Dynamic corrosion test device and method

Abstract

The invention belongs to the field of dynamic corrosion of metal materials, and discloses a dynamic corrosion test device and method. The device comprises power supply equipment, a heating furnace and a corrosive medium container, the power supply equipment is arranged outside the heating furnace; the corrosive medium container is arranged in the heating furnace; the heating furnace is provided with temperature control equipment; the temperature control equipment is used for dynamically stabilizing the temperature of the molten corrosion medium arranged in the corrosion medium container, the temperature of the alloy sample arranged in the corrosion medium container and connected with the positive electrode of the power supply equipment and the temperature of the alloy sample arranged in the corrosion medium container and connected with the negative electrode of the power supply equipment. According to the invention, the dynamic corrosion test of the metal material in different current densities, temperatures and corrosion media in a wide temperature range can be realized.

Description

Technical Field

[0001] The invention belongs to the field of dynamic corrosion of metal materials, and more specifically, relates to a dynamic corrosion test device and method. Background Art

[0002] Corrosion-resistant alloys, represented by nickel-based alloys, are widely used in the manufacture of core components of nuclear power plants and key structures of chemical processing. These alloys are mostly used in harsh environments such as high temperature, strong current, and molten corrosive media. The corrosion performance of alloys is a key performance indicator for material selection in the nuclear power field.

[0003] At present, only a few scholars have studied the corrosion test of corrosion-resistant alloys. For example, Jen-Hsien Hsu et al. studied the corrosion behavior of In693 alloy in iron phosphate molten glass at 1000℃-1190℃ (Jen-Hsien Hsu et al., 2013; Jen-Hsien Hsu et al., 2014); R. Halder et al. studied the corrosion behavior of In693 alloy in borate at 1000℃ (R. Halder et al., 2016).

[0004] The above existing studies are mostly conducted under static conditions, only considering the effects of corrosive media and high temperature, and lacking an alloy corrosion test device and method under dynamic conditions such as power supply and flow. Therefore, the present invention designs a dynamic corrosion test device and method. Summary of the invention

[0005] The purpose of the present invention is to provide a dynamic corrosion test device and method to address the deficiencies of the prior art. The present invention can realize dynamic corrosion tests of metal materials in different current densities, temperatures, and corrosive media within a wide temperature range.

[0006] In order to achieve the above-mentioned object, the present invention provides a dynamic corrosion test device on one hand, the device comprises a power supply device, a heating furnace and a corrosive medium container;

[0007] The power supply device is arranged outside the heating furnace;

[0008] The corrosive medium container is arranged inside the heating furnace;

[0009] The heating furnace is provided with a temperature control device, which is used to achieve dynamic stability of the temperature of the molten corrosive medium arranged in the corrosive medium container, the temperature of the alloy sample arranged in the corrosive medium container and connected to the positive electrode of the power supply device, and the temperature of the alloy sample arranged in the corrosive medium container and connected to the negative electrode of the power supply device.

[0010] In the present invention, "dynamic stability of temperature" means that the temperature of the molten corrosive medium disposed in the corrosive medium container, the temperature of the alloy sample disposed in the corrosive medium container and connected to the positive electrode of the power supply device, and the temperature of the alloy sample disposed in the corrosive medium container and connected to the negative electrode of the power supply device are constant within the range of the test required temperature (900-1200°C).

[0011] According to the present invention, preferably, the corrosive medium container is a crucible, and the material and size of the crucible are determined according to the service environment of the alloy sample.

[0012] According to the present invention, preferably, the crucible is at least one of a chrome corundum crucible, a corundum crucible, a zirconium corundum crucible and a chrome zirconium corundum crucible.

[0013] According to the present invention, preferably, the dimensions of the crucible include: an inner diameter of 100-250 mm and a height of 100-200 mm; the crucible is provided with a crucible cover, and the dimensions of the crucible cover are 150-300 mm in diameter and 5-10 mm in thickness.

[0014] According to the present invention, preferably, the device further comprises a metallographic microscope and a scanning electron microscope.

[0015] In the present invention, according to the dynamic corrosion test device of the present invention, the size of the alloy sample is designed and the alloy sample is processed. According to the present invention, preferably, the alloy sample is in a sheet shape, and more preferably, the length of the alloy sample is 200-400 mm, the width is 30-90 mm, and the thickness is 5-10 mm.

[0016] In the present invention, the heating furnace is provided with a cover, and the power line passes through the cover of the heating furnace, so that the alloy sample connected to the positive electrode of the power device and the alloy sample connected to the negative electrode of the power device are inserted into the molten corrosive medium. The gas environment in the heating furnace is air.

[0017] Another aspect of the present invention provides a dynamic corrosion test method, which is carried out in the device and comprises the following steps:

[0018] S1: Measure and record the thickness of the alloy sample connected to the positive electrode of the power supply device and the thickness of the alloy sample connected to the negative electrode of the power supply device;

[0019] S2: heating the corrosive medium in a heating furnace to the temperature required for the test and keeping the temperature constant to obtain a molten corrosive medium;

[0020] S3: inserting the alloy sample connected to the positive electrode of the power supply device and the alloy sample connected to the negative electrode of the power supply device into the molten corrosive medium, and turning on the power supply;

[0021] S4: When the temperature of the alloy sample reaches the required temperature for the test, timing is started; when the timing reaches a preset time, the post-test sample is taken out to measure the thickness of the surface corrosion layer of the post-test sample and analyze the element composition of the surface corrosion products of the post-test sample.

[0022] According to the present invention, preferably, before step S1, the method further comprises mechanically grinding and polishing the alloy sample to a mirror surface. As a preferred solution, the alloy sample is mechanically ground on 600#, 800#, 1000#, 1200#, and 2000# water-abrasive sandpaper, respectively, and then polished with a polishing paste with a particle size of 2.5 μm to a mirror surface.

[0023] According to the present invention, preferably, the alloy sample is In693 alloy and / or Inconel 758 alloy.

[0024] In the present invention, the service environment of the alloy sample includes the type and specific material composition of the corrosive medium. Therefore, the present invention selects the corrosive medium according to the service environment requirements of the alloy sample. According to the present invention, preferably, the corrosive medium is at least one of borosilicate glass, iron phosphate glass and aluminosilicate.

[0025] According to the present invention, preferably, the power source is an AC power source, and the current density of different intensities is achieved inside the sample by adjusting the AC voltage, and the current density is 0.5-2.0A / cm 2 , the AC voltage is 200-400V and the frequency is 40-80Hz.

[0026] According to the present invention, preferably, the temperature required for the test is 900-1200°C.

[0027] According to the present invention, preferably, the preset time is 0.5-42 days.

[0028] In the present invention, according to the current requirements of the alloy dynamic corrosion test method of the present invention, the relevant parameters of the AC power supply, including current density, AC voltage, and frequency, are designed; according to the temperature requirements required for the test, the heating power, resistance wire, and temperature measuring thermocouple of the heating furnace are designed.

[0029] According to the present invention, preferably, the thickness of the surface corrosion layer of the sample after the test is measured using a metallographic microscope; the method also includes calculating the average annual corrosion rate of the alloy sample through the thickness of the surface corrosion layer of the sample after the test.

[0030] In the present invention, the influence of residual corrosive medium on the surface can be eliminated by using a metallographic microscope. After the test sample is taken out of the device, the molten corrosive medium on the surface of the test sample is removed to prepare a microstructure observation sample. After mechanical grinding and polishing, the microstructure observation sample is observed under a metallographic microscope and the thickness of the corrosion layer is measured to calculate the average annual corrosion rate of the alloy.

[0031] According to the present invention, preferably, the elemental composition analysis of the surface corrosion products of the test sample after the test is performed using a scanning electron microscope.

[0032] The beneficial effects of the technical solution of the present invention are as follows:

[0033] (1) The dynamic corrosion test device and test method of the present invention can adjust the loading current, voltage and frequency to test the corrosion resistance of alloy samples under different temperature, current density, time and corrosive medium conditions, and quantify the corrosion rate and analyze the elemental composition of corrosion products.

[0034] (2) After the alloy samples were subjected to dynamic corrosion tests under different temperature, current density, time and corrosive medium conditions on the device of the present invention, the present invention also accurately measured the thickness of the corrosion layer of the alloy samples by optical microscopy, and characterized the corrosion products by scanning electron microscopy.

[0035] (3) The present invention can ensure that the temperature of the corrosive medium is constant during the dynamic corrosion test process by coordinated regulation of the heating furnace and the heating furnace temperature control equipment.

[0036] (4) The present invention can be applied to dynamic corrosion performance testing of corrosion-resistant alloys, with convenient operation, accurate control, reliable data and high efficiency.

[0037] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0039] Figure 1 A schematic diagram of a dynamic corrosion test device provided by the present invention is shown.

[0040] Figure 2 The results show that the In693 alloy of Example 1 of the present invention is heated to 1000°C and the current density is 1.0A / cm 2 Corrosion products from the dynamic corrosion behavior test under molten iron-phosphate glass conditions (SEM).

[0041] Figure 3 The results show that the In693 alloy of Example 2 of the present invention is 2 Corrosion products from the dynamic corrosion behavior test under molten iron phosphate glass conditions (SEM, 50μm).

[0042] The following are the descriptions of the reference numerals:

[0043] 1. Power supply equipment, 2. Alloy specimen, 3. Corrosive medium container, 4. Molten corrosive medium, 5. Heating furnace. DETAILED DESCRIPTION

[0044] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0045] Example 1

[0046] This embodiment provides a dynamic corrosion test device, such as Figure 1 As shown, the device comprises a power supply device 1, a heating furnace 5 and a corrosive medium container 3;

[0047] The power supply device 1 is arranged outside the heating furnace 5; the heating furnace 5 is a resistance furnace.

[0048] The corrosive medium container 3 is arranged inside the heating furnace 5; according to the service environment of the In693 alloy sample, the corrosive medium container 3 is a chrome corundum crucible, and the dimensions of the crucible include: an inner diameter of 150 mm and a height of 150 mm; the crucible is provided with a crucible cover, and the crucible cover has a diameter of 200 mm and a thickness of 3 mm.

[0049] The heating furnace is provided with a temperature control device, which is used to achieve dynamic stability of the temperature of the molten corrosive medium 4 arranged in the corrosive medium container 3, the temperature of the alloy sample 2 arranged in the corrosive medium container and connected to the positive electrode of the power supply device, and the temperature of the alloy sample 2 arranged in the corrosive medium container and connected to the negative electrode of the power supply device.

[0050] Alloy sample 2 is In693 alloy in sheet form. Alloy sample 2 has a length of 300 mm, a width of 34 mm, and a thickness of 8.4 mm.

[0051] The apparatus further includes a metallographic microscope (not shown) and a scanning electron microscope (not shown).

[0052] This embodiment also provides a dynamic corrosion test method for In693 alloy at a temperature of 1000°C and a current density of 1.0 A / cm 2 The dynamic corrosion behavior test under molten iron phosphate glass conditions includes the following steps:

[0053] S1: Process two alloy samples to obtain two alloy samples with a length of 300 mm, a width of 34 mm, and a thickness of 8.4 mm; mechanically grind the two alloy samples on 600#, 800#, 1000#, 1200#, and 2000# water-abrasive sandpaper, respectively, and then polish them with a polishing paste with a particle size of 2.5 μm to a mirror surface; then clamp the two alloy samples to the positive and negative electrodes of the power supply; measure and record the thickness of the alloy sample connected to the positive electrode of the power supply device and the thickness of the alloy sample connected to the negative electrode of the power supply device;

[0054] S2: pouring molten iron phosphate glass into a chrome corundum spinel crucible, and then heating the corrosive medium to 1000° C. in a heating furnace and keeping the temperature for 1 hour to obtain molten iron phosphate glass;

[0055] S3: insert the alloy sample connected to the positive electrode of the power supply device and the alloy sample connected to the negative electrode of the power supply device into the molten corrosive medium, turn on the power supply, and the AC voltage is 380V and the current density is 1.0A / cm 2 , frequency is 50Hz;

[0056] S4: When the temperature of the alloy sample reaches 1000°C, start timing; after 7 days, take out the post-test sample; after taking out the post-test sample from the device, remove the molten corrosive medium on the surface of the post-test sample and prepare a microstructure observation sample. After mechanical grinding and polishing, the microstructure observation sample is observed under a metallographic microscope and the thickness of the corrosion layer is measured, the average annual corrosion rate of the alloy is calculated, and the elemental composition analysis of the surface corrosion products (oxidation products) of the post-test sample is performed using a scanning electron microscope.

[0057] The results show that In693 alloy has a 2 The average annual corrosion rate under current is 1.1 mm / year; Figure 2 As shown, the corrosion product after dynamic corrosion is Cr 2 O 3 and Al 2 O 3 .

[0058] Example 2

[0059] This embodiment provides a dynamic corrosion test device. The device of this embodiment is different from that of Embodiment 1 only in that:

[0060] The corrosive medium container is a corundum crucible;

[0061] This embodiment also provides a dynamic corrosion test method for In693 alloy at a temperature of 1150°C and a current density of 2.0 A / cm 2 The dynamic corrosion behavior test under molten iron phosphate glass conditions includes the following steps:

[0062] S1: the same as step S1 of embodiment 1;

[0063] S2: pouring the iron phosphate glass into a corundum crucible, and then heating the corrosive medium to 1150° C. in a heating furnace and keeping the temperature for 1 hour to obtain molten iron phosphate glass;

[0064] S3: insert the alloy sample connected to the positive electrode of the power supply device and the alloy sample connected to the negative electrode of the power supply device into the molten corrosive medium, turn on the power supply, and the AC voltage is 380V and the current density is 2.0A / cm 2 , frequency is 50Hz;

[0065] S4: When the temperature of the alloy sample reaches 1050°C, start timing; after 7 days, take out the post-test sample; after taking out the post-test sample from the device, remove the molten corrosive medium on the surface of the post-test sample and prepare a microstructure observation sample. After mechanical grinding and polishing, the microstructure observation sample is observed under a metallographic microscope and the thickness of the corrosion layer is measured, the average annual corrosion rate of the alloy is calculated, and the elemental composition analysis of the surface corrosion products (oxidation products) of the post-test sample is performed using a scanning electron microscope.

[0066] The results show that In693 alloy has a 2 The average annual corrosion rate under current is 2.06 mm / year; Figure 3 As shown, the corrosion product after dynamic corrosion is Cr 2 O 3 and Al 2 O 3 .

[0067] The results of the above embodiments show that the present invention can realize dynamic corrosion test of alloy samples, evaluate the corrosion rate of alloys under different dynamic corrosion parameters, and characterize the corrosion products after dynamic corrosion. The advantages of the present invention are that the dynamic corrosion test device can realize dynamic corrosion test at different temperatures, current densities, corrosive media and time; it can accurately measure the thickness of the corrosion layer and analyze the elemental composition of the corrosion products.

[0068] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A dynamic corrosion test device, characterized in that: The device comprises a power supply device, a heating furnace and a corrosive medium container; The power supply device is arranged outside the heating furnace; The corrosive medium container is arranged inside the heating furnace; The heating furnace is provided with a temperature control device, which is used to achieve dynamic stability of the temperature of the molten corrosive medium arranged in the corrosive medium container, the temperature of the alloy sample arranged in the corrosive medium container and connected to the positive electrode of the power supply device, and the temperature of the alloy sample arranged in the corrosive medium container and connected to the negative electrode of the power supply device.

2. The dynamic corrosion testing device according to claim 1, wherein: The corrosive medium container is a crucible, and the material and size of the crucible are determined according to the service environment of the alloy sample; Preferably, the crucible is at least one of a chrome corundum crucible, a corundum crucible, a zirconium corundum crucible and a chrome zirconium corundum crucible; Preferably, the dimensions of the crucible include: an inner diameter of 100-250 mm and a height of 100-200 mm; the crucible is provided with a crucible cover, and the dimensions of the crucible cover are 150-300 mm in diameter and 5-10 mm in thickness.

3. The dynamic corrosion testing device according to claim 1, wherein: The device also includes a metallographic microscope and a scanning electron microscope.

4. The dynamic corrosion testing device according to claim 1, wherein: The alloy sample is in sheet form. Preferably, the alloy sample has a length of 200-400 mm, a width of 30-90 mm, and a thickness of 5-10 mm.

5. A dynamic corrosion test method, characterized in that: The method is carried out in the device according to any one of claims 1 to 4, comprising the following steps: S1: Measure and record the thickness of the alloy sample connected to the positive electrode of the power supply device and the thickness of the alloy sample connected to the negative electrode of the power supply device; S2: heating the corrosive medium in a heating furnace to the temperature required for the test and keeping the temperature constant to obtain a molten corrosive medium; S3: inserting the alloy sample connected to the positive electrode of the power supply device and the alloy sample connected to the negative electrode of the power supply device into the molten corrosive medium, and turning on the power supply; S4: When the temperature of the alloy sample reaches the required temperature for the test, timing is started; when the timing reaches a preset time, the post-test sample is taken out to measure the thickness of the surface corrosion layer of the post-test sample and analyze the element composition of the surface corrosion products of the post-test sample.

6. The dynamic corrosion test method according to claim 5, wherein: Before step S1, the method further comprises performing mechanical grinding and polishing on the alloy sample; The alloy sample is In693 alloy and / or Inconel 758 alloy; The corrosive medium is at least one of borosilicate glass, iron phosphate glass and aluminosilicate.

7. The dynamic corrosion test method according to claim 5, wherein: The power source is an AC power source with a current density of 0.5-2.0A / cm 2 , the AC voltage is 220-400V and the frequency is 40-80Hz.

8. The dynamic corrosion test method according to claim 5, wherein: The temperature required for the test is 900-1200°C.

9. The dynamic corrosion test method according to claim 5, wherein: The preset time is 0.5-42 days.

10. The dynamic corrosion test method according to claim 5, wherein: The thickness of the surface corrosion layer of the sample after the test is measured using a metallographic microscope; the method also includes calculating the average annual corrosion rate of the alloy sample based on the thickness of the surface corrosion layer of the sample after the test; The elemental composition analysis of the surface corrosion products of the test specimens was performed using a scanning electron microscope.

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