Method for testing oxidation resistance of novel Pt-based alloy

Abstract

The invention relates to the technical field of Pt-based alloy performance testing, and discloses a novel Pt-based alloy oxidation resistance testing method which comprises the following steps: S1, carrying out linear cutting on a Pt-based alloy; s2, polishing the surface of the Pt-based alloy, measuring the surface of the Pt-based alloy by using a vernier caliper, and inputting surface area data of the Pt-based alloy into an analysis platform; s3, the Pt-based alloy is cleaned, and then the Pt-based alloy is dried; s4, the Pt-based alloy is put into the crucible, the reaction furnace is closed, and air in the reaction furnace is exhausted; s5, the Pt-based alloy is heated, after the temperature in the reaction furnace reaches 1300 DEG C, dry air is introduced into the reaction furnace, constant-temperature oxidation is continuously conducted for 100 h, and meanwhile the Pt-based alloy is weighed through an analytical balance; s6, the mass variation of the Pt-based alloy in unit area is obtained through analysis of the analysis platform; and S7, after constant-temperature oxidation is conducted for 100 h, the Pt-based alloy is taken out and cut through a diamond wire, the structure morphology is shot and observed, and the oxidation resistance of the Pt-based alloy is judged through the structure morphology. According to the method, the operation can be simplified, and the accuracy of evaluating the oxidation resistance of the Pt-based alloy is improved.

Description

Technical Field

[0001] This invention relates to the field of Pt-based alloy performance testing technology, and specifically to a novel method for testing the oxidation resistance of Pt-based alloys. Background Technology

[0002] Pt-based alloys, due to their excellent high-temperature strength, creep resistance, and good chemical stability, have significant application prospects in fields such as hot-end components of aerospace engines and high-temperature molds in the glass industry. During long-term high-temperature service, the oxidation resistance of Pt-based alloys is a key factor determining their service life. Accurately assessing the long-term oxidation resistance of Pt-based alloys under extreme high-temperature environments is crucial for material selection, composition optimization, and practical applications.

[0003] Currently, the commonly used method for evaluating the high-temperature oxidation resistance of Pt-based alloys is the intermittent weighing method. This method typically involves placing the sample in a high-temperature furnace for oxidation for a certain period, then removing it, cooling it to room temperature, weighing it, and then returning it to the furnace for further oxidation, repeating this cycle. This method has significant drawbacks: the sample undergoes heating and cooling processes with each weighing, and repeated thermal cycling accumulates thermal stress in the oxide layer, easily leading to cracking or even peeling, thus compromising its protective properties and causing the test results to deviate from the true performance of Pt-based alloys under continuous high-temperature service conditions; the frequent handling, cooling, and weighing processes easily introduce human error, affecting the accuracy of the mass change data; it cannot record the instantaneous changes in alloy mass during oxidation in real time and continuously, making it difficult to accurately capture oxidation kinetics; and for long-term oxidation tests, the frequent handling, cooling, and weighing processes are cumbersome and time-consuming. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the present invention aims to provide a novel method for testing the oxidation resistance of Pt-based alloys, simulating the real performance of Pt-based alloys under continuous high-temperature service conditions, recording the mass change of Pt-based alloys in real time, accurately and continuously during oxidation, simplifying the operation, and improving the accuracy of evaluating the long-term oxidation resistance of Pt-based alloys under extreme high-temperature environments.

[0005] The technical solution adopted in this invention is as follows: A novel method for testing the oxidation resistance of Pt-based alloys, comprising the following steps: S1: Pt-based alloys are wire-cut using diamond wire to obtain regular square prism-shaped Pt-based alloys; S2: Grind the surface of the Pt-based alloy after cutting, measure the surface area of ​​the Pt-based alloy and calculate the surface area of ​​the Pt-based alloy, and input the surface area data of the Pt-based alloy into the analysis platform; S3: Clean the polished Pt-based alloy with an ultrasonic cleaner, and then dry the cleaned Pt-based alloy. S4: Place the dried Pt-based alloy into the crucible inside the reactor, close the reactor, and remove the air from the reactor. S5: Heat the Pt-based alloy in the reactor. After the temperature in the reactor reaches 1300℃, dry air is introduced into the reactor and the oxidation is carried out at a constant temperature for 100 hours. At the same time, the Pt-based alloy is weighed by an analytical balance. S6: The analytical balance transmits the mass data of the Pt-based alloy acquired in real time to the analysis platform. The analysis platform analyzes the mass change of the Pt-based alloy and the surface area of ​​the Pt-based alloy to obtain the mass change per unit area of ​​the Pt-based alloy. The oxidation resistance of the Pt-based alloy is judged by the magnitude of the mass change per unit area. S7: After constant temperature oxidation for 100 hours, the Pt-based alloy is cooled and taken out of the furnace crucible. The oxidized Pt-based alloy is then cut with diamond wire and the microstructure is photographed and observed. The oxidation resistance of the Pt-based alloy is judged by the microstructure.

[0006] In a preferred embodiment of the present invention, S1 further includes the following steps: S11: Wire cutting of Pt-based alloy with diamond wire at a speed of 0.1 mm / min to 0.5 mm / min is performed to cut two opposite sides of a square prism-shaped Pt-based alloy in parallel, resulting in a regular square prism-shaped Pt-based alloy.

[0007] In a preferred embodiment of the present invention, S2 further includes the following steps: S21: Grind the surface of the Pt-based alloy after cutting, measure the length and width of the six surfaces of the Pt-based alloy with vernier calipers, and calculate the area of ​​the corresponding surface of the Pt-based alloy based on the length and width of each surface. S22: The surface area of ​​the Pt-based alloy is obtained by summing the areas of each surface of the Pt-based alloy, and the surface area data of the Pt-based alloy is input into the analysis platform.

[0008] In a preferred embodiment of the present invention, S4 further includes the following steps: S41: Place the dried Pt-based alloy into the crucible inside the reactor and turn off the reactor; S42: Turn on the vacuum pump to extract the gas from the reactor; S43: After extracting the gas from the reactor, nitrogen protective gas is introduced; S44: After the gas pressure inside the reactor reaches 400mbar~600mbar, stop the nitrogen protection gas is introduced into the reactor; S45: Repeat S42-S44 to complete the gas washing operation.

[0009] In a preferred embodiment of the present invention, S42 further includes the following step: S421: Turn on the vacuum pump to extract the gas from the reactor. After evacuation, the pressure inside the reactor is 5.0 x 10⁻⁶. -3 mbar ~ 8.0 x 10 -3 mbar.

[0010] In a preferred embodiment of the present invention, S43 further includes the following steps: S431: After the gas in the reactor is extracted, nitrogen protective gas is introduced. The nitrogen protective gas is introduced into the reactor at a rate of 200 ml / min.

[0011] In a preferred embodiment of the present invention, S5 further includes the following steps: S51: Nitrogen protective gas is continuously introduced into the reactor to heat the Pt-based alloy inside the reactor. After the temperature inside the reactor reaches 1300℃, the nitrogen protective gas is stopped from being introduced into the reactor. S52: Dry air is introduced into the reactor and oxidation is carried out at a constant temperature for 100 hours. S53: While dry air is introduced into the reactor, the analytical balance weighs the Pt-based alloy and obtains the mass of the Pt-based alloy in the reactor in real time.

[0012] In a preferred embodiment of the present invention, S51 further includes the following steps: S511: When the gas pressure inside the reactor reaches 800 mbar or more, nitrogen protective gas is continuously introduced into the reactor at a rate of 40 ml / min. S512: Heating of Pt-based alloy in the reactor. The heating rate in the reactor is 30℃ / min. After the temperature in the reactor reaches 1300℃, the nitrogen protective gas is stopped from being introduced into the reactor.

[0013] In a preferred embodiment of the present invention, S52 further includes the following steps: S521: Introduce dry air into the reactor at a flow rate of 40 ml / min and continue constant temperature oxidation for 100 h.

[0014] In a preferred embodiment of the present invention, S7 further includes the following step: S71: After constant temperature oxidation for 100 hours, the temperature inside the reactor is reduced at a rate of 30℃ / min. S72: After the Pt-based alloy has cooled, remove the Pt-based alloy from the reactor crucible; S73: Then, use a diamond wire to cut the oxidized Pt-based alloy along the central axis of the longest side of the Pt-based alloy, polish the cross section, and use electron probe microanalysis to photograph the surface and cross section of the Pt-based alloy to observe the morphology of the oxide layer. The oxidation resistance of the Pt-based alloy can be judged by the morphology of the oxide layer.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention creatively proposes different methods for testing antioxidant properties, which can simulate the real performance of Pt-based alloys under continuous high-temperature service conditions. It records the mass change of Pt-based alloys in real time, accurately and continuously during oxidation, simplifies the operation, and improves the accuracy of evaluating the long-term antioxidant properties of Pt-based alloys under extreme high-temperature environments. Specifically, during diamond wire cutting, the cutting line has certain textures, so the surface of the cut alloy block will have many striped depressions. This will also increase the surface area of ​​Pt-based alloys in contact with oxygen. Polishing the Pt-based alloy before oxidation can make the protruding textures on the contact surface with oxygen as close to the same plane as possible, making the measurement more accurate. In addition, the surfaces of Pt-based alloys after diamond wire cutting are not completely parallel. Calculating the surface area according to a regular cuboid will cause changes. Calculating each surface separately can avoid this error. This invention improves the accuracy of the test by cutting and polishing the Pt-based alloy. In the heating stage before oxidation begins, nitrogen protective gas is introduced into the reactor to prevent oxidation of the Pt-based alloy during the heating process. This ensures that the oxidation experiment of the Pt-based alloy only occurs after the temperature reaches 1300℃ and during a small cooling process, accurately simulating the operating environment of high-temperature components (most high-temperature components operate in environments where the heating process is very fast, reaching the target temperature within a few seconds, so this invention only conducts experiments after the temperature reaches the target temperature). This invention uses an analytical balance to obtain the mass of the Pt-based alloy in the crucible of the reaction furnace in real time and transmits the Pt-based alloy mass data to the analysis platform in real time. This eliminates the need for multiple cooling, heating, and weighing cycles, making the entire oxidation experiment continuous. The recording of mass data is also real-time, avoiding the tedious process of repeatedly taking samples and weighing during oxidation. This process avoids mass errors caused by operator subjectivity during weighing and prevents the accumulation of thermal stress in the oxide layer due to multiple sampling and cooling, reducing the phenomenon of oxide layer cracking caused by thermal stress. This results in a more complete oxide layer structure, simplifies the operation, and makes the mass change of the Pt-based alloy during oxidation closer to the actual value. This allows for accurate acquisition of the mass change per unit area of ​​the Pt-based alloy, improving the accuracy of evaluating the long-term oxidation resistance of Pt-based alloys under extreme high-temperature environments. It also provides oxidation kinetic data and oxide layer morphology information that truly reflect the practical potential of Pt-based alloys, effectively assisting in guiding material selection, composition optimization, and practical applications. Attached Figure Description

[0016] Figure 1 This is an oxidation kinetic curve of the Pt-based alloys prepared in Examples 1-6 of the test method for the oxidation resistance of the novel Pt-based alloys of the present invention; Figure 2This is the Pt alloy prepared in Example 1 of the test method for the oxidation resistance of the novel Pt-based alloy of the present invention. 82 Al 12 Electron probe microanalysis (EPMA) image of the surface of Cr6 alloy after oxidation experiment; Figure 3 This is the Pt alloy prepared in Example 1 of the test method for the oxidation resistance of the novel Pt-based alloy of the present invention. 82 Al 12 Electron probe microanalysis (EPMA) image of the cross section of Cr6 alloy after oxidation experiment; Figure 4 This is the Pt alloy prepared in Example 2 of the test method for the oxidation resistance of the novel Pt-based alloy of the present invention. 79 Ir3Al 12 Electron probe microanalysis (EPMA) image of the surface of Cr6 alloy after oxidation experiment; Figure 5 This is the Pt alloy prepared in Example 2 of the test method for the oxidation resistance of the novel Pt-based alloy of the present invention. 79 Ir3Al 12 Electron probe microanalysis (EPMA) image of the cross section of Cr6 alloy after oxidation experiment; Figure 6 This is the Pt alloy prepared in Example 3 of the test method for the oxidation resistance of the novel Pt-based alloy of the present invention. 74 Ir3Al 12 Electron probe microanalysis (EPMA) image of the surface of Cr6Ni5 alloy after oxidation experiment; Figure 7 This is the Pt alloy prepared in Example 3 of the test method for the oxidation resistance of the novel Pt-based alloy of the present invention. 74 Ir3Al 12 Electron probe microanalysis (EPMA) image of the cross section of Cr6Ni5 alloy after oxidation experiment; Figure 8 This is the Pt alloy prepared in Example 4 of the test method for the oxidation resistance of the novel Pt-based alloy of the present invention. 75 Ir 25 Electron probe microanalysis (EPMA) image of the alloy surface after oxidation experiment; Figure 9 This is the Pt alloy prepared in Example 4 of the test method for the oxidation resistance of the novel Pt-based alloy of the present invention. 75 Ir 25 Electron probe microanalysis (EPMA) image of the cross-section after alloy oxidation experiment; Figure 10 This is the Pt alloy prepared in Example 5 of the test method for the oxidation resistance of the novel Pt-based alloy of the present invention. 91 Electron probe microanalysis (EPMA) image of the surface of Ir3Cr6 alloy after oxidation experiment; Figure 11This is the Pt alloy prepared in Example 5 of the test method for the oxidation resistance of the novel Pt-based alloy of the present invention. 91 Electron probe microanalysis (EPMA) image of the cross section of Ir3Cr6 alloy after oxidation experiment; Figure 12 This is the Pt alloy prepared in Example 6 of the test method for the oxidation resistance of the novel Pt-based alloy of the present invention. 85 Ir3Al 12 Electron probe microanalysis (EPMA) image of the alloy surface after oxidation experiment; Figure 13 This is the Pt alloy prepared in Example 6 of the test method for the oxidation resistance of the novel Pt-based alloy of the present invention. 85 Ir3Al 12 Electron probe microanalysis (EPMA) image of the cross-section after alloy oxidation experiment; Figure 14 These are X-ray diffraction patterns of the Pt-based alloys prepared in Examples 1-6 of the present invention after oxidation, based on the test method for the oxidation resistance of the novel Pt-based alloys of the present invention. Figure 15 This is a flowchart of the test method for the oxidation resistance of the novel Pt-based alloy of the present invention. Detailed Implementation

[0017] Typical embodiments embodying the features and advantages of the present invention will be specifically described in the following description. It should be understood that the present invention can have various variations in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations herein are for illustrative purposes only and not intended to limit the present invention.

[0018] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] Example 1 Test methods for the oxidation resistance of novel Pt-based alloys, such as... Figure 15 As shown, it includes the following steps: S1: Pt-based alloys with regular square prisms are obtained by wire cutting with diamond wire. Specifically, S1 also includes the following steps: S11: Wire cutting of Pt-based alloy with diamond wire at a speed of 0.1 mm / min to 0.5 mm / min is performed to cut two opposite sides of a square prism-shaped Pt-based alloy in parallel, resulting in a regular square prism-shaped Pt-based alloy.

[0020] S2: Grind the surface of the Pt-based alloy after cutting, measure the surface area of ​​the Pt-based alloy with a vernier caliper and calculate the surface area of ​​the Pt-based alloy, and input the surface area data of the Pt-based alloy into the analysis platform; Specifically, S2 also includes the following steps: S21: Grind the surface of the Pt-based alloy after cutting, measure the length and width of the six surfaces of the Pt-based alloy with vernier calipers, and calculate the area of ​​the corresponding surface of the Pt-based alloy based on the length and width of each surface. S22: The surface area of ​​the Pt-based alloy is obtained by summing the areas of each surface of the Pt-based alloy, and the surface area data of the Pt-based alloy is input into the analysis platform.

[0021] S3: Clean the polished Pt-based alloy with an ultrasonic cleaner, and then dry the cleaned Pt-based alloy. S4: Place the dried Pt-based alloy into the crucible inside the reactor, close the reactor, and remove the air from the reactor. Specifically, S4 also includes the following steps: S41: Place the dried Pt-based alloy into the crucible inside the reactor and turn off the reactor; S42: Turn on the vacuum pump to extract the gas from the reactor; Specifically, S42 also includes the following steps: S421: Turn on the vacuum pump to extract the gas from the reactor. After evacuation, the pressure inside the reactor is 5.0 x 10⁻⁶. -3 mbar ~ 8.0 x 10 -3 mbar.

[0022] S43: After extracting the gas from the reactor, nitrogen protective gas is introduced; Specifically, S43 also includes the following steps: S431: After the gas in the reactor is extracted, nitrogen protective gas is introduced. The nitrogen protective gas is introduced into the reactor at a rate of 200 ml / min.

[0023] S44: After the gas pressure inside the reactor reaches 400mbar~600mbar, stop the nitrogen protection gas is introduced into the reactor; S45: Repeat S42-S44 to complete the gas washing operation.

[0024] S5: Heat the Pt-based alloy in the reactor. After the temperature in the reactor reaches 1300℃, dry air is introduced into the reactor and the oxidation is carried out at a constant temperature for 100 hours. At the same time, the Pt-based alloy is weighed by an analytical balance. Specifically, S5 also includes the following steps: S51: Nitrogen protective gas is continuously introduced into the reactor to heat the Pt-based alloy inside the reactor. After the temperature inside the reactor reaches 1300℃, the nitrogen protective gas is stopped from being introduced into the reactor. Specifically, S51 also includes the following steps: S511: When the gas pressure inside the reactor reaches 800 mbar or more, nitrogen protective gas is continuously introduced into the reactor at a rate of 40 ml / min. S512: Heating of Pt-based alloy in the reactor. The heating rate in the reactor is 30℃ / min. After the temperature in the reactor reaches 1300℃, the nitrogen protective gas is stopped from being introduced into the reactor.

[0025] S52: Dry air is introduced into the reactor and oxidation is carried out at a constant temperature for 100 hours. Specifically, S52 also includes the following steps: S521: Introduce dry air into the reactor at a flow rate of 40 ml / min and continue constant temperature oxidation for 100 h.

[0026] S53: While dry air is introduced into the reactor, the analytical balance weighs the Pt-based alloy and obtains the mass of the Pt-based alloy in the reactor in real time.

[0027] S6: The analytical balance transmits the mass data of the Pt-based alloy acquired in real time to the analysis platform. The analysis platform analyzes the mass change of the Pt-based alloy and the surface area of ​​the Pt-based alloy to obtain the mass change per unit area of ​​the Pt-based alloy. The oxidation resistance of the Pt-based alloy is judged by the magnitude of the mass change per unit area. In this embodiment, the change in mass per unit area is equal to the change in mass of the Pt-based alloy divided by the surface area of ​​the Pt-based alloy.

[0028] S7: After constant temperature oxidation for 100 hours, the Pt-based alloy is cooled and taken out of the furnace crucible. The oxidized Pt-based alloy is then cut with diamond wire and the microstructure is photographed and observed. The oxidation resistance of the Pt-based alloy is judged by the microstructure.

[0029] Specifically, S7 also includes the following steps: S71: After constant temperature oxidation for 100 hours, the temperature inside the reactor is reduced at a rate of 30℃ / min. S72: After the Pt-based alloy has cooled, remove the Pt-based alloy from the reactor crucible; S73: Then, use a diamond wire to cut the oxidized Pt-based alloy along the central axis of the longest side of the Pt-based alloy, polish the cross section, and use electron probe microanalysis to photograph the surface and cross section of the Pt-based alloy to observe the morphology of the oxide layer. The oxidation resistance of the Pt-based alloy can be judged by the morphology of the oxide layer.

[0030] In this embodiment, electron probe microanalysis is used to bombard the sample surface with a focused electron beam and excite characteristic X-rays. Combined with scanning electron microscopy, the morphology of the oxide layer on the alloy surface and the distribution of elements therein can be detected. At the same time, the morphology and element distribution of the cross-sectional oxide layer can also be detected.

[0031] In this embodiment, the reactor is a single graphite furnace, such as the TGA series, the analytical balance can be FLEXIBALANCE, and the analytical platform can be Themys TG.

[0032] The following example illustrates the composition of a Pt-based alloy with atomic percentages of 82% Pt, 12% Al, and 6% Cr: Explanation: Powdered alloys were smelted according to the percentage of alloying elements and then heat-treated to obtain the test alloy billet (Pt-based alloy).

[0033] S1: Wire cutting of Pt-based alloy with diamond wire at a speed of 0.2 mm / min was performed to cut two opposite sides of a square prism-shaped Pt-based alloy, resulting in a 6x6x8 mm square prism-shaped Pt-based alloy. S2: Grind the surface of the Pt-based alloy after cutting to make the six surfaces of the Pt-based alloy flat. Use vernier calipers to measure the length and width of the six surfaces of the Pt-based alloy respectively. Calculate the area of ​​the corresponding surface of the Pt-based alloy based on the length and width of each surface. Summate the areas of each surface of the Pt-based alloy to obtain the surface area of ​​the Pt-based alloy. Input the surface area data of the Pt-based alloy into the analysis platform. S3: Use an ultrasonic cleaner with anhydrous ethanol to ultrasonically clean and polish the Pt-based alloy, and then dry the cleaned Pt-based alloy. S4: Place the dried Pt-based alloy into the crucible inside the reactor, close the reactor, and turn on the vacuum pump to extract the gas (air contained within the reactor itself) from the reactor. After evacuation, the pressure inside the reactor is 7.0 x 10⁻⁶. -3 After the gas in the reactor is extracted, nitrogen protective gas is introduced. When the gas pressure in the reactor reaches 500 mbar, nitrogen protective gas is introduced to stop the flow of nitrogen protective gas. The nitrogen protective gas is introduced into the reactor at a rate of 200 ml / min. The process of evacuating the reactor and introducing nitrogen protective gas is repeated twice to complete the gas washing operation. S5: When the gas pressure inside the reactor reaches 810 mbar, nitrogen protective gas is continuously introduced into the reactor at a rate of 40 ml / min. The Pt-based alloy inside the reactor is heated at a rate of 30 °C / min. After the temperature inside the reactor reaches 1300 °C, the nitrogen protective gas is stopped, and dry air is introduced into the reactor at a flow rate of 40 ml / min. The oxidation is carried out at a constant temperature for 100 hours. While the dry air is introduced into the reactor, the Pt-based alloy is weighed using an analytical balance. The mass of the Pt-based alloy inside the reactor is obtained in real time using the analytical balance. S6: The analytical balance transmits the mass data of the Pt-based alloy acquired in real time to the analysis platform. The analysis platform analyzes the mass change of the Pt-based alloy and the surface area of ​​the Pt-based alloy to obtain the mass change per unit area of ​​the Pt-based alloy. The oxidation resistance of the Pt-based alloy is judged by the magnitude of the mass change per unit area. S7: After constant temperature oxidation for 100 hours, the cooling rate in the reactor is 30℃ / min. After the Pt-based alloy cools down, it is taken out of the reactor crucible. Then, the oxidized Pt-based alloy is cut along the central axis of the longest side of the Pt-based alloy with a diamond wire. The cross section is polished. Electron probe microanalysis is used to photograph the alloy surface and cross section to observe the morphology of the oxide layer. The oxidation resistance of the Pt-based alloy is judged by the morphology of the oxide layer.

[0034] Example 2 This embodiment is basically the same as Embodiment 1, except that the atomic percentages of each element in the Pt-based alloy are 79% Pt, 3% Ir, 12% Al, and 6% Cr.

[0035] Example 3 This embodiment is basically the same as Embodiment 1, except that the atomic percentage of each element in the Pt-based alloy is 74% Pt, 3% Ir, 12% Al, 6% Cr, and 5% Ni.

[0036] Example 4 This embodiment is basically the same as Embodiment 1, except that the atomic percentage of each element in the Pt-based alloy is 75% Pt and 25% Ir.

[0037] Example 5 This embodiment is basically the same as Embodiment 1, except that the atomic percentage of each element in the Pt-based alloy is 91% Pt, 3% Ir, and 6% Cr.

[0038] Example 6 This embodiment is basically the same as Embodiment 1, except that the atomic percentage of each element in the Pt-based alloy is 85% Pt, 3% Ir, and 12% Al.

[0039] Table 1. Atomic percentages of each element in Pt-based alloys in Examples 1-6 Table 2. Changes in mass per unit area of ​​Pt-based alloys after oxidation in Examples 1-6 Analysis of the test results from Examples 1-6 shows that: Figure 1 This is an oxidation kinetics curve of the Pt-based alloys prepared in Examples 1-6 of this invention. From the calculation results of the mass change per unit area in Table 2, the oxidation resistance of the Pt-based alloys in Examples 1-6 after 100 hours of isothermal oxidation, from highest to lowest, is as follows: Pt 74 Ir3Al 12 Cr6Ni5 (Example 3) > Pt 79 Ir3Al 12 Cr6 (Example 2) > Pt 82 Al 12 Cr6 (Example 1) > Pt 85 Ir3Al 12 (Example 6) > Pt 91 Ir3Cr6 (Example 5) > Pt 75 Ir 25 (Example 4) This is consistent with the predicted antioxidant performance results during alloy composition design. On the other hand, since the equipment detects the quality of the alloy throughout the entire oxidation process, the test results can be considered to correspond to the true value of the alloy quality change. The test method designed in this invention is more reliable and the test results are more effective.

[0040] from Figure 1 As can be seen from Examples 4-6, the three alloys showed significant weight gain, indicating severe oxidation. In Examples 1-3, after 10 hours of isothermal oxidation, the oxidation kinetic curves of the alloys tended to flatten with increasing oxidation time, and the mass change per unit area remained consistently low. Furthermore, the mass change curves with oxidation time generally followed a parabolic pattern. Looking at the enlarged view of the mass change curves from 80 to 100 hours, the Pt alloy in Example 3 showed a significant increase in mass. 74 Ir3Al 12 The Cr6Ni5 alloy may exhibit better oxidation resistance after 100 hours.

[0041] A comparison of Examples 1-6 above shows that, after being oxidized at 1300℃ for 100 hours, the alloy in Example 4 has significantly fewer alloying elements, with the largest change in mass per unit area being approximately 25.18 mg / cm³. 2 This indicates the worst antioxidant performance; while the alloy in Example 3 showed the smallest change in mass per unit area, approximately 0.73 mg / cm³. 2The oxidation resistance was the best. As the oxidation time increased, the mass change rate of the six Pt-based alloy samples tended to stabilize. This is because the oxides formed on the sample surface and the oxidation state tended to stabilize. The oxidation rate of the three alloys in Examples 4-6 remained high, while the oxidation rate of the three alloys in Examples 4-6 remained very low after the oxide layer stabilized.

[0042] like Figure 2 The Pt prepared in Example 1 of this invention 82 Al 12 Electron probe microanalysis (EPMA) image of the surface of Cr6 alloy after oxidation experiment, Pt 82 Al 12 The surface of the Cr6 alloy has formed a complete oxide layer without cracks or pores. The main alloying elements on the surface are Al and O, with a small amount of Pt and Cr. Since they are on the surface of the oxide layer and separated from the internal alloy, and Pt and its oxides are volatile at high temperatures, the Pt on the surface may be due to Pt vapor deposition during cooling after the oxide layer has stabilized.

[0043] like Figure 3 The Pt prepared in Example 1 of this invention 82 Al 12 Electron probe microanalysis (EPMA) image of the cross-section of Cr6 alloy after oxidation experiment, Pt 82 Al 12 The oxide layer formed on the surface of Cr6 alloy began to become more uniform in thickness and more complete, without any damage; in terms of thickness, the α-Al2O3 oxide layer was about 7.3 μm thick.

[0044] like Figure 4 The Pt prepared in Example 2 of this invention 79 Ir3Al 12 Electron probe microanalysis (EPMA) image of the surface of Cr6 alloy after oxidation experiment, Pt 79 Ir3Al 12 In addition to the formation of a dense α-Al2O3 oxide layer on the surface of the Cr6 alloy, there is less distribution of Pt elements in the matrix, and some Cr enrichment areas appear.

[0045] like Figure 5 The Pt prepared in Example 2 of this invention 79 Ir3Al 12 Electron probe microanalysis (EPMA) image of the cross-section of Cr6 alloy after oxidation experiment, compared with Pt in Example 1. 82 Al 12 Similar to Cr6 alloy, after high-temperature oxidation, Pt alloy... 79 Ir3Al 12An α-Al₂O₃ oxide layer was also formed on the Cr₆ surface, and the oxide layer was uniform and dense. The difference was that the oxide layer thickness was reduced to about 6.3 μm.

[0046] like Figure 6 The Pt prepared in Example 3 of this invention 74 Ir3Al 12 Electron probe microanalysis (EPMA) image of the Cr6Ni5 alloy surface after oxidation experiment. From the morphology of the oxide layer on the alloy surface, the oxide film generated in Example 3 during the oxidation process is continuous and complete, without any pores or cracks, and the base alloy is protected.

[0047] like Figure 7 The Pt prepared in Example 3 of this invention 74 Ir3Al 12 Electron probe microanalysis (EPMA) images of the cross-section of Cr6Ni5 alloy after oxidation experiment, combined with... Figure 14 The X-ray diffraction patterns of the Pt-based alloys prepared in Examples 1-6 after oxidation show that Cr2O3 is also present in the oxide layer, which is mainly composed of α-Al2O3, as well as some Ni elements. The main oxide is NiAl2O4. This indicates that the oxide layer composition of Example 3 has become more complex. It can be calculated from the figure that the thickness of the oxide layer composed of the three oxides is about 9.7 μm.

[0048] like Figure 8 The Pt prepared in Example 4 of this invention 75 Ir 25 Electron probe microanalysis (EPMA) image of the alloy surface after oxidation experiment, Pt 75 Ir 25 After oxidation, the alloy surface developed a large number of cracks and holes. Overall, the arrangement of these oxidation pits and holes follows a certain pattern: with larger oxidation cracks as boundaries, the holes inside the boundaries are arranged in parallel with the same direction.

[0049] like Figure 9 The Pt prepared in Example 4 of this invention 75 Ir 25 The electron probe microanalysis (EPMA) image of the cross-section after the alloy oxidation experiment clearly shows that Pt 75 Ir 25 The alloy surface does not form a stable oxide layer, and the alloy is in direct contact with the external oxygen-containing environment. Since the two elements Pt and Ir themselves, as well as the oxides they generate, are volatile at high temperatures, the surface of the alloy in contact with the air is not smooth and contains many pores.

[0050] like Figure 10 The Pt prepared in Example 5 of this invention91 Electron probe microanalysis (EPMA) image of the surface of Ir3Cr6 alloy after oxidation experiment, Pt 91 The surface of the Ir3Cr6 alloy also showed numerous oxide pores and some continuous cracks, Pt 91 The pores formed in the Ir3Cr6 alloy are mostly regular circles, indicating that the cause of the oxide pits formed in the two examples is different from that in Example 4.

[0051] like Figure 11 The Pt prepared in Example 5 of this invention 91 Electron probe microanalysis (EPMA) image of the cross-section of Ir3Cr6 alloy after oxidation experiment, Pt 91 Similar to Example 4, no stable oxide layer was formed on the surface of the Ir3Cr6 alloy. The alloy matrix was in direct contact with the external oxygen-containing environment, and the alloy's oxidation resistance was not significantly improved. Under the action of oxygen erosion, many holes and cracks appeared on the surface and inside the alloy, and the alloy failed to a certain extent. As can be seen from the oxygen element distribution diagram, the oxygen content is the highest at the location of the holes left by the erosion.

[0052] like Figure 12 The Pt prepared in Example 6 of this invention 85 Ir3Al 12 Electron probe microanalysis (EPMA) image of the surface of the alloy after oxidation experiment, Pt 85 Ir3Al 12 An oxidized coating forms on the alloy surface, providing some protection to the substrate. (Pt) 85 Ir3Al 12 The coating formed after the alloy oxidizes is grooved and uneven, with a large number of continuous, long cracks.

[0053] like Figure 13 The Pt prepared in Example 6 of this invention 85 Ir3Al 12 Electron probe microanalysis (EPMA) image of the cross-section after alloy oxidation experiment, Pt 85 Ir3Al 12 The thickness of the α-Al2O3 oxide layer formed by the alloy is uneven. Observation and calculation revealed that the thinnest part of the α-Al2O3 oxide layer is about 6.72 μm, while the thickest part reaches 11.58 μm.

[0054] As shown in Examples 1-6, the addition of the four alloying elements Ir, Al, Cr, and Ni is crucial for improving the oxidation resistance of Pt-based alloy materials. When Ir is lacking, the oxide layer forms slowly and cannot protect the base alloy in a short time. When Al is lacking, it is difficult for a protective oxide layer to form on the surface of the Pt-based alloy material, and most of the oxides volatilize. When Cr is lacking, the formed α-Al₂O₃ oxide layer is difficult to be dense and continuous. When Ni is lacking, a multi-layered composite oxide layer cannot be formed. Furthermore, the amount of each alloying element added also significantly affects the oxidation resistance of the alloy. Excessive addition of Ir increases the amount of volatile oxides generated, accelerating the oxidation rate. This is consistent with the predicted oxidation resistance results during alloy composition design.

[0055] Comparative Example 1 This comparative example is basically the same as Example 3. The atomic percentages of each alloying element in the Pt-based alloy are 74% Pt, 3% Ir, 12% Al, 6% Cr, and 5% Ni. The difference is that, in S2, the length and width of the six surfaces of the Pt-based alloy are measured with vernier calipers, and the area of ​​the corresponding surface of the Pt-based alloy is calculated based on the length and width of each surface. The surface area of ​​the Pt-based alloy is obtained by summing the areas of each surface, and the surface area data of the Pt-based alloy is input into the analysis platform.

[0056] Comparative Example 2 This comparative example is basically the same as Example 3. The atomic percentages of each alloying element in the Pt-based alloy are 74% Pt, 3% Ir, 12% Al, 6% Cr, and 5% Ni. The difference is that, in S4, the dried Pt-based alloy is placed in a crucible inside the reactor and the reactor is closed; in S5, the Pt-based alloy inside the reactor is heated at a rate of 30°C / min, and dry air is introduced into the reactor at a flow rate of 40 ml / min. After the temperature inside the reactor reaches 1300°C, it is continuously oxidized at a constant temperature for 100 hours. While the dry air is introduced into the reactor, the Pt-based alloy is weighed using an analytical balance. The mass of the Pt-based alloy inside the reactor is obtained in real time by the analytical balance.

[0057] Comparative Example 3 This comparative example is basically the same as Example 3. The atomic percentages of each alloying element in the Pt-based alloy are 74% Pt, 3% Ir, 12% Al, 6% Cr, and 5% Ni. The difference is that: S4: Weigh the dried Pt-based alloy and place it in a crucible in a tube furnace, then close the tube furnace; S5: After oxidizing the tube furnace to 1300℃ for 1 hour, take out the Pt-based alloy and let it cool. Weigh the Pt-based alloy again with a balance and then put it back into the tube furnace. Repeat the weighing and oxidation process. Stop the oxidation after 100 hours. During the first 20 hours, weigh the Pt-based alloy every hour. During the period from 20 hours to 100 hours, weigh the Pt-based alloy every 10 hours.

[0058] Table 3. Mass change per unit area of ​​Pt-based alloys in Examples 3 and 1-3 after oxidation at 1300℃ for 100 h. name Change in mass per unit area after oxidation (mg / cm⁻²) Example 3 0.7306 Comparative Example 1 1.2379 Comparative Example 2 0.8452 Comparative Example 3 0.3015 As shown in Table 3, the test results of the same Pt-based alloy sample will vary depending on the test method used.

[0059] A comparison between Example 3 and Comparative Example 1 shows that the alloy surface in Comparative Example 1, before oxidation, was not polished, and the final test value was 1.2379 mg / cm³. 2 This is significantly greater than the actual value of 0.7306 mg / cm³ measured in Example 3. 2 This indicates that the cutting marks remaining from the cutting process increased the actual contact area between the alloy and oxygen, while the calculated surface area was smaller than the actual contact area between the alloy and oxygen. Therefore, the actual test result was higher than that of Example 3. A comparison between Example 3 and Comparative Example 2 shows that the result of Comparative Example 2 was 0.8452 mg / cm³. 2 This is also greater than in Example 3, indicating that the oxidation process at the onset of oxidation during heating increases the actual oxidation time of the alloy. Comparing Example 3 and Comparative Example 3, it can be seen that the measured value in Comparative Example 3 is 0.3015 mg / cm³. 2 The results were too low compared to Example 3, which is due to errors that can easily occur during the weighing process. The novel method for testing the oxidation resistance of Pt-based alloy materials used in this invention can not only provide more accurate experimental results but also simplify the experimental process and make it safer.

[0060] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A novel method for testing the oxidation resistance of Pt-based alloys, characterized in that: Includes the following steps: S1: Pt-based alloys with regular square prisms are obtained by wire cutting with diamond wire. S2: Grind the surface of the Pt-based alloy after cutting, measure the surface area of ​​the Pt-based alloy with a vernier caliper and calculate the surface area of ​​the Pt-based alloy, and input the surface area data of the Pt-based alloy into the analysis platform; S3: Clean the polished Pt-based alloy with an ultrasonic cleaner, and then dry the cleaned Pt-based alloy. S4: Place the dried Pt-based alloy into the crucible inside the reactor, close the reactor, and remove the air from the reactor. S5: Heat the Pt-based alloy in the reactor. After the temperature in the reactor reaches 1300℃, dry air is introduced into the reactor and the oxidation is carried out at a constant temperature for 100 hours. At the same time, the Pt-based alloy is weighed by an analytical balance. S6: The analytical balance transmits the mass data of the Pt-based alloy acquired in real time to the analysis platform. The analysis platform analyzes the mass change of the Pt-based alloy and the surface area of ​​the Pt-based alloy to obtain the mass change per unit area of ​​the Pt-based alloy. The oxidation resistance of the Pt-based alloy is judged by the magnitude of the mass change per unit area. S7: After constant temperature oxidation for 100 hours, the Pt-based alloy is cooled and taken out of the furnace crucible. The oxidized Pt-based alloy is then cut with diamond wire and the microstructure is photographed and observed. The oxidation resistance of the Pt-based alloy is judged by the microstructure.

2. The method for testing the oxidation resistance of the novel Pt-based alloy according to claim 1, characterized in that: S1 also includes the following steps: S11: Wire cutting of Pt-based alloy with diamond wire at a speed of 0.1 mm / min to 0.5 mm / min is performed to cut two opposite sides of a square prism-shaped Pt-based alloy in parallel, resulting in a regular square prism-shaped Pt-based alloy.

3. The method for testing the oxidation resistance of the novel Pt-based alloy according to claim 1, characterized in that: S2 also includes the following steps: S21: Grind the surface of the Pt-based alloy after cutting, measure the length and width of the six surfaces of the Pt-based alloy with vernier calipers, and calculate the area of ​​the corresponding surface of the Pt-based alloy based on the length and width of each surface. S22: The surface area of ​​the Pt-based alloy is obtained by summing the areas of each surface of the Pt-based alloy, and the surface area data of the Pt-based alloy is input into the analysis platform.

4. The method for testing the oxidation resistance of the novel Pt-based alloy according to claim 1, characterized in that: S4 also includes the following steps: S41: Place the dried Pt-based alloy into the crucible inside the reactor and turn off the reactor; S42: Turn on the vacuum pump to extract the gas from the reactor; S43: After extracting the gas from the reactor, nitrogen protective gas is introduced; S44: After the gas pressure inside the reactor reaches 400mbar~600mbar, stop the nitrogen protection gas is introduced into the reactor; S45: Repeat S42-S44 to complete the gas washing operation.

5. The method for testing the oxidation resistance of the novel Pt-based alloy according to claim 4, characterized in that: S42 also includes the following steps: S421: Turn on the vacuum pump to extract the gas from the reactor. After evacuation, the pressure inside the reactor is 5.0 x 10⁻⁶. -3 mbar ~ 8.0 x 10 -3 mbar.

6. The method for testing the oxidation resistance of the novel Pt-based alloy according to claim 4, characterized in that: S43 also includes the following steps: S431: After the gas in the reactor is extracted, nitrogen protective gas is introduced. The nitrogen protective gas is introduced into the reactor at a rate of 200 ml / min.

7. The method for testing the oxidation resistance of the novel Pt-based alloy according to claim 1, characterized in that: S5 also includes the following steps: S51: Nitrogen protective gas is continuously introduced into the reactor to heat the Pt-based alloy inside the reactor. After the temperature inside the reactor reaches 1300℃, the nitrogen protective gas is stopped from being introduced into the reactor. S52: Dry air is introduced into the reactor and oxidation is carried out at a constant temperature for 100 hours. S53: While dry air is introduced into the reactor, the analytical balance weighs the Pt-based alloy and obtains the mass of the Pt-based alloy in the reactor in real time.

8. The method for testing the oxidation resistance of the novel Pt-based alloy according to claim 7, characterized in that: S51 also includes the following steps: S511: When the gas pressure inside the reactor reaches 800 mbar or more, nitrogen protective gas is continuously introduced into the reactor at a rate of 40 ml / min. S512: Heating of Pt-based alloy in the reactor. The heating rate in the reactor is 30℃ / min. After the temperature in the reactor reaches 1300℃, the nitrogen protective gas is stopped from being introduced into the reactor.

9. The method for testing the oxidation resistance of the novel Pt-based alloy according to claim 7, characterized in that: S52 also includes the following steps: S521: Introduce dry air into the reactor at a flow rate of 40 ml / min and continue constant temperature oxidation for 100 h.

10. The method for testing the oxidation resistance of the novel Pt-based alloy according to claim 1, characterized in that: S7 also includes the following steps: S71: After constant temperature oxidation for 100 hours, the temperature inside the reactor is reduced at a rate of 30℃ / min. S72: After the Pt-based alloy has cooled, remove the Pt-based alloy from the reactor crucible; S73: Then, use a diamond wire to cut the oxidized Pt-based alloy along the central axis of the longest side of the Pt-based alloy, polish the cross section, and use electron probe microanalysis to photograph the surface and cross section of the Pt-based alloy to observe the morphology of the oxide layer. The oxidation resistance of the Pt-based alloy can be judged by the morphology of the oxide layer.

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