CN110133090B - In-situ hydrogen charging experimental device - Google Patents

Abstract

The invention discloses an in-situ hydrogen charging experimental device which comprises a base, a lower shell and an upper cover body. The longitudinal section of the lower shell is of a convex structure, the lower shell is fixed on the base through a locking bolt, symmetrically arranged through holes are formed in the lower shell and the upper cover body, and the upper cover body is fixed on the lower shell through a fastening screw. The hollow inner chamber of lower casing is equipped with the indent microscope carrier, and upper cover body center is equipped with the syringe needle test hole, and the syringe needle test hole sets up directly over the microscope carrier. The upper cover body is also provided with a wire connecting hole, two sides of the upper convex part of the lower shell are provided with a pair of bulges, and two sides of the upper cover body are provided with grooves matched with the bulges. The invention has novel structural design and convenient use, and can carry out in-situ hydrogen charging test on a hydrogen charging sample. The invention is suitable for the instruments using probes for measuring such as nano indentation, atomic force microscope and the like.

Description

An in-situ hydrogen charging experimental device

Technical field

The invention relates to the technical field of electrochemical experiments, specifically an in-situ hydrogen charging experimental device.

Background technique

Hydrogen has the adverse effects of hydrogen-induced plasticity loss and hydrogen-induced fracture resistance reduction on almost all metals. These phenomena are generally referred to as hydrogen embrittlement. Hydrogen may enter the material during its preparation, processing and use. Therefore, studying the effects of hydrogen on materials has become key to using materials safely and economically.

In order to study the effect of hydrogen on materials, mechanical testing of hydrogen-containing specimens is required. Commonly used hydrogen charging methods include aqueous solution electrolytic hydrogen charging, molten salt electrolytic hydrogen charging and gas phase hydrogen charging. Among them, aqueous solution electrolytic hydrogen charging is the most widely used because of its safety and ease of operation.

Conventional mechanical experiments, such as uniaxial tensile experiments, can reflect the impact of hydrogen on materials at the macro scale. However, with the deepening of research, the impact of hydrogen on materials at the microscopic scale, especially the impact of hydrogen on different phases of metallic materials, is becoming more and more important. Research on the microscopic scale often requires the use of small probes to determine the area of study, such as nanoindentation equipment and other equipment.

The traditional testing method is to take out the sample after hydrogen charging for testing. In the interval between the completion of hydrogen charging and the start of the test, the hydrogen in the material will combine into hydrogen and overflow, affecting the accuracy of the experimental results; in addition, in order to ensure the hydrogen content during the test concentration, often charging the sample with hydrogen for a long time will cause damage to the surface of the sample, which is not conducive to the next test. In-situ testing can always maintain a high hydrogen concentration at the test site, reduce hydrogen charging time, and prevent hydrogen gas from overflowing. Therefore, it is very beneficial to conduct continuous online testing while charging the sample with hydrogen to study the impact of hydrogen on materials.

As mentioned above, probe-type equipment such as nanoindenters can test the performance of materials at a microscopic scale. However, there is currently no device that enables such equipment to continuously test online while charging the sample with hydrogen, which is not sufficient. It meets the current requirements for studying the hydrogen embrittlement phenomenon of materials on a microscopic scale.

Contents of the invention

The object of the present invention is to provide an in-situ hydrogen charging experimental device, which can realize continuous online testing of samples while charging hydrogen, so as to solve the problems raised in the above background technology.

In order to achieve the above objects, the present invention provides the following technical solutions:

An in-situ hydrogen charging experimental device includes a base, a lower shell and an upper cover. The lower shell has a "convex" longitudinal cross-section, and the lower shell is fixed on the base through locking bolts. The lower shell and the upper cover are provided with symmetrically arranged through holes, and the upper cover is fixed on the lower shell through fastening screws; the center of the lower shell is provided with a cylindrical hollow inner cavity, and the hollow inner cavity is provided with There is a carrier platform, and the height of the carrier platform is lower than the upper edge of the hollow inner cavity; a needle test hole is provided in the center of the upper cover body, and the needle test hole is set directly above the carrier platform, and the upper cover body is also provided with a needle test hole. There are wire holes; protrusions are provided on opposite sides of the upper convex part of the lower housing, and grooves matching the protrusions are provided on opposite sides of the upper cover; and an outward-facing protrusion is provided inside the protrusion. Overflow port; the convex side wall of the lower housing is provided with a liquid inlet, and the opposite side wall is provided with a liquid outlet; a rubber sealing gasket is installed at the connection between the lower housing and the base.

Preferably, the carrier adopts a concave carrier, and the carrier adopts a cylindrical structure.

Preferably, the base, lower shell and upper cover are all made of organic glass polymer material.

A method of using an in-situ hydrogen charging experimental device includes the following steps:

A. First, connect the liquid inlet on the lower shell to the flow pump through the liquid inlet pipe, and then connect the liquid outlet to the container through the liquid outlet pipe;

B. Place the round sample after welding the wires on the stage, pass the wires through the wire holes, and use a syringe to inject the hydrogen-filled solution directly into the lower case so that the liquid level is 1 mm below the surface of the sample;

C. Put the platinum counter electrode through the wire hole into the hydrogen charging solution, and then fix the upper cover and lower shell with fastening bolts;

D. Connect the wire welded to the sample and the platinum counter electrode to the electrochemical workstation, and then turn on the electrochemical workstation according to the preset current density of the experiment;

E. Turn on the flow pump, which sends the hydrogen-charging solution into the lower housing through the liquid inlet and discharges it from the liquid outlet to the external container. The hydrogen-charging solution inside the lower housing continuously circulates;

F. Finally, after the hydrogen-filled solution level is stable, operate the probe into the needle test hole to perform experimental operations.

The beneficial effects of the present invention are:

(1) The invention has a novel structural design, is easy to use, and can continuously conduct in-situ mechanical property testing of hydrogen-charged samples. The invention is suitable for instruments using probes for measurement such as nanoindentation and atomic force microscopes.

(2) The present invention uses a flow pump to update the hydrogen charging solution, ensuring that there is fresh solution in the container and ensuring the concentration of hydrogen charging.

(3) The arrangement of the upper cover of the present invention plays a role in limiting the position of the probe and protects the safety of the sensor above the probe.

(4) The invention has a compact design and can be used normally even with machines with short probes.

(5) The present invention uses a concave stage, which not only limits the degree of freedom of the circular sample, but also ensures the stiffness of the sample, so that the experiment can proceed smoothly.

(6) The base, lower shell and upper cover of the present invention are all made of polymer materials, which have excellent wear resistance and corrosion resistance, are not easily damaged, and have a long service life.

Description of the drawings

Figure 1 is a schematic structural diagram of the present invention.

Figure 2 is a schematic structural diagram of the lower housing of the present invention.

Figure 3 is a schematic structural diagram of the upper cover body of the present invention.

Among them, 1 base, 2 lower shell, 3 upper cover, 4 fastening screws, 5 stage, 6 needle test holes, 7 wire holes, 8 protrusions, 9 grooves, 10 overflow port, 11 liquid inlet , 12 liquid outlets.

Figure 4 shows optical micrographs of 2205 duplex stainless steel before and after hydrogen charging, a before hydrogen charging, b hydrogen charging for 1 hour, and c hydrogen charging for 5 hours.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

An in-situ hydrogen charging experimental device, including a base 1, a lower housing 2 and an upper cover 3. The lower housing 2 has a "convex" shaped structure in its longitudinal section, and is fixed on the lower housing 2 by locking bolts. On the base 1, the lower housing 2 and the upper cover 3 are provided with symmetrically arranged through holes. The upper cover 3 is fixed to the lower housing 2 through fastening screws 4. The center of the lower housing 2 A cylindrical hollow inner cavity is provided, and the hollow inner cavity is provided with a platform 5. The height of the platform 5 is lower than the upper edge of the hollow inner cavity; the upper cover 3 is provided with an indentation needle test hole 6 in the center, and the The indentation needle test hole 6 is arranged directly above the carrier 5. The upper cover 3 is also provided with a wire connection hole 7. The opposite sides of the upper convex part of the lower housing 2 are provided with protrusions 8. The upper cover 3 is provided with grooves 9 matching the protrusions 8 on opposite sides. The protrusions 8 are provided with an outward overflow opening 10 inside. The upper convex side wall of the lower housing 2 is provided with a groove 9 There is a liquid inlet 11, and a liquid outlet 12 is provided on the opposite side. The liquid inlet 11 is connected to a flow pump through a liquid inlet pipe, and the liquid outlet 12 is connected to a container through a liquid outlet pipe. The present invention uses a flow pump to Renew the hydrogen charging solution to ensure there is fresh solution in the container. A rubber sealing gasket is installed at the connection between the lower housing 2 and the base 1 .

In the present invention, the arrangement of the upper cover 3 plays a position-limiting role for the probe and protects the safety of the sensor above the probe.

In the present invention, the carrier 5 adopts a concave carrier, which is lower than the upper edge of the hollow inner cavity, and the carrier 5 adopts a cylindrical structure. The present invention uses a concave stage, which not only limits the degree of freedom of the circular sample, but also ensures the stiffness of the sample, so that the experiment can proceed smoothly.

In the present invention, the base 1, the lower shell 2 and the upper cover 3 are all made of organic glass polymer materials, which have excellent wear resistance and corrosion resistance, are not easily damaged, and have a long service life.

The method of using the in-situ hydrogenation experimental device of the present invention includes the following steps:

A. First, connect the liquid inlet 11 on the lower housing 2 to the flow pump through the liquid inlet pipe, and then connect the liquid outlet 12 to the container through the liquid outlet pipe;

B. Place the circular sample after welding the wires on the stage 5, pass the wires through the wire holes 7, and use a syringe to directly inject the hydrogen-filled solution into the lower housing 2 so that the liquid level is 1 mm below the surface of the sample;

C. Put the platinum counter electrode through the wire hole 7 and put it into the hydrogen charging solution, and then fix the upper cover 3 and the lower case 2 with the fastening screws 4;

D. Connect the wire welded to the sample and the platinum counter electrode to the electrochemical workstation, and then turn on the electrochemical workstation according to the preset current density of the experiment;

E. Turn on the flow pump, which sends the hydrogen-charged solution into the interior of the lower housing 2 through the liquid inlet 11, and discharges it from the liquid outlet 12 to the external container. The hydrogen-charged solution inside the lower housing 2 is continuously circulated;

F. Finally, after the hydrogen-charging solution level is stable, operate the probe into the needle test hole 6 to perform experimental operations.

Example 1

Taking the in-situ hydrogen charging test of 2205 duplex stainless steel in Hysitron's TI-premier nanoindentation instrument as an example, the specific implementation is as follows:

1. Connect the liquid inlet 11 on the lower housing 2 to the flow pump through the liquid inlet pipe, and then connect the liquid outlet 12 to the solution collection container through the liquid outlet pipe;

2. Place the 2205 duplex stainless steel round specimen with the ground and polished wires welded onto the stage 5, pass the wires through the wire holes 7, and use a syringe to directly inject the hydrogen-filled solution into the lower housing 2 so that the liquid level does not pass the test. The sample surface is 1 mm. In this example, the hydrogenation solution is a mixed solution containing 0.5mol/L sulfuric acid and 1g/L thiourea;

3. Put the platinum counter electrode through the wire hole 7 and put it into the hydrogen charging solution, and then fix the upper cover 3 and the lower case 2 with the fastening screws 4;

4. Fix the entire device on the sample table of TI-premier through the screw holes, connect the wires welded to the sample and the platinum counter electrode to the electrochemical workstation, and close the TI-premier sample compartment door.

5. Open the electrochemical workstation according to the current density preset by the experiment, and turn on the flow pump. The flow pump will send the hydrogen-charged solution into the interior of the lower housing 2 through the liquid inlet 11, and discharge it from the liquid outlet 12 to the external solution collection container. , the hydrogen-filled solution inside the lower housing 2 circulates continuously;

6. Find the sample testing area under the TI-premier optical microscope and adjust the machine to the appropriate height. Move the sample stage so that the probe enters the needle test hole 6, and conduct the experimental operation after the hydrogen-charged solution level is stable.

Figure 4 shows the optical micrographs of 2205 duplex stainless steel before and after hydrogen charging at a current density of 10 mA/ ^cm2 . a is before hydrogen charging, b is after 1 hour of hydrogen charging, and c is after 5 hours of hydrogen charging. Through this device, experiments can be conducted continuously online. It can be seen that the longer the hydrogen charging time, the rougher the surface of the sample. Rough surfaces will result in larger displacements and lower calculated hardness compared to smooth surfaces.

In summary, the present invention has a novel structural design, is easy to use, and can conduct in-situ hydrogen charging tests on hydrogen-charged samples. The invention is suitable for instruments using probes for measurement such as nanoindentation and atomic force microscopes.

Claims (2)

1. An in-situ hydrogen charging experimental device, including a base (1), a lower housing (2) and an upper cover (3), characterized in that: the lower housing (2) has a "convex" longitudinal cross-section structure, the lower housing (2) is fixed on the base (1) through locking bolts, the lower housing (2) and the upper cover (3) are provided with symmetrically arranged through holes, and the upper cover The body (3) is fixed on the lower housing (2) through fastening screws (4); the center of the lower housing (2) is provided with a cylindrical hollow inner cavity, and the hollow inner cavity is provided with a loading platform (5), which carries The height of the platform (5) is lower than the upper edge of the hollow inner cavity; a needle test hole (6) is provided in the center of the upper cover body (3), and the needle test hole (6) is set in front of the carrier platform (5). Above, the upper cover (3) is also provided with a wire hole (7). The circular sample after welding the wire is placed on the stage (5), and the wire passes through the wire hole (7); the lower shell Protrusions (8) are provided on opposite sides of the upper convex part of the body (2), and grooves (9) matching the protrusions (8) are provided on opposite sides of the upper cover body (3); There is an outward overflow port (10) inside the lower housing (8); the convex side wall of the lower housing (2) is provided with a liquid inlet (11), and the opposite side wall is provided with a liquid outlet. (12); A rubber sealing gasket is installed at the connection between the lower housing (2) and the base (1); The carrier (5) adopts a concave carrier, and the carrier (5) adopts a cylindrical structure; The base (1), lower housing (2) and upper cover (3) are all made of organic glass materials. 2. A method for carrying out in-situ hydrogenation experiments using an in-situ hydrogenation experiment device according to claim 1, which is characterized in that: A. First connect the liquid inlet (11) on the lower housing (2) to the flow pump through the liquid inlet pipe, and then connect the liquid outlet (12) to the container through the liquid outlet pipe; B. Use a syringe to directly inject the hydrogen-charging solution into the lower housing (2) so that the liquid level is 1 mm below the surface of the sample; C. Put the platinum counter electrode through the wire hole (7) into the hydrogen charging solution, and then secure the upper cover (3) and the lower shell (2) with fastening bolts; D. Connect the wire welded to the sample and the platinum counter electrode to the electrochemical workstation, and then turn on the electrochemical workstation according to the preset current density of the experiment; E. Turn on the flow pump. The flow pump will send the hydrogen-filled solution into the inside of the lower housing (2) through the liquid inlet (11), and discharge it from the liquid outlet (12) to the external container. Inside the lower housing (2) The hydrogen-charged solution is continuously circulated; F. Finally, after the hydrogen-filled solution level is stable, operate the probe into the needle test hole (6) to perform experimental operations.