Titanium boride composite ceramic material and method for manufacturing the same

Abstract

The present disclosure provides a titanium boride composite ceramic material and a preparation method thereof. The preparation method comprises: S1, preparing a phenolic resin-absolute ethanol solution; S2, adding TiB2 powder and Ni powder into the phenolic resin-absolute ethanol solution in sequence and stirring; S3, pouring the first mixture into a ball mill tank for mixing to obtain a second mixture; S4, collecting the second mixture and performing water bath heating and stirring, and drying to obtain a third mixture; S5, grinding and sieving the third mixture to obtain a mixed powder; S6, molding the mixed powder to obtain a plurality of first green bodies; S7, performing carbonization treatment on the first green bodies to obtain a plurality of second green bodies; S8, uniformly applying the first mixed liquid to the inner wall and outer wall of a graphite crucible and then air-drying; S9, equidistantly placing the second green bodies into the graphite crucible, uniformly covering pure silicon on the plurality of second green bodies, and placing the graphite crucible into a furnace for vacuum infiltration, and finally cooling to obtain a titanium boride ceramic composite material.

Description

Technical Field

[0001] This invention relates to the field of ceramic materials technology, and in particular to a titanium boride composite ceramic material and its preparation method. Background Technology

[0002] Due to its high hardness, high elastic modulus, and good wear resistance, TiB2 can be used in structural materials such as cutting tools and bulletproof materials, especially for the protection of heavy armored vehicles. Meanwhile, its good electrical conductivity makes it suitable as a functional material in the electronics and electrical engineering fields, such as electrode materials and electronic components.

[0003] The sintering of common TiB2 ceramic materials mainly involves methods such as pressureless sintering, hot pressing, and spark plasma sintering, which utilize direct contact between particles to achieve solid-phase material diffusion. Specifically, this is achieved through atomic diffusion between particles in the formed green body. These sintering methods require high sintering temperatures, consume a lot of energy, and require precise equipment. Furthermore, it is difficult to achieve densification, often necessitating the addition of sintering aids to lower the sintering temperature and regulate the energy and structure of grain boundaries to promote sintering. In contrast, reaction sintering involves infiltrating liquid silicon into a porous carbon-containing green body at high temperatures. The powder reacts with the infiltrated silicon, promoting densification while simultaneously introducing other phases in situ to form a composite ceramic material. This method is simple and significantly reduces costs, and it can also achieve net-size sintering of samples. Under conditions with lower requirements for powder quality, it can also produce products with excellent mechanical properties and high density. However, the wettability between TiB2 and Si is poor during reaction sintering, and the silicon infiltration process is not smooth, affecting the preparation, production, and subsequent use of reaction-sintered TiB2 ceramic composite materials. Summary of the Invention

[0004] One of the technical problems to be solved by this disclosure is that the wettability between TiB2 and Si is poor during existing reaction sintering, and the free Si in the composite material is detrimental to the material properties, thus affecting the later use of reaction sintered TiB2 ceramic composite materials.

[0005] To address the aforementioned technical problems, this disclosure provides a method for preparing titanium boride composite ceramic materials, comprising:

[0006] S1. Mix anhydrous ethanol and phenolic resin uniformly at room temperature to obtain a phenolic resin-anhydrous ethanol solution.

[0007] S2. Add TiB2 powder and Ni powder sequentially to the phenolic resin-anhydrous ethanol solution in S1 and stir until the first state is reached to obtain the first mixture;

[0008] Among them, the density of TiB2 powder is lower than that of Ni powder, and the first state is that there is no stratification phenomenon between Ni powder and TiB2 powder.

[0009] S3. Pour the first mixture into a ball mill jar for mixing to obtain the second mixture;

[0010] S4. Collect the second mixture in S3 and heat and stir it in a water bath to remove the anhydrous ethanol in the second mixture until the second mixture becomes viscous. After drying, the third mixture is obtained.

[0011] S5. Grind, sieve and granulate the third mixture in S4 to obtain a mixed powder;

[0012] S6. The mixed powder in S5 is molded into a certain volume to obtain several first blanks;

[0013] S7. Several first blanks from S6 are carbonized under argon protection to obtain several second blanks;

[0014] S8. Mix BN powder and anhydrous ethanol and sonicate to obtain a first mixed liquid with viscosity. Apply the first mixed liquid evenly to the inner and outer walls of the graphite crucible and then let it dry to prevent the Si in the second blank from reacting with the C in the graphite crucible.

[0015] S9. Place several second blanks from S7 at equal intervals into a graphite crucible, uniformly cover the several second blanks with pure silicon, place the entire graphite crucible into a high-temperature furnace for melting and infiltration under vacuum, and finally cool the graphite crucible to obtain titanium boride ceramic composite material.

[0016] In some embodiments, in the aforementioned method for preparing titanium boride composite ceramic materials, the carbon content of the phenolic resin in S1 is 50.32%, and the mass ratio of anhydrous ethanol to phenolic resin is 1:0.3974.

[0017] In some embodiments, in the aforementioned method for preparing titanium boride composite ceramic materials, the ball milling time in S3 is 12 hours.

[0018] In some embodiments, in the aforementioned method for preparing titanium boride composite ceramic materials, the water bath heating temperature in S4 is 70°C.

[0019] In some embodiments, in the aforementioned method for preparing titanium boride composite ceramic materials, the sieve mesh size in step S5 is 60 mesh.

[0020] In some embodiments, in the aforementioned method for preparing titanium boride composite ceramic materials, the pressure load in S6 is 200 MPa, and the holding time for molding is 10 s.

[0021] In some embodiments, in the aforementioned method for preparing titanium boride composite ceramic materials, the heating rate of the carbonization treatment in S7 is 1℃ / min, the carbonization temperature is 700℃, and the carbonization holding time is 3h.

[0022] In some embodiments, in the aforementioned method for preparing titanium boride composite ceramic materials, the ultrasonic time for the BN powder and anhydrous ethanol mixture in S8 is 5 min.

[0023] In some embodiments, in the aforementioned method for preparing titanium boride composite ceramic materials, during the melting and infiltration process of S9, the high-temperature furnace is first heated from room temperature to 1200°C in 2 hours, and then heated to 1550°C at a rate of 5°C / min for 1 hour of melting and infiltration.

[0024] The second aspect of this application provides a titanium boride composite ceramic material, which is prepared using the aforementioned titanium boride composite ceramic material preparation method.

[0025] Through the above technical solution, this disclosure provides a titanium boride composite ceramic material and its preparation method. Using titanium boride powder, phenolic resin, and Ni powder as raw materials, a TiB2 ceramic composite material is prepared after reactive melting and sintering. Ni is introduced into the raw materials in powder form. The introduction of metallic Ni improves the wettability of Si on the TiB2 matrix during melting and infiltration, making Si infiltration easier and increasing the SiC content generated during melting and infiltration, thereby reducing the free Si content in the composite material. Furthermore, the introduction of Ni leads to the formation of NiSi2 in the composite material after reactive sintering, which can serve as another phase material to improve the properties of the titanium boride composite ceramic material. This improves the Vickers hardness and electrical conductivity of the titanium boride ceramic composite material. Compared with traditional sintering methods, this method is not only less difficult and less costly to operate, but also produces titanium boride multiphase ceramics with good mechanical properties and high density, which is beneficial for the later use of titanium boride ceramic composite materials. Attached Figure Description

[0026] Figure 1 (a) is a SEM image of the cross section of a sample obtained by reaction sintering without the introduction of Ni in a titanium boride composite ceramic material and its preparation method disclosed in this embodiment.

[0027] Figure 1 (b) is a SEM image of the cross section of a sample obtained by introducing Ni through reaction sintering in a titanium boride composite ceramic material and its preparation method disclosed in this embodiment.

[0028] Figure 2 This is a high-magnification SEM image of the cross-section of a sample obtained by reaction sintering without the introduction of Ni in a titanium boride composite ceramic material and its preparation method disclosed in this embodiment.

[0029] Figure 3This is an X-ray diffraction pattern of a titanium boride composite ceramic material and its preparation method disclosed in this embodiment, showing composite ceramic materials with different Ni contents.

[0030] Figure 4 This is a SEM backscattering image of a titanium boride composite ceramic material with a Ni content of 20 wt.% disclosed in this embodiment and its preparation method.

[0031] Figure 5 This is an analysis diagram of the EDS composition of different regions of a 20wt.% Ni-containing composite ceramic material in the titanium boride composite ceramic material and its preparation method disclosed in this embodiment.

[0032] Figure 6 This is a SEM backscattering image of a titanium boride composite ceramic material and its preparation method disclosed in this embodiment, showing composite ceramic materials with different Ni contents. Detailed Implementation

[0033] The present invention will be described in detail below with reference to embodiments.

[0034] The information on the raw materials used in the embodiments of the present invention is shown in Table 1 below.

[0035] Table 1

[0036]

[0037] The titanium boride powder used in this invention has a particle size d 50 =5μm, purity is 99%; nickel powder particle size d 50 =5μm, purity is 99%; the phenolic resin used is 2124 series thermosetting (novolac type) phenolic resin, with a solid content of 55% and free phenol content ≤16%; the silicon block used is industrial pure silicon with a purity of 99%.

[0038] In this embodiment of the invention, the Archimedes displacement method is used to determine the bulk density and open porosity of titanium boride composite ceramic materials.

[0039] In this embodiment of the invention, the resistivity of titanium boride composite material is measured using the four-probe method.

[0040] In this embodiment of the invention, the Vickers hardness test method is the Vickers indentation hardness test.

[0041] In the embodiments of the present invention, the bending strength and fracture toughness of titanium boride composite ceramic materials were determined by the three-point bending method and the single-sided notched beam method, respectively.

[0042] In this embodiment of the invention, a scanning electron microscope equipped with an EDS spectrometer is used to observe the microstructure of the composite material.

[0043] In this embodiment of the invention, X-ray diffraction was used to analyze the phase composition of the ceramic composite material. The prepared titanium boride ceramic composite material consists of four phases: TiB2, SiC, NiSi2, and free Si.

[0044] Comparative Example 1

[0045] S1. At room temperature, first stir 10 wt.% phenolic resin and 100 g anhydrous ethanol until they are evenly mixed.

[0046] S2. Add 90 wt.% TiB2 to the phenolic resin-anhydrous ethanol solution in S1 and stir thoroughly at room temperature to obtain the first mixture.

[0047] S3. Transfer the first mixture into a ball mill jar and ball mill for 12 hours to obtain the second mixture;

[0048] S4. Spread the second mixture from S3 evenly in a large petri dish and dry it in a 70℃ oven for 24 hours to obtain the third mixture.

[0049] S5. Grind and granulate the third mixture in S4 using a 60-mesh sieve to obtain a mixed powder;

[0050] S6. Weigh the mixed powder and pour it into the mold and spread it evenly. Hold the pressure under a load of 200MPa for 10s, and then demold to obtain several first blanks, namely TiB2 blanks.

[0051] S7. Several first blanks from S6 are placed into a quartz crucible and then placed in a tube furnace. After sealing and evacuating to a vacuum, flowing argon gas is introduced and heated to 700℃ at a rate of 1℃ / min and held for 3 hours to carbonize the first blanks, thereby obtaining several second blanks, namely TiB2 / C composite blanks.

[0052] S8. Mix BN powder and anhydrous ethanol and sonicate to obtain a first mixed liquid with viscosity. Apply the first mixed liquid evenly to the inner and outer walls of the graphite crucible and then let it dry.

[0053] S9. The carbonized second blanks are placed evenly in a graphite crucible coated with a first mixed liquid of BN powder and anhydrous ethanol. Elemental silicon particles are spread evenly on several of the second blanks. The graphite crucibles are then placed in a graphite vacuum furnace for melting and infiltration reaction. The vacuum degree of melting and infiltration is 40 Pa to 60 Pa, and the melting and infiltration temperature is 1550 °C. The temperature is first raised from room temperature to 1200 °C over 2 hours, and then raised to the melting and infiltration temperature at a rate of 5 °C / min. The temperature is held at this temperature for 1 hour. Finally, the sintered body is taken out after cooling in the furnace. The excess elemental silicon on the surface of the sintered body is polished off to obtain the reaction-sintered titanium boride composite ceramic material.

[0054] Among them, the morphology of the interface fracture surface is as follows Figure 1As shown in (a), a clear stratification phenomenon was observed, with three distinct regions: I, II, and III. These three regions represent the permeated region, the permeated-impermeable transition region, and the impermeable region, respectively. The fracture surface photograph of the ceramic composite material under high magnification is shown below. Figure 2 As shown, it can be observed that the microstructure of the composite material in the permeation zone (Ⅰ) is uniform, such as... Figure 2 As shown in (a), the TiB2 particles in the raw material have good density and few small pores. The phenolic resin in the raw material exists in the form of free carbon and has a low content. The TiB2 particles are exposed in the permeated-unpermeated transition zone (II), as shown in (a). Figure 2 As shown in (b), there are many pores, the material is not dense enough, and the content of free C increases, as shown in the white area in the figure; in the unpermeable area (Ⅲ), TiB2 particles and free C are the main components, the density is poor and there are many pores, that is, there are obvious connection areas between the various color blocks.

[0055] Example 1

[0056] The method is the same as in Comparative Example 1, except that:

[0057] During the S2 mixing process, low-density TiB2 powder is first added to the phenolic resin-anhydrous ethanol solution and stirred evenly. Then, high-density Ni powder is added until the high-density Ni and low-density TiB2 no longer separate into layers, thus obtaining the first mixture. The content of Ni in the first mixture is 10 wt.% and the content of TiB2 is 90 wt.%.

[0058] The final ceramic composite sample exhibited complete penetration and a relatively uniform microstructure; furthermore, the flexural strength of the ceramic composite was tested to be 137 MPa, and the fracture toughness was 3.9 MPa·m. 1 / 2 Its Vickers hardness is 7.3 GPa, and its bulk density is 3.36 g·cm³. –3 The open porosity is 6.14%, the NiSi2 particle size is 4.5 μm, and the resistivity is 6.85 × 10⁻⁶. -7 Ω·m; Meanwhile, the fracture surface image of this composite material is as follows: Figure 1 As shown in (b), compared to the composite material without Ni, the ceramic composite material in this example exhibits a uniform microstructure and complete infiltration during sintering; the X-ray diffraction pattern of this composite material is as follows. Figure 3 As shown in the figure, the composite material consists of four components: TiB2, SiC, NiSi2, and Si. This is because during the silicon infiltration sintering process, the infiltrated Si reacts with the Ni in the raw material to form NiSi2. The SEM backscattered image of this composite material is shown below. Figure 6(a) It was observed that the composite material consisted of four phases: light gray, bright white, black, and dark gray. Analysis revealed that the bright white region was the NiSi2 phase, the light gray region was the TiB2 phase, the dark gray region was the Si and SiC composite region, and the black region was the SiC phase.

[0059] Example 2

[0060] The method is the same as in Example 1, except that:

[0061] The Ni content in the first mixture of S2 is 20 wt.%.

[0062] The final ceramic composite sample exhibited complete penetration and a relatively uniform microstructure. The flexural strength of the ceramic composite was 135 MPa, and its fracture toughness was 3.7 MPa·m. 1 / 2 Its Vickers hardness is 7.3 GPa, and its bulk density is 3.46 g·cm³. –3 The open porosity is 8.12%, the NiSi2 particle size is 5.3 μm, and the resistivity is 9.35 × 10⁻⁶. -7 Ω·m; the X-ray diffraction pattern of the composite material is as follows Figure 3 20 wt.% of; Figure 4 Its high-magnification SEM backscattered image; the EDS composition analysis results of each region of the composite material are shown in the figure. Figure 5 The SEM backscattered image of the composite material is as follows: Figure 6 (b) Analysis shows that the bright white area is the NiSi2 phase, the light gray area is the TiB2 phase, the dark gray area is the Si and SiC composite area, and the black area is SiC.

[0063] Example 3

[0064] The method is the same as in Example 1, except that:

[0065] The Ni content in the first mixture of S2 is 30 wt.%.

[0066] The final ceramic composite sample exhibited complete penetration and a relatively uniform microstructure. Testing revealed that the flexural strength of the ceramic composite was 112 MPa, and its fracture toughness was 3.65 MPa·m. 1 / 2 Its Vickers hardness is 12.2 GPa, and its bulk density is 3.50 g·cm³. –3 The open porosity is 8.99%, the NiSi2 particle size is 5.8 μm, and the resistivity is 5.84 × 10⁻⁶. -7 Ω·m; the X-ray diffraction pattern of the composite material is as follows Figure 3 30 wt.% of the composite material; SEM backscattered image of the composite material is as follows: Figure 6 (c)

[0067] Example 4

[0068] The method is the same as in Example 1, except that:

[0069] The Ni content in the first mixture of S2 is 40 wt.%.

[0070] The final ceramic composite sample exhibited complete penetration and a relatively uniform microstructure; the flexural strength of the ceramic composite was 106 MPa, and the fracture toughness was 3.1 MPa·m. 1 / 2 Its Vickers hardness is 12.7 GPa, and its bulk density is 3.56 g·cm³. –3 The open porosity is 9.72%, the NiSi2 particle size is 6.2 μm, and the resistivity is 6.90 × 10⁻⁶. -7 Ω·m; the X-ray diffraction pattern of the composite material is as follows Figure 3 As shown in 40 wt.%, observe Figure 3 It can be seen that as the Ni content in the raw materials increases, the intensity of the main diffraction peak of SiC gradually increases, indicating that the content of newly formed SiC in the composite material increases. This demonstrates that Ni can indeed improve the wettability between TiB2 and Si to a certain extent, allowing liquid Si to penetrate more easily into the preform. The SEM backscattered image of this composite material is shown below. Figure 6 (d)

[0071] The above embodiments should be understood as being used only to illustrate the present invention more clearly, and not to limit the scope of the present invention. Modifications of the present invention by those skilled in the art in various equivalent forms all fall within the scope defined by the appended claims.

Claims

1. A method for preparing a titanium boride composite ceramic material, characterized in that: Includes the following steps: S1. Mix anhydrous ethanol and phenolic resin uniformly at room temperature to obtain a phenolic resin-anhydrous ethanol solution. S2. TiB2 powder and Ni powder are added sequentially to the phenolic resin-anhydrous ethanol solution in S1 and stirred until the first state is reached to obtain the first mixture. The density of TiB2 powder is lower than that of Ni powder. The first state is characterized by no stratification between Ni powder and TiB2 powder. The Ni content is 10 wt.%, 20 wt.%, 30 wt.%, or 40 wt.%. S3. Pour the first mixture into a ball mill jar for mixing to obtain the second mixture; S4. Collect the second mixture from S3 and heat and stir it in a water bath to remove the anhydrous ethanol from the second mixture until the second mixture becomes viscous. After drying, the third mixture is obtained. S5. Grind, sieve and granulate the third mixture from S4 to obtain a mixed powder; S6. The mixed powder from S5 is molded into a certain volume to obtain several first blanks; S7. The plurality of first blanks in S6 are carbonized under argon protection to obtain a plurality of second blanks; S8. Mix BN powder and anhydrous ethanol and sonicate to obtain a first mixed liquid with viscosity. Apply the first mixed liquid evenly to the inner and outer walls of the graphite crucible and then let it dry. S9. Place the plurality of second blanks from S7 into a graphite crucible at equal intervals, uniformly cover the plurality of second blanks with pure silicon, place the graphite crucible as a whole into a high-temperature furnace for melting and infiltration under vacuum, and finally cool the graphite crucible to obtain titanium boride ceramic composite material. The introduction of metallic Ni improves the wettability of Si on the TiB2 matrix during the melting process, making Si infiltration easier and increasing the SiC content generated during the melting process, thereby reducing the content of free Si in the composite material. Furthermore, the introduction of Ni leads to the formation of NiSi2 in the composite material after reaction sintering.

2. The method for preparing a titanium boride composite ceramic material according to claim 1, characterized in that, The phenolic resin in S1 has a carbon content of 50.32%, and the mass ratio of anhydrous ethanol to phenolic resin is 1:0.3974.

3. The method for preparing a titanium boride composite ceramic material according to claim 1, characterized in that, The ball milling time in S3 is 12 hours.

4. The method for preparing a titanium boride composite ceramic material according to claim 1, characterized in that, The water bath heating temperature in S4 is 70 ℃.

5. The method for preparing a titanium boride composite ceramic material according to claim 1, characterized in that, The sieve mesh size for S5 is 60 mesh.

6. The method for preparing a titanium boride composite ceramic material according to claim 1, characterized in that, The pressure load in S6 is 200 MPa, and the holding time for compression molding is 10 s.

7. The method for preparing a titanium boride composite ceramic material according to claim 1, characterized in that, The heating rate for carbonization in S7 is 1 ℃ / min, the carbonization temperature is 700 ℃, and the holding time for carbonization is 3 h.

8. The method for preparing a titanium boride composite ceramic material according to claim 1, characterized in that, The ultrasonic time for the BN powder and anhydrous ethanol mixture in S8 is 5 min.

9. The method for preparing a titanium boride composite ceramic material according to claim 1, characterized in that, During the melting and infiltration process of S9, the high-temperature furnace first raises the temperature from room temperature to 1200 ℃ in 2 hours, and then raises the temperature to 1550 ℃ at a rate of 5 ℃ / min for 1 hour of melting and infiltration.

10. A titanium boride composite ceramic material, characterized in that, The titanium boride composite ceramic material is prepared using any one of the preparation methods described in claims 1-9.

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