阅读说明：本技术 一种致密化碳化钛复合陶瓷的制备方法 (Preparation method of densified titanium carbide composite ceramic ) 是由 茹红强 孙卫康 王春华 于 2020-12-30 设计创作，主要内容包括：本发明提供一种致密化碳化钛复合陶瓷的制备方法,所述复合陶瓷的原料中,TiC粉、添加剂、烧结助剂、钛源、C源的质量比为(30-80):(0-75):(0-30):(0-35):(0-25),在原料中,引入钛源、C源,通过原位反应,在碳化钛陶瓷基体中合成超细的碳化钛晶粒,提高了硼化锆的烧结活性,有利于致密化,相对密度95%以上；同时引入添加剂和烧结助剂,有利于形成液相,促进碳化钛颗粒之间重新排列,便于形成烧结颈,本发明制得的TiC复合陶瓷材料具有致密度高、高硬度、高韧性、低电阻率等性能,便于大规模自动化生产。(The invention provides a preparation method of densified titanium carbide composite ceramic, wherein the raw materials of the composite ceramic comprise TiC powder, additives, sintering aids, titanium sources and C sources in a mass ratio of (30-80): 0-75): 0-30): 0-35): 0-25, the titanium sources and the C sources are introduced into the raw materials, and superfine titanium carbide crystal grains are synthesized in a titanium carbide ceramic matrix through in-situ reaction, so that the sintering activity of zirconium boride is improved, the densification is facilitated, and the relative density is more than 95%; meanwhile, the additive and the sintering aid are introduced, so that the formation of a liquid phase is facilitated, the rearrangement of titanium carbide particles is promoted, and the formation of a sintering neck is facilitated.)

1. The preparation method of the densified titanium carbide composite ceramic is characterized in that raw materials of the composite ceramic comprise TiC powder, an additive, a sintering aid, a titanium source and a C source, wherein the mass ratio of the TiC powder to the additive to the sintering aid to the titanium source to the C source is (30-80): 0-75): 0-30): 0-35): 0-25.

2. The preparation method according to claim 1, wherein the additive is one or more of tungsten carbide, silicon carbide, boron carbide, aluminum oxide, silicon nitride and aluminum nitride.

3. The process according to claim 1, wherein said TiC powder has an average particle size of 0.4 to 5 μm and a purity of more than 96%.

4. The preparation method according to claim 1, wherein the C source can be one or more of phenolic resin, graphite powder, carbon black and graphene.

5. The method as claimed in claim 1, wherein the titanium source is selected from the group consisting of Ti powder, TiCl₄、TiO₂One or more of powder and butyl titanate.

6. The preparation method according to claim 1, wherein the sintering aid is one or more of calcium oxide, magnesium oxide, yttrium oxide, cerium oxide and lanthanum oxide.

7. The method as claimed in claim 1, wherein the method comprises mixing the raw material with the binder and the liquid medium to form a slurry, wherein the mass ratio of the raw material to the binder to the liquid medium is 100 (20-150): (120-180).

8. The method of claim 7, wherein the binder is selected from the group consisting of phenolic resin, PVA, and PVB; the liquid medium may be water, acetone or ethanol.

9. The method according to claim 7, wherein the method comprises sintering, and the sintering atmosphere can be one or two of vacuum, argon and hydrogen.

10. The preparation method according to claim 7, wherein the preparation method comprises sieving granulation, and the sieving granulation has a sieve mesh size of 40-100 meshes.

11. The method as claimed in claim 7, wherein the method comprises compression molding at a pressure of 100 MPa to 250 MPa.

Technical Field

The invention belongs to the technical field of ceramic materials, and particularly relates to a preparation method of densified titanium carbide composite ceramic.

Background

Titanium carbide ceramics have excellent characteristics of high strength, good heat conduction, low resistivity, high temperature oxidation resistance, chemical corrosion resistance and the like, and are often used in the fields of cutting tools, wear-resistant components, electrical contact components, nuclear fusion reactors and the like. However, titanium carbide is a superhard material and is difficult to sinter and densify.

At present, the densified titanium carbide composite ceramic can be obtained by sintering modes such as hot pressing, SPS, self-propagating and the like; however, the hot-pressing sintering process is adopted, the upper surface and the lower surface of the product bear great pressure, the shape of the product is usually a plate or a sheet, and the shape is simple and cannot be complicated, so the shape is limited; furthermore, the number of products sintered per batch is also limited due to product compression. Although the SPS and the self-propagating sintering process have no requirement on the shape of a product, the two sintering processes limit the inner cavity of the sintering furnace to have very small size and extremely low yield, are limited to experimental research and research at present and are not suitable for large-scale industrial production.

The invention patent CN102390999A discloses a liquid phase sintered SiC-TiC composite ceramic and a preparation method thereof, wherein the liquid phase sintered SiC-TiC composite ceramic is prepared from 15-50 wt% of titanium carbide, 40-80 wt% of silicon carbide, 5-10 wt% of sintering aid Al2O3 and Y2O3 through burdening, pulping, molding, drying and sintering, the normal temperature rupture strength of the SiC-TiC composite ceramic is improved to 580MPa, and the fracture toughness is improved to 7.8 MPa.m 1/2, but the density of the ceramic prepared by the method is not high.

The invention patent CN110330318A discloses a micro-nano composite ceramic material, which takes micron alumina as a matrix, micron tungsten carbide and nano titanium carbide as second phase materials and graphene as a strengthening and toughening phase, and has the advantages of bending strength of 550.92 +/-25.55 MPa, hardness of 23.54 +/-0.63 GPa and fracture toughness of 8.76 +/-0.51 MPa.m^1/2However, although the hot-pressing sintering process is adopted, the sample can obtain higher comprehensive performance, but the shape, the size and the number of the sample are greatly limited, and the hot-pressing sintering process is not suitable for large-scale mass production.

Disclosure of Invention

In order to solve the problems in the prior art and further optimize the prior process, the invention provides a preparation method of densified titanium carbide composite ceramic, so as to achieve the aim of preparing titanium carbide composite ceramic with high compactness, strong shape plasticity and convenience for large-scale mass production.

In order to solve the technical problems, the invention adopts the following technical scheme:

a preparation method of densified titanium carbide composite ceramic is characterized in that raw materials of the composite ceramic comprise TiC powder, an additive, a sintering aid, a titanium source and a C source, wherein the mass ratio of the TiC powder to the additive to the sintering aid to the titanium source to the C source is (30-80): 0-75): 0-30): 0-35): 0-25;

the additive can be one or more of tungsten carbide, silicon carbide, boron carbide, aluminum oxide, silicon nitride and aluminum nitride;

the average particle size of the TiC powder is 0.4-5 mu m, and the purity is more than 96%;

the C source can be one or more of phenolic resin, graphite powder, carbon black and graphene;

the titanium source can be Ti powder or TiCl₄、TiO₂One or more of powder and butyl titanate;

the sintering aid can be one or more of calcium oxide, magnesium oxide, yttrium oxide, cerium oxide and lanthanum oxide;

the preparation method comprises the following steps:

(1) mixing the raw materials, the binding agent and a liquid medium into slurry, and carrying out ball milling in a ball milling tank;

(2) carrying out spray granulation on the mixed slurry or drying the mixed slurry in a drying oven at 40-100 ℃ and then manually sieving and granulating;

(3) putting the granulated powder into a mold, and performing compression molding to prepare a ceramic green body;

(4) putting the pressed ceramic green body into a drying oven at 100-250 ℃ for drying;

(5) putting the green body into high-temperature sintering, and performing reaction sintering at 1800-2150 ℃ to obtain a densified TiC composite ceramic material;

the mass ratio of the raw materials, the binding agent and the liquid medium is 100 (20-150): 120-180);

the binder may be phenolic resin, PVA or PVB;

the liquid medium may be water, acetone or ethanol;

sintering, wherein the sintering atmosphere can be one or two of vacuum, argon and hydrogen;

sieving and granulating, wherein the specification of a screen is 40-100 meshes;

and (3) compression molding, wherein the pressure is 100-250 MPa.

The method adopts a pressureless sintering process, and the shape, the size and the number of samples are not limited because the samples do not need to be pressurized; and a titanium source and a carbon source are introduced into the raw materials, Ti + C = TiC, TiO2+3C = TiC +2CO, so that the sintering activity of the titanium carbide is improved, the densification is promoted, and the ultrafine titanium carbide particles have dispersion strengthening effect on a ceramic matrix and a formed liquid phase, so that the comprehensive performance is improved, the comprehensive performance obtained by a pressureless sintering process is similar to that obtained by hot-pressing sintering, and the pressureless sintering process is suitable for large-scale mass production.

By adopting the technical scheme, the invention has the beneficial effects that:

1. by adopting the preparation method of the densified titanium carbide composite ceramic, the titanium source and the C source are introduced into the raw materials, and the superfine titanium carbide crystal grains are synthesized in the titanium carbide ceramic matrix through in-situ reaction, so that the sintering activity of zirconium boride is improved, densification is facilitated, and the relative density is 95-99%;

2. by adopting the preparation method of the densified titanium carbide composite ceramic, the additive and the sintering aid are introduced into the raw materials, so that the liquid phase is favorably formed, the rearrangement of titanium carbide particles is promoted, and the sintering neck is conveniently formed, thereby reducing the sintering temperature which is 1850-;

3. by adopting the preparation method of the densified titanium carbide composite ceramic, the bending strength and the fracture toughness of the composite ceramic are improved, the bending strength reaches 485-619MPa, and the fracture toughness reaches 4.73-8.12 MPa.m 1/2;

4. by adopting the preparation method of the densified titanium carbide composite ceramic, the porosity of the titanium carbide composite ceramic is reduced, and the porosity is 0.31-0.82%; meanwhile, the Vickers hardness reaches 19.50-26.09 GPa;

5. by adopting the preparation method of the densified titanium carbide composite ceramic, the resistivity of the titanium carbide composite ceramic material can reach 4.07 multiplied by 10^-6-6.44×10^-5Ω·m；

6. The invention adopts a pressureless sintering process, can prepare products with plastic shapes, has simple process, low requirement on equipment, low product cost and high performance, is convenient for large-scale automatic production, and has huge market practical value.

Drawings

FIG. 1 is a drawing of a strip sample of a TiC-SiC composite ceramic material in example 1 of the present invention.

FIG. 2 is a metallographic microscopic view of a TiC-SiC composite ceramic material in example 1 of the present invention.

FIG. 3 is a drawing of a bar-shaped sample made of a TiC-WC composite ceramic material in example 2 of the present invention.

FIG. 4 is a metallographic micrograph of a TiC-WC composite ceramic material obtained in example 2 of the present invention.

FIG. 5 is a SEM and EDS picture of a TiC-WC composite ceramic material in example 2 of the invention.

FIG. 6 is TiC-Al in example 3 of the present invention₂O₃And (3) a strip sample object diagram of the composite ceramic material.

FIG. 7 is TiC-Al in example 3 of the present invention₂O₃And (3) metallographic micrographs of the composite ceramic material.

The specific implementation mode is as follows:

the invention is further illustrated below with reference to specific examples.

Example 1

A preparation method of densified titanium carbide composite ceramic comprises the following steps:

(1) mixing TiC powder, silicon carbide and aluminum oxide serving as additives, yttrium oxide serving as a sintering aid, Ti powder and graphene into mixed powder according to the mass ratio of 50:65:4:10:3, mixing the mixed powder, a binding agent of 5% PVA solution and liquid medium deionized water into slurry according to the mass ratio of 100:20:150, and carrying out ball milling in a ball milling tank;

the average particle size of the TiC powder is 0.8 mu m, and the purity is 99.9%;

the mass ratio of the silicon carbide to the aluminum oxide is 15: 1;

(2) carrying out spray granulation on the mixed slurry;

(3) putting the granulated powder into a mold, and performing compression molding by a press machine under the pressure of 150MPa to obtain a green body;

(4) putting the pressed ceramic green body into a drying oven at 150 ℃ for drying and discharging the water in the body;

(5) putting the green body into sintering, heating to 1600 ℃ in a vacuum state, preserving heat for 30min, then filling argon, preserving heat for 180min when the sintering temperature reaches 2150 ℃, and obtaining the TiC-SiC composite ceramic material;

the TiC-SiC composite ceramic material strip sample prepared in the embodiment is shown in fig. 1, and the metallographic micrograph is shown in fig. 2; tests show that the TiC-SiC composite ceramic material has the relative density of 98.52 percent, the porosity of 0.31 percent, the bending strength of 619MPa and the fracture toughness of 8.12 MPa.m^1/2A Vickers hardness of 26.09GPa and a resistivity of 6.44X 10^-5Ω·m。

Example 2

A preparation method of densified titanium carbide composite ceramic comprises the following steps:

(1) mixing TiC powder, tungsten carbide as an additive, cerium oxide as a sintering aid, titanium oxide powder and graphite powder in a mass ratio of 65:10:5:35:12 to form mixed powder, mixing the mixed powder, a binding agent of 5% phenolic resin solution and liquid medium ethanol in a mass ratio of 100:30:180 to form slurry, and performing ball milling in a ball milling tank;

the average particle size of the TiC powder is 0.5 mu m, and the purity is 98.5%;

(2) drying the ball-milled slurry in a drying oven at 80 ℃, manually grinding and crushing the powder, and sieving the powder by a 100-mesh sieve for granulation;

(3) putting the granulated powder into a mold, and performing compression molding by a press machine under the pressure of 200MPa to obtain a green body;

(4) putting the pressed ceramic green body into a drying oven at 200 ℃ for drying and discharging the water in the body;

(5) putting the green body into sintering, heating to 1550 ℃ in a vacuum state, preserving heat for 60min, preserving heat for 120min when the sintering temperature reaches 2050 ℃, and obtaining a TiC-WC composite ceramic material;

the TiC-WC composite ceramic material strip sample prepared in this example is shown in fig. 3, the metallographic micrograph is shown in fig. 4, and the SEM and EDS are shown in fig. 5; after testing, the TiC-WC composite potteryThe relative density of the porcelain material was 95.73%, the porosity was 0.82%, the bending strength was 525MPa, and the fracture toughness was 7.17MPa · m^1/2A Vickers hardness of 25.78GPa and a resistivity of 4.07 x 10^-6Ω·m。

Example 3

A preparation method of densified titanium carbide composite ceramic comprises the following steps:

(1) mixing TiC powder, additive aluminum oxide, sintering aid magnesium oxide, titanium oxide powder and carbon black =55:35:5:18:9 into mixed powder according to the mass ratio, mixing the mixed powder, a bonding agent with the concentration of 5% PVB and a liquid medium acetone =100:150:120 into slurry, and carrying out ball milling in a ball milling tank;

the average particle size of the TiC powder is 1.0 mu m, and the purity is 99 percent;

(2) drying the slurry subjected to ball milling in a drying oven at 100 ℃, manually grinding and crushing the powder, and sieving the powder with a 80-mesh sieve for granulation;

(3) putting the granulated powder into a mold, and performing compression molding by a press machine under the pressure of 250MPa to obtain a green body;

(4) putting the pressed ceramic green body into a drying oven at 250 ℃ for drying and discharging the water in the body;

(5) placing the green body into sintering, heating to 1300 deg.C under argon gas state, maintaining for 60min, and maintaining for 90min when sintering temperature is 1850 deg.C to obtain TiC-Al₂O₃A composite ceramic material;

TiC-Al prepared in this example₂O₃The composite ceramic material strip sample is shown in figure 6, and the metallographic microscopic picture is shown in figure 7; the TiC-Al is tested₂O₃The composite ceramic material had a relative density of 97.14%, a porosity of 0.72%, a bending strength of 485MPa, and a fracture toughness of 4.37MPa m^1/2A Vickers hardness of 19.50GPa and a resistivity of 7.62X 10^-6Ω·m。

The above description is only an embodiment of the present invention, and is not intended to limit the scope of the present invention, and various changes may be made in the above embodiment of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The invention has not been described in detail in order to avoid obscuring the invention.