阅读说明：本技术 一种碳化硼增强二硼化钛基金属陶瓷及其制备方法和应用 (Boron carbide reinforced titanium diboride-based metal ceramic and preparation method and application thereof ) 是由 许亮 谭大旺 郭伟明 林华泰 于 2019-09-04 设计创作，主要内容包括：本发明属于陶瓷切削刀具领域,公开了一种碳化硼(B<Sub>4</Sub>C)增强二硼化钛(TiB<Sub>2</Sub>)基金属陶瓷及其制备方法和应用。所述碳化硼增强二硼化钛基金属陶瓷是将TiB<Sub>2</Sub>-B<Sub>4</Sub>C陶瓷粉和粘结剂WC、Co、Mo球磨混合,干燥后得到混合粉体,再将混合粉体在真空中升温至1000～1500℃,再在氩气的保护下,轴向加压为30～50MPa下,升温至1750～1900℃,经放电等离子烧结制得。本发明B<Sub>4</Sub>C增强TiB<Sub>2</Sub>基金属陶瓷具有硬度高,化学稳定性好,较好的耐磨性和切削性能,可应用于难加工材料的切削刀具领域中。(The invention belongs to the field of ceramic cutting tools and discloses boron carbide (B) 4 C) Enhanced titanium diboride (TiB) 2 ) A base metal ceramic and a preparation method and application thereof. The boron carbide reinforced titanium diboride-based cermet is prepared by mixing TiB 2 ‑B 4 And C, ball-milling and mixing the ceramic powder with binders WC, Co and Mo, drying to obtain mixed powder, heating the mixed powder to 1000-1500 ℃ in vacuum, heating to 1750-1900 ℃ under the protection of argon and axial pressurization of 30-50 MPa, and performing spark plasma sintering to obtain the ceramic powder. Invention B 4 C enhanced TiB 2 The base cermet has high hardness, high chemical stability, high wear resistance and high cutting performance, and may be used in cutting tool for hard-to-machine material.)

1. A boron carbide reinforced titanium diboride-based cermet, characterized in that the boron carbide reinforced titanium diboride-based cermet is prepared by mixing TiB₂-B₄And C, ball-milling and mixing the ceramic powder with binders WC, Co and Mo, drying to obtain mixed powder, heating the mixed powder to 1000-1500 ℃ in vacuum, heating to 1750-1900 ℃ under the protection of argon and axial pressurization of 30-50 MPa, and performing spark plasma sintering to obtain the ceramic powder.

2. The boron carbide-reinforced titanium diboride-based cermet according to claim 1, wherein the boron carbide-reinforced titanium diboride-based cermet has a densification of 98 to 100Percent, the hardness of the boron carbide reinforced titanium diboride-based cermet is 18-24 GPa, and the fracture toughness of the boron carbide reinforced titanium diboride-based cermet is 6-11 MPa.m^1/2(ii) a The bending strength of the boron carbide reinforced titanium diboride-based cermet ranges from 800 MPa to 1500 MPa.

3. The boron carbide-reinforced titanium diboride-based cermet according to claim 1, wherein the TiB₂：B₄C: WC: co: the mass ratio of Mo is (56-76): (14-19): (3-20): (1-2): (1-8).

4. The boron carbide reinforced titanium diboride-based cermet according to claim 1, wherein the cemented carbide balls for ball milling are YG6 balls, the rotation speed of the ball milling is 200-400 rpm, and the time of the ball milling and mixing is 4-12 h.

5. The boron carbide-reinforced titanium diboride-based cermet according to claim 1, wherein the TiB₂The purity of the powder is 98-99.99 wt.%, and the particle size is 0.5-3 μm; b is₄The purity of the C powder is 97-99.99 wt.%, and the particle size is 0.5-1.5 μm; the purity of the WC powder is 99-99.9 wt.%, and the particle size of the WC powder is 0.3-1 μm; the purity of the Co powder and the purity of the Mo powder are both 98-99.9 wt.%, and the particle sizes of the Co powder and the Mo powder are both 1-5 μm.

6. The boron carbide-reinforced titanium diboride-based cermet according to claim 1, wherein the rate of temperature increase to 1000 to 1500 ℃ is 150 to 300 ℃/min, and the rate of temperature increase to 1750 to 1900 ℃ is 50 to 100 ℃/min.

7. The boron carbide-reinforced titanium diboride-based cermet according to claim 1, wherein the sintering time is 5-20 min.

8. The method for preparing the boron carbide enhanced titanium diboride-based cermet according to any of claims 1-7, comprising the specific steps of:

s1, mixing TiB₂-B₄Mixing the C ceramic powder with the binders WC, Co and Mo, and drying to obtain TiB₂-B₄Mixed powder of C-WC-Co-Mo;

s2, mixing TiB₂-B₄Placing the mixed powder of C-WC-Co-Mo into a graphite die of a discharge plasma sintering furnace, heating to 1000-1500 ℃ at 150-300 ℃/min under the condition of a vacuum degree of less than 1mbar, then filling 1atm of argon, axially pressurizing to 30-50 MPa after filling, heating to 1750-1900 ℃ at 50-100 ℃/min at the same time of beginning filling, sintering for 5-20 min, cooling to 700-900 ℃ at 50-150 ℃/min, axially releasing pressure, and cooling along with the furnace to obtain B₄C enhanced TiB₂A base cermet.

9. Use of the boron carbide reinforced titanium diboride based cermet according to any one of claims 1 to 7 in the field of cutting tools.

10. The use of the boron carbide reinforced titanium diboride-based cermet according to claim 9 in the cutting tool field, wherein the boron carbide reinforced titanium diboride-based cermet cutting tool has a relative density of 98 to 100%, the hardness of the boron carbide reinforced titanium diboride-based cermet cutting tool is 18 to 24GPa, and the fracture toughness of the boron carbide reinforced titanium diboride-based cermet cutting tool is 6 to 11 MPa-m^1/2(ii) a The boron carbide reinforced titanium diboride-based cermet cutter has the bending strength of 800-1500 MPa.

Technical Field

The invention belongs to the technical field of ceramic cutting tools, and particularly relates to boron carbide (B)₄C) Enhanced titanium diboride (TiB)₂) A base metal ceramic and a preparation method and application thereof.

Background

Cermet is a composite consisting of a metallic binder phase and a ceramic hard phase. Has the characteristics of high hardness, good heat resistance and the like, and is commonly used for machining cutting tools. The traditional metal ceramic takes carbide such as titanium carbide, titanium carbonitride and the like as a hard phase matrix, and takes a metal phase as a binder, so that the cutting performance of the metal ceramic is superior to that of hard alloy.

Boride is a ceramic with high melting point and high hardness, and has excellent high-temperature resistance and wear resistance. The novel boride-based cermet has better high-temperature strength due to higher hardness of hard phase than carbide, thereby having better cutting performance and being used for cutting difficult-to-process materials at high speed. The boride-based cermet at present is mainly TiB₂Mainly, is suitable for high-speed cutting hardening stainless steel, hardening titanium alloy and other difficult-to-process materials. Compared with pure titanium boride ceramic, the hardness of the existing titanium boride-based cermet is lower, and the toughness of the existing titanium boride-based cermet is poorer than that of the traditional cermet, so that the application range of the cermet is limited, and particularly the high-speed processing performance of the cermet is limited. The high-temperature strength of the titanium boride-based cermet can be kept by adding the additive and the second phase and controlling the sintering process, and meanwhile, the toughness and the hardness are greatly improved, so that the high-hardness high-toughness high-temperature-resistant titanium boride-based cermet cutter material is obtained. The boron carbide is a ceramic material with low density, high hardness, high wear resistance and good stability, has good physical and chemical compatibility with titanium boride, can play a strong role in hardening and toughening when added into the titanium boride-based cermet, and the obtained reinforced titanium boride-based cermet has higher hardness and also has the function of toughening. Due to the excellent mechanical property, the cutting tool used for high-speed machining can obtain better machining performance than the traditional metal ceramic and non-reinforced titanium boride-based metal ceramic tools. At present, the boride-based ceramic material prepared by the technology and the application thereof in the field of cutters are not reported.

Disclosure of Invention

To solve the above-mentioned disadvantages and drawbacks of the prior art, it is an object of the present invention to provide a boron carbide (B)₄C) Enhanced titanium diboride (TiB)₂) A base cermet.

In addition to the inventionOne purpose is to provide a structure B₄C enhanced TiB₂A preparation method of the base cermet. The method comprises the steps of mixing TiB₂-B₄C powder and binding agents WC, Co and Mo are used as raw materials, and B is realized by Spark Plasma Sintering (SPS)₄C enhanced TiB₂And (3) preparing the base cermet.

It is a further object of the present invention to provide a composition as defined above₄C enhanced TiB₂Application of the base cermet.

The purpose of the invention is realized by the following technical scheme:

a boron carbide reinforced titanium diboride-based cermet is prepared by mixing TiB₂-B₄And C, ball-milling and mixing the ceramic powder with binders WC, Co and Mo, drying to obtain mixed powder, heating the mixed powder to 1000-1500 ℃ in vacuum, heating to 1750-1900 ℃ under the protection of argon and axial pressurization of 30-50 MPa, and performing spark plasma sintering to obtain the ceramic powder.

Preferably, the compactness of the boron carbide reinforced titanium diboride-based cermet is 98-100%, the hardness of the boron carbide reinforced titanium diboride-based cermet is 18-24 GPa, and the fracture toughness of the boron carbide reinforced titanium diboride-based cermet is 6-11 MPa-m^1/2(ii) a The bending strength of the boron carbide reinforced titanium diboride-based cermet ranges from 800 MPa to 1500 MPa.

Preferably, the TiB₂：B₄C: WC: co: the mass ratio of Mo is (56-76): (14-19): (3-20): (1-2): (1-8).

Preferably, the hard alloy balls for ball milling are YG6 balls, the rotation speed of the ball milling is 200-400 r/min, and the time for ball milling and mixing is 4-12 h.

Preferably, the TiB₂The purity of the powder is 98-99.99 wt.%, and the particle size is 0.5-3 μm; b is₄The purity of the C powder is 97-99.99 wt.%, and the particle size is 0.5-1.5 μm; the purity of the WC powder is 99-99.9 wt.%, and the particle size of the WC powder is 0.3-1 μm; the purity of the Co powder and the purity of the Mo powder are both 98-99.9 wt.%, and the particle sizes of the Co powder and the Mo powder are both 1-5 μm.

Preferably, the heating rate of the temperature rise to 1000-1500 ℃ is 150-300 ℃/min, and the heating rate of the temperature rise to 1750-1900 ℃ is 50-100 ℃/min.

Preferably, the sintering time is 5-20 min.

The preparation method of the boron carbide reinforced titanium diboride-based cermet comprises the following specific steps:

s1, mixing TiB₂-B₄Mixing the C ceramic powder with the binders WC, Co and Mo, and drying to obtain TiB₂-B₄Mixed powder of C-WC-Co-Mo;

s2, mixing TiB₂-B₄Placing the mixed powder of C-WC-Co-Mo into a graphite die of a discharge plasma sintering furnace, heating to 1000-1500 ℃ at 150-300 ℃/min under the condition of a vacuum degree of less than 1mbar, then filling 1atm of argon, axially pressurizing to 30-50 MPa after filling, heating to 1750-1900 ℃ at 50-100 ℃/min at the same time of beginning filling, sintering for 5-20 min, cooling to 700-900 ℃ at 50-150 ℃/min, axially releasing pressure, and cooling along with the furnace to obtain B₄C enhanced TiB₂A base cermet.

The boron carbide reinforced titanium diboride-based cermet is applied to the field of cutting tools.

Preferably, the relative density of the boron carbide reinforced titanium diboride-based cermet cutter is 98-100%, and B is₄C enhanced TiB₂The hardness of the base metal ceramic cutter is 18-24 GPa, and B₄C enhanced TiB₂The fracture toughness of the base metal ceramic cutter is 6-11 MPa.m^1/2(ii) a B is₄C enhanced TiB₂The bending strength of the base cermet cutter is 800-1500 MPa.

Compared with the prior art, the invention has the following beneficial effects:

1. b of the invention₄C enhanced TiB₂The base cermets have high hardness and high wear resistance properties, mainly due to B₄C has excellent hardness, can inhibit the growth of crystal grains in the sintering process, and simultaneously shortens the sintering time by means of rapid spark plasma sintering on the premise of ensuring the densityThe growth time of the crystal grains realizes the preparation of the fine-grained, high-hardness, high-strength and high-toughness titanium boride-based cermet.

2. The invention is due to B₄C enhanced TiB₂The base cermet has higher hardness than the conventional cermet and the non-reinforced titanium boride-based cermet, has better toughness and strength than the conventional ceramic cutters such as alumina, silicon nitride and the like, and can further improve hardness by inhibiting the growth of crystal grains, so that the base cermet has good wear resistance and cutting performance, and the cutting tool B has good wear resistance and cutting performance₄C enhanced TiB₂The base metal ceramic cutter can be applied to high-speed processing of difficult-to-process materials, and the processing performance of the base metal ceramic cutter is greatly superior to that of the traditional carbide base metal ceramic and non-reinforced titanium boride base metal ceramic.

Drawings

FIG. 1 shows B obtained in example 1₄C enhanced TiB₂And (3) a microscopic morphology picture of the base metal ceramic blank.

FIG. 2 shows non-reinforced TiB prepared in comparative example 1₂And (3) a microscopic morphology picture of the base metal ceramic blank.

Detailed Description

The following examples are presented to further illustrate the present invention and should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated. Unless otherwise indicated, reagents and materials used in the following examples are commercially available.