High-damage-tolerance layered ceramic and preparation method thereof
By preparing MOBC high-damage-tolerant layered ceramics, the problems of easy decomposition and non-conductivity of existing layered ceramics in high-temperature and complex environments have been solved, achieving high-temperature stability and semiconductor properties, and expanding its applications in high-temperature, optoelectronic, and catalysis fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-25
- Publication Date
- 2026-03-27
AI Technical Summary
Existing high-damage-tolerance layered ceramics are mostly non-conductive, which limits their application in the semiconductor field. They are also prone to decomposition in high-temperature and complex environments, and have poor resistance to moisture and acids and alkalis, which limits their application in even higher-temperature environments.
The crystal structure of MOBC high damage-tolerant layered ceramic is adopted, which is composed of alternating stacked MO layers and BC layers. M is a rare earth metal element, O is oxygen element, B is boron element, and C is carbon element. By controlling the element ratio and hot pressing process, a high damage-tolerant layered ceramic with semiconductor properties is formed.
It achieves the stability and semiconductor properties of high-damage-tolerant layered ceramics at high temperatures, with a decomposition temperature exceeding 1950℃. It has good potential for mechanical, thermal, optical, and electrical applications, and its band gap is tunable, expanding its applications in high-temperature, optoelectronic, and catalytic fields.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of layered ceramics, in particular to a high damage tolerance layered ceramic and a preparation method thereof. BACKGROUND
[0002] Traditional super-high-temperature ceramics such as transition metal carbides and borides have good high-temperature stability, but due to their intrinsic brittleness, they are prone to rigid rupture of chemical bonds under external force, resulting in crack propagation and structural failure. High damage tolerance layered ceramics have a strong electronic structure anisotropy and weak interlayer bonding, which can compensate for the shortcomings of transition metal carbides and borides such as brittleness and poor oxidation resistance, and have certain application value in high-temperature, aerospace and other complex environments. Through decades of research and development, it has been found that high damage tolerance layered ceramics not only have good application prospects in high-temperature extreme environments, but also have unique application value in the fields of optics, electricity, magnetism and other fields.
[0003] Currently, high damage tolerance layered ceramics mainly include ternary layered carbides and rare earth borocarbides. The ternary layered carbides have a general chemical formula of M n+1 AX n (MXA), M is a transition metal element, A is an A main group element, and X is a carbon (C), nitrogen (N) or other element. The crystal structure of the ternary layered carbide is alternately stacked with M-X and A atomic layers, and it has wide application potential in the fields of aerospace, neutron absorption, optoelectronics, medical treatment and other fields. However, due to the weak interlayer bonding between M-X and A layers in the MAX crystal structure, it is not resistant to humid environment, not resistant to acid and alkali, and easily decomposed at high temperature (1400℃), which limits its application in higher temperature complex environment. The rare earth borocarbide, such as YB2C2, is alternately stacked with yttrium and borocarbon layers, and has good interlayer bonding, which can realize high-temperature stability, but lacks application value in the fields of optoelectronics and catalysis. In addition, the currently reported high damage tolerance layered ceramics are mostly non-conductors, which limits their application in the field of semiconductors.
[0004] Therefore, it is urgent to find a series of new high damage tolerance layered ceramics to expand the application of layered ceramic family in the fields of high temperature, optoelectronics, catalysis, semiconductor and other fields. SUMMARY
[0005] In view of the shortcomings of the prior art, the purpose of the present application is to provide a high damage tolerance layered ceramic and a preparation method thereof, which aims to solve the problem that the existing high damage tolerance layered ceramics are mostly non-conductors, which restricts their application and development.
[0006] The technical scheme of the present application is as follows:
[0007] In a first aspect, the present application provides a high damage tolerance layered ceramic, wherein the high damage tolerance layered ceramic comprises elements M, O, B and C, the crystal structure of the high damage tolerance layered ceramic is composed of M-O layers and B-C layers stacked alternately, and the high damage tolerance layered ceramic is a semiconductor; wherein M is a rare earth metal element, O is an oxygen element, B is a boron element, and C is a carbon element.
[0008] Optionally, the high damage tolerance layered ceramic comprises elements M, O, B and C, and the crystal structure of the high damage tolerance layered ceramic is composed of M-O layers and B-C layers stacked alternately.
[0009] Optionally, M is selected from one of Y, Gd, Dy, Ho and Er.
[0010] Optionally, the high damage tolerance layered ceramic has a tunable band gap.
[0011] In a second aspect, the present application provides a preparation method of the high damage tolerance layered ceramic, comprising the following steps:
[0012] mixing an oxide containing a rare earth metal element, boron carbide and carbon according to a mass ratio of 6-11.5:0.5-3:1-5, and then performing ball milling to obtain a powder;
[0013] heating the powder to 1000-2100 DEG C, and then performing pressure holding for a predetermined time to obtain the high damage tolerance layered ceramic.
[0014] Optionally, the ball milling is performed in ethanol or water as a medium, and the ball milling time is 0.5-20 h.
[0015] Optionally, before the step of heating the powder to 1000-2100 DEG C, the method further comprises the following steps: drying the powder, and heating the dried powder to 1000-2100 DEG C.
[0016] Optionally, the drying time is 0.5-10 h.
[0017] Optionally, the predetermined time is 0.5-20 h.
[0018] Optionally, the pressure holding pressure is 0-300 MPa.
[0019] Optionally, the heating is performed at a heating rate of 0.2-300 DEG C / min under vacuum, oxygen, hydrogen or inert gas to 1000-2100 DEG C.
[0020] Optionally, the step of heating the powder to 1000-2100 DEG C, and then performing pressure holding for a predetermined time specifically comprises:
[0021] Put the powder into a graphite mold, and put the graphite mold with the powder into a hot-pressing furnace; wherein the pre-pressing of the graphite mold is 0-50 MPa;
[0022] The hot-pressing furnace is heated at a heating rate of 0.2-300℃ / min to 1000-2100℃ under vacuum, oxygen, hydrogen or inert gas, and then is kept at the temperature and pressure for 0.5-20h, wherein the pressure of the graphite mold is 0-300 MPa.
[0023] Beneficial effects: The high damage tolerance layered ceramic (also referred to as M-O-B-C high damage tolerance layered ceramic) provided by the application is a new type of high damage tolerance layered ceramic, which has a hardness close to that of graphite and boron nitride, and is much lower than that of the reported MAX phase high damage tolerance layered ceramic. However, unlike the traditional MAX phase, the M-O-B-C high damage tolerance layered ceramic has the properties of a semiconductor, and the band gap can be adjusted by doping rare earth metal elements such as Sc, La and Ce, or light elements such as B, C and N, and is a promising semiconductor layered material with adjustable band gap, which has good potential in the applications of force, heat, light, electricity and magnetism.
[0024] In addition, the decomposition temperature of the MAX phase is about 1400℃, while the decomposition temperature of the M-O-B-C high damage tolerance layered ceramic is above 1950℃, and the application in the high-temperature field has good potential. BRIEF DESCRIPTION OF DRAWINGS
[0025] Figure 1 XRD patterns of Y-O-B-C, Gd-O-B-C, Dy-O-B-C, Ho-O-B-C and Er-O-B-C.
[0026] Figure 2 Fracture scanning electron microscope (SEM) pattern of Y-O-B-C.
[0027] Figure 3 Microhardness test result pattern of Y-O-B-C.
[0028] Figure 4 Indentation pattern of Y-O-B-C. DETAILED DESCRIPTION
[0029] The application provides a high damage tolerance layered ceramic and a preparation method thereof. To make the purpose, technical scheme and effects of the application more clear and explicit, the application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the application, and are not used to limit the application.
[0030] The embodiment of the present application provides a high damage tolerance layered ceramic, wherein the high damage tolerance layered ceramic is composed of M, O, B and C, the crystal structure of the high damage tolerance layered ceramic is composed of M-O layers and B-C layers which are alternately stacked, and the high damage tolerance layered ceramic is a semiconductor; wherein M is a rare earth metal element, O is an oxygen element, B is a boron element, and C is a carbon element.
[0031] In an embodiment, the high damage tolerance layered ceramic is composed of M, O, B and C, and the crystal structure of the high damage tolerance layered ceramic is composed of M-O layers and B-C layers which are alternately stacked.
[0032] The M-O-B-C high damage tolerance layered ceramic in the embodiment of the present application is composed of M, O, B and C, there are van der Waals weak bonds between layers, the crystal structure is alternately stacked by M-O layers and B-C layers, and the M-O-B-C high damage tolerance layered ceramic has good high damage tolerance and better high-temperature thermal stability.
[0033] The M-O-B-C high damage tolerance layered ceramic in the embodiment of the present application is a new type of high damage tolerance layered ceramic, the hardness is close to that of graphite and boron nitride, and is far lower than that of the reported MAX phase high damage tolerance layered ceramic. However, unlike the traditional MAX phase, the M-O-B-C high damage tolerance layered ceramic has the properties of a semiconductor, and the band gap can be adjusted by doping Sc, La, Ce and other rare earth metal elements or B, C and N in the M-O-B-C high damage tolerance layered ceramic, so that the M-O-B-C high damage tolerance layered ceramic is a promising semiconductor layered ceramic with adjustable band gap, and has good potential in the applications of force, heat, light, electricity and magnetism.
[0034] In addition, the decomposition temperature of the MAX phase is about 1400 DEG C, while the decomposition temperature of the M-O-B-C high damage tolerance layered ceramic is above 1950 DEG C, and the M-O-B-C high damage tolerance layered ceramic has good potential in the application in the high-temperature field.
[0035] In the embodiment of the present application, the rare earth metal element includes at least one of scandium (Sc), yttrium (Y), lanthanum (La) in the lanthanide series, cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu).
[0036] In an embodiment, the M is selected from one of Y, Gd, Dy, Ho and Er.
[0037] The embodiment of the present application provides a preparation method of a high damage tolerance layered ceramic, and the preparation method comprises the following steps.
[0038] Mixing the oxide containing rare earth metal elements, boron carbide and carbon according to the mass ratio of 6-11.5:0.5-3:1-5, then ball milling to obtain the powder;
[0039] Heating the powder to 1000-2100℃, then holding for a predetermined time to obtain the high damage tolerance layered ceramic.
[0040] The embodiment of the present application is crucial in that the mass ratio of the oxide containing rare earth metal elements, boron carbide and carbon is controlled to be 6-11.5:0.5-3:1-5, so as to finally prepare the M-O-B-C high damage tolerance layered ceramic. The M-O-B-C high damage tolerance layered ceramic is composed of M, O, B and C four elements, the crystal structure is the M-O layer and the B-C layer alternately stacking, there is a van der Waals weak bond between the layers, and it has good high damage tolerance and better high temperature thermal stability.
[0041] The M-O-B-C high damage tolerance layered ceramic prepared by the embodiment of the present application is a new type of high damage tolerance layered ceramic, the hardness is close to that of graphite and boron nitride, and is far lower than that of the reported MAX phase high damage tolerance layered ceramic. However, unlike the traditional MAX phase, the M-O-B-C high damage tolerance layered ceramic has the properties of a semiconductor, and the band gap can be adjusted by doping Sc, La, Ce and other rare earth metal elements or B, C, N and other light elements in the M-O-B-C high damage tolerance layered ceramic, and it is a promising band gap adjustable semiconductor layered material, and has good potential in the applications of force, heat, light, electricity and magnetism.
[0042] In addition, the decomposition temperature of the MAX phase is about 1000℃, while the decomposition temperature of the M-O-B-C high damage tolerance layered ceramic is above 1950℃, and it has good potential in the application in the high temperature field.
[0043] In an embodiment, the ball milling conditions include: using ethanol or water as the medium, and the ball milling time is 0.5-20h, such as 0.5h, 1h, 3h, 5h, 8h, 10h, 15h, 18h, 20h or any value in the value range composed of any two values in the above numerical values as the end points.
[0044] In an embodiment, before the step of heating the powder to 1000-2100℃ (such as 1000℃, 1050℃, 1200℃, 1300℃, 1500℃, 1800℃, 1900℃, 2000℃, 2100℃ or any value in the value range composed of any two values in the above numerical values as the end points), it further includes the step of drying the powder, and heating the dried powder to 1000-2100℃.
[0045] In one embodiment, the drying time is 0.5-10h, such as 0.5h, 1h, 3h, 5h, 8h, 10h, or any value within a range bounded by, and including, any two of the foregoing values.
[0046] In one embodiment, the predetermined time is 0.5-20h, such as 0.5h, 1h, 3h, 5h, 8h, 10h, 15h, 18h, 20h, or any value within a range bounded by, and including, any two of the foregoing values.
[0047] In one embodiment, the pressure during the holding is 0-300MPa, such as 0MPa, 10MPa, 50MPa, 80MPa, 100MPa, 130MPa, 150MPa, 200MPa, 240MPa, 270MPa, 300MPa, or any value within a range bounded by, and including, any two of the foregoing values.
[0048] In one embodiment, the temperature is raised to 1000-2100℃ at a rate of 0.2-300℃ / min (such as 0.2℃ / min, 20℃ / min, 50℃ / min, 80℃ / min, 100℃ / min, 120℃ / min, 150℃ / min, 200℃ / min, 250℃ / min, 260℃ / min, 280℃ / min, 300℃ / min, or any value within a range bounded by, and including, any two of the foregoing values) under vacuum, oxygen, hydrogen, or inert gas.
[0049] In one embodiment, the temperature is raised to 1000-2100℃, and then the step of holding at the temperature for a predetermined time is performed, which specifically comprises:
[0050] The powder is placed into a graphite mold, and the graphite mold with the powder (for transferring pressure to the powder to solidify the powder) is placed into a hot-pressing furnace; wherein the pre-pressing pressure of the graphite mold is 0-50MPa;
[0051] The hot-pressing furnace is raised to 1000-2100℃ at a rate of 0.2-300℃ / min under vacuum, oxygen, hydrogen, or inert gas, and then held for 0.5-20h, wherein the pressure of the graphite mold is 0-300MPa.
[0052] The application is further described in detail below through specific examples.
[0053] Example 1
[0054] The high damage tolerance layered ceramic provided in this example has a preparation method comprising the following steps:
[0055] Firstly, oxides containing yttrium (Y) rare earth metal elements, boron carbide (B4C) and carbon (C) are put into a ball mill jar in a mass ratio of 8.5:1:2, and are ball milled for 5 h in water as a medium to obtain a powder.
[0056] Secondly, the powder is put into a drying oven for drying for 6 h.
[0057] Then, the dried powder is put into a graphite mold, pre-pressed at 40 MPa, and the graphite mold is put into a hot-pressing furnace, heated to 1700℃ at a rate of 3℃ / min under vacuum, held for 0.5 h, and kept at 40 MPa to obtain a Y-O-B-C bulk material (i.e., Y-O-B-C high damage tolerance layered ceramic).
[0058] Example 2
[0059] The same as Example 1, except that the Y rare earth metal elements are replaced by Gd, Dy, Ho and Er rare earth metal elements respectively, and finally Gd-O-B-C, Dy-O-B-C, Ho-O-B-C and Er-O-B-C bulk materials are obtained respectively.
[0060] The materials obtained in Examples 1-2 are tested, and the test results are as follows:
[0061] Figure 1 The XRD patterns of Y-O-B-C, Gd-O-B-C, Dy-O-B-C, Ho-O-B-C and Er-O-B-C obtained in Examples 1-2 are shown in FIG. 1, from which it can be seen that M-O-B-C bulk materials are successfully obtained, and the peak position appears a slight shift as the atomic radius of the rare earth metal elements increases. Figure 1
[0062] Figure 2 The fracture scanning electron microscope (SEM) pattern of Y-O-B-C obtained in Example 1 is shown in FIG. 2, from which it can be seen that Y-O-B-C exhibits a clear layered structure, and obvious kink texture appears after stress. Figure 2
[0063] The hardness of Y-O-B-C obtained in Example 1 is tested by a microhardness tester, and the test results are shown in FIG. 3, in which #1 is the hardness test result of the horizontal plane, and #2 is the hardness test result of the cross section, and the results show that Y-O-B-C has obvious anisotropy in different directions, showing obvious layered material characteristics; in addition, the microhardness of M-O-B-C is lower than 1 GPa, close to the microhardness of graphite and boron nitride. Figure 3
[0064] The resistivity of Y-O-B-C prepared in Example 1 is tested by four-probe method, and the test result shows that the resistivity of the material is 10 -2 -10 2 Ω·cm, which shows semiconductor property.
[0065] Figure 4 The indentation graph of Y-O-B-C prepared in Example 1 is shown in Figure 2, from which it can be known that the grains of Y-O-B-C are extruded, twisted and free of crack propagation after the surface of Y-O-B-C is stressed, which proves that the interlayer has good damage tolerance effect. Figure 4
[0066] In conclusion, the high damage tolerance layered ceramic and the preparation method thereof provided by the present application, M-O-B-C is a new type of high damage tolerance layered ceramic, the hardness of which is close to that of graphite and boron nitride, and is far lower than that of MAX and rare earth boron carbide reported at present, and the high damage tolerance layered ceramic has semiconductor property, and the band gap can be adjusted by doping metal elements such as Sc, La and Ce or light elements such as B, C and N in the high damage tolerance layered ceramic, so the high damage tolerance layered ceramic is a promising semiconductor layered material with adjustable band gap, and has good potential in the application of force, heat, light, electricity and magnetism. In addition, the decomposition temperature of MAX phase is about 1400 DEG C, while the decomposition temperature of the high damage tolerance layered ceramic reaches above 1950 DEG C, so the high damage tolerance layered ceramic has good potential in the application in high temperature field.
[0067] It should be understood that the application of the present application is not limited to the above examples, and the above description can be improved or changed by those skilled in the art, and all these improvements and changes shall belong to the protection scope of the appended claims of the present application.
Claims
1. A high-damage-tolerance layered ceramic, characterized in that, The high-damage-tolerant layered ceramic is composed of M, O, B and C. The crystal structure of the high-damage-tolerant layered ceramic consists of alternating stacked MO layers and BC layers. The high-damage-tolerant layered ceramic is a semiconductor. Among them, M is a rare earth metal element, O is oxygen element, B is boron element, and C is carbon element.
2. The high-damage-tolerance layered ceramic according to claim 1, characterized in that, The high-damage-tolerant layered ceramic is composed of M, O, B and C, and its crystal structure consists of alternating stacked MO and BC layers.
3. The high-damage-tolerant layered ceramic according to claim 1, characterized in that, M is selected from one of Y, Gd, Dy, Ho, and Er.
4. The high-damage-tolerant layered ceramic according to claim 1, characterized in that, The high-damage-tolerant layered ceramic bandgap is adjustable.
5. A method for preparing a high-damage-tolerant layered ceramic according to any one of claims 1-4, characterized in that, Includes the following steps: Oxides containing rare earth metal elements, boron carbide, and carbon are mixed in a mass ratio of 6-11.5:0.5-3:1-5, and then ball-milled to obtain powder. The powder is heated to 1000-2100℃ and then kept under heat and pressure for a predetermined time to obtain the high-damage-tolerance layered ceramic.
6. The method for preparing high-damage-tolerant layered ceramics according to claim 5, characterized in that, The ball milling conditions include: using ethanol or water as the medium, and milling for 0.5-20 hours.
7. The method for preparing high-damage-tolerant layered ceramics according to claim 5, characterized in that, Before the step of heating the powder to 1000-2100°C, the method further includes the step of drying the powder and heating the dried powder to 1000-2100°C. The drying time is 0.5-10 hours.
8. The method for preparing high-damage-tolerant layered ceramics according to claim 5, characterized in that, The predetermined time is 0.5-20 hours; The pressure for holding the pressure is 0-300 MPa.
9. The method for preparing high-damage-tolerant layered ceramics according to claim 5, characterized in that, Heating to 1000-2100℃ at a heating rate of 0.2-300℃ / min under vacuum, oxygen, hydrogen, or inert gas.
10. The method for preparing high-damage-tolerant layered ceramics according to claim 5, characterized in that, The process of heating the powder to 1000-2100℃ and then holding it under heat and pressure for a predetermined time specifically includes: The powder is placed into a graphite mold, and the graphite mold containing the powder is placed into a hot press furnace; wherein the pre-compression of the graphite mold is 0-50 MPa; The hot press furnace is heated to 1000-2100℃ at a heating rate of 0.2-300℃ / min under vacuum, oxygen, hydrogen or inert gas, and then held at temperature and pressure for 0.5-20h, wherein the pressure of the graphite mold is 0-300MPa.