Low-metal-phase TiB2-based metal ceramic doped with rare earth oxide and preparation method thereof

Abstract

The invention discloses low-metal-phase TiB2-based metal ceramic doped with rare earth oxide and a preparation method of the low-metal-phase TiB2-based metal ceramic. The TiB2-based metal ceramic comprises the following components in percentage by mass: 74-75wt.% of TiB2, 1-5wt. %, 19 to 21 wt.% of SiC; 4 to 6 wt.% of Ni; and Y2O3: 0 wt.%-1 wt.%. The preparation method comprises the following steps: preparing mixed powder, carrying out vacuum drying, carrying out compression molding, and finally sintering to obtain the low-metal-phase TiB2-based metal ceramic composite material doped with the rare earth oxide, wherein the volume density is 4.11-4.33 g / cm < 3 >, the hardness is 12.78-16.53 GPa, the fracture toughness is 6.06-7.66 MPa.m < 1 / 2 >, and the average grain size is 1.14-1.98 [mu] m. The spark plasma sintering technology adopting segmented heating has the characteristics of simple process flow, easiness in control of production conditions, low vacuum, full-density sintering and the like, and has wide application prospects in the fields of cutting tools, wear-resistant materials, mold linings and the like.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic materials, and in particular to a rare earth oxide-doped low-metal phase TiB2-based cermet and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of manufacturing technology and the increasing demand for applications, metal ceramics are increasingly used in processing and manufacturing, aerospace, nuclear energy and other fields. As a new type of composite material, metal ceramics have attracted extensive attention and research in the field of materials science for their unique combination of properties - high toughness and plasticity of metals and high melting point, corrosion resistance and wear resistance of ceramics.

[0003] TiB2-based cermets have high hardness, good chemical stability, good wear resistance, strong thermal and electrical conductivity, can be cut by electric spark wire, and a lubricating film is formed on the surface during high-speed cutting in the air, which can effectively reduce friction. It is an ideal tool material. At present, the composition of this type of tool has changed from a single component to a multi-component composite ceramic, and has been used in the cutting of materials such as stainless steel, mold steel, carbon steel and Hastelloy. However, due to the low fracture toughness and poor sintering performance of TiB2-based cermets, it is difficult to sinter below 2000°C, and excessively high sintering temperatures will deteriorate the required densification and mechanical properties, thus greatly limiting its practical application. For example, in the application of tools, it cannot meet its general requirements, and it is easy to crack during high-speed cutting, which reduces the service life of the tool and greatly reduces the scope of use.

[0004] In order to obtain TiB2-based cermets with high hardness, high strength and high toughness, some studies have changed their microstructure by adding sintering aids and changing the sintering method, thereby improving their sinterability and toughness. Adding no less than 8wt.% bonding agent has a significant effect on improving the comprehensive properties such as hardness, toughness and strength.

[0005] Chinese Patent Publication No. CN202010416184.5 discloses a core-shell structured TiB2-based cermet and a preparation method thereof. This patent controls the particle size of the raw material powders of the three hard phases TiB2, TiC, and WC, and adjusts the mass ratio of TiC to WC to prepare a TiB2-TiC-based cermet composite material with a "TiC core-(Ti, W)C shell" structure + a "TiB2 core-(Ti, W)(B, C) shell" structure, and improves the sintering performance by adding more than 18wt.% of metal binder phases Co and Ni, thereby improving the overall hardness, strength and fracture toughness of the material. However, from a microstructural point of view, the WC distribution is uneven, and the hardness of the cermet is not high.

[0006] Chinese Patent Publication No. CN202010416239.2 discloses a core-shell structure reinforced TiB2-TiC-based cermet and a preparation method thereof. The TiB2-based cermet has made a small change in the composition of the above-mentioned patent, mainly increasing the TiC content to form a more proportional "TiC core-(Ti,W)C shell" structure, further improving the fracture toughness and flexural strength of the TiB2-based cermet, but the hardness is slightly reduced.

[0007] For metal ceramics with high temperatures in local areas during service, the metal binder phase is prone to oxidation, resulting in a significant reduction in the hardness and strength of the TiB2-based metal ceramics, and a significant reduction in the life of the tool. The high-temperature performance of the core-shell structured TiB2-based metal ceramics in the above patents cannot meet the demand. Therefore, optimizing the composition and sintering process of the metal ceramics on the basis of forming a core-shell structure, regulating the organization and structure of the metal ceramics, avoiding the formation of brittle compounds, and improving the hardness, fracture toughness and bending strength of the low-metal phase TiB2-based metal ceramics have become technical problems that need to be solved in this field, which are of great significance for promoting the application of TiB2-based metal ceramics in cutting tools, wear-resistant materials, mold linings and other fields. Summary of the invention

[0008] The purpose of the present invention is to solve the problems in the background technology and to provide a low-metallic phase TiB2-based cermet doped with rare earth oxides and a preparation method thereof. The cermet mainly uses TiB2 as a hard phase and Ni as a bonding phase, and then introduces a second hard phase SiC and a trace amount of rare earth oxides. A certain amount of WC is introduced by ball milling, and a core-shell structure is formed through a dissolution-precipitation mechanism, thereby preparing a low-metallic phase TiB2-based cermet doped with rare earth oxides.

[0009] In order to achieve the above object, the present invention adopts the following technical scheme: a method for preparing a low-metal phase TiB2-based cermet doped with rare earth oxide. TiB2, rare earth oxide, SiC and nickel powder are ball-milled and mixed, and after the powder is evenly mixed, it is pressed into a graphite mold and subjected to spark plasma sintering to obtain a TiB2-based cermet sample, such as Figure 1 shown.

[0010] Calculated by mass percentage, the TiB2 content is 74wt.%-75wt.%; the SiC content is 19-21wt.%; the nickel powder content is 4-6wt.%; and the rare earth oxide content is 0wt.%-1wt.%.

[0011] The rare earth oxide is Y2O3.

[0012] The average particle size of TiB2 is 3-8 μm, and the average particle sizes of SiC, Ni and Y2O3 are all less than 1 μm, so as to facilitate rapid reaction during the sintering process.

[0013] The prepared metal ceramic has a core-shell structure with TiB2 as the core and (Ti, W) (B, C) solid solution as the shell. The core-shell structure has a low stress and high coherence interface. The added Y2O3 particles do not grow and have a size of <1μm, which plays a pinning and strengthening role on the grain boundaries. The small amount of added metal Ni reduces the sintering temperature, increases the density, and reduces the content of the metal phase through diffusion reaction, which is beneficial to improving the high temperature performance of the metal ceramic.

[0014] Furthermore, the above method comprises the following specific steps:

[0015] (1) TiB2, SiC, Ni, and Y2O3 powders are weighed according to mass percentage, loaded into a ball mill, and anhydrous ethanol is added at 100% to 120% of the mass of the powders, and then mixed by a planetary ball mill;

[0016] (2) After ball milling for 12 hours, vacuum drying was performed at 60°C-70°C for 8 hours to obtain a TiB2-based metal-ceramic mixed powder;

[0017] (3) The uniformly mixed powder is loaded into a graphite mold and preliminarily pressed into shape using a tablet press so that the powder is tightly sealed in the graphite paper;

[0018] (4) placing the mold filled with powder in a sintering furnace prepared by powder metallurgy for SPS sintering;

[0019] (5) After sintering, demolding is performed to obtain a bulk ceramic sample. The volume density of the TiB2-based cermet after sintering is 4.11-4.33 g / cm 3 , hardness is 12.78-16.53GPa, fracture toughness is 6.06-7.66MPa·m 1 / 2 , the average grain size is 1.14-1.98μm.

[0020] The ball milling medium in step (2) is WC balls, the ball-to-material ratio is 10:1, and the ball milling speed is 300 r / min.

[0021] The SPS sintering process in step (4) is as follows: the sintering temperature is 1550-1650°C, the sintering pressure is 30MPa; the heating step is to heat from room temperature to 650°C for 6 minutes, then heat to 1250°C at a heating rate of 50-150°C per minute for 6 minutes, and then heat to 1250°C at a heating rate of 0-100°C per minute for 7 minutes to 1600°C, and keep warm for 7 minutes, and then cool to room temperature with the furnace, and keep vacuum throughout the process, with a vacuum degree of 10 -3 -10 -1 Pa.

[0022] Compared with the prior art, the low-metal phase TiB2-based cermet doped with rare earth oxides and the preparation method thereof using the above technical solution have the following significant effects:

[0023] (1) The present invention adopts a method for preparing a low-metal phase TiB2-based cermet doped with rare earth oxides. The addition of rare earth oxides plays a role in refining the grains. While significantly reducing the metal phase, the cermet still has good fracture toughness. The addition of rare earth oxides not only improves the core-shell ratio of the TiB2-based cermet and reduces the sintering temperature, but also improves the compactness of the ceramic material and the comprehensive performance of the composite material;

[0024] (2) The present invention uses TiB2 as a matrix, Ni as a binder phase, and SiC as a second hard phase. A certain amount of WC is introduced by ball milling, and a core-shell structure mainly composed of "TiB2 core-(Ti, W)(B, C) shell" is formed through a dissolution-precipitation mechanism. A transition layer is formed between the TiB2 hard phase particles and the binder phase, thereby improving the interface bonding strength and the fracture toughness of the material. The WC content can be adjusted by controlling the ball milling time and rotation speed, thereby affecting the composition of the shell in the core-shell structure. The operation is simple.

[0025] (3) The present invention adopts the spark plasma sintering technology with segmented heating. The first half achieves rapid densification of the material at a relatively low temperature with a heating rate of 50-150°C per minute, which helps to inhibit grain growth and maintain the microstructure of the original particles of the material. The second half reduces the heating rate to 0-100°C per minute to achieve gradient sintering, reducing the microscopic defects and internal stress of the material that may be introduced by rapid heating. This technology has the characteristics of low vacuum sintering, simple process flow, and low cost.

[0026] (4) The Ni content added in the present invention is only 4-6wt.%. During the sintering process, the Ni element diffuses and most of it enters other compounds, which significantly reduces the content of metal phases with weak oxidation resistance and corrosion resistance, thereby improving the high-temperature performance of the TiB2-based metal ceramic and expanding its application temperature and application field. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A process roadmap of the rare earth oxide-doped low-metal phase TiB2-based cermet and its preparation method of the present invention;

[0028] Figure 2 It is a diagram showing the change of the microstructure of the low-metal phase TiB2-based cermet doped with rare earth oxides according to the present invention with different Y2O3 doping amounts;

[0029] Figure 3 This is a graph showing the density of the low-metal phase TiB2-based cermet doped with rare earth oxides in this embodiment as a function of different Y2O3 doping amounts;

[0030] Figure 4 This is a graph showing how the hardness and fracture toughness of the low-metallic phase TiB2-based cermet doped with rare earth oxides in this embodiment vary with different Y2O3 doping amounts. DETAILED DESCRIPTION

[0031] In order to further understand the content of the present invention, the present invention is now described in detail in conjunction with the accompanying drawings and embodiments.

[0032] Embodiment 1:

[0033] This embodiment is to prepare a TiB2-20wt.%SiC-5wt.%Ni-0.3wt.%Y2O3 composite ceramic sample by spark plasma sintering technology. The specific steps in this embodiment are as follows:

[0034] (1) Take 29.88 g of commercially available TiB2 powder with a purity of >99.5% and an average particle size of 3-8 μm; take 8 g of SiC powder with a purity of >99.5% and 2 g of Ni powder with a purity of 99.9% and an average particle size of <1 μm; take 0.12 g of Y2O3 powder; put the four powders into a ball mill, add 100%-120% of the mass of the powder into the ball mill, and mix them evenly;

[0035] (2) the four powders were subjected to planetary ball milling for 12 h, and then vacuum dried at 70 °C for 8 h to obtain a uniformly mixed powder;

[0036] (3) Take 20 g of the mixed powder and put it into a graphite mold. After preliminary pressing and molding using a tablet press, remove the upper and lower columns and gaskets to check whether the powder in the mold has leaked out, so that the powder is completely sealed in the graphite paper and the powder is fully sintered;

[0037] (4) After sintering, demolding is performed to take out the sample from the mold and remove the surface graphite paper to obtain a low-metal phase TiB2-based cermet sample doped with 0.3 wt.% Y2O3;

[0038] (5) The preliminary sample obtained in (4) is subjected to wire cutting to cut out a rectangular area less than 2 cm, and then mounted to obtain a cylindrical metallographic sample with a height of 1 cm;

[0039] (6) The mounted sample is subjected to metallographic processing to obtain the finished product.

[0040] A low-metal phase TiB2-based cermet doped with 0.3wt.% Y2O3 is prepared by the above preparation method.

[0041] The ball milling medium in (2) is WC ball, the ball-to-material ratio is 10:1, and the ball milling speed is 300 r / min.

[0042] The SPS sintering process of (4) is as follows: the first stage is to heat up from room temperature to 650°C within 6 minutes, the second stage is to heat up at a heating rate of 100°C per minute for 6 minutes, after heating to 1250°C, the heating rate is increased to 1600°C at a heating rate of 50°C per minute for 7 minutes, and then cooled to room temperature with the furnace. The sintering pressure is 30MPa and the vacuum degree is 5×10 -2 Pa.

[0043] The wire cutting speed of (5) is 220 mm 2 / min, the current is 3A.

[0044] The metallographic treatment of (6) is as follows: the samples are processed with 80#, 180#, 240#, 400#, 600#, 800# and 1000# sandpapers respectively to make the sample surface smooth and scratch-free, and then the sample is polished to a mirror surface and ultrasonically cleaned for 5 minutes to obtain the finished product.

[0045] The volume density of the low-metal phase TiB2-based cermet doped with 0.3 wt.% Y2O3 prepared in this embodiment is 4.26 g / cm 3 , hardness is 16.5GPa, fracture toughness is 7.2MPa·m 1 / 2 , the average grain size is 1.9μm.

[0046] Embodiment 2:

[0047] This embodiment is to prepare a TiB2-20wt.%SiC-5wt.%Ni-0.5wt.%Y2O3 composite ceramic sample by spark plasma sintering technology. The specific steps in this embodiment are as follows:

[0048] (1) Take 29.8 g of commercially available TiB2 powder with a purity of >99.5% and an average particle size of 3-8 μm; take 8 g of SiC powder with a purity of >99.5% and 2 g of Ni powder with a purity of 99.9% and an average particle size of <1 μm; take 0.2 g of Y2O3 powder; put the four powders into a ball mill, add 100%-120% of the mass of the powder into the ball mill, and mix them evenly;

[0049] (2) the four powders were subjected to planetary ball milling for 12 h, and then vacuum dried at 70 °C for 8 h to obtain a uniformly mixed powder;

[0050] (3) Take 20 g of the mixed powder and put it into a graphite mold. After preliminary pressing and molding using a tablet press, remove the upper and lower columns and gaskets to check whether the powder in the mold has leaked out, so that the powder is completely sealed in the graphite paper and the powder is fully sintered;

[0051] (4) After sintering, demolding is performed to take out the sample from the mold and remove the surface graphite paper to obtain a low-metal phase TiB2-based cermet sample doped with 0.5 wt.% Y2O3;

[0052] (5) The preliminary sample obtained in (4) is subjected to wire cutting to cut out a rectangular area less than 2 cm, and then mounted to obtain a cylindrical metallographic sample with a height of 1 cm;

[0053] (6) The mounted sample is subjected to metallographic processing to obtain the finished product.

[0054] A low-metal phase TiB2-based cermet doped with 0.5wt.% Y2O3 is prepared by the above preparation method.

[0055] The ball milling medium in (2) is WC ball, the ball-to-powder ratio is 10:1, and the ball milling speed is 300 r / min.

[0056] The SPS sintering process of (4) is as follows: the first stage is to heat up from room temperature to 650°C within 6 minutes, the second stage is to heat up at a heating rate of 100°C per minute for 6 minutes, after heating to 1250°C, the heating rate is increased to 1600°C at a heating rate of 50°C per minute for 7 minutes, and then cooled to room temperature with the furnace. The sintering pressure is 30MPa and the vacuum degree is 5×10 -2 Pa.

[0057] The wire cutting speed of (5) is 220 mm 2 / min, the current is 3A.

[0058] The metallographic treatment of (6) is as follows: the samples are processed with 80#, 180#, 240#, 400#, 600#, 800# and 1000# sandpapers respectively to make the sample surface smooth and scratch-free, and then the sample is polished to a mirror surface and ultrasonically cleaned for 5 minutes to obtain the finished product.

[0059] The volume density of the low-metal phase TiB2-based cermet doped with 0.5 wt.% Y2O3 prepared in this embodiment is 4.33 g / cm 3 , hardness is 16.27GPa, fracture toughness is 7.66MPa·m 1 / 2 , the average grain size is 1.2μm.

[0060] Embodiment 3:

[0061] This embodiment is to prepare a TiB2-20wt.%SiC-5wt.%Ni-1wt.%Y2O3 composite ceramic sample by spark plasma sintering technology. The specific steps in this embodiment are as follows:

[0062] (1) Take 29.6 g of commercially available TiB2 powder with a purity of >99.5% and an average particle size of 3-8 μm; take 8 g of SiC powder with a purity of >99.5% and 2 g of Ni powder with a purity of 99.9% and an average particle size of <1 μm; take 0.4 g of Y2O3 powder; put the four powders into a ball mill, add 100%-120% of the mass of the powder into the ball mill, and mix them evenly;

[0063] (2) the four powders were subjected to planetary ball milling for 12 h, and then vacuum dried at 70 °C for 8 h to obtain a uniformly mixed powder;

[0064] (3) Take 20 g of the mixed powder and put it into a graphite mold. After preliminary pressing and molding using a tablet press, remove the upper and lower columns and gaskets to check whether the powder in the mold has leaked out, so that the powder is completely sealed in the graphite paper and the powder is fully sintered;

[0065] (4) After sintering, demolding is performed to take out the sample from the mold and remove the surface graphite paper to obtain a low-metal phase TiB2-based cermet sample doped with 1 wt.% Y2O3;

[0066] (5) The preliminary sample obtained in (4) is subjected to wire cutting to cut out a rectangular area less than 2 cm, and then mounted to obtain a cylindrical metallographic sample with a height of 1 cm;

[0067] (6) The mounted sample is subjected to metallographic processing to obtain the finished product.

[0068] A low-metal phase TiB2-based cermet doped with 1wt.% Y2O3 is prepared by the above preparation method.

[0069] The ball milling medium in (2) is WC ball, the ball-to-powder ratio is 10:1, and the ball milling speed is 300 r / min.

[0070] The SPS sintering process of (4) is as follows: the first stage is to heat up from room temperature to 650°C within 6 minutes, the second stage is to heat up at a heating rate of 100°C per minute for 6 minutes, after heating to 1250°C, the heating rate is increased to 1600°C at a heating rate of 50°C per minute for 7 minutes, and then cooled to room temperature with the furnace. The sintering pressure is 30MPa and the vacuum degree is 5×10 -2 Pa.

[0071] The wire cutting speed of (5) is 220 mm 2 / min, the current is 3A.

[0072] The metallographic treatment of (6) is as follows: the samples are processed with 80#, 180#, 240#, 400#, 600#, 800# and 1000# sandpapers respectively to make the sample surface smooth and scratch-free, and then the sample is polished to a mirror surface and ultrasonically cleaned for 5 minutes to obtain the finished product.

[0073] The volume density of the low-metal phase TiB2-based cermet doped with 1 wt.% Y2O3 prepared in this embodiment is 4.30 g / cm 3 , hardness is 16.5GPa, fracture toughness is 7.56MPa·m 1 / 2 , the average grain size is 1.14μm.

[0074] Comparative Example:

[0075] This comparative example is to prepare a TiB2-20wt.%SiC-5wt.%Ni composite ceramic sample by spark plasma sintering technology. The specific steps in this comparative example are as follows:

[0076] (1) Take 30g of commercially available TiB2 powder with a purity of >99.5% and an average particle size of 3-8μm; take 8g of SiC powder with a purity of >99.5% and 2g of Ni powder with a purity of 99.9% and an average particle size of <1μm; put the four powders into a ball mill, add 100%-120% of the mass of the powder into the ball mill, and mix them evenly;

[0077] (2) the four powders were subjected to planetary ball milling for 12 h, and then vacuum dried at 70 °C for 8 h to obtain a uniformly mixed powder;

[0078] (3) Take 20 g of the mixed powder and put it into a graphite mold. After preliminary pressing and molding using a tablet press, remove the upper and lower columns and gaskets to check whether the powder in the mold has leaked out, so that the powder is completely sealed in the graphite paper and the powder is fully sintered;

[0079] (4) After sintering, demolding is performed to take out the sample from the mold and remove the surface graphite paper to obtain an undoped low-metal phase TiB2-based cermet sample;

[0080] (5) The preliminary sample obtained in (4) is subjected to wire cutting to cut out a rectangular area less than 2 cm, and then mounted to obtain a cylindrical metallographic sample with a height of 1 cm;

[0081] (6) The mounted sample is subjected to metallographic processing to obtain the finished product.

[0082] An undoped low-metal phase TiB2-based cermet is prepared by the above-mentioned preparation method.

[0083] The ball milling medium in (2) is WC ball, the ball-to-powder ratio is 10:1, and the ball milling speed is 300 r / min.

[0084] The SPS sintering process of (4) is as follows: the first stage is to heat up from room temperature to 650°C within 6 minutes, the second stage is to heat up at a heating rate of 100°C per minute for 6 minutes, after heating to 1250°C, the heating rate is increased to 1600°C at a heating rate of 50°C per minute for 7 minutes, and then cooled to room temperature with the furnace. The sintering pressure is 30MPa and the vacuum degree is 5×10 -2 Pa.

[0085] The wire cutting speed of (5) is 220 mm 2 / min, the current is 3A.

[0086] The metallographic treatment of (6) is as follows: the samples are processed with 80#, 180#, 240#, 400#, 600#, 800# and 1000# sandpapers respectively to make the sample surface smooth and scratch-free, and then the sample is polished to a mirror surface and ultrasonically cleaned for 5 minutes to obtain the finished product.

[0087] The volume density of the undoped low-metal phase TiB2-based cermet prepared in this comparative example is 4.11 g / cm 3 , hardness is 12.8GPa, fracture toughness is 6.06MPa·m 1 / 2 , the average grain size is 2.0μm.

[0088] The morphology of the Y2O3-doped low-metal phase TiB2-based cermet samples prepared in Examples 1-3 and the TiB2-based cermet prepared in the comparative example was characterized. Figure 2 shown.

[0089] The properties of the Y2O3-doped low-metal phase TiB2-based cermet samples prepared in Examples 1-3 and the TiB2-based cermet prepared in the comparative example were tested, and the results are as follows: Figure 3 , 4 shown.

[0090] From the comparison between Examples 1-3 and the comparative example, it can be seen that after adding an appropriate amount of rare earth oxide, the structure of the prepared metal ceramic sample is significantly refined and evenly distributed, the core-shell structure is also well improved, and the addition of rare earth oxide improves the comprehensive performance of the TiB2-based metal ceramic. When the content of rare earth oxide is adjusted, its performance also changes slightly, among which the low-metal phase TiB2-based metal ceramic doped with 0.5wt.% Y2O3 has the best structure and performance.

[0091] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a low-metal phase TiB2-based cermet doped with rare earth oxides, characterized in that: The following steps are involved: TiB2, rare earth oxide, SiC and nickel powder are ball-milled and mixed, and after being evenly mixed, the powder is put into a graphite mold for pressing and forming, and spark plasma sintering is performed to obtain a TiB2-based metal ceramic sample.

2. The method for preparing a rare earth oxide-doped low-metal phase TiB2-based cermet according to claim 1, characterized in that: Calculated by mass percentage, the TiB2 content is 74wt.%-75wt.%; the SiC content is 19-21wt.%; the nickel powder content is 4-6wt.%; and the rare earth oxide content is 0wt.%-1wt.%.

3. The method for preparing a rare earth oxide-doped low-metal phase TiB2-based cermet according to claim 1, characterized in that: The rare earth oxide is Y2O3.

4. The method for preparing a rare earth oxide-doped low-metal phase TiB2-based cermet according to claim 1, characterized in that: The average particle size of TiB2 is 3-8 μm, and the average particle sizes of SiC, Ni and Y2O3 are all less than 1 μm, so as to facilitate rapid reaction during the sintering process.

5. The method for preparing a rare earth oxide-doped low-metal phase TiB2-based cermet according to claim 4, characterized in that: The prepared metal ceramic has a core-shell structure with TiB2 as the core and (Ti, W) (B, C) solid solution as the shell. The core-shell structure has a low stress and high coherence interface. The added Y2O3 particles do not grow and have a size of <1μm, which plays a pinning and strengthening role on the grain boundaries. The small amount of added metal Ni reduces the sintering temperature, increases the density, and reduces the content of the metal phase through diffusion reaction, which is beneficial to improving the high temperature performance of the metal ceramic.

6. The method for preparing a rare earth oxide-doped low-metal phase TiB2-based cermet according to any one of claims 1 to 5, further comprising the following specific steps: (1) TiB2, SiC, Ni, and Y2O3 powders are weighed according to mass percentage, loaded into a ball mill, and anhydrous ethanol is added at 100% to 120% of the mass of the powders, and then mixed by a planetary ball mill; (2) After ball milling for 12 hours, vacuum drying was performed at 60°C-70°C for 8 hours to obtain a TiB2-based metal-ceramic mixed powder; (3) The uniformly mixed powder is loaded into a graphite mold and preliminarily pressed into shape using a tablet press so that the powder is tightly sealed in the graphite paper; (4) placing the mold filled with powder in a sintering furnace prepared by powder metallurgy for SPS sintering; (5) After sintering, demolding is performed to obtain a bulk ceramic sample. The volume density of the TiB2-based cermet after sintering is 4.11-4.33 g / cm 3 , hardness is 12.78-16.53GPa, fracture toughness is 6.06-7.66MPa·m 1 / 2 , the average grain size is 1.14-1.98μm.

7. The method for preparing a rare earth oxide-doped low-metal phase TiB2-based cermet according to claim 6, characterized in that: The ball milling medium in step (2) is WC balls, the ball-to-powder ratio is 10:1, and the ball milling speed is 300 r / min.

8. The method for preparing a rare earth oxide-doped low-metal phase TiB2-based cermet according to claim 6, characterized in that: The SPS sintering process in step (4) is as follows: the sintering temperature is 1550-1650°C, the sintering pressure is 30MPa; the heating step is to heat from room temperature to 650°C over 6 minutes, then heat to 1250°C at a heating rate of 50-150°C per minute for 6 minutes, and then heat to 1250°C at a heating rate of 0-100°C per minute for 7 minutes to 1600°C, and keep warm for 7 minutes, and then cool to room temperature with the furnace, and keep vacuum throughout the process, with a vacuum degree of 10 -3 -10 -1 Pa.

9. A method for preparing a low-metallic phase TiB2-based cermet doped with rare earth oxides, characterized in that: The invention is prepared by the preparation method described in any one of claims 1 to 9.

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