Pretreatment method of ultra-low oxygen content test sample in rhenium alloy

Abstract

The invention discloses a pretreatment method of an ultra-low oxygen content test sample in rhenium alloy. The treatment method comprises the following specific steps: firstly, preparing a mixed acid solution; the method comprises the following steps: pretreating a to-be-treated rhenium alloy sample to obtain a sample; placing the obtained mixed acid solution in a beaker, heating to a certain temperature, placing the obtained sample in the mixed acid solution, and carrying out pickling treatment for a certain period of time; and taking out the sample, carrying out ultrasonic cleaning with alcohol for multiple times to remove the pickling solution, finally, carrying out cold air blow-drying with an air blower, and carrying out vacuum sealing to obtain the rhenium alloy sample for testing. The pickling method is simple, the rhenium alloy sample with good surface brightness can be obtained by controlling parameters such as the pickling solution ratio, the pickling temperature and the pickling time of the pickling process, and the oxygen content of the rhenium alloy sample is obviously reduced compared with that of the untreated rhenium alloy sample.

Description

Technical Field

[0001] The present invention belongs to the field of surface treatment of metal materials, and particularly relates to a pretreatment method for test samples with ultra-low oxygen content in rhenium alloys. Background Art

[0002] Metallic rhenium has high hardness, high strength, good plasticity, excellent thermal shock resistance and creep resistance. As an alloying element added, it can improve the properties of metals. For example, in common molybdenum-rhenium and tungsten-rhenium alloys, the addition of rhenium can not only improve the strength and plasticity of the alloy, but also improve its processing performance and reduce the ductile-brittle transition temperature. Therefore, rhenium alloys are widely used in many fields such as aerospace, nuclear industry, and chemical industry. The oxygen content in rhenium alloys has an important impact on the material properties. Excessive oxygen content will cause embrittlement of the material, seriously affecting the processing and service performance of the material. At high temperatures, the influence of oxygen content is more significant. Oxygen atoms may be more likely to enter the grain boundaries and defects of the alloy at high temperatures, reducing the strength and stability of the alloy at high temperatures, thereby affecting its service life and reliability. In addition, high contents of element impurities such as carbon and nitrogen will also increase the risk of crack generation in the alloy finished products. Therefore, in some special fields that require the use of high-purity alloy materials, there are often strict requirements for the content of gas impurity elements such as oxygen in rhenium alloy materials. However, during the plastic processing of alloys, it is inevitable that due to factors such as high temperature and experimental environment, the surface of the alloy will come into contact with oxygen in the air, and then an oxide film will be formed on the surface, affecting the final test results of the alloy oxygen content. Therefore, how to effectively remove the oxide film on the alloy surface so that the test results can more truly reflect the elemental composition inside the material is crucial for the evaluation of the comprehensive performance of alloy materials.

[0003] Before performing ultra-low oxygen content tests, it is necessary to strictly pretreat the samples to eliminate factors that may interfere with the test results. All along, manual grinding and pickling are relatively common methods for removing the oxide scale on the surface of rhenium alloy samples. However, for rhenium alloy samples with ultra-low oxygen content, using the manual grinding method has low efficiency, long processing time, and heat will be generated during the grinding and polishing process, resulting in partial oxidation on the sample surface, making it difficult to reflect the true oxygen content of the sample. General pickling methods often use a mixed acid of nitric acid and hydrofluoric acid for pickling. However, for test samples, it is difficult to control the time, and it is extremely easy to over-corrode, still making it difficult to meet the test requirements of ultra-low oxygen content. Moreover, hydrofluoric acid is highly dangerous and prone to causing safety hazards during use.

[0004] Therefore, exploring an efficient, stable and safe pretreatment method for test samples with ultra-low oxygen content in rhenium alloys can provide important supplements and expansions for this field. Summary of the Invention

[0005] The present invention discloses a pretreatment method for a test sample with ultra-low oxygen content in a rhenium alloy to solve any one of the above and other potential problems in the prior art.

[0006] To solve the above technical problems, the technical solution of the present invention is: a pretreatment method for a test sample with ultra-low oxygen content in a rhenium alloy, and the pretreatment method specifically includes the following steps;

[0007] S1) Preparation of a mixed acid solution;

[0008] S2) Pretreat the rhenium alloy sample to be processed to obtain a test specimen;

[0009] S3) Place the mixed acid solution obtained in S1) in a beaker, heat it to a certain temperature, and place the test specimen obtained in S2) in the mixed acid solution for pickling treatment for a certain period of time;

[0010] S4) Take out the test specimen, ultrasonically clean it with alcohol multiple times to remove the pickling solution, and finally blow it dry with a hair dryer and seal it in a vacuum to obtain a rhenium alloy test specimen for testing.

[0011] Further, the mixed acid solution includes concentrated hydrochloric acid with a content of 1.0 - 1.5 mol / L, phosphoric acid with a content of 7.0 - 8.0 mol / L, and organic weak acid with a content of 0.6 - 0.8 mol / L.

[0012] Further, the organic weak acid is citric acid.

[0013] Further, the pretreatment in S2) is specifically: make the rhenium alloy sample into short wires or small pieces, then completely immerse the sample with alcohol, ultrasonically clean it for at least 5 minutes, and replace the alcohol at least twice during this period.

[0014] Further, the heating temperature in S3) is: 30 - 35 °C, and the treatment time is 3 - 10 minutes.

[0015] Further, the heating method in S3) is oil bath heating.

[0016] Further, the oxygen content of the rhenium alloy test specimen obtained by the pretreatment method is reduced to 20% - 30%, and the C content is reduced to 40% - 60%.

[0017] The hydrochloric acid, phosphoric acid, and citric acid pickling process adopted by the present invention, its core mechanism is to dissolve the surface oxides, remove the adsorbed oxygen, and inhibit re-oxidation through the synergistic effect of multiple acids.

[0018] The main function of hydrochloric acid is to quickly dissolve the oxide layer on the metal surface; phosphoric acid has a certain degreasing ability, can emulsify grease, help remove the oil stain on the metal surface, and phosphoric acid can form a dense phosphate film on the metal surface to inhibit the over-corrosion of the matrix metal and prevent the regeneration of the oxide layer; the citrate radical in citric acid can form a water-soluble complex with metal ions to prevent the re-oxidation and deposition of metal ions.

[0019] The combination of the three acids, HCl provides a high H + concentration to quickly initiate the dissolution of the oxide layer, H3PO4 buffers the pH: to avoid out-of-control matrix corrosion caused by local over-acidity, and citric acid adjusts the redox potential: to maintain the system in a mildly reducing environment and inhibit oxygen adsorption.

[0020] The beneficial effects of the present invention are as follows: Due to the adoption of the above technical solution, the mixed acid raw materials in the method of the present invention are cheap and easily available, the operation is simple, the practicability is strong, the treatment effect is good, it is relatively safe, and it is applicable to rhenium alloy samples of different shapes and sizes. When processing rhenium alloy samples with ultra-low oxygen content, it can remove the surface oxide scale while avoiding the introduction of external oxygen elements, more truly reflect the oxygen element content of the material itself, and also has a certain effect of reducing the content of gas impurity elements such as carbon and nitrogen. Description of the Drawings

[0021] Figure 1 It is a flow chart of a pre-treatment method for a test sample with ultra-low oxygen content in a rhenium alloy of the present invention. Detailed Embodiments

[0022] The technical solution of the present invention will be further described below in conjunction with the drawings and specific embodiments.

[0023] The purpose of the present invention is to provide a pre-treatment method for a test sample with ultra-low oxygen content in a rhenium alloy. The method is simple to operate, has a remarkable effect, can significantly reduce the oxygen element impurity content of the sample, and obtain more real data.

[0024] As Figure 1 shown, a pre-treatment method for a test sample with ultra-low oxygen content in a rhenium alloy of the present invention includes the following steps;

[0025] 1) Sample pre-treatment: First, perform appropriate processing on the rhenium alloy sample according to its type to make it into short filaments or small pieces, and then completely immerse the sample in alcohol and ultrasonically clean it for 5 minutes, replacing the alcohol twice during this period.

[0026] 2) Sequentially take concentrated hydrochloric acid, phosphoric acid, and citric acid, and prepare a mixed pickling solution of 1.0 - 1.5 mol / L hydrochloric acid, 7.0 - 8.0 mol / L phosphoric acid, and 0.6 - 0.8 mol / L citric acid. After stirring evenly with a glass rod, take an appropriate amount of the acid solution with a beaker, then place the beaker in an oil bath. When the temperature rises to 30 - 35 °C, immediately put the rhenium alloy sample for pickling, and the treatment time is 3 - 10 minutes.

[0027] 3) Immediately put the sample into alcohol after taking it out, completely immerse the sample, and clean it in an ultrasonic environment for 5 minutes, during which the alcohol is changed twice. After cleaning, blow it dry with a hair dryer under cold air, and then immediately vacuum package it for testing.

[0028] The core of the above pretreatment method for ultra-low oxygen content test samples in a rhenium alloy lies in: the preparation of the pickling solution and the treatment time.

[0029] Example 1

[0030] A pretreatment method for ultra-low oxygen content test samples in a rhenium alloy, the specific method includes the following steps:

[0031] (1) Pretreat the rhenium alloy wire.

[0032] Cut the rhenium alloy wire into small segments of about 0.2 - 0.3 g with clean pliers, and ultrasonically clean it with alcohol three times.

[0033] (2) Mixed acid pickling treatment:

[0034] Sequentially take concentrated hydrochloric acid, phosphoric acid, and citric acid, and prepare a mixed pickling solution of 1.5 mol / L hydrochloric acid, 7.0 mol / L phosphoric acid, and 0.6 mol / L citric acid. After stirring evenly with a glass rod, take an appropriate amount of the acid solution with a beaker, then place the beaker in an oil bath. When the temperature rises to 30 °C, put the rhenium alloy wire for pickling, and the treatment time is 5 minutes.

[0035] (3) After pickling is completed, immediately take out the sample and ultrasonically clean it in alcohol that can immerse the sample, change the alcohol twice during this period, and finally blow it dry with a hair dryer under cold air, and then immediately vacuum package it for testing. The test results are shown in Table 1.

[0036] Table 1 Changes in the contents of O and C impurity elements in molybdenum rhenium alloy wire before and after pickling

[0037]

[0038] Example 2

[0039] A pretreatment method for ultra-low oxygen content test samples in a rhenium alloy, the specific method includes the following steps:

[0040] (1) Pretreat the rhenium alloy bar.

[0041] Use a lathe to turn the rhenium alloy rod into a thin rod and clamp it into small pieces weighing about 0.2 - 0.3 g. The turning chips are used to test the C content, and the small pieces are used to test the O content. Ultrasonically clean the small pieces and turning chips with alcohol multiple times to initially wash away the cutting fluid and surface impurities.

[0042] (2) Pickling treatment with mixed acids:

[0043] Take concentrated hydrochloric acid, phosphoric acid, and citric acid in sequence, and prepare a mixed pickling solution of 1.5 mol / L hydrochloric acid, 7.5 mol / L phosphoric acid, and 0.8 mol / L citric acid. After stirring evenly with a glass rod, take an appropriate amount of the acid solution with a beaker, then place the beaker in an oil bath. When the temperature rises to 35 °C, put the sample in for pickling, and the treatment time is 10 minutes.

[0044] (3) After the pickling is completed, immediately take out the sample and ultrasonically clean it in alcohol that can submerge the sample. Replace the alcohol twice during this period. Finally, blow it dry with a hair dryer and immediately vacuum package it for testing. The test results are shown in Table 2.

[0045] Table 2 Changes in the contents of O and C impurity elements in rhenium alloy blocks and chips before and after pickling

[0046]

[0047] The above has introduced in detail a pretreatment method for a sample for testing ultra - low oxygen content in a rhenium alloy provided by an embodiment of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

[0048] As used in the specification and claims, certain terms are used to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. The specification and claims do not use the difference in names as a way to distinguish components, but use the difference in functions of components as the criterion for distinction. As mentioned throughout the specification and claims, "comprising" and "including" are open - ended terms, so they should be interpreted as "comprising / including but not limited to". "Roughly" means within an acceptable error range. Those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The subsequent description in the specification is for the preferred implementation manner of implementing the present application, but the description is for the purpose of explaining the general principle of the present application and is not used to limit the scope of the present application. The protection scope of the present application shall be subject to what is defined by the appended claims.

[0049] It should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a commodity or system comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or elements inherent to such commodity or system. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the commodity or system comprising said element.

[0050] It should be understood that the term "and / or" used herein is merely a description of the relationship between associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0051] The above description shows and describes several preferred embodiments of the present application. However, as previously mentioned, it should be understood that the present application is not limited to the forms disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the application concept described herein through the above teachings or the techniques or knowledge in the relevant field. And any changes and modifications made by those skilled in the art that do not depart from the spirit and scope of the present application shall fall within the protection scope of the appended claims of the present application.

Claims

1. A method for pre-treating a sample for testing ultra-low oxygen content in a rhenium alloy, characterized in that: The pre-treatment method specifically comprises the following steps: S1) preparing mixed acid solution; S2) pretreating the rhenium alloy sample to be processed to obtain a sample; S3) heating the mixed acid solution obtained in S1) to a certain temperature in a beaker, placing the sample obtained in S2) in the mixed acid solution for pickling for a certain period of time; S4) taking out the sample, using alcohol ultrasonic cleaning for multiple times to remove the pickling solution, and finally drying it with cold air from a hair dryer and vacuum sealing it to obtain a rhenium alloy sample for testing.

2. The pre-treatment method according to claim 1, characterized in that: The mixed acid solution includes concentrated hydrochloric acid with a content of 1.0-1.5 mol / L, phosphoric acid with a content of 7.0-8.0 mol / L and organic weak acid with a content of 0.6-0.8 mol / L.

3. The pre-treatment method according to claim 2, characterized in that: The organic weak acid is citric acid.

4. The pre-treatment method according to claim 1, characterized in that: The pretreatment of S2) is specifically as follows: the rhenium alloy sample is made into short wires or small pieces, and then the sample is completely immersed in alcohol, and ultrasonically cleaned for at least 5 minutes, during which the alcohol is replaced at least twice.

5. The pre-treatment method according to claim 1, characterized in that: The heating temperature in S3) is 30-35°C and the treatment time is 3-10 minutes.

6. The pre-treatment method according to claim 1, characterized in that: The heating method in S3) is oil bath heating.

7. The pre-treatment method according to claim 1, characterized in that: The pre-treatment method reduces the oxygen content of the rhenium alloy sample to 20% to 30%, and the C content to 40% to 60%.

Images