A method and device for testing the corrosion resistance of nickel-coated diamond micro-powder

Abstract

The present application relates to the field of nickel-coated diamond micro-powder corrosion resistance testing, and discloses a nickel-coated diamond micro-powder corrosion resistance testing method and device. Sampling: a certain mass of nickel-coated superhard material sample to be tested is taken; liquid preparation: an acidic corrosion liquid is prepared, the acidic corrosion liquid being prepared by mixing dilute nitric acid and dilute hydrochloric acid; reaction and collection: the nickel-coated superhard material sample is mixed with the acidic corrosion liquid, so that the nickel coating in the nickel-coated superhard material sample fully reacts with the acidic corrosion liquid, and the gas generated in the reaction is collected; measurement: the volume of the collected gas is measured; evaluation: according to the speed of the gas generation or the total volume of the gas, the corrosion resistance of the nickel-coated superhard material sample is evaluated.

Description

Technical Field

[0001] This invention relates to the field of corrosion resistance testing technology for nickel-coated diamond micropowder, and more specifically, to a method and apparatus for testing the corrosion resistance of nickel-coated diamond micropowder. Background Technology

[0002] Diamond powder possesses excellent properties such as high hardness and high thermal conductivity, and is widely used in abrasives, thermal conductive materials, and other fields. To improve the bonding performance between diamond powder and the matrix, metal coating is commonly used, with nickel coating being one of the most frequently employed methods. Magnetron sputtering dry coating technology offers advantages such as dense coatings and strong adhesion; however, the corrosion resistance of nickel-coated diamond powder prepared under different process parameters varies, necessitating the development of rapid and accurate testing methods for evaluation.

[0003] Currently, standards for evaluating the corrosion resistance of materials (such as the weight loss method) are not applicable to ultrafine nickel-coated diamond powder with a D50 < 10 μm because:

[0004] Poor repeatability: Powder is easily lost, and the weighing error is extremely large;

[0005] High safety risk: The reaction takes place in an open container, producing toxic gases (NOx).

[0006] Limited resolution: It cannot reflect the rapid dynamic corrosion process in real time and quantitatively;

[0007] Low throughput: cumbersome operation and long cycle time;

[0008] Therefore, it is of great significance to develop a simple, rapid, and effective method for testing the corrosion resistance of nickel-coated diamond powder. Summary of the Invention

[0009] To address at least one of the aforementioned problems, the present invention first provides a method for testing the corrosion resistance of nickel-coated diamond micropowder, comprising the following steps:

[0010] Sampling: Weigh the sample of the nickel-plated superhard material to be tested;

[0011] Solution preparation: Prepare an acidic etching solution, which is prepared by mixing dilute nitric acid and dilute hydrochloric acid;

[0012] Reaction and Collection: The nickel-coated superhard material sample is mixed with the acidic etching solution to allow the nickel coating in the nickel-coated superhard material sample to fully react with the acidic etching solution, and the gas produced by the reaction is collected;

[0013] Measurement: Measure the volume of the collected gas;

[0014] Evaluation: The corrosion resistance of the nickel-plated superhard material sample is evaluated based on the rate of gas generation or the total volume of the gas.

[0015] Optionally, in the sampling step, the particle size analysis parameters of the powder particles of the nickel-coated superhard material sample weighed are in the range of 1~20μm.

[0016] Optionally, the weight gain of the weighed nickel-plated superhard material sample ranges from 4% to 41%.

[0017] Optionally, in the solution preparation step, the acidic corrosive solution is prepared by mixing and diluting dilute nitric acid and dilute hydrochloric acid of equal concentration, wherein the volume ratio of the dilute nitric acid to the dilute hydrochloric acid is in the range of 1:(3~5).

[0018] Optionally, in the reaction and collection steps, the reaction is carried out in a closed reaction device, the mixing is performed by a constant temperature stirring device using magnetic stirring, and all the generated gas is introduced into a drainage and gas collection device for drying and collection.

[0019] Optionally, the measurement step involves measuring and recording the gas volume collected at different time points during the reaction process in real time using the liquid displacement method.

[0020] Optionally, the evaluation step is as follows: under the same reaction time, the slower the gas production rate or the less the total gas production, the denser the nickel coating and the better its corrosion resistance.

[0021] Optionally, the nickel-coated superhard material sample is nickel-coated diamond micropowder or nickel-coated cubic boron nitride.

[0022] Compared to existing technologies, the corrosion resistance testing method for nickel-coated diamond micropowder in this invention offers several advantages: the sampling step utilizes a precision balance for micro-sampling, eliminating the need for post-reaction weighing; the sampling process is simple and lossless. This solves the weighing error problem caused by the easy loss of powder (especially ultrafine powders with D50 < 10 μm) during washing, filtration, and drying before and after the reaction in traditional weight loss methods.

[0023] The principle of this method is as follows: the nickel coating in a nickel-plated superhard material reacts with an acidic corrosive solution to generate nitric oxide (NO). Since the superhard material is selected from materials that do not react with the acidic corrosive solution (such as diamond, cubic boron nitride, etc.), there is a stoichiometric relationship between the nitric oxide gas production and the corrosion resistance of the nickel coating involved in the reaction. Under isothermal and pressure-controlled conditions, the change in gas volume directly corresponds to the amount of substance dissolved in the nickel coating, thus enabling quantitative tracking of the corrosion process. By collecting and measuring nitric oxide gas, the macroscopic corrosion rate is converted into a measurable gas generation rate. Furthermore, by recording the volume of gas generated at different time points during the reaction in real time, the chemical corrosion process can be transformed into a dynamic curve changing over time, or the total volume of gas generated at the end of the reaction can be recorded to directly evaluate the overall corrosion resistance of the nickel coating.

[0024] Under the same test conditions (sample mass, etchant concentration, temperature, stirring speed, etc.), the rate of gas generation reflects the average rate of reaction between the nickel coating and the acidic etchant, while the total volume of gas generated reflects the total amount of nickel coating material (or coating thickness) that can be etched in the sample. The denser the coating and the fewer defects, the slower the etchant penetration and the lower the reaction rate; the thicker the coating, the longer the time required for complete dissolution and the greater the total gas production.

[0025] In addition, the present invention provides a device for testing the corrosion resistance of nickel-coated diamond micropowder, used to implement the corrosion resistance testing method for nickel-coated diamond micropowder as described above, comprising:

[0026] A closed reaction apparatus includes a reaction flask, a sample bottle, a first thermometer, and a top cover on the reaction flask. The top cover has a sample inlet, a gas outlet, and a temperature measuring port. The sample bottle is sealed to the sample inlet. The first thermometer passes through the temperature measuring port to monitor the liquid temperature inside the reaction flask. When the acidic corrosive solution is placed inside the reaction flask, the nickel-plated superhard material sample is placed inside the sample bottle.

[0027] A constant temperature stirring device is used to uniformly disperse ultrafine powder and allow it to react fully. The constant temperature stirring device includes a heat-collecting magnetic stirrer, a constant temperature water bath, and a second thermometer. The reaction flask is placed in the constant temperature water bath, which is placed on the heat-collecting magnetic stirrer. The second thermometer (mounted on a bracket) extends into the constant temperature water bath to detect the temperature.

[0028] A drainage gas collection device is used to accurately measure gas volume. The drainage gas collection device includes a gas guide pipe, a drying pipe, a three-way valve, an explosion-proof valve, a gas measuring pipe, and a water level balance bottle. The two ends of the gas guide pipe are respectively connected to the gas outlet and the explosion-proof valve. The two ends of the drying pipe are respectively connected to one channel of the explosion-proof valve and the three-way valve. The other two channels of the three-way valve are respectively connected to the gas measuring pipe and an external container. The water level balance bottle and the gas measuring pipe are connected by a connecting pipe.

[0029] Optionally, both the gas measuring tube and the water level balance bottle contain saturated saline solution, and the connecting tube is U-shaped.

[0030] Compared with the prior art, the nickel-coated diamond micropowder corrosion resistance testing device and the above-mentioned nickel-coated diamond micropowder corrosion resistance testing method have the same advantages over the prior art, and will not be repeated here. Attached Figure Description

[0031] Figure 1 This is a step diagram of the method for testing the corrosion resistance of nickel-coated diamond micropowder according to an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of the nickel-coated diamond micropowder corrosion resistance testing device according to an embodiment of the present invention.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1. Reaction flask; 2. Sample bottle; 3. First thermometer; 4. Top cap; 5. Heat-collecting magnetic stirrer; 6. Constant temperature water bath; 7. Second thermometer; 8. Gas delivery tube; 9. Drying tube; 10. Three-way valve; 11. Explosion-proof valve; 12. Gas measuring tube; 13. Water level balance bottle; 14. Support. Detailed Implementation

[0035] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0036] This invention provides a method for testing the corrosion resistance of nickel-coated diamond micropowder, combined with... Figure 1 and Figure 2 As shown, it includes the following steps:

[0037] Sampling: Weigh a certain mass of the nickel-plated superhard material sample to be tested;

[0038] Solution preparation: Prepare an acidic etching solution, which is prepared by mixing dilute nitric acid and dilute hydrochloric acid;

[0039] Reaction and Collection: The nickel-coated superhard material sample is mixed with the acidic etching solution to allow the nickel coating in the nickel-coated superhard material sample to fully react with the acidic etching solution, and the gas produced by the reaction is collected;

[0040] Measurement: Measure the volume of the collected gas;

[0041] Evaluation: The corrosion resistance of the nickel-plated superhard material sample is evaluated based on the rate of gas generation or the total volume of the gas.

[0042] The sampling process can be performed using a precision balance for micro-sampling, eliminating the need for post-reaction weighing. This method is simple and lossless. It solves the weighing error problem caused by the easy loss of powders (especially ultrafine powders with D50 < 10 μm) during washing, filtration, and drying before and after the reaction in traditional loss-of-weight methods.

[0043] The principle of this method lies in the fact that the nickel coating in nickel-plated superhard materials reacts with acidic corrosive solutions to generate nitric oxide (NO). Since the superhard material is selected to be non-reactive (e.g., diamond, cubic boron nitride), there is a stoichiometric relationship between the nitric oxide gas production and the corrosion resistance of the nickel coating involved in the reaction. Under isothermal and pressure-controlled conditions, the change in gas volume directly corresponds to the amount of substance dissolved in the nickel coating, thus enabling quantitative tracking of the corrosion process. By collecting and measuring nitric oxide gas, the macroscopic corrosion rate is converted into a measurable gas generation rate. Furthermore, by recording the volume of gas generated at different time points during the reaction in real time, the chemical corrosion process can be transformed into a dynamic curve changing over time, or the total volume of gas generated at the end of the reaction can be recorded to directly evaluate the overall corrosion resistance of the nickel coating.

[0044] Based on the gas quantification method, under the same test conditions (sample mass, etchant concentration, temperature, stirring speed, etc.), the rate of gas generation reflects the average reaction rate between the nickel coating and the acidic etchant, while the total volume of gas generated reflects the total amount of nickel coating material (or coating thickness) that can be etched in the sample. The denser the coating and the fewer defects, the slower the etchant penetration and the lower the reaction rate; the thicker the coating, the longer the time required for complete dissolution and the greater the total gas production.

[0045] Optionally, in the sampling step, the particle size analysis parameter (D50) of the powder particles of the nickel-coated superhard material sample is in the range of 1~20μm. In this embodiment, the particle size analysis parameter D50 of the nickel-coated superhard material sample is selected as 4~8μm, mainly for experiments on micron-sized powders.

[0046] Optionally, the weight gain of the weighed nickel-coated superhard material sample ranges from 4% to 41%. In this embodiment, the weight gain range of the nickel-coated superhard material sample is selected as 5% to 40%, and the weight gain rate directly reflects the thickness of the nickel coating layer.

[0047] Optionally, in the solution preparation step, the acidic corrosive solution is prepared by mixing dilute nitric acid and dilute hydrochloric acid of equal concentration, wherein the volume ratio of the dilute nitric acid to the dilute hydrochloric acid is in the range of 1:(3~5).

[0048] By precisely controlling the mixing ratio of dilute nitric acid and dilute hydrochloric acid (e.g., a volume ratio of 1:3), the reaction rate can be stabilized, ensuring that the corrosion process is both rapid enough to complete the test within a reasonable time, and not so violent as to be uncontrollable or cause splashing. Equal concentration mixing guarantees the homogeneity and repeatability of the reaction system.

[0049] The prepared acidic etching solution reacts gently and controllably with the nickel-plated superhard material, significantly reducing the instantaneous and massive generation of toxic nitrogen oxides (NOx) gas and improving the safety of the testing process. Simultaneously, the standardized solution preparation process ensures consistent corrosion conditions across different batches, eliminating errors caused by differences in the etching solution and making corrosion resistance evaluations more comparable across different batches.

[0050] Metallic nickel (Ni) is soluble in an acidic etching solution prepared from dilute nitric acid and dilute hydrochloric acid, primarily due to the oxidizing effect of nitric acid and the complexing effect of chloride ions. Although the concentrations of each component in the acidic etching solution are low, reactions may still occur after prolonged contact. The main reaction equation can be expressed as:

[0051]

[0052] Complexation reaction: in chloride ions In an environment of excessive amounts, the generated It will react further to form light green hexachloronickelate ions, which helps to drive the reaction to continue.

[0053]

[0054] If the nickel layer on the powder surface oxidizes, it will form a thin film of nickel oxide (NiO, usually green or gray). This film acts like a sturdy "protective suit" for the nickel, effectively preventing the internal metal from being further oxidized. This is one of the reasons why nickel has good corrosion resistance. Nickel oxide will react with acidic corrosive solutions, dissolving and exposing the fresh nickel inside, where the main reaction described above will then occur. The reaction formula for nickel oxide is as follows:

[0055]

[0056] Optionally, in the reaction and collection steps, the reaction is carried out in a closed reaction device, the mixing is performed by a constant temperature stirring device using magnetic stirring, and all the generated gas is introduced into a drainage and gas collection device for drying and collection.

[0057] The closed environment created by the closed reaction device ensures zero leakage collection of the generated gas, which not only prevents toxic nitrogen monoxide gas from escaping into the air, but also protects the occupational health and safety of the operators.

[0058] The constant-temperature stirring device has the functions of temperature regulation and magnetic stirring. The basic principle of magnetic stirring is to use the principle of like poles repelling and unlike poles attracting in magnetic fields. The magnetic field drives a magnetic stir bar placed in the container to rotate in a circular motion, thereby achieving the purpose of stirring the liquid. In the closed reaction device, by magnetically stirring the nickel-coated superhard material sample (nickel is magnetic), it is ensured that the nickel coating of each nickel-coated diamond microparticle can fully contact the acidic etching solution, and the reaction is complete. This overcomes the defect of powder agglomeration that prevents the internal nickel layer from contacting the etching solution, ensuring the sufficiency of the reaction and the validity of the measurement results.

[0059] The drainage and gas collection device draws the gas produced by the reaction out of the closed reaction device through a closed pipeline, and collects it after drying, preventing the gas from escaping to the outside while ensuring the accuracy of the volume detection of the generated gas.

[0060] Optionally, the nickel-coated superhard material sample is nickel-coated diamond micropowder or nickel-coated cubic boron nitride.

[0061] The common feature of nickel-coated diamond micropowder and nickel-coated cubic boron nitride is that neither the diamond nor the cubic boron nitride micropowder coated with a nickel layer reacts with acidic corrosive solutions. Similarly, it can also be applied to other nickel-coated superhard materials with the same common characteristics to test their corrosion resistance.

[0062] Optionally, the measurement step involves measuring and recording the gas volume collected at different time points during the reaction process in real time using the liquid displacement method.

[0063] In this embodiment, the principle of the drainage method is the same as that of the water displacement method commonly used in chemical experiments. However, the difference is that since the nitric oxide gas generated after the reaction between the nickel layer and the acidic corrosion solution is slightly soluble in water, the liquid used in the drainage method should be a nitric oxide-poorly soluble liquid (such as saturated saline solution) to prevent measurement errors.

[0064] Optionally, the evaluation step is as follows: under the same reaction time, the lower the gas production rate or the less the total gas production, the denser the nickel coating and the better its corrosion resistance.

[0065] Specifically: the more gas produced within a certain time frame, the thinner the oxide layer and the less corrosive the powder. The denser the nickel layer, the slower the reaction, the less gas is generated, and the stronger the corrosion resistance of the coating.

[0066] In practice, various samples can be selected for comparative experiments to evaluate the corrosion resistance. Specific examples are as follows:

[0067] Both existing samples A and B are magnetron sputtered nickel-coated diamond powders with a D50 of 5.2 μm and a weight gain of 20%.

[0068] Test Procedure: Add 20 mL of 1 mol / L acidic etching solution (prepared at a volume ratio of dilute nitric acid: dilute hydrochloric acid = 1:3) to two identical apparatuses. Weigh 1.0000 g of sample A and 1.0000 g of sample B respectively, and then quickly add them to two sealed reaction flasks 1 through the two sample addition ports. Turn on the stirring and maintain the temperature (25℃). The gas produced by the reaction in both apparatuses will expel the saturated saline solution in the gas measuring tube 12. Record the total volume of gas produced in each apparatus within 10 minutes and compare and evaluate the results.

[0069] Results: The total gas production volume of sample A was measured to be 2.1 mL, and that of sample B was 3.0 mL, proving that the nickel coating of sample A is denser and has better corrosion resistance.

[0070] like Figure 2 As shown, another embodiment of the present invention provides a device for testing the corrosion resistance of nickel-coated diamond micropowder, used to implement the method for testing the corrosion resistance of nickel-coated diamond micropowder as described above, including:

[0071] A closed reaction apparatus includes a reaction flask 1, a sample bottle 2, a first thermometer 3, and a top cover 4 on the reaction flask 1. The top cover 4 has a sample inlet, a vent, and a temperature measuring port. The sample bottle 2 is sealed to the sample inlet. The first thermometer 3 passes through the temperature measuring port to monitor the liquid temperature inside the reaction flask 1. When the reaction flask 1 contains the acidic etching solution, the sample bottle 2 contains the nickel-plated superhard material sample; when the reaction flask 1 contains the nickel-plated superhard material sample, the sample bottle 2 contains the acidic etching solution. The sample bottle 2 is inverted and inserted into the top cover 4, and the sample bottle 2 is equipped with a switch valve. The reaction flask 1 is equipped with a thermostatic jacket. (The above devices are all existing experimental equipment, and their details are not described here.)

[0072] A constant temperature stirring device is used to uniformly disperse ultrafine powder and allow it to react fully. The constant temperature stirring device includes a heat-collecting magnetic stirrer 5, a constant temperature water bath 6, and a second thermometer 7. The reaction flask 1 is placed in the constant temperature water bath 6, which is placed on the heat-collecting magnetic stirrer 5. The second thermometer 7 is mounted on a bracket 14 and extends into the constant temperature water bath 6 to detect the temperature.

[0073] The heat-collecting magnetic stirrer 5 is existing technology. Combined with its built-in heating and temperature control system, it can heat and control the sample temperature according to specific experimental requirements, maintaining the necessary temperature conditions to ensure the liquid mixes to the required level. The constant-temperature water bath 6 is a water-filled pot or other container. The heat-collecting magnetic stirrer 5 heats the constant-temperature water bath 6, thus achieving a water-insulated, sealed reaction device. This maintains a stable temperature of the heated object, ensures uniform heating of the reaction process, facilitates observation, and avoids bumping.

[0074] A drainage gas collection device is used to accurately measure gas volume. The drainage gas collection device includes a gas guide pipe 8, a drying pipe 9, a three-way valve 10, an explosion-proof valve 11, a gas measuring pipe 12, and a water level balance bottle 13. The two ends of the gas guide pipe 8 are respectively connected to the gas outlet and the explosion-proof valve 11. The two ends of the drying pipe 9 are respectively connected to one channel of the explosion-proof valve 11 and the three-way valve 10. The other two channels of the three-way valve 10 are respectively connected to the gas measuring pipe 12 and an external container. The water level balance bottle 13 and the gas measuring pipe 12 are connected by a connecting pipe.

[0075] The drying tube 9 is a device used in chemical experiments to dry gases or remove impurities from them. It typically has connectors at both ends for connecting tubing, and contains a solid desiccant or impurity remover in the middle. When gas flows into the drying tube 9 from one end, water or other impurities in the gas react chemically with the desiccant or impurity remover, causing the water or impurities to separate from the gas, and relatively pure gas flows out from the other end. A precision gas measuring tube 12 is used for water displacement and gas collection. Its slender design allows even minute volume changes to be clearly read, greatly improving the sensitivity and accuracy of the measurement, making it particularly suitable for testing small samples with low gas yields. (The above devices are all existing experimental equipment; their details are not elaborated here.)

[0076] The core principle of exhaust is to use a three-way valve 10 to switch the gas path and use the liquid in the water level balance bottle 13 to "push away" or "replace" the original gas in the pipeline, so as to ensure the purity of the gas collected later.

[0077] Specific steps:

[0078] Phase 1: Emptying the pipeline (Preparation Phase)

[0079] Adjust the three-way valve 10: Switch the three-way valve 10 to the exhaust state. At this time, the three valves of the three-way valve 10 are open, connecting the drying tube 9, the gas measuring tube 12, and the outlet to the outside (or waste liquid / safety container).

[0080] Raise the water level balance bottle 13: Raise the water level balance bottle 13. The liquid (saturated saline) in the bottle is forced into the gas measuring tube 12 under the action of gravity, and continues to flow along the pipeline through the drying tube 9 until it reaches the gas delivery tube 8.

[0081] Gas is discharged: The incoming liquid pushes the original air trapped in the gas measuring tube 12, drying tube 9 and gas guide tube 8 forward. When the liquid is seen to flow continuously (or a certain amount flows out) from the exhaust port of the three-way valve 10 used to connect to the outside, it can be considered that the original gas in the entire pipeline from the outlet of reaction bottle 1 to the three-way valve 10 has been basically discharged and filled with liquid.

[0082] Phase Two: Begin Collection (Phase Switching)

[0083] Switching the three-way valve 10: Quickly switch the three-way valve 10 from the exhaust state to the collection state. At this time, the three-way valve 10 directly connects the air guide pipe 8 and the air measuring pipe 12, while closing the exhaust port connected to the outside.

[0084] Reaction initiation and collection: The sample is added to the acidic corrosive solution to start the chemical reaction. The generated gas enters the gas delivery tube 8, which has been partially blocked by liquid. A small amount of liquid in the tube is pushed back to the gas measuring tube 12 after passing through the drying tube 9 (the desiccant in the drying tube 9 is made of a material that does not react with saturated brine) and the gas is collected.

[0085] Adjusting the liquid level balance: By lowering the water level balance bottle 13, the pressure inside and outside the gas measuring tube 12 is balanced (the liquid levels are equal), and the accurate volume of the generated gas can be read.

[0086] Optionally, both the gas measuring tube 12 and the water level balance bottle 13 are filled with saturated saline solution, and the connecting tube is U-shaped. Using saturated saline solution as the liquid in the water level balance bottle 13, its low gas solubility minimizes gas dissolution loss in the liquid.

[0087] Compared with the prior art, the present invention has the following beneficial effects:

[0088] Precise quantification: Direct calculation based on gas volume avoids errors caused by powder loss.

[0089] Sensitive and efficient: It responds quickly to micro powders, and tests are usually completed within tens of minutes.

[0090] Safe and reliable: The fully enclosed system ensures that toxic gases are safely collected and that there is no operational risk.

[0091] Highly specialized: Specifically designed to address the testing challenges of ultrafine coated powders and strong acid systems.

[0092] The above embodiments are merely illustrative of several implementation methods of this disclosure, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this disclosure, and these modifications and improvements all fall within the protection scope of this disclosure.

Claims

1. A method for testing the corrosion resistance of nickel-coated diamond micropowder, characterized in that, Includes the following steps: Sampling: Weigh the sample of the nickel-plated superhard material to be tested; Solution preparation: Prepare an acidic etching solution, which is prepared by mixing dilute nitric acid and dilute hydrochloric acid; Reaction and Collection: The nickel-coated superhard material sample is mixed with the acidic etching solution to allow the nickel coating in the nickel-coated superhard material sample to fully react with the acidic etching solution, and the gas produced by the reaction is collected; Measurement: Measure the volume of the collected gas; Evaluation: The corrosion resistance of the nickel-plated superhard material sample is evaluated based on the rate of gas generation or the total volume of the gas.

2. The method for testing the corrosion resistance of nickel-coated diamond micropowder according to claim 1, characterized in that, In the sampling step, the particle size analysis parameters of the powder particles of the nickel-coated superhard material sample weighed are in the range of 1~20μm.

3. The method for testing the corrosion resistance of nickel-coated diamond micropowder according to claim 2, characterized in that, The weight gain of the weighed nickel-plated superhard material samples ranged from 4% to 41%.

4. The method for testing the corrosion resistance of nickel-coated diamond micropowder according to claim 1, characterized in that, In the solution preparation step, the acidic corrosive solution is prepared by dilute nitric acid and dilute hydrochloric acid of equal concentration, and the mixing volume ratio of the dilute nitric acid and the dilute hydrochloric acid is in the range of 1:(3~5).

5. The method for testing the corrosion resistance of nickel-coated diamond micropowder according to claim 1, characterized in that, In the reaction and collection steps, the reaction is carried out in a closed reaction device, the mixing is performed by a constant temperature stirring device with magnetic stirring, and all the generated gas is introduced into a drainage and gas collection device for drying and collection.

6. The method for testing the corrosion resistance of nickel-coated diamond micropowder according to claim 1, characterized in that, The measurement step involves measuring and recording the gas volume collected at different time points during the reaction process in real time using the liquid displacement method.

7. The method for testing the corrosion resistance of nickel-coated diamond micropowder according to claim 1, characterized in that, The evaluation steps are as follows: under the same reaction time, the slower the gas production rate or the less the total gas production, the denser the nickel coating and the better its corrosion resistance.

8. The method for testing the corrosion resistance of nickel-coated diamond micropowder according to any one of claims 1-7, characterized in that, The nickel-coated superhard material sample is nickel-coated diamond micropowder or nickel-coated cubic boron nitride.

9. A device for testing the corrosion resistance of nickel-coated diamond micropowder, used to implement the method for testing the corrosion resistance of nickel-coated diamond micropowder as described in any one of claims 1-8, characterized in that, include: A closed reaction apparatus, comprising a reaction flask (1), a sample bottle (2), a first thermometer (3), and a top cover (4) covering the reaction flask (1). The top cover (4) is provided with a sample inlet, a gas outlet, and a temperature measuring port. The sample bottle (2) is sealed to the sample inlet. The first thermometer (3) passes through the temperature measuring port to monitor the liquid temperature inside the reaction flask (1). When an acidic corrosive liquid is placed inside the reaction flask (1), the nickel-plated superhard material sample is placed inside the sample bottle (2). A constant temperature stirring device is used to uniformly disperse ultrafine powder and allow it to react fully. The constant temperature stirring device includes a heat-collecting magnetic stirrer (5), a constant temperature water bath (6), and a second thermometer (7). The reaction flask (1) is placed in the constant temperature water bath (6), and the constant temperature water bath (6) is placed on the heat-collecting magnetic stirrer (5). The second thermometer (7) extends into the constant temperature water bath (6) to detect the temperature. A drainage gas collection device is used to accurately measure gas volume. The drainage gas collection device includes a gas guide pipe (8), a drying pipe (9), a three-way valve (10), an explosion-proof valve (11), a gas measuring pipe (12), and a water level balance bottle (13). The two ends of the gas guide pipe (8) are respectively connected to the gas outlet and the explosion-proof valve (11). The two ends of the drying pipe (9) are respectively connected to one channel of the explosion-proof valve (11) and the three-way valve (10). The other two channels of the three-way valve (10) are respectively connected to the gas measuring pipe (12) and an external container. The water level balance bottle (13) and the gas measuring pipe (12) are connected by a connecting pipe.

10. The device for testing the corrosion resistance of nickel-coated diamond micropowder according to claim 9, characterized in that, Both the gas measuring tube (12) and the water level balance bottle (13) contain saturated saline solution, and the connecting tube is U-shaped.

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