A ceramic material and a method for generating ceramic dislocations and applications thereof

Abstract

The present invention discloses a ceramic material and a method for generating ceramic dislocations and applications thereof. The method for generating ceramic dislocations comprises the following steps: using a spherical indenter as a loading indenter to load and scratch the surface of an ABO3 perovskite ceramic; the A is selected from Sr or K; and the B is selected from Ti or Nb. The spherical indenter used in the present invention scratches the surface of the ABO3 perovskite ceramic, effectively avoiding stress concentration. Using the ABO3 perovskite ceramic as a model material, dislocations are effectively generated in the ABO3 perovskite ceramic without generating macroscopic cracks. The plastic deformation zone of the dislocations generated by the present invention can reach the millimeter level or above. This further improves the mechanical properties of the ceramic material, such as hardness, strength, and plasticity.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic materials, and in particular to a ceramic material and a method for generating ceramic dislocations and applications thereof. Background Art

[0002] Ceramic materials are widely used in energy, national defense, communications, high-end electronic equipment and medical devices due to their high hardness, good biocompatibility, excellent corrosion resistance and high temperature resistance. However, the fatal disadvantage of ceramic materials is their high room temperature brittleness and extremely poor mechanical reliability. Therefore, brittle fracture failure is very likely to occur during production, processing and daily use, which directly leads to economic losses. Therefore, the development of ceramic materials with excellent mechanical properties has become a focus of current research. Dislocations, as common linear defects in crystalline materials, play a dominant role in the plastic deformation of materials. Introducing dislocations into ceramic materials can effectively improve their plastic deformation ability and enhance their fracture toughness. At present, common dislocation introduction methods in ceramics include high-temperature volume compression, room-temperature surface friction and nanoindentation. However, high-temperature volume compression has the disadvantages of complex processing technology and time-consuming. The depth of dislocations introduced by surface friction is shallow and the dislocation density is difficult to control. Nanoindentation has the disadvantages of small dislocation area and easy generation of microcracks.

[0003] Therefore, there is an urgent need to develop a simple, efficient, and dislocation-resistant method for preparing ceramic materials that has controllable dislocation density and is less prone to cracking. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the first aspect of the present invention provides a method for generating dislocations in a ceramic material, which enables the ceramic material to generate a large number of dislocations at room temperature without generating macro cracks.

[0005] The second aspect of the present invention also provides a ceramic material.

[0006] The third aspect of the present invention further provides an application of a ceramic material.

[0007] According to a first aspect of the present invention, a method for generating dislocations in a ceramic material is provided, comprising the following steps:

[0008] The surface of the ABO3 perovskite ceramic is loaded and scratched using a spherical indenter as a loading indenter.

[0009] The A is selected from Sr or K; the B is selected from Ti or Nb.

[0010] A method for generating dislocations in ceramic materials according to an embodiment of the present invention has at least the following beneficial effects:

[0011] The dislocation generation method of the present invention can be performed at room temperature. The spherical indenter used in the present invention scratches the surface of the ABO3 perovskite ceramic, effectively avoiding stress concentration. Using the ABO3 perovskite ceramic as a model material, dislocations are effectively generated in the ABO3 perovskite ceramic without generating macroscopic cracks. The plastic deformation zone of the dislocations generated in the present invention can reach millimeters or above. This further enhances the mechanical properties of the ceramic material, including hardness, strength, and plasticity.

[0012] According to some embodiments of the present invention, the load used in the scratching step is 1 N to 10 N. Thus, by controlling different loads and changing the applied normal stress, the effect of the room temperature scratching process on the surface integrity of the ABO3 perovskite ceramic can be regulated.

[0013] According to some embodiments of the present invention, the scribing speed is 0.1 mm / s to 1 mm / s.

[0014] According to some embodiments of the present invention, the scribing step uses a scribing distance of 1 mm to 5 mm.

[0015] According to some embodiments of the present invention, the scribing step is performed in the presence of a lubricant. Thus, the addition of a lubricant to the ABO3 perovskite ceramic surface and the indenter surface during the scribing process can effectively reduce friction and wear, and lower the risk of wear particle generation.

[0016] According to some embodiments of the present invention, the diameter of the spherical indenter is 2.5-5 mm.

[0017] According to some embodiments of the present invention, the material of the spherical indenter is selected from one of Al2O3, Si3N4 or stainless steel.

[0018] According to some embodiments of the present invention, the adopted scribing direction is unidirectional / bidirectional scribing.

[0019] According to some embodiments of the present invention, the number of scratchings is 1 to 100. Thus, the present invention can simply control the dislocation density and dislocation distribution of the ABO3 perovskite ceramic material by controlling the number of scratchings.

[0020] According to an embodiment of the second aspect of the present invention, a ceramic material is provided, which is obtained by processing using the dislocation generation method described above in the present invention.

[0021] The ceramic material according to the embodiment of the present invention has at least the following beneficial effects:

[0022] The ceramic material obtained by the method of the present invention has a high dislocation density and does not generate cracks, thereby further improving the hardness and plasticity of the ceramic material.

[0023] According to some embodiments of the present invention, the dislocation density of the ceramic material is 1×10 12 ~9×10 15 m -2 .

[0024] A third aspect of the present invention provides a use of the above-mentioned ceramic material in electronic equipment and medical devices.

[0025] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0027] Figure 1 This is a schematic diagram of the principle of a room temperature surface processing device according to an embodiment of the present invention;

[0028] Figure 2 This is an optical microscopic image of a scratched plastic zone containing a dislocation structure generated from a (001) SrTiO3 single crystal according to Example 1 of the present invention;

[0029] Figure 3 TEM image of the dislocation structure inside the plastic zone of the (001) SrTiO3 single crystal generated in Example 1 of the present invention;

[0030] Figure 4 This is a SEM image of the (001) SrTiO3 microcolumns after 15% plastic deformation after prefabricated dislocation in Example 1 of the present invention. DETAILED DESCRIPTION

[0031] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0032] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0033] The room temperature surface processing device used in the present invention will be briefly described below. Figure 1, the room temperature surface processing equipment includes a moving stage, a sensor, an indenter fixture, a spherical indenter and a ceramic sample. The moving direction of the moving stage is the x and y direction. The spherical indenter is fixed in the indenter fixture and placed under the sensor, while the ceramic sample is fixed above the moving stage. The working principle of the surface processing equipment is as follows: ① Set the loading parameters in the software on the computer side of the device, including normal loading load, loading rate, holding time, number of cyclic loading, etc., start the surface cycle program, the indenter first contacts the sample surface, and starts loading after reaching the set load at the set loading speed. ② Set the scratching parameters and program in the software on the computer side of the device, including direction, load, loading speed, scratching speed, scratching distance and scratching duration, etc. The indenter is lowered to the top of the ceramic sample and kept at a certain distance, and the scratching program is started. The indenter first descends at a certain speed and contacts the sample surface, and is loaded according to the loading speed set in the program to reach the set load, and scratches are performed at the set scratching speed. When the scratching stops, wait for it to reach the end time of the scratching, and then the indenter is lifted up to complete the scratching.

[0034] Example 1

[0035] This example provides a method for generating ceramic dislocations based on surface plastic processing at room temperature. The steps are as follows:

[0036] S1: Use (001) surface SrTiO3 ceramic single crystal as raw material, polish its surface, and fix the SrTiO3 ceramic single crystal on Figure 1 On the mobile stage shown;

[0037] S2: Using an Al2O3 indenter with a diameter of 5 mm, a normal load of 5 N, a scratching speed of 0.1 mm / s, and a scratching distance of 2 mm;

[0038] S3: The scratch test is performed from left to right, with the number of scratches being 10× (× represents the number of cyclic scratches), to obtain 10×-SrTiO3 ceramics.

[0039] Example 2

[0040] This example provides a method for generating ceramic dislocations based on room temperature surface processing, and the steps are as follows:

[0041] S1: Use (001) surface SrTiO3 ceramic single crystal as raw material, polish its surface, and fix the SrTiO3 ceramic single crystal on Figure 1 On the mobile stage shown;

[0042] S2: Using an Al2O3 indenter with a diameter of 5 mm, a normal load of 5 N, a scratching speed of 0.1 mm / s, and a scratching distance of 2 mm;

[0043] S3: The scratch test was performed from left to right with a scratching frequency of 30×, resulting in 30×-SrTiO3 ceramics.

[0044] Example 3

[0045] This example provides a method for generating ceramic dislocations based on room temperature surface processing, and the steps are as follows:

[0046] S1: Use (001) face KNbO3 ceramic single crystal as raw material, polish its surface, and fix the KNbO3 ceramic single crystal on Figure 1 On the mobile stage shown;

[0047] S2: Using an Al2O3 indenter with a diameter of 5 mm, a normal load of 10 N, a scratching speed of 0.5 mm / s, and a scratching distance of 2 mm;

[0048] S3: The scratch test is performed from left to right with a scratching frequency of 10×, and 10×-KNbO3 ceramics are obtained.

[0049] Example 4

[0050] This example provides a method for generating ceramic dislocations based on room temperature surface processing, and the steps are as follows:

[0051] S1: Use (001) face KNbO3 ceramic single crystal as raw material, polish its surface, and fix the KNbO3 ceramic single crystal on Figure 1 On the mobile stage shown;

[0052] S2: Using an Al2O3 indenter with a diameter of 5 mm, a normal load of 10 N, a scratching speed of 0.5 mm / s, and a scratching distance of 2 mm;

[0053] S3: The scratch test was performed from left to right with a scratching frequency of 30×, resulting in 30×-KNbO3 ceramics.

[0054] Example 5

[0055] This example provides a method for generating dislocations in ceramic materials. The steps are basically the same as those in Example 1, except that the load is 3N.

[0056] Example 6

[0057] This example provides a method for generating dislocations in ceramic materials. The steps are basically the same as those in Example 3, except that the scratching speed is 1 mm / s.

[0058] Example 7

[0059] This example provides a method for generating dislocations in ceramic materials. The steps are basically the same as those in Example 1, except that the number of scratching times is 5×.

[0060] Comparative Example 1

[0061] Comparative Example 1 provides a (001) SrTiO3 single crystal without scratching, the dislocation density of which is about 10 10 m -2 ~10 11 m -2 .

[0062] Comparative Example 2

[0063] Comparative Example 2 provides a (001) KNbO3 single crystal that has not been scratched and has a dislocation density of about 10 10 m -2 ~10 11 m -2 .

[0064] Performance Testing

[0065] Transmission electron microscopy was used to observe the microstructure of the scratched plastic zone, as well as the changes in the dislocation density and dislocation structure. Vickers indentation was used to test the Vickers hardness of SrTiO3 single crystals and KNbO3 single crystals obtained with different scratch parameters in the examples. Micropillars with a diameter of 1 μm and a height of 3 μm were prepared using a focused ion beam and subjected to compression testing using a nanoindenter (Hystron, TI950) at a strain rate of 10 -3 s -1 The effects of different scratch parameters on the mechanical properties of SrTiO3 single crystal and KNbO3 single crystal ceramics were tested with a deformation of 15%. The mechanical property data of the embodiment and the comparative example obtained by the test are shown in Table 1.

[0066] Table 1

[0067]

[0068] As shown in Table 1, the functional ceramic material provided by the present invention, after the room-temperature scratching dislocations are generated, has high plastic deformation capacity and high Vickers hardness (the greater the compression plasticity, the higher the room-temperature plastic deformation capacity). Comparative Examples 1 and 2 are samples that were not scratched at room temperature and did not introduce high-density dislocations. Both samples had extremely poor compression plasticity and low hardness values, and did not meet the requirements.

[0069] Depend on Figure 2 It can be seen that the scratched plastic zone formed on the surface of the (001) SrTiO3 single crystal after 10× scratching provided by the present invention does not show obvious macro cracks, and a large number of high-density slip bands perpendicular to each other along the

[100] and

[010] directions are generated on the scratched surface.

[0070] Figure 3The transmission electron microscope images show the microstructure of the scratched surface provided by the present invention. It can be seen that a large number of 45° dislocation lines are generated inside the (001) SrTiO3 single crystal after 10× scratching, and the dislocation density is 8×10 13 m -2 .

[0071] Figure 4 The (001) SrTiO3 single crystal after 15% compression deformation in the provided Example 1 did not break or show obvious microcracks, indicating that the (001) SrTiO3 single crystal provided by the present invention after room temperature scratched dislocation generation has high plastic deformation ability and meets the requirements of use.

[0072] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the scope of the present invention.

Claims

1. A method for generating ceramic dislocations, characterized in that: The steps include: The surface of the ABO3 perovskite ceramic is loaded and scratched using a spherical indenter as a loading indenter. The AB is selected from SrTi or KNb; the load used in the scratching step is 1 N to 10 N; The scribing speed is 0.1 mm / s to 1 mm / s; The scribing distance used in the scribing step is 1 mm to 5 mm; The diameter of the spherical indenter is 2.5-5 mm.

2. The method for generating ceramic dislocations according to claim 1, wherein: The scribing step is performed in an environment where a lubricant is added.

3. The method for generating ceramic dislocations according to claim 1, wherein: The ABO3 perovskite ceramic is first polished.

4. A ceramic material, characterized in that It is obtained by processing the dislocation generation method according to any one of claims 1 to 3.

5. The ceramic material according to claim 4, characterized in that The dislocation density of the ceramic material is 1×10 12 ~9×10 15 m -2 .

6. Use of the ceramic material according to claim 4 or 5 in electronic equipment and medical devices.

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