A method for high throughput measurement of high temperature stress rupture life of platinum-based materials

Abstract

The application discloses a method for high-flux measurement of high-temperature endurance life of platinum-based materials, and belongs to the technical field of performance testing of platinum-based materials. According to the characteristics of oxidation resistance and weldability of platinum-based materials, different platinum-based material sample heads and tails are welded into a whole sample, the heads and tails of the whole sample are fixed on pull rods respectively, a load is applied on the tail rod, atmospheric high-temperature endurance test is carried out at a certain temperature, the time of fracture of a platinum-based material sample is the endurance life of the material under the stress, the remaining sample is welded into a new whole platinum-based material sample after the platinum-based material sample is cut off, and the high-temperature endurance test is continuously carried out, and the endurance life of different platinum-based materials under the same stress or different stresses is obtained through cumulative calculation after all platinum-based material samples are fractured. The method improves the measurement of endurance life of different platinum-based materials, different stresses and long time under low stress conditions, is high in efficiency, and saves a large amount of time and money cost.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of performance test of platinum-based materials, and particularly relates to a method for measuring high-temperature endurance life of platinum-based materials at high flux. BACKGROUND

[0002] The platinum-based materials include platinum-based alloy materials, platinum-based oxide particle reinforced composite materials, platinum-based composite materials, etc. Common platinum-based alloy materials are Pt, PtRh alloy, PtPdRh alloy, PtAu alloy and PtIr alloy. According to the classification of oxides, common oxides of the platinum-based oxide particle reinforced composite materials are ZrO2, CeO2 and Y2O3. The platinum-based composite materials mainly include Pt / PtRh, Pt / PtPd, Pt / Ni and Pt / Ti layered or filamentous composite materials. The platinum-based materials have excellent oxidation resistance, corrosion resistance and creep resistance, and are widely used in the fields of analytical crucibles, glass fiber manufacturing, crystal growth crucibles, heating wires and high-temperature thermocouples.

[0003] In addition to good oxidation resistance, high-temperature materials also need to have good high-temperature mechanical properties. One of the important evaluation indexes is the endurance life under certain stress conditions. The endurance life represents the time from the beginning of stress to the failure of the material under the conditions of constant temperature and constant stress. The general rule is that the lower the temperature and the smaller the stress, the longer the endurance life (several days to several decades). The endurance life of platinum-based materials is usually tested at a temperature above 900 DEG C and a stress of 2 MPa-50 MPa, and the endurance life is several hours to several years.

[0004] At present, the endurance life of high-temperature materials is mainly measured by a rod-shaped sample under tension stress in a vertical high-temperature furnace at a set temperature. Usually, only one sample can be measured in one furnace. For platinum-based materials, which are relatively expensive, wire and sheet samples are usually used for measurement, and only one sample can be measured in one furnace. Especially under low temperature and low stress conditions, the test is not only laborious, time-consuming and costly, but also has low efficiency and high cost. How to solve the problem of high flux endurance life test under multiple sample and multiple stress conditions in one furnace has become a problem to be solved. SUMMARY

[0005] In view of the above shortcomings of the prior art, the application provides a method for measuring high-temperature endurance life of platinum-based materials at high flux. According to the characteristics of oxidation resistance and mutual welding of the cold welding machine of the platinum-based materials, different platinum-based materials, forms and sizes of wire and foil are effectively combined, so that the high flux endurance life test of platinum-based materials under different materials and different stresses at the same temperature is realized.

[0006] To achieve the above object, the technical scheme adopted by the application is that:

[0007] A method for high-throughput measurement of high-temperature stress-rupture life of platinum-based materials, comprising the following steps:

[0008] (1) setting different platinum-based material samples to be the same length of samples;

[0009] (2) welding each platinum-based material sample to be a complete platinum-based material sample A in a head-to-tail manner and numbering each platinum-based material sample, and then welding the head and tail of the platinum-based material sample A on platinum alloy pull rods;

[0010] (3) then placing in a high-temperature environment, applying a load on the tail platinum alloy pull rod, and then starting a high-temperature stress-rupture test; recording the number, fracture time and diameter of the platinum-based material sample that is broken in the test, calculating the corresponding stress through the diameter, and recording the time as the stress-rupture life of the platinum-based material sample under the corresponding stress;

[0011] (4) removing the broken platinum-based material sample, and welding the upper and lower platinum-based material samples of the broken platinum-based material sample to be a new complete platinum-based material sample B;

[0012] (5) repeating steps (3) and (4) until all platinum-based material samples are broken, and calculating the stress-rupture life of each platinum-based material sample under the corresponding stress by accumulation.

[0013] As a preferred embodiment of the present application, the platinum-based material samples are samples with consistent cross sections.

[0014] As a preferred embodiment of the present application, the platinum-based material samples are wire, sheet, strip or foil.

[0015] As a preferred embodiment of the present application, in step (1), the diameters of different platinum-based material samples are the same or different.

[0016] As a preferred embodiment of the present application, each platinum-based material sample is welded in a head-to-tail order from large to small in diameter, which can reduce the stress of the lower platinum-based material sample.

[0017] As a preferred embodiment of the present application, the number of platinum-based material samples is more than one.

[0018] As a preferred embodiment of the present application, the number of platinum-based material samples is more than two.

[0019] As a preferred embodiment of the present application, the welding is spherical welding, the surface is spherical, and the surface is relatively smooth, and the stress concentration is relatively small.

[0020] As a preferred embodiment of the present application, in the step (2), the corresponding stress is calculated by formula: σ=F / A, wherein F is the external force applied on the material, i.e. the sum of the applied load and the mass of the tail platinum alloy pull rod, in units of N, and A is the cross-sectional area of the material, in units of mm 2 .

[0021] As a preferred embodiment of the present application, the platinum-based material is Pt, PtRh, PtIr, PtPd, oxide dispersion strengthened platinum, or other oxidation-resistant platinum-based materials.

[0022] As a preferred embodiment of the present application, each platinum-based material sample is welded by a cold welding machine under argon protection.

[0023] As a preferred embodiment of the present application, the head of the platinum alloy pull rod of the welded platinum-based material sample A is externally on the upper end of the high-temperature environment.

[0024] As a preferred embodiment of the present application, the atmosphere of the high-temperature durability test is air.

[0025] Compared with the prior art, the present application has the following beneficial effects: the present application effectively combines wire and foil materials of different platinum-based materials, forms, and sizes by utilizing the characteristics of oxidation resistance of platinum-based materials and mutual welding using a cold welding machine, thereby realizing high-throughput testing of the durability life of platinum-based materials of different materials and different stresses at the same temperature. In addition, the method for measuring the high-temperature durability life of platinum-based materials in high throughput according to the present application effectively solves the problem that the conventional test method can only test one material and one stress condition at a time, and solves the problem of long test time, up to several years, under low stress conditions for one material, effectively saving test time. Moreover, the high-temperature durability life of the platinum-based material tested according to the test method of the present application has high accuracy and is consistent with the high-temperature durability life of the platinum-based material tested alone. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The figure is a schematic diagram of the method for measuring the high-temperature durability life of platinum-based materials in high throughput according to the present application.

[0027] In the figure, T represents the load applied on the platinum alloy pull rod; L represents the number of platinum-based material samples, wherein L n , n is 1, 2, 3, 4, or 5, representing the nth platinum-based material sample; N represents the welded node, wherein N m , m is 1, 2, 3, 4, 5, or 6, representing the mth welded node. DETAILED DESCRIPTION

[0028] In order to better illustrate the purpose, technical scheme, and advantages of the present application, the present application will be further described below in conjunction with specific examples.

[0029] Example 1

[0030] The high temperature stress-rupture life of Pt, PtRh5, PtRh7, PtRh10, PtRh13 at a tensile stress of 5 MPa and 1100°C was measured, including the following steps:

[0031] (1) Five pieces of Pt, PtRh5, PtRh7, PtRh10, PtRh13 wire with a diameter of φ0.2 mm and a length L of 30 mm were cut respectively.

[0032] (2) Then the five pieces of wire were connected head to tail in the order of Pt, PtRh5, PtRh7, PtRh10, PtRh13 and welded into one whole piece of wire using a cold welding machine under argon protection, with a spherical weld at the joint, and sequentially numbered as L1, L2, L3, L4, L5. The head of the wire L1 was welded to a 2 mm diameter PtRh6 alloy upper pull rod, and the tail of the wire L5 was welded to a 2 mm diameter PtRh6 alloy lower pull rod. The mass of the PtRh6 alloy lower pull rod was weighed before welding.

[0033] (3) Then the wire and alloy pull rod were placed vertically in a vertical high temperature tube furnace which had been maintained at a temperature of 1100°C, and a load of a total mass of 16 grams was loaded on the tail pull rod (the sum of the mass of the tail pull rod m and the applied load m1), thereby starting the atmospheric high temperature stress-rupture test.

[0034] (4) If the wire broke during the test, the time was recorded, and the whole piece of wire was taken out to observe the position number of the wire breakage to determine the material type and diameter. The time that had been recorded was the stress-rupture life of the material at 5 MPa and 1100°C.

[0035] (5) After the broken wire was cut off and sampled, the upper and lower wires were welded into a new whole piece of wire using a cold welding machine.

[0036] (6) The new whole piece of wire was placed in the furnace to continue the high temperature stress-rupture test, and steps (3), (4), and (5) were repeated until all the wires broke. The stress-rupture life of Pt, PtRh5, PtRh7, PtRh10, PtRh13 at 5 MPa and 1100°C was obtained by cumulative calculation.

[0037] Comparative Example 1

[0038] The high temperature stress-rupture life of Pt, PtRh5, PtRh7, PtRh10, PtRh13 at a tensile stress of 5 MPa and 1100°C was measured, including the following steps:

[0039] (1) Cut 5 pieces of Pt, PtRh5, PtRh7, PtRh10, PtRh13 wire with diameter φ0.2 mm and length L of 30 mm, respectively.

[0040] (2) Weld the head of the Pt wire to the upper pull rod of PtRh6 alloy with diameter of 2 mm, and weld the tail of the Pt wire to the lower pull rod of PtRh6 alloy with diameter of 2 mm. Before welding, weigh the mass m of the lower pull rod of PtRh6 alloy.

[0041] (3) Then vertically place the Pt wire and the alloy pull rod into the vertical high-temperature tube furnace which has been kept at a temperature of 1100℃, and load a total mass of 16 grams on the tail pull rod (the sum of the mass m of the tail pull rod and the applied load m1), so as to start the atmospheric high-temperature durability test, and record the time of wire fracture, which is the durability life of the material under the condition of 5 MPa and 1100℃.

[0042] (4) Perform atmospheric high-temperature durability test on PtRh5, PtRh7, PtRh10, and PtRh13 according to steps (2) and (3).

[0043] The high-temperature durability life of Pt, PtRh5, PtRh7, PtRh10, and PtRh13 tested in Example 1 under the condition of tensile stress of 5 MPa and 1100℃ is 150 hours, 200 hours, 300 hours, 400 hours, and 500 hours, respectively, which is consistent with the high-temperature durability life of Pt, PtRh5, PtRh7, PtRh10, and PtRh13 tested in Comparative Example 1 under the condition of tensile stress of 5 MPa and 1100℃.

[0044] Example 2

[0045] Measure the high-temperature durability life of PtRh10 under the condition of tensile stress of 5 MPa, 10 MPa, 15 MPa, and 20 MPa at 1150℃, including the following steps:

[0046] (1) Cut 4 pieces of PtRh10 wire with diameter of φ0.7 mm, φ0.5 mm, φ0.4 mm, and φ0.35 mm, and length L of 30 mm, respectively.

[0047] (2) Weld the 4 pieces of wire into one whole piece of wire according to the order from thick to thin using an argon gas protected cold welding machine, with the welding part being spherical, and sequentially numbered as L1, L2, L3, and L4. Weld the head of wire L1 to the upper pull rod of PtRh6 alloy with diameter of 2 mm, and weld the tail of wire L4 to the lower pull rod of PtRh6 alloy with diameter of 2 mm. Before welding, weigh the mass m of the lower pull rod of PtRh6 alloy.

[0048] (3) Next, the wire and alloy rod are vertically placed in a vertical high-temperature tube furnace which has been maintained at 1150°C, and a load of a total of 200 grams is applied to the tail rod (the sum of the mass of the tail rod m and the applied load ml), thereby starting the atmospheric high-temperature durability test.

[0049] (4) If the wire breaks during the test, the time is recorded, and the entire wire is removed to observe which section of the wire broke, and the material type and diameter are determined according to the position number, and the time recorded is the durability life of the material under the corresponding stress conditions at 1150°C.

[0050] (5) The broken wire is then cut off and sampled, and the wire above and below the wire is welded into a new whole wire using a cold welding machine.

[0051] (6) The wire is then placed in the furnace for continued high-temperature durability testing, and steps (3), (4), and (5) are repeated until all the wires break, and the durability life of PtRh10 at 1150°C under conditions of 5 MPa, 10 MPa, 15 MPa, and 20 MPa is obtained by cumulative calculation.

[0052] Comparative Example 2

[0053] The high-temperature durability life of PtRh10 at 1150°C under conditions of tensile stress of 5 MPa, 10 MPa, 15 MPa, and 20 MPa is measured, including the following steps:

[0054] (1) PtRh10 wires with diameters of φ0.7 mm, φ0.5 mm, φ0.4 mm, and φ0.35 mm and a length L of 30 mm are cut.

[0055] (2) The head of the PtRh10 wire with a diameter of φ0.7 mm is welded to a PtRh6 alloy upper rod with a diameter of 2 mm, and the tail of the PtRh10 wire is welded to a PtRh6 alloy lower rod with a diameter of 2 mm, and the mass of the PtRh6 alloy lower rod is weighed before welding.

[0056] (3) Next, the PtRh10 wire and alloy rod are vertically placed in a vertical high-temperature tube furnace which has been maintained at 1150°C, and a load of a total of 16 grams is applied to the tail rod (the sum of the mass of the tail rod m and the applied load ml), thereby starting the atmospheric high-temperature durability test, and the time at which the wire breaks is recorded, which is the durability life of the material at 5 MPa and 1150°C.

[0057] (4) PtRh10 with diameter of φ0.5 mm, φ0.4 mm, φ0.35 mm respectively are subjected to atmospheric high temperature durability test according to steps (2) and (3), and the high temperature durability life of PtRh10 at 1150°C under tensile stress of 10 MPa, 15 MPa, 20 MPa respectively is obtained.

[0058] The high temperature durability life of PtRh10 tested in Example 2 at 1150°C under tensile stress of 5 MPa, 10 MPa, 15 MPa, 20 MPa respectively is 300 hours, 200 hours, 160 hours, 60 hours respectively, which is consistent with the high temperature durability life of PtRh10 tested in Comparative Example 2 at 1150°C under tensile stress of 5 MPa, 10 MPa, 15 MPa, 20 MPa respectively.

[0059] Example 3

[0060] The high temperature durability life of PtRh10, Pt / ZrO2 at 1250°C under tensile stress of 5 MPa, 10 MPa, 15 MPa, 20 MPa respectively is measured, including the following steps:

[0061] (1) 4 pieces of PtRh10 wire with length L of 20 mm and diameter of φ0.7 mm, φ0.5 mm, φ0.4 mm, φ0.35 mm respectively, and 4 pieces of Pt / ZrO2 wire are cut respectively.

[0062] (2) The 8 pieces of wire are connected end to end in the order of diameter from thick to thin by using a cold welding machine with argon protection to form a whole piece of wire, the welding part is spherical, and is sequentially numbered as L1, L2, L3, L4, L5, L6, L7, L8, and then the head of the wire L1 is welded on the PtRh6 alloy pull rod with a diameter of 2 mm, and the tail of the wire L8 is welded on the PtRh6 alloy lower pull rod with a diameter of 2 mm, and the mass m of the PtRh6 alloy lower pull rod is weighed before welding.

[0063] (3) The wire and alloy pull rod are vertically placed in the vertical high temperature tube furnace which has been kept at 1250°C, and a load of 200 grams in mass is loaded on the tail pull rod (the sum of the mass m of the tail pull rod and the applied load m1), so as to start the atmospheric high temperature durability test.

[0064] (4) If the wire breaks during the test, the time is recorded, and the whole piece of wire is taken out to observe which segment of the wire breaks, and the material type and diameter are determined according to the position number, and the time recorded is the durability life of the material under the corresponding stress condition at 1250°C.

[0065] (5) After the broken wire is cut off and sampled, the wire above and below the wire is welded into a new whole wire by a cold welding machine.

[0066] (6) And put into the furnace to continue high temperature stress rupture test, repeat steps (3), (4), (5) until all the wires are broken, and the stress rupture life of the two platinum-based materials at 1250°C under the conditions of 5MPa, 10MPa, 15MPa and 20MPa can be obtained by cumulative calculation.

[0067] Comparative Example 3

[0068] The high temperature stress rupture life of PtRh10 and Pt / ZrO2 at 1250°C under the conditions of tensile stress of 5MPa, 10MPa, 15MPa and 20MPa was measured, including the following steps:

[0069] (1) Respectively cut 4 wires of PtRh10 and Pt / ZrO2 with a length of 20mm and a diameter of φ0.7mm, φ0.5mm, φ0.4mm and φ0.35mm, respectively, a total of 8 wires.

[0070] (2) The head of the PtRh10 wire with a diameter of φ0.7mm was welded on the pull rod of the PtRh6 alloy with a diameter of 2mm, and the tail of the PtRh10 wire with a diameter of φ0.7mm was welded on the lower pull rod of the PtRh6 alloy, and the mass of the lower pull rod of the PtRh6 alloy was weighed before welding.

[0071] (3) Then the PtRh10 wire with a diameter of φ0.7mm and the alloy pull rod were vertically placed in the vertical high temperature tube furnace which had been kept at 1250°C, and a load of 16 grams was loaded on the tail pull rod (the sum of the mass m of the tail pull rod and the applied load m1), thereby starting the atmospheric high temperature stress rupture test, and the time of wire fracture was recorded, which was the stress rupture life of the material at 5MPa and 1250°C.

[0072] (4) The PtRh10 wires with diameters of φ0.5mm, φ0.4mm and φ0.35mm, and the Pt / ZrO2 wires with diameters of φ0.7mm, φ0.5mm, φ0.4mm and φ0.35mm were subjected to atmospheric high temperature stress rupture test according to steps (2) and (3), respectively, to obtain the high temperature stress rupture life of the PtRh10 wire and the Pt / ZrO2 wire at 1250°C under the conditions of tensile stress of 5MPa, 10MPa, 15MPa and 20MPa, respectively.

[0073] The high temperature stress-rupture life of PtRh10 tested in Example 3 at 1250℃ under tensile stress of 5MPa, 10MPa, 15MPa and 20MPa is 200 hours, 100 hours, 80 hours and 40 hours respectively, and the high temperature stress-rupture life of Pt / ZrO2 wire at 1250℃ under tensile stress of 5MPa, 10MPa, 15MPa and 20MPa is 800 hours, 600 hours, 500 hours and 300 hours respectively, which is consistent with the high temperature stress-rupture life of PtRh10 and Pt / ZrO2 wire tested in Comparative Example 3 at 1250℃ under tensile stress of 5MPa, 10MPa, 15MPa and 20MPa respectively.

[0074] Example 4

[0075] The high temperature stress-rupture life of Pt, PtRh5, PtIr5, PtPd5 and PtAu5 at 20MPa tensile stress and 1300℃ is measured, including the following steps:

[0076] (1) Cut 5 pieces of Pt, PtRh5, PtIr5, PtPd5 and PtAu5 wire with diameter of φ0.43mm and length of 30mm respectively.

[0077] (2) Weld the 5 pieces of wire into one whole piece of wire in the order of Pt, PtRh5, PtIr5, PtPd5 and PtAu5 using a cold welding machine under argon protection, with the welding part being spherical, and sequentially numbered as L1, L2, L3, L4 and L5. Then, the head of wire L1 is welded on a 2mm diameter PtRh6 alloy upper pull rod, and the tail of wire L5 is welded on a 2mm diameter PtRh6 alloy lower pull rod. The mass of the PtRh6 alloy lower pull rod is weighed before welding.

[0078] (3) Then, the wire and PtRh6 alloy rod are vertically placed in a vertical high temperature tube furnace which has been kept at 1300℃, and a load of 300 grams (which is the sum of the mass of the tail pull rod m and the applied load m1) is loaded on the tail pull rod, so as to start the atmospheric high temperature stress-rupture test.

[0079] (4) If the wire breaks during the test, the time is recorded, and the whole wire is taken out to observe which section of the wire breaks, and the material type and diameter are determined according to the position number. The time recorded is the stress-rupture life of the material at 20MPa and 1300℃.

[0080] (5) Then, the broken wire is cut off and sampled, and the upper and lower wires are welded into a new whole piece of wire using a cold welding machine.

[0081] (6) and put into the furnace to continue the high temperature durability test, repeat steps (3), (4), (5) until all the wire is broken, and the durability life of several platinum-based materials at 20 MPa, 1300 °C can be obtained by cumulative calculation.

[0082] Comparative Example 4

[0083] The high temperature durability life of Pt, PtRh5, PtIr5, PtPd5, PtAu5 at 20 MPa, 1300 °C was measured respectively, including the following steps:

[0084] (1) Pt, PtRh5, PtIr5, PtPd5, PtAu5 wire with diameter φ0.43 mm and length L of 30 mm was cut respectively.

[0085] (2) The head of Pt wire was welded on the PtRh6 alloy pull rod with diameter of 2 mm, and the tail of Pt wire was welded on the PtRh6 alloy lower pull rod with diameter of 2 mm. The mass m of the lower pull rod was weighed before welding.

[0086] (3) Then the Pt wire and alloy pull rod were vertically placed in the vertical high temperature tube furnace which had been kept at 1300 °C, and a load of 16 grams was loaded on the tail pull rod (the sum of the mass m of the tail pull rod and the load m1), thereby starting the atmospheric high temperature durability test, and the time of wire fracture was recorded, which was the durability life of the material at 20 MPa, 1300 °C.

[0087] (4) PtRh5, PtIr5, PtPd5, PtAu5 with diameter φ0.43 mm were subjected to atmospheric high temperature durability test according to steps (2) and (3) respectively.

[0088] The high temperature durability life of Pt, PtRh5, PtIr5, PtPd5, PtAu5 tested in Example 4 at 20 MPa, 1300 °C was 5 hours, 20 hours, 60 hours, 15 hours, and 30 hours respectively, which was consistent with the high temperature durability life of Pt, PtRh5, PtIr5, PtPd5, PtAu5 tested in Comparative Example 4 at 20 MPa, 1300 °C.

[0089] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the present application and are not a limitation on the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method of high-throughput measurement of high-temperature stress rupture life of platinum-based materials, characterized in that, It comprises the following steps: (1) setting different platinum-based material samples to the same length, same diameter or different samples; (2) according to the head-to-tail connection, welding each platinum-based material sample of the same length into a complete platinum-based material sample A and numbering each platinum-based material sample, then welding the head and tail of the platinum-based material sample A on the platinum alloy pull rod; each platinum-based material sample is welded in the order of head-to-tail connection according to the diameter from large to small; the welding is spherical welding; (3) then put it into a high temperature environment, apply a load on the platinum alloy pull rod at the tail, then start the high temperature durability test; record the number, fracture time and diameter of the platinum-based material sample that breaks in the test, calculate the corresponding stress through the diameter, and record the time as the durability life of the platinum-based material sample under the corresponding stress; (4) remove the broken platinum-based material sample, then weld the adjacent upper and lower platinum-based material samples of the broken platinum-based material sample into a new complete platinum-based material sample B; (5) repeat steps (3) and (4) until all platinum-based material samples are broken, and the durability life of each platinum-based material sample under the corresponding stress is obtained by cumulative calculation.

2. The method of claim 1, wherein the high temperature stress rupture life of the platinum group material is measured at a temperature of 800°C to 1200°C. The platinum-based material sample is a sample with consistent cross section.

3. The method of claim 1, wherein the method is performed at a temperature of 800- 1200°C. The platinum-based material sample is a wire, a sheet, a strip or a foil.

4. The method of claim 1, wherein the platinum-based material is selected from the group consisting of platinum, palladium, rhodium, ruthenium, iridium, osmium, rhenium, and alloys thereof. The number of platinum-based material samples is one or more.

5. The method for high-throughput measurement of high-temperature life of platinum-based materials according to claim 1, characterized in that, Each platinum-based material sample is welded by a cold welding machine with argon protection.

6. The method of claim 1, wherein the platinum-based material is selected from the group consisting of platinum, palladium, rhodium, ruthenium, iridium, osmium, rhenium, and combinations thereof. In the step (3), the corresponding stress is calculated by formula: σ=F / A, wherein F is the external force applied on the material, i.e. the sum of the applied load and the mass of the tail platinum alloy pull rod, in units of N, and A is the cross-sectional area of the material, in units of m 2 .

7. The method of claim 1, wherein the platinum-based material is selected from the group consisting of platinum, palladium, rhodium, ruthenium, iridium, osmium, rhenium, and combinations thereof. The atmosphere of the high temperature durability test is air.

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