, mix them evenly to obtain ferric chloride hydrochloric acid aqueous solution.

[0031] (2) Preparation of the second corrosive agent: accurately weigh 20g of copper dichloride (CuCl2), measure 100ml of concentrated ammonia water, mix them evenly to obtain a copper dichloride ammonia solution.

[0032] 2. Preparation of the sample to be tested: (1) A sample is cut from the QBe2.0 beryllium bronze material, and the surface to be inspected is successively rough polished (starting from 320# sandpaper and gradually polishing), fine polished (to 1000# or above sandpaper), and then mechanically polished using diamond polishing paste or an alumina suspension to obtain a bright and traceless mirror surface.

[0033] (2) The polished surface is washed with clean water and alcohol and dried.

[0034] 3. Corrosion display: (1) A small piece of degreasing cotton is clamped with tweezers, and the first etchant is fully dipped. The surface to be inspected is uniformly and gently rubbed for about 1-2 seconds, and the surface is observed to turn gray-white instantaneously.

[0035] (2) The surface is immediately rinsed with a large amount of clean water to wash away all the acidic etchant.

[0036] (3) Clean degreasing cotton is used to dip the second etchant, and the surface after rinsing is also gently rubbed for about 2-3 seconds. The surface is observed to turn light yellow-brown, and the rubbing is stopped.

[0037] (4) The surface is immediately rinsed with a large amount of clean water to wash away all the alkaline etchant.

[0038] (5) The surface of the sample is rinsed with anhydrous ethanol to quickly dehydrate.

[0039] (6) The surface of the sample is completely dried with the cold wind or low-temperature warm wind of an electric hair dryer.

[0040] 4. Observation: The treated sample is placed under an optical metallographic microscope, and clear and continuous grain boundaries can be observed, and the grain size level is easy to evaluate, as shown in Figure 1 .

[0041] Example Two: This example shows a grain size display method for QBe1.9 beryllium bronze, and the steps are basically the same as those of Example One, with the difference being: The second etchant is prepared by mixing 10g of copper dichloride and 100ml of ammonia water.

[0042] After completing the first cycle of "one etching → one washing → two etching → two washing", according to the preliminary observation, the grain boundaries are not deep enough, so the cycle is repeated once (i.e. a total of 2 cycles), and then the final alcohol rinsing and drying steps are performed.

[0043] The QBe1.9 beryllium bronze sample after this treatment shows very clear and high-contrast grain structure under a metallographic microscope, as shown in Figure 2 .

[0044] The above description is merely that of the preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art, based on the technical range disclosed in the present application and the technical concept of the present application, can make equivalent replacements or changes within the technical range disclosed in the present application and the technical concept of the present application, and such should be encompassed within the scope of protection of the present application. Therefore, the scope of protection of the present application should be subject to the scope of protection of the claims.

Claims

1. A method for displaying the grain size of beryllium bronze, characterized in that, Includes the following steps: S1. Sample preparation: Grind and polish the inspection surface of the beryllium bronze sample to obtain a mirror surface and clean it. S2, First corrosion: The inspection surface is etched by wiping with a first etchant; S3. First cleaning: Clean the first corrosive agent off the inspection surface; S4. Secondary corrosion: Use a second corrosive agent to wipe and corrode the inspection surface; S5. Second cleaning: Clean away the second corrosive agent on the inspection surface; S6. Drying: Dry the inspection surface in preparation for observation; The first corrosive agent is an aqueous solution of ferric chloride hydrochloric acid, and the second corrosive agent is an aqueous solution of copper dichloride ammonia.

2. The method for displaying beryllium bronze grain size according to claim 1, characterized in that, After the S5 secondary cleaning step and before the S6 drying step, there is a repeating step: repeating the first corrosion to the second cleaning step at least once.

3. The method for displaying beryllium bronze grain size according to claim 1 or 2, characterized in that, The first corrosive agent consists of the following components: 5g ferric chloride, 10ml hydrochloric acid, and 100ml water.

4. The method for displaying beryllium bronze grain size according to claim 1 or 2, characterized in that, The second corrosive agent consists of: 8g to 20g of copper dichloride and 8ml to 100ml of ammonia.

5. The method for displaying beryllium bronze grain size according to claim 4, characterized in that, The second corrosive agent consists of: 10g of copper dichloride and 100ml of ammonia.

6. The method for displaying beryllium bronze grain size according to claim 4, characterized in that, The second corrosive agent consists of: 20g of copper dichloride and 100ml of ammonia.

7. The method for displaying beryllium bronze grain size according to claim 1 or 2, characterized in that, The duration of the primary corrosion and the secondary corrosion are each independently between 1 second and 4 seconds.

8. The method for displaying beryllium bronze grain size according to claim 1 or 2, characterized in that, The wiping corrosion is performed using degreased cotton soaked in the corresponding corrosive agent.

9. The method for displaying beryllium bronze grain size according to claim 1 or 2, characterized in that, The drying process includes rinsing with anhydrous ethanol followed by drying with a hair dryer.

10. A beryllium bronze grain size etching agent combination for use in the method of any one of claims 1 to 9, characterized in that, It consists of a first corrosive agent and a second corrosive agent; The first corrosive agent is an aqueous solution of ferric chloride hydrochloric acid; The second corrosive agent is an aqueous solution of copper dichloride and ammonia.

Images