Method and device for testing degradation rate of medical magnesium metal

Abstract

The invention discloses a method and a device for testing the degradation rate of medical magnesium metal, and belongs to the technical field of medical materials. In the method for testing the degradation rate of the medical magnesium metal, provided by the invention, the pretreated medical magnesium metal is soaked in a closed container containing corrosive liquid by combining with the device for testing the degradation rate of the medical magnesium metal, and the system pressure in the soaking process is kept to be less than or equal to 5kPa by utilizing a vacuum pump; hydrogen generated in the magnesium metal corrosion process can be prevented from being adhered to the testing device, so that the reliability and the stability of the testing method are remarkably improved; in addition, according to the method for testing the degradation rate of the medical magnesium metal, the size of the degradation surface area of the medical magnesium metal in the soaking process is obtained through an optical microscope, and early monitoring of degradation of the medical magnesium metal can be achieved. In addition, the method for testing the degradation rate of the medical magnesium metal, provided by the invention, is simple to operate and simple in data processing, and can be beneficial to practical application.

Description

Technical Field

[0001] The invention belongs to the field of medical technology, and in particular relates to a testing method and a testing device for the degradation rate of medical magnesium metal. Background Art

[0002] Medical magnesium and magnesium alloys have broad application prospects in the fields of orthopedics and cardiovascular implant materials due to their good biocompatibility and degradability. In practical applications, the degradation rate of different magnesium alloys will be affected by their microstructure, impurity element content and the environment in which they are located. For example, studies have shown that an increase in the content of impurity elements such as Fe, Ni, Cu, etc. will significantly reduce the degradation rate of magnesium alloys. In addition, magnesium alloys also perform differently in different degradation media. For example, in concentrated NaCl solution, the intrinsic degradation rate of high-purity magnesium is 0.3 mm / a. The degradation rate of magnesium alloys is one of the important considerations for its use as a medical material. In order to accurately evaluate the degradation performance of medical magnesium alloys, a variety of degradation rate test methods are usually used.

[0003] The first method is the weight loss method, which is a common method for measuring the degradation rate of magnesium alloys. The degradation rate is calculated by weighing the mass change of the sample in the degradation medium. This method is simple and easy to use; however, it is a non-in-situ and non-continuous evaluation method, which means that it is impossible to monitor the degradation process of the material in real time, making it difficult to accurately predict the service stability of the material, which makes this method difficult to understand and reveal the degradation mechanism of the material; at the same time, the weight loss method requires multiple sets of parallel experiments, and the operation is cumbersome, the experimental cycle is long, and it is not suitable for rapid evaluation, which is an obvious disadvantage for application scenarios that require rapid results; in addition, the key to the weight loss method is to completely remove the degradation products without damaging the base metal. However, this is often difficult to achieve in actual operation. Some degradation products may adhere to the surface of the sample, resulting in stoichiometric uncertainty, which will also affect the final degradation rate calculation results. The second method is the hydrogen evolution method, which is also one of the commonly used degradation rate measurement methods. The degradation rate is calculated by collecting and measuring the amount and rate of hydrogen released during the degradation process. It is suitable for the study of the degradation behavior of magnesium and magnesium alloys. However, in the hydrogen evolution method, some hydrogen often adheres to the funnel wall and the burette, and hydrogen bubbles are easy to adhere to the sample surface; the electrolyte is rarely pre-saturated with hydrogen before the experiment, which will lead to the underestimation of the hydrogen evolution rate. The third method is the solution method. According to the anodic reaction process of magnesium degradation, as the magnesium metal dissolves, the change in magnesium ion concentration can be used to evaluate its degradation rate; however, in the solution method test, due to the low solubility of magnesium hydroxide, the degradation product of magnesium, most of the magnesium ions may still be stored in the precipitated degradation products, so the amount of magnesium ions produced by magnesium dissolution may be underestimated. The fourth method is the electrochemical impedance spectroscopy (EIS) method, which evaluates the degradation behavior by analyzing the impedance spectrum of the degradation electrode, but its accuracy and reliability need further research, especially the need to accurately understand the Stern-Geary coefficient B and the resistance value extracted from the EIS measurement; in addition, this method is short-term and destructive, and has extremely high requirements for test equipment and environment, and it is difficult to achieve an ideal state. The fifth method is the polarization curve method, which can draw a polarization curve by measuring the current density of the degradation electrode at different potentials, and estimate the degradation rate by Tafel extrapolation; this method can provide important information about the degradation kinetics, but it also requires precise experimental conditions and data processing.

[0004] Therefore, there is still a lack of in-situ, intuitive, sustainable, easy-to-operate and data-processing testing methods for the degradation rate of magnesium metal. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method and a device for testing the degradation rate of medical magnesium metal which can be in situ, intuitive, sustainable, simple to operate and process data, and has excellent stability of the testing method.

[0006] To achieve the above object, in a first aspect of the present invention, the present invention provides a method for testing the degradation rate of medical magnesium metal, the testing method comprising the following steps:

[0007] (1) immersing the pretreated medical magnesium metal in a corrosive liquid, and obtaining the degradation surface area of ​​the medical magnesium metal and the ratio of the degradation surface area to the total surface area during the immersion process;

[0008] (2) After the immersion is completed, the medical magnesium metal is taken out and post-processed to obtain the average degradation depth of the medical magnesium metal and calculate the average degradation rate of the medical magnesium metal;

[0009] In the step (1), the system pressure is ≤5 kPa during the immersion process.

[0010] In the test method for the degradation rate of medical magnesium metal provided by the present invention, by immersing the pretreated medical magnesium metal in an aggressive liquid and maintaining the system pressure ≤5kPa during the immersion process, the hydrogen generated during the corrosion process of the medical magnesium metal can be prevented from adhering to the test device, thereby significantly improving the reliability and stability of the test method; and the test method for the degradation rate of medical magnesium metal provided by the present invention can achieve early monitoring of the degradation of medical magnesium metal by obtaining the size of the degradation surface area of ​​the medical magnesium metal during the immersion process and the proportion of the degradation surface area to the total surface area. In addition, the test method for the degradation rate of medical magnesium metal provided by the present invention is simple to operate and simple to process data, which can be beneficial to practical applications.

[0011] As a preferred embodiment of the test method of the present invention, the average degradation rate of medical magnesium metal v = (S 降解 *h) / (S 总 *t);

[0012] Among them, S 降解 mm 2 Degradation surface area for medical magnesium metal;

[0013] h mm is the average degradation depth of medical magnesium metal;

[0014] S 总 mm 2 is the total surface area of ​​medical magnesium metal;

[0015] t year is the immersion time of medical magnesium metal.

[0016] As a preferred embodiment of the testing method of the present invention, the corrosive liquid includes any one of physiological saline, phosphate buffered saline, simulated body fluid, and Hank's solution.

[0017] As a preferred embodiment of the testing method of the present invention, the medical magnesium metal includes pure magnesium or magnesium alloy.

[0018] As a preferred embodiment of the test method of the present invention, the immersion temperature is 37±0.5°C.

[0019] The preferred immersion temperature of the present invention is 37±0.5° C., which can better reflect the degradation rate of medical magnesium metal in the human body, thereby providing an important experimental basis for predicting the degradation behavior of magnesium metal in the in vivo environment.

[0020] Preferably, the soaking time is 0.2-1h.

[0021] The preferred immersion time of the present invention is 0.2-1h, which can better realize the early degradation monitoring of medical magnesium metal, and within the above immersion time range, the stability of the test method is excellent.

[0022] As a preferred embodiment of the testing method of the present invention, the pretreatment is grinding and polishing the medical magnesium metal.

[0023] Preferably, the grinding and polishing is performed by sequentially using 600 mesh, 1000 mesh, 2000 mesh, and 5000 mesh sandpaper.

[0024] Grinding and polishing the medical magnesium metal for pretreatment can effectively remove the oxide scale and impurities on the surface of the medical magnesium metal, so that the degradation rate can better reflect the degradation rate of the medical magnesium metal itself.

[0025] As a preferred embodiment of the testing method of the present invention, the post-treatment is to cold-mount the medical magnesium metal after immersion, and then grind and polish it.

[0026] Preferably, the cold mounting is performed using acrylic powder and a curing agent. Specifically, the cold mounting comprises: mixing the metallographic acrylic resin powder and the curing agent in a weight ratio of 1:0.8, stirring slowly to avoid the generation of bubbles, and casting and filling the mold after the metallographic acrylic resin powder is completely dissolved.

[0027] Preferably, the grinding and polishing is performed using a grinding and polishing machine.

[0028] In the second aspect of the present invention, the present invention provides a testing device for the degradation rate of medical magnesium metal, the testing device comprising a closed container and a vacuum pump, a water inlet pump, a water outlet pump and an optical microscope connected to the closed container, and a sample stage is arranged in the closed container.

[0029] As a preferred embodiment of the testing device of the present invention, the testing device further comprises a water inlet trough and a water outlet trough, the water inlet trough is connected to the sealed container via a water inlet pump, and the water outlet trough is connected to the sealed container via a water outlet pump.

[0030] As a preferred embodiment of the testing device of the present invention, the testing device further includes a heating device.

[0031] Preferably, the heating device comprises an oil bath or a water bath.

[0032] As a preferred embodiment of the testing device of the present invention, the vacuum pump and the sealed container are connected via an air conduit, and a first control valve is provided on the air conduit.

[0033] As a preferred embodiment of the testing device of the present invention, a second control valve is also provided on the closed container.

[0034] As a preferred embodiment of the testing device of the present invention, the optical microscope is connected to an optical microscope screen and a mouse controller, and a data storage interface is also provided on the optical microscope.

[0035] As a preferred embodiment of the testing device of the present invention, a third control valve is further provided in the water inlet pump and the sealed container.

[0036] As a preferred embodiment of the testing device of the present invention, a fourth control valve is further provided in the water outlet pump and the sealed container.

[0037] As a preferred embodiment of the testing device of the present invention, the heating device further includes a thermometer.

[0038] In the third aspect of the present invention, the present invention provides the application of the test method for the degradation rate of medical magnesium metal in early real-time monitoring of the degradation of medical magnesium metal.

[0039] The test method for the degradation rate of medical magnesium metal provided by the present invention observes the degradation surface area of ​​medical magnesium metal through an optical microscope and compares it with the total surface area of ​​medical magnesium metal, so as to realize early degradation monitoring of medical magnesium metal.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] In the test method for the degradation rate of medical magnesium metal provided by the present invention, by combining the test device for the degradation rate of medical magnesium metal provided by the present invention, the pretreated medical magnesium metal is placed in a closed container containing a corrosive liquid for immersion, and a vacuum pump is used to maintain the system pressure ≤5kPa during the immersion process, which can avoid the hydrogen generated during the corrosion of the magnesium metal from adhering to the test device, thereby significantly improving the reliability and stability of the test method; and the test method for the degradation rate of medical magnesium metal provided by the present invention can achieve early monitoring of the degradation of medical magnesium metal by obtaining the size of the degradation surface area of ​​the medical magnesium metal during the immersion process and the proportion of the degradation surface area to the total surface area using an optical microscope. In addition, the test method for the degradation rate of medical magnesium metal provided by the present invention is simple to operate and simple to process data, which can be beneficial to practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Schematic diagram of the test device for the degradation rate of medical magnesium metal:

[0043] 1-vacuum pump, 2-air conduit, 3-first control valve, 4-data storage interface of optical microscope, 5-optical microscope, 6-second control valve, 7-optical microscope screen, 8-heating device, 9-thermometer, 10-water inlet pump, 11-third control valve, 12-water inlet tank, 13-sealed container, 14-sample stage, 15-fourth control valve, 16-water outlet pump, 17-water outlet tank, 18-mouse controller;

[0044] Figure 2 This is a diagram showing the surface results during the test of the degradation rate of medical magnesium metal monitored by an optical microscope in Example 2. DETAILED DESCRIPTION

[0045] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0046] Unless otherwise specified, the reagents, methods and equipment used in the present invention are all conventional reagents, methods and equipment in the art; and unless otherwise specified, the raw materials used in parallel experiments are from the same batch of raw materials.

[0047] Example 1

[0048] An embodiment of the present invention provides a test device for the degradation rate of medical magnesium metal. The schematic diagram of the test device is as follows: Figure 1As shown, it includes a closed container 13 and a vacuum pump 1, a water inlet pump 10, a water outlet pump 16 and an optical microscope 5 connected to the closed container 13, a sample stage 14 is arranged in the closed container 13, the test device also includes a water inlet tank 12 and a water outlet tank 17, the water inlet tank 12 is connected to the closed container 13 through the water inlet pump 10, the water outlet tank 17 is connected to the closed container 13 through the water outlet pump 16, the test device also includes a heating device 8, and a thermometer 9 is arranged in the heating device 8;

[0049] The vacuum pump 1 and the sealed container 13 are connected via an air duct 2, and a first control valve 3 is provided on the air duct 2; a second control valve 6 is also provided on the sealed container 13; the optical microscope 5 is connected to an optical microscope screen 7 and a mouse controller 18, and a data storage interface 4 is also provided on the optical microscope 5; a third control valve 11 is also provided in the water inlet pump 10 and the sealed container 13; a fourth control valve 15 is also provided in the water outlet pump 16 and the sealed container 13.

[0050] In the test device for the degradation rate of medical magnesium metal provided by the embodiment of the present invention, the vacuum pump 1 can evacuate the closed container 13 to a vacuum degree below 5 kPa; the second control valve 6 is at the upper end of the closed container 13, and is a switch that controls the connection between the closed container and the atmosphere; the introduction of the optical microscope screen 7 can observe the image in real time, and realize the real-time monitoring of the early degradation of medical magnesium metal; the heating device 8 can ensure the constant temperature of the system, and the heating device can accommodate the closed container 13, the water inlet tank 12 and the water outlet tank 17.

[0051] Example 2

[0052] The embodiment of the present invention provides a method for testing the degradation rate of medical magnesium metal, and the testing method comprises the following steps:

[0053] (1) Cut the commercially available medical AZ31 magnesium alloy into pieces with a size of 1 mm*1 mm*0.5 mm as test samples, select three identical workpieces as parallel samples, select sandpapers of 600 mesh, 1000 mesh, 2000 mesh, and 5000 mesh in sequence, and use a grinder to polish the workpieces to remove surface oxide scale and impurities and expose the metallic luster, thereby obtaining the pretreated AZ31 magnesium alloy;

[0054] (2) The pretreated AZ31 magnesium alloy is placed on a sample table 14 in a sealed container 13, the water inlet pump 10 and the third control valve 11 are turned on, physiological saline is introduced from the water inlet tank 12 until the magnesium alloy is immersed and then closed, and then the first control valve 3 is opened, and the vacuum pump 1 is used to continuously evacuate the sealed container 13 until the vacuum degree above the physiological saline is ≤5 kPa and the vacuum degree is maintained at ≤5 kPa throughout the immersion process. During the immersion process, the temperature is controlled at 37±0.5°C by the heating device 8 and the thermometer 9, and the surface degradation of the magnesium alloy during the immersion process is obtained by an optical microscope 5. At the same time, the image recognition digitization software ImageJ is used to collect the area of ​​the reacted area on the surface of the magnesium alloy and the total surface area of ​​the magnesium alloy to obtain the degradation surface area S 降解 mm 2 and the total surface area S 总 mm 2 , calculate the degradation surface area ratio = degradation surface area S 降解 / Total surface area S 总 , realizing early monitoring of magnesium alloy degradation; the monitoring results are shown in the figure Figure 2 As shown;

[0055] (3) After soaking for 0.5 h, the magnesium alloy was taken out, and commercially available metallographic acrylic powder and curing agent were mixed in a mass ratio of 1:0.8, and stirred slowly to avoid the generation of bubbles. After the metallographic acrylic powder was completely dissolved, the magnesium alloy was cast into a mold, and then after sufficient curing, it was polished with sandpaper selected from 600 mesh, 1000 mesh, and 3000 mesh in sequence, and then polished with diamond polishing paste. Finally, the average degradation depth of the cross section was measured under a scanning electron microscope.

[0056] (4) Calculate the average degradation rate of magnesium alloy v = (S 降解 *h) / (S 总 *t), and the relative average deviation of the three samples tested in parallel is calculated; where t is the immersion time in years;

[0057] The calculation formulas for the relative average deviation of the average degradation rate and the percentage of degradation surface area are as follows: relative average deviation = average deviation / average value × 100%; the average deviation is the sum of the deviations between the measured values ​​of each sample and the average value divided by the number of parallel samples; the average value is the arithmetic mean of the measured values ​​of all parallel samples.

[0058] Example 3

[0059] The embodiment of the present invention provides a method for testing the degradation rate of medical magnesium metal. The only difference between the testing method and Example 2 is that the immersion time is 0.2 h.

[0060] Example 4

[0061] The embodiment of the present invention provides a method for testing the degradation rate of medical magnesium metal. The only difference between the testing method and Example 2 is that the immersion time is 1 hour.

[0062] Example 5

[0063] The embodiment of the present invention provides a method for testing the degradation rate of medical magnesium metal. The only difference between the testing method and Example 2 is that the immersion time is 0.1 h.

[0064] Example 6

[0065] The embodiment of the present invention provides a method for testing the degradation rate of medical magnesium metal. The only difference between the testing method and Example 2 is that the immersion time is 24 hours.

[0066] Example 7

[0067] The embodiment of the present invention provides a method for testing the degradation rate of medical magnesium metal. The only difference between the testing method and Example 2 is that the immersion time is 96 hours.

[0068] Example 8

[0069] The embodiment of the present invention provides a method for testing the degradation rate of medical magnesium metal. The only difference between the testing method and Example 2 is that the magnesium metal is high-purity magnesium (purity is 99.99%).

[0070] Example 9

[0071] The embodiment of the present invention provides a method for testing the degradation rate of medical magnesium metal. The only difference between the testing method and embodiment 2 is that simulated body fluid is used instead of normal saline.

[0072] Comparative Example 1

[0073] The comparative example of the present invention provides a test method for the degradation rate of medical magnesium metal. The only difference between the test method and Example 2 is that no vacuum is drawn in step (2).

[0074] Comparative Example 2

[0075] The comparative example of the present invention provides a method for testing the degradation rate of medical magnesium metal. The only difference between the test method and Example 2 is that in step (2), the vacuum pump 1 is used to evacuate the sealed container 13 until the vacuum degree above the physiological saline is ≤5 kPa, and then the vacuum is not continued.

[0076] Comparative Example 3

[0077] The comparative example of the present invention provides a method for testing the degradation rate of medical magnesium metal, specifically a hydrogen evolution method, and the testing method comprises the following steps:

[0078] (1) Cut the commercially available medical AZ31 magnesium alloy into pieces with a size of 1 mm*1 mm*0.5 mm as test samples, select three identical workpieces as parallel samples, select sandpapers of 600 mesh, 1000 mesh, 2000 mesh, and 5000 mesh in sequence, and use a grinder and polisher to polish the workpieces to remove surface oxide scale and impurities and expose the metallic luster, thereby obtaining the pretreated AZ31 magnesium alloy;

[0079] (2) Pour a certain amount of simulated body fluid into a container, place the AZ31 magnesium alloy in a beaker, invert the funnel-shaped cover to cover the entire workpiece, and connect a burette to the tail end of the cover; evacuate the inside of the burette and suck the simulated body fluid to the highest volume scale of the burette, and seal the sealable hose; set the immersion monitoring time to 0.5h, record the scale changes of the simulated body fluid level drop, and obtain the amount of hydrogen produced by the AZ31 magnesium alloy; then calculate the degradation rate of the magnesium alloy R = v*87.3 / (ρ*t), where R is the degradation rate (mm / a), v is the volume of hydrogen released (ml), t is the corrosion time (hours), and ρ is the density of magnesium metal (g / cm 3 ) and the relative average deviation of the three samples tested in parallel was calculated.

[0080] Comparative Example 4

[0081] The comparative example of the present invention provides a test method for the degradation rate of medical magnesium metal. The only difference between the test method and comparative example 3 is that the immersion time is 24 hours.

[0082] Comparative Example 5

[0083] The comparative example of the present invention provides a method for testing the degradation rate of medical magnesium metal, specifically a weight loss method, and the testing method comprises the following steps:

[0084] (1) Cut the commercially available medical AZ31 magnesium alloy into pieces with a size of 1 mm*1 mm*0.5 mm as test samples, select three identical workpieces as parallel samples, select sandpapers of 600 mesh, 1000 mesh, 2000 mesh, and 5000 mesh in sequence, and use a grinder and polisher to polish the workpieces to remove surface oxide scale and impurities and expose the metallic luster, thereby obtaining the pretreated AZ31 magnesium alloy;

[0085] (2) Pour a certain amount of physiological saline into a container, place the AZ31 magnesium alloy in a beaker, dry the sample before the immersion test and record the weight of the sample. After soaking in physiological saline for 0.5 h, soak the sample in chromic acid solution to remove corrosion products, then wash with deionized water and dry overnight. Record the weight of the sample again. Finally, calculate the average degradation rate according to ASTM G1-03, and calculate the relative average deviation of the three samples tested in parallel.

[0086] Comparative Example 6

[0087] The comparative example of the present invention provides a test method for the degradation rate of medical magnesium metal. The only difference between the test method and comparative example 5 is that the immersion time is 24 hours.

[0088] Effect example

[0089] The effect example of the present invention records the average degradation rate of magnesium metal monitored by Examples 2-9 and Comparative Examples 1-6 and the relative average deviation of three parallel samples. The obtained results are shown in Table 1;

[0090] Table 1

[0091]

[0092]

[0093] It can be seen from Table 1 that when the test device and the test method provided by the present invention are used to test the average degradation rate of medical magnesium metal, the test results obtained are highly stable, and the relative average deviation of the average degradation rate is below 8.8%. In the early monitoring, the relative average deviation of the degradation surface area ratio is below 7.8%;

[0094] It can be seen from Example 2 and Comparative Examples 1-2 that when no vacuum is drawn during the test or the vacuum environment during the immersion process is not maintained, the average degradation rate obtained decreases slightly, and the average degradation rate relative to the average deviation also shows a significant increasing trend; at the same time, in the early monitoring, the degradation surface area relative to the average deviation also shows a certain increasing trend;

[0095] It can be seen from Example 9 and Comparative Examples 3 and 4 that when the hydrogen evolution method is used for testing, the degradation rate obtained is low. This is because the amount of hydrogen generated in the early reaction (Comparative Example 3) is very small, hidden between the loose degradation product layers, and no large bubbles are formed to leave the workpiece surface, so it is difficult to collect hydrogen and the degradation rate of the magnesium alloy cannot be evaluated. In the middle and late stages of the degradation detection (Comparative Example 4), it can be observed that some bubbles adhere to the workpiece surface, which will affect the degradation process of the workpiece and produce a large error in the reading, thus resulting in an increase in the average degradation rate relative to the average deviation;

[0096] It can be seen from Example 2 and Comparative Examples 5 and 6 that when the weight loss method is used for testing, the degradation rate obtained is also low. This is because more bubbles adhere to the surface during the immersion process, which affects the actual degradation process. At the same time, this method cannot achieve real-time monitoring.

[0097] Finally, it should be noted that the above embodiments are intended to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for testing the degradation rate of medical magnesium metal, characterized in that: The test method comprises the following steps: (1) immersing the pretreated medical magnesium metal in a corrosive liquid, and obtaining the degradation surface area of ​​the medical magnesium metal and the ratio of the degradation surface area to the total surface area during the immersion process; (2) After the immersion is completed, the medical magnesium metal is taken out and post-processed to obtain the average degradation depth of the medical magnesium metal and calculate the average degradation rate of the medical magnesium metal; In the step (1), the system pressure is ≤5 kPa during the immersion process.

2. The testing method according to claim 1, characterized in that: The average degradation rate of medical magnesium metal v = (S 降解 *h) / (S 总 *t); Among them, S 降解 mm 2 Degradation surface area for medical magnesium metal; h mm is the average degradation depth of medical magnesium metal; S 总 mm 2 is the total surface area of ​​medical magnesium metal; t year is the immersion time of medical magnesium metal.

3. The testing method according to claim 1, characterized in that: The corrosive liquid includes any one of physiological saline, phosphate buffered saline, simulated body fluid, and Hank's solution; And / or, the medical magnesium metal includes pure magnesium or a magnesium alloy.

4. The testing method according to claim 1, characterized in that: The immersion temperature is 37±0.5°C.

5. The testing method according to claim 1, characterized in that: The pretreatment is grinding and polishing the medical magnesium metal; And / or, the post-treatment is to cold mount the medical magnesium metal after soaking, and then grind and polish it.

6. A test device for the degradation rate of medical magnesium metal, characterized in that: The testing device comprises a sealed container and a vacuum pump, a water inlet pump, a water outlet pump and an optical microscope connected to the sealed container. A sample stage is arranged in the sealed container.

7. The testing device according to claim 6, characterized in that: The testing device also includes a water inlet trough and a water outlet trough. The water inlet trough is connected to the closed container via a water inlet pump, and the water outlet trough is connected to the closed container via a water outlet pump.

8. The testing device according to claim 6, characterized in that: The testing device also includes a heating device.

9. Use of the test method for the degradation rate of medical magnesium metal according to any one of claims 1 to 5 in early real-time monitoring of the degradation of medical magnesium metal.

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