阅读说明：本技术 一种碳氮化物基金属陶瓷及制备工艺 (Carbonitride-based cermet and preparation process thereof ) 是由 郭伟 于 2019-09-05 设计创作，主要内容包括：一种碳氮化物基金属陶瓷及制备工艺,上述碳氮化物基金属陶瓷组分中,硬质相的作用是提高材料的高温红硬性,分散相的作用是提高材料的冲击韧性,添加分散相固溶体可使生产出来的材料金相组织更加均匀,改善了硬质相的相结构组成,使碳氮化物基金属陶瓷材料的強度和韧性都有大幅提升。本发明实施例提供的碳氮化物基金属陶瓷,制作成刀片后,后刀面磨损值达到Vb＝0.2mm时的切削时间高达27min,明显优于现有技术制备的相同配方刀片的切削时间,刃口无崩坏。(In the component of the carbonitride-based cermet, a hard phase has the function of improving the high-temperature red hardness of the material, a disperse phase has the function of improving the impact toughness of the material, and the addition of a disperse phase solid solution can ensure that the metallographic structure of the produced material is more uniform, improve the phase structure composition of the hard phase and greatly improve the strength and the toughness of the carbonitride-based cermet material. After the carbonitride-based cermet provided by the embodiment of the invention is manufactured into a blade, the cutting time is as long as 27min when the wear value of a rear cutter face reaches Vb equal to 0.2mm, the cutting time is obviously superior to that of a blade with the same formula prepared by the prior art, and the cutting edge is not broken.)

1. The carbonitride-based cermet is characterized by comprising the following components in parts by weight:

10-30 parts of a bonding phase,

10 to 30 parts of a hard phase,

30-70 parts of a dispersed phase,

the hard phase is (Ti, W, M) CN solid solution, wherein M is at least one of Hf, Zr and V;

the dispersed phase is (Ti, Ta, Nb, Mo) CN solid solution.

2. The carbonitride-based cermet according to claim 1, wherein the binder phase is Co powder and Ni powder in a mass ratio of (1-2): 1.

3. The carbonitride-based cermet according to claim 2, characterized in that the Co powder has an average particle diameter of 0.8 to 1.5 μm.

4. The carbonitride-based cermet according to claim 2, characterized in that the Ni powder has an average particle diameter of 0.5 to 1.5 μm.

5. The carbonitride-based cermet according to claim 1, characterized in that the molar percentages of Ti, W and M in solid solution in the (Ti, W, M) CN are:

W：15～30mol％，

M：3～15mol％，

the balance being Ti.

6. The carbonitride-based cermet according to claim 1, characterized in that the (Ti, Ta, Nb, Mo) CN solid solution comprises the following components in percentage by mass:

TiN：10～30％

TaC：10～20％

NbC：10～20％

Mo₂C：20～30％

the balance being TiC.

7. The process for producing a carbonitride based cermet according to any one of claims 1 to 6, characterized by comprising the steps of:

s1: weighing the bonding phase and the hard phase according to the proportion, and wet-grinding and uniformly mixing to obtain mixed powder;

s2: adding a forming agent into the mixed powder obtained in the step S1, drying, granulating, and then pressing and forming to obtain a blank body;

s3: and (5) sintering the blank obtained in the step S2 to obtain the carbonitride-based cermet.

8. The process for preparing carbonitride-based cermet according to claim 7, wherein the wet milling medium of step S1 is absolute ethanol.

9. The process for preparing a carbonitride based cermet according to claim 7 wherein the forming agent is PEG.

10. The process for preparing carbonitride based cermet according to claim 7, wherein the sintering temperature is 1450-1500 ℃ and the sintering time is 1-2 hours.

Technical Field

The invention belongs to the technical field of metal ceramics, and particularly relates to carbonitride based metal ceramic and a preparation process thereof.

Background

Hard tool materials for metal working are important components of the manufacturing industry, and determine the machining efficiency, precision, quality and cost of parts in the manufacturing industry. Hard tool materials generally have high hardness, toughness, wear resistance, oxidation resistance, and the like, and are classified into high-speed steels, hard alloys, cermets, and the like according to their components. Cermets have high temperature hardness and strength, but are less ductile and are commonly used for high speed finishing.

Cermets are a class of composite materials consisting of inorganic nonmetallic phases (oxides, carbides, nitrides, etc.) and metallic (or alloy) binder phases. Generally, the ceramic phase particles account for about 15-85% of the total volume of the material and are dispersed in the bonding phase metal. The TiC-based cermet was first developed and commercialized by german scientists in 1929, but the early TiC-based cermet has great material brittleness due to poor wettability of hard particles and nickel, and thus the application is greatly limited. Until the middle and later stages of the 50 th century, Ford research and development personnel find that Mo is added into TiC-Ni base cermet to improve the wettability of a metal matrix to a hard phase and prevent hard particles from growing up, so that the hardness and toughness of the material are greatly improved, and the material is beginning to be widely applied to the field of cutting tools.

In order to improve the cutting performance of titanium carbide-based cermets used as cutting tool materials, TiN, WC, TaC, Nb, Mo are usually added in the prior art₂C. HfC, ZrC, VC and the like are used as additives to increase the sinterability and improve the microstructure of the material, but the effect is not ideal.

Disclosure of Invention

In order to solve the problem of poor cutting performance of titanium carbide-based cermets used as cutting tool materials in the prior art, an object of an embodiment of the present invention is to provide a carbonitride-based cermet. Another object of the embodiments of the present invention is to provide a process for preparing the carbonitride-based cermet.

In order to achieve the purpose, the embodiment of the invention adopts the following technical scheme:

the carbonitride base cermet comprises the following components in parts by weight:

10-30 parts of a bonding phase,

10 to 30 parts of a hard phase,

30-70 parts of a dispersed phase,

the hard phase is (Ti, W, M) CN solid solution, and the M is at least one of Hf, Zr and V;

the dispersed phase is (Ti, Ta, Nb, Mo) CN solid solution.

In the carbonitride-based cermet component, the addition of the hard phase has the effect of improving the high-temperature red hardness of the material, and the addition of the dispersed phase has the effect of improving the phase structure composition of the hard phase, so that the produced material tissue is more uniform, and the toughness of the carbonitride-based cermet material is greatly improved. By combining the factors, the final cermet material has high toughness, high-temperature red hardness, and excellent wear resistance, heat resistance and impact resistance.

In addition, the carbonitride-based cermet according to the embodiment of the present invention may be prepared by using hard phase (Ti, W, M) CN solid solutions and dispersed phase (Ti, Ta, Nb, Mo) CN solid solutions with different chemical compositions according to different requirements.

When the titanium carbide-based cermet is used as a cutting tool material, the added TiN not only has the effect of inhibiting the growth of crystal grains, but also has the effect of reducing the friction coefficient between the material and a workpiece, so that the crater resistance is improved, and the wear resistance of the cermet material is improved. Through the test, the following results are found: when the content of TiN is less than 10%, the above-mentioned effect cannot be obtained; on the other hand, when the content of TiN is more than 25%, not only the wettability with the binder phase is adversely affected, but also the toughness of the matrix material is lowered, so that the content of TiN is only 25% at the maximum.

WC is known to have the effect of improving the wettability of the titanium carbide-based cermet to the hard phase, thereby improving the toughness of the titanium carbide-based cermet. But WC in an amount of less than 10% does not perform the above-mentioned function. On the other hand, if the addition amount exceeds 30%, the oxidation resistance and wear resistance of the carbide-based cermet tend to be lowered, and the addition amount is 30% at the maximum.

The addition of HfC, ZrC and VC can not only improve the hardness of the hard phase, but also improve the bonding strength of the grain boundary between the hard phase and the bonding phase, thereby remarkably improving the wear resistance and the heat resistance of the titanium carbide-based metal ceramic. If the amount of HfC, ZrC and VC added is less than 0.5%, the above effect cannot be obtained, and if the amount is more than 5%, the wettability of the binder phase and the hard phase is lowered, so that the toughness of the titanium carbide-based cermet is lowered.

The hard phase is added for improving the red hardness of the metal ceramic material and improving the wear resistance of the cutter material. Because the high-temperature red hardness of WC, HfC, ZrC and VC is better than that of TiC, the high-temperature performance of the material can be improved after the high-temperature red hardness is added. The amount of the hard phase added is 10 to 30% based on the whole material, and if it exceeds 30%, the toughness of the material may be deteriorated.

The purpose of adding TaC and NbC into the titanium carbide-based cermet is to improve the high-temperature strength of the matrix material, and Ta and Nb generated by partial decomposition of TaC and NbC form a solid solution with the binder phase, and further improve the strength of the binder phase. When the addition amount of TaC and NbC is less than 3%, the above-mentioned effects are not obtained, and on the other hand, when the addition amount is 50%, the wear resistance and oxidation resistance tendency of the titanium carbide-based cermet is lowered, and therefore 50% of TiC is added at most.

Mo and Mo are known₂C has the function of improving the wettability of the relative hard phase of the bonding, thereby improving the toughness of the titanium carbide-based metal ceramic. But Mo₂The addition of C below 10% does not serve the above-mentioned purpose; on the other hand, if the addition amount exceeds 30%, the oxidation resistance and wear resistance of the titanium carbide-based cermet will be reduced, so the addition amount is not more than 30%.

By adding TiN, WC, Mo₂C, TaC and the like, can properly reduce the content of TiC and expand the application range of the TiC-based cermet cutting tool, and the prior art adopts TiN, WC and Mo₂C. TaC, etc., in the form of pure carbides, while TiN, WC, Mo₂C. TaC and the like are added in a solid solution form (W, Ti, Ta, Mo) CN, so that the effect is better, and the product quality is more stable.

The metallographic structure of the produced material is more uniform by adding the disperse phase solid solution, the phase structure of the hard phase is improved, the toughness of the material is greatly improved, the effect can be achieved only when the addition amount of the hard phase is more than 30%, and the addition proportion is more than 50% when the better performance is obtained so as to form a continuous network structure.

The hard phase solid solution and the disperse phase solid solution of the additive adopted in the embodiment of the invention are in the form of solid solutions, and the hard alloy is prepared by only mixing the two solid solutions with the bonding phase. In the prior art, the additive is usually a plurality of different carbide or nitride alloy powders, and during preparation, different carbide or nitride alloy powder additives, such as TiC powder, TaC powder, ZrC powder and the like, need to be added respectively, however, various different additives are added respectively, on one hand, different additives need to be weighed separately, and multiple weighing can cause error accumulation, and finally the accuracy of the total amount of the additive is affected; on the other hand, the purity of various additives is different, and the purity of the final product is difficult to control by adding various additives, so that the final product contains more impurities easily. The additive provided by the embodiment of the invention is in the form of two solid solutions, various elements needing to be added can be prepared into the solid solutions in advance according to the performance requirements of the metal ceramics, only one substance of the solid solutions needs to be added when the hard alloy is prepared, and errors caused by multiple weighing and impurities possibly brought by various different additives are avoided.

Preferably, the amount of dispersed phase added is greater than 30% to be effective.

It is further preferred that the amount of dispersed phase is greater than 50% in order to form a continuous tissue structure.

Preferably, the bonding phase is formed by mixing Co powder and Ni powder according to the mass ratio of (1-2): 1.

More preferably, the average particle size of the Co powder is 0.8 to 1.5 μm.

Still more preferably, the average particle size of the Co powder is 1.0. mu.m.

More preferably, the average particle size of the Ni powder is 0.5 to 1.5 μm.

Still more preferably, the Ni powder has an average particle diameter of 0.8 μm.

Preferably, the average particle size of the hard phase is 1 to 2 μm.

Preferably, the molar percentages of Ti, W and M in the (Ti, W, M) CN solid solution are:

W：15～30mol％，

M：3～15mol％，

the balance being Ti.

Preferably, the particle size of the dispersed phase solid solution powder is controlled to be 2-3 μm.

Preferably, the (Ti, Ta, Nb, Mo) CN solid solution comprises the following components in percentage by mass:

TiN：10～30％

TaC：10～20％

NbC：10～20％

Mo₂C：20～30％

the balance being TiC.

Preferably, in the (Ti, Ta, Nb, Mo) CN solid solution, TiC, TiN, TaC, NbC and Mo₂The mass ratio of C is 30:30:10:10: 20.

The preparation process of the carbonitride-based cermet comprises the following steps:

s1: weighing the bonding phase and the hard phase according to the proportion, and wet-grinding and uniformly mixing to obtain mixed powder;

s2: adding a forming agent into the mixed powder obtained in the step S1, drying, granulating, and then pressing and forming to obtain a blank body;

s3: and (5) sintering the blank obtained in the step S2 to obtain the carbonitride-based cermet.

Preferably, the wet milling medium of step S1 is absolute ethanol. The addition amount of the absolute ethyl alcohol is 700mL per kilogram of the powder raw material.

Preferably, the wet milling time is 36-60 h.

Further preferably, the time for wet milling is 48 h.

Preferably, the ball-material ratio of wet grinding is (4-6): 1.

further preferably, the wet-milled balls/material ratio is 5: 1.

preferably, the forming agent is PEG. The concentration of PEG was 4%.

Preferably, the sintering temperature is 1450-1500 ℃, and the sintering time is 1-2 h.

The embodiment of the invention has the beneficial effects

After the carbonitride-based cermet provided by the embodiment of the invention is manufactured into a blade, the cutting time is as long as 27min when the wear value of a rear cutter face reaches Vb of 0.2mm, the cutting time is obviously superior to that of a blade with the same formula prepared by the prior art, and the cutting edge is not broken.

Drawings

FIG. 1 is a metallographic structure diagram of a cermet cutting material A prepared in example 5.

FIG. 2 is a metallographic structure diagram of a cermet cutting material B prepared in comparative example 1.

Detailed Description

The embodiment of the invention provides carbonitride-based cermet and a preparation process thereof. In the carbonitride-based cermet component, the hard phase has the effect of improving the high-temperature red hardness of the material, the dispersed phase has the effect of improving the impact toughness of the material, the metallographic structure of the produced material is more uniform by adding the dispersed phase solid solution, the phase structure composition of the hard phase is improved, and the strength and the toughness of the carbonitride-based cermet material are greatly improved.

In order to better understand the above technical solutions, the above technical solutions will be described in detail with reference to specific embodiments.