阅读说明：本技术 一种耐磨WC-Co-Ti3SiC2硬质合金及其制备方法 (Wear-resistant WC-Co-Ti3SiC2Hard alloy and preparation method thereof ) 是由 弓满锋 李萌 张程煜 莫德云 夏小群 梅芳 湛广平 顾雨晴 于 2020-10-15 设计创作，主要内容包括：本发明提供了一种耐磨WC-Co-Ti_3SiC_2硬质合金及其制备方法,属于硬质合金材料技术领域。本发明利用钛硅碳所具有的自润滑性和耐磨性好等优点,通过控制Ti_3SiC_2的质量百分含量能够使得硬质合金在室温下保持较优的耐磨性与润滑性。本发明通过控制真空液相烧结过程的温度和通入氩气的流量,能够避免Ti_3SiC_2材料在高温高压下的分解,又可防止Co粘结相的挥发,从而充分发挥Ti_3SiC_2材料的自润滑和耐磨性好等优点,进而提高硬质合金的耐磨性和硬度。本发明制备的硬质合金具有硬度高、耐磨性好等优点,且具有较低磨擦系数和自润滑性,可广泛应用于耐磨件、刀具和钻探工具等领域。(The invention provides wear-resistant WC-Co-Ti 3 SiC 2 Hard alloy and a preparation method thereof, belonging to the technical field of hard alloy materials. The invention utilizes the advantages of good self-lubricity and wear resistance of titanium silicon carbon and controls Ti 3 SiC 2 The mass percentage of the hard alloy can ensure that the hard alloy keeps better wear resistance and lubricity at room temperature. The invention can avoid Ti by controlling the temperature of the vacuum liquid phase sintering process and the flow of the introduced argon 3 SiC 2 The material is decomposed at high temperature and high pressure, and the volatilization of Co binding phase can be prevented, thereby fully exerting Ti 3 SiC 2 The material has good self-lubricating and wear-resisting propertiesAnd the like, thereby improving the wear resistance and hardness of the hard alloy. The hard alloy prepared by the invention has the advantages of high hardness, good wear resistance and the like, has lower friction coefficient and self-lubricating property, and can be widely applied to the fields of wear-resistant parts, cutters, drilling tools and the like.)

1. Wear-resistant WC-Co-Ti₃SiC₂The preparation method of the hard alloy is characterized by comprising the following steps:

mixing a hard alloy raw material with a forming agent, and performing ball milling to obtain mixed powder;

pressing the mixed powder to obtain a formed green body;

carrying out vacuum liquid phase sintering on the formed green body under the argon atmosphere to obtain the wear-resistant WC-Co-Ti₃SiC₂Hard alloy; the temperature of the vacuum liquid phase sintering is 1350-1450 ℃; the flow of argon in the argon atmosphere is 5-20 slm;

the hard alloy comprises the following components in percentage by mass:

77-93.8% of tungsten carbide, 6-15% of cobalt powder and 0.2-8% of titanium silicon carbon.

2. The preparation method according to claim 1, wherein the particle sizes of tungsten carbide, cobalt powder and titanium silicon carbon in the hard alloy raw material are independently 0.2-5.0 μm.

3. The preparation method according to claim 1, wherein the forming agent is polyethylene glycol, and the mass ratio of the cemented carbide raw material to the forming agent is 1 (0.01-0.03).

4. The preparation method of the high-speed ball mill is characterized in that a ball milling medium is absolute ethyl alcohol, the ball milling time is 24-72 hours, the rotation speed of the ball milling is 200-300 r/min, and the ball-to-material ratio of the ball milling is (5-10): 1.

5. The preparation method according to claim 1, wherein after the ball milling is completed, the method further comprises drying the material obtained by the ball milling to obtain mixed powder; the drying temperature is 70-80 ℃, the drying time is 4-10 h, and the drying is carried out in a vacuum rotary evaporator.

6. The production method according to claim 1, wherein the pressure of the pressing is 200 to 400MPa, and the dwell time is 0.5 to 5 min.

7. The preparation method according to claim 1, wherein the holding time of the vacuum liquid phase sintering is 1-2 h.

8. The method according to claim 7, wherein the vacuum liquid phase sintering process comprises: at a vacuum degree of 10^-2～10^-3And under the condition of Pa, heating from room temperature to 1250 ℃, starting to introduce argon, continuously heating to the temperature of the vacuum liquid phase sintering, performing vacuum liquid phase sintering, then cooling to 1100 ℃, and stopping introducing argon.

9. Wear-resistant WC-Co-Ti prepared by the preparation method of any one of claims 1 to 8₃SiC₂Hard alloy.

10. Wear resistant WC-Co-Ti as claimed in claim 9₃SiC₂Hard alloy, characterized in that the wear resistant WC-Co-Ti₃SiC₂The hard alloy has a Vickers microhardness of 16-20 GPa and a fracture toughness of 6-9 MPa.m^1/2。

Technical Field

The invention relates to the technical field of hard alloy materials, in particular to wear-resistant WC-Co-Ti₃SiC₂Hard alloy and a preparation method thereof.

Background

Cemented carbide is an alloy material obtained by high-temperature sintering of a high-hardness refractory metal carbide powder (WC, TiC, TiN, etc.) as a main phase and a transition metal cobalt (Co), nickel (Ni), iron (Fe), etc. as a binder phase. Because Co has good wettability, yield and work hardening behavior, and WC has the characteristics of high melting point, hardness, chemical stability and thermal stability, the WC-Co hard alloy has many excellent properties such as high strength, high hardness and high toughness, and is widely applied to the fields of cutting, drilling, mining, machining, wear-resistant parts and the like.

In view of the development of cemented carbide tools toward high efficiency, high precision, high reliability and specialization, and with the advent, development and application of high-speed continuous dry machining technology, precision machining technology, green manufacturing and machining technology, micro-and nano-machining and various difficult-to-machine material technology, micro-and nano-machining and various difficult-to-machine materials, higher and more recent requirements are being placed on tool materials. Particularly, when processing difficult-to-process materials such as nickel-based high-temperature alloy and the like, the common grain size hard alloy cutter has the problems of edge breakage, serious abrasion of a rear cutter face and the like, so that higher requirements on the hardness, strength and abrasion resistance of the hard alloy cutter material are met.

Disclosure of Invention

The invention aims to provide wear-resistant WC-Co-Ti₃SiC₂The surface of the hard alloy prepared by the invention has good wear resistance and friction reduction, and the hard alloy has the advantages of high hardness, good wear resistance and long service life.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides wear-resistant WC-Co-Ti₃SiC₂The preparation method of the hard alloy comprises the following steps:

mixing a hard alloy raw material with a forming agent, and performing ball milling to obtain mixed powder;

pressing the mixed powder to obtain a formed green body;

carrying out vacuum liquid phase sintering on the formed green body under the argon atmosphere to obtain the wear-resistant WC-Co-Ti₃SiC₂Hard alloy; the temperature of the vacuum liquid phase sintering is 1350-1450 ℃; the flow of argon in the argon atmosphere is 5-20 slm;

the hard alloy comprises the following components in percentage by mass:

77-93.8% of tungsten carbide, 6-15% of cobalt powder and 0.2-8% of titanium silicon carbon.

Preferably, the particle sizes of tungsten carbide, cobalt powder and titanium silicon carbon in the hard alloy raw material are independently 0.2-5.0 μm.

Preferably, the forming agent is polyethylene glycol, and the mass ratio of the hard alloy raw material to the forming agent is 1 (0.01-0.03).

Preferably, the ball milling medium is absolute ethyl alcohol, the ball milling time is 24-72 hours, the ball milling rotating speed is 200-300 r/min, and the ball-to-material ratio of the ball milling is (5-10): 1.

Preferably, after the ball milling is finished, drying the materials obtained by the ball milling to obtain mixed powder; the drying temperature is 70-80 ℃, the drying time is 4-10 h, and the drying is carried out in a vacuum rotary evaporator.

Preferably, the pressing pressure is 200-400 MPa, and the pressure maintaining time is 0.5-5 min.

Preferably, the heat preservation time of the vacuum liquid phase sintering is 1-2 h.

Preferably, the vacuum liquid phase sintering process comprises: at a vacuum degree of 10^-2～10^-3And under the condition of Pa, heating from room temperature to 1250 ℃, starting to introduce argon, continuously heating to the temperature of the vacuum liquid phase sintering, performing vacuum liquid phase sintering, then cooling to 1100 ℃, and stopping introducing argon.

The invention provides wear-resistant WC-Co-Ti prepared by the preparation method in the technical scheme₃SiC₂Hard alloy.

Preferably, the wear-resistant WC-Co-Ti₃SiC₂The hard alloy has a Vickers microhardness of 16-20 GPa and a fracture toughness of 6-9 MPa.m^1/2。

The invention provides wear-resistant WC-Co-Ti₃SiC₂The preparation method of the hard alloy comprises the following steps: mixing a hard alloy raw material with a forming agent, and performing ball milling to obtain mixed powder; sequentially pressing the mixed powder to obtain a formed green body; carrying out vacuum liquid phase sintering on the formed green body under the argon atmosphere to obtain the wear-resistant WC-Co-Ti₃SiC₂Hard alloy; the temperature of the vacuum liquid phase sintering is 1350-1450 ℃; the flow of argon in the argon atmosphere is 5-20 slm; the hard alloy comprises the following components in percentage by mass: 77-93.8% of tungsten carbide, 6-15% of cobalt powder and 0.2-8% of titanium silicon carbon. The invention utilizes the advantages of good self-lubricity and wear resistance of titanium silicon carbon and controls Ti₃SiC₂The mass percentage of the hard alloy can ensure that the hard alloy keeps better wear resistance and lubricity at room temperature. The invention can avoid Ti by controlling the temperature of the vacuum liquid phase sintering process and the flow of the introduced argon₃SiC₂The material can be decomposed at high temperature and high pressure, and can be prevented from decompositionThe Co binder phase is volatilized, thereby fully exerting Ti₃SiC₂The material has the advantages of good self-lubricating property and wear resistance, and the like, and the self-lubricating property can improve the antifriction property of the hard alloy. The results of the examples show that WC-Co-Ti prepared according to the invention₃SiC₂The hard alloy has a hardness of 16-20 GPa and a fracture toughness of 6-9 MPa.m^1/2With no addition of Ti₃SiC₂Compared with WC-Co hard alloy, the WC-Co-Ti of the invention₃SiC₂The friction coefficient of the hard alloy is reduced by nearly 27.44%, and the wear resistance is improved by nearly 87.01%. Therefore, the hard alloy prepared by the invention has the advantages of high hardness, good wear resistance and the like, has lower friction coefficient and self-lubricating property, and can be widely applied to the fields of wear-resistant parts, cutters, drilling tools and the like.

According to the invention, tungsten carbide, cobalt powder and titanium silicon carbon are mixed and ball-milled, and vacuum liquid phase sintering is carried out under a protective atmosphere to prepare the hard alloy, so that the process stability and repeatability are strong, the preparation of raw materials, the process and equipment are relatively simple, and the manufacturing cost is low.

Drawings

FIG. 1 is an XRD characterization diagram of the hard alloys prepared in examples 1-3 and comparative example 1;

FIG. 2 is a graph showing the relationship between the friction coefficient and time of the cemented carbide manufactured in examples 1-3 and comparative example 1.

Detailed Description

The invention provides wear-resistant WC-Co-Ti₃SiC₂The preparation method of the hard alloy comprises the following steps:

mixing a hard alloy raw material with a forming agent, and performing ball milling to obtain mixed powder;

pressing the mixed powder to obtain a formed green body;

carrying out vacuum liquid phase sintering on the formed green body under the argon atmosphere to obtain the wear-resistant WC-Co-Ti₃SiC₂Hard alloy; the temperature of the vacuum liquid phase sintering is 1350-1450 ℃; the flow of argon in the argon atmosphere is 5-20 slm;

the hard alloy comprises the following components in percentage by mass:

77-93.8% of tungsten carbide, 6-15% of cobalt powder and 0.2-8% of titanium silicon carbon.

In the present invention, unless otherwise specified, all the starting materials required for the preparation are commercially available products well known to those skilled in the art.

According to the invention, a hard alloy raw material and a forming agent are mixed and subjected to ball milling to obtain mixed powder. In the invention, the hard alloy raw material comprises the following components in percentage by mass: 77-93.8% of tungsten carbide, 6-15% of cobalt powder and 0.2-8% of titanium silicon carbon.

The hard alloy raw material comprises, by mass, 77-93.8% of tungsten carbide, preferably 83-91% of tungsten carbide, and more preferably 88-90% of tungsten carbide. In the present invention, the tungsten carbide is preferably used in the form of powder, and the particle size of the tungsten carbide is preferably 0.2 to 5.0 μm. The invention uses tungsten carbide as the basic raw material of hard alloy.

The hard alloy comprises, by mass, 6-15% of cobalt powder, preferably 8-12% of cobalt powder, and more preferably 8.0-10% of cobalt powder. In the invention, the particle size of the cobalt powder is preferably 0.2-5.0 μm. The present invention utilizes cobalt as the binder phase.

The hard alloy raw material comprises titanium silicon carbon (Ti) in percentage by mass₃SiC₂) 0.2 to 8%, preferably 0.5 to 5%, more preferably 1 to 2.5%, and further preferably 2.0%. In the present invention, the titanium silicon carbon is preferably used in the form of powder, and the Ti is₃SiC₂The particle diameter of (A) is preferably 0.2 to 5.0. mu.m. The invention utilizes Ti₃SiC₂The titanium silicon carbide alloy has the advantages of good self-lubrication and wear resistance, and the like, and the mass percentage of the titanium silicon carbide is controlled to be within the range, so that the hard alloy can keep better wear resistance and self-lubrication at room temperature.

In the invention, the forming agent is preferably polyethylene glycol, and the mass ratio of the hard alloy raw material to the forming agent is preferably 1 (0.01-0.03). The invention utilizes a forming agent to bond fine powder particles into coarse aggregates so as to improve the flowability of the powder.

The process of mixing the cemented carbide raw material and the forming agent is not particularly limited in the present invention, and the raw materials can be uniformly mixed according to a process well known in the art.

In the invention, the ball milling medium is preferably absolute ethyl alcohol, the ball milling time is preferably 24-72 h, more preferably 30-60 h, and further preferably 36-48 h, the rotation speed of the ball milling is preferably 200-300 r/min, more preferably 220-280 r/min, and further preferably 250-275 r/min, and the ball-to-material ratio of the ball milling is preferably (5-10): 1, and more preferably 10: 1. The ball milling equipment is not particularly limited in the invention, and any ball milling equipment which is well known in the art and can achieve the above parameters can be adopted, such as a ball mill. The invention makes the powder material mixed evenly by the ball milling process.

In the invention, after the ball milling is finished, preferably, the method further comprises the step of drying the materials obtained by the ball milling to obtain mixed powder; the drying temperature is preferably 70-80 ℃, more preferably 75 ℃, the drying time is preferably 4-10 h, more preferably 5-8 h, and further preferably 6-7 h, and the drying is preferably carried out in a vacuum rotary evaporator. The invention evaporates off the ball milling medium by drying.

After the mixed powder is obtained, the mixed powder is pressed. In the invention, the pressing pressure is preferably 200-400 MPa, and more preferably 250-350 MPa; the pressure maintaining time of the pressing is preferably 0.5-5 min. The equipment for the green compact of the present invention is not particularly limited, and equipment known in the art may be used. The invention obtains the shaped green body by pressing.

After the formed green body is obtained, the invention carries out vacuum liquid phase sintering on the formed green body under the argon atmosphere to obtain the wear-resistant WC-Co-Ti₃SiC₂Hard alloy; the temperature of the vacuum liquid phase sintering is 1350-1450 ℃; the flow of argon in the argon atmosphere is 5-20 slm, preferably 5-10 slm. In the invention, the temperature of the vacuum liquid phase sintering is preferably 1360-1420 ℃, more preferably 1370-1400 ℃, and the heat preservation time is preferably 1-2 h. In the present invention, the vacuum liquid phase sintering is preferably performed in a vacuum high-temperature atmosphere furnace.

In the present invention, the vacuum liquid phase sintering process preferably includes: at a vacuum degree of 10^-2～10^-3Under the condition of Pa, heating from room temperature to 1250 ℃ at a heating rate of 7 ℃/min, starting introducing argon, continuously heating to the temperature of the vacuum liquid phase sintering at a heating rate of 3 ℃/min, carrying out vacuum liquid phase sintering, then cooling to 1100 ℃ along with the furnace, stopping introducing argon, and then cooling to room temperature to obtain the wear-resistant WC-Co-Ti-alloy material₃SiC₂Hard alloy.

The invention can prevent the volatilization of the Co binding phase by controlling the temperature in the vacuum liquid phase sintering process and the flow of the introduced argon, and the proper sintering temperature can make the alloy material more compact, thereby improving the hardness of the material. Meanwhile, the Ti can be avoided by controlling the temperature in the vacuum liquid phase sintering process and the flow of the introduced argon₃SiC₂The material is decomposed under high temperature and high pressure, thereby fully exerting Ti₃SiC₂The self-lubricating property of the material can improve the wear resistance of the hard alloy.

The invention provides wear-resistant WC-Co-Ti prepared by the preparation method in the technical scheme₃SiC₂Hard alloy. In the present invention, the wear-resistant WC-Co-Ti₃SiC₂The hard alloy has a Vickers microhardness of 16-20 GPa and a fracture toughness of 6-9 MPa.m^1/2(ii) a With no addition of Ti₃SiC₂Compared with WC-Co hard alloy, the friction coefficient is reduced by nearly 27.44%, and the wear resistance is improved by nearly 87.01%.

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The hard alloy comprises the following raw materials in percentage by weight: ti₃SiC₂0.5% of powder, carbonized89.5% of tungsten powder and 10% of cobalt powder; the grain diameters are respectively 3 μm, 1 μm and 1 μm;

mixing the hard alloy raw material with 2 wt% (mass ratio of polyethylene glycol to hard alloy raw material) of polyethylene glycol, and carrying out ball milling for 48 hours, wherein the ball milling medium is absolute ethyl alcohol, and the ball-to-material ratio is 10:1, the rotating speed of a main shaft of a ball mill is 300r/min, the obtained ball-milled material is dried for 6 hours at 80 ℃ in a vacuum rotary evaporator to obtain mixed powder, and the mixed powder is pressed under the pressure of 300MPa for 1min to obtain a molded green body; putting the formed green body into a vacuum high-temperature atmosphere furnace, wherein the vacuum degree is 10^-2～10^-3Heating the mixture to 1250 ℃ from room temperature at a heating rate of 7 ℃/min under the Pa condition, introducing argon (the flow is 5-10 slm), continuously heating the mixture to 1380 ℃ at a heating rate of 3 ℃/min, carrying out vacuum liquid-phase sintering for 1h, then cooling the mixture to 1100 ℃, stopping introducing the argon, continuously cooling the mixture to room temperature along with the furnace to obtain the wear-resistant WC-Co-Ti alloy powder₃SiC₂Cemented carbide, noted WC-Co-0.5% Ti₃SiC₂。

Example 2

This example differs from example 1 in that: the hard alloy comprises the following raw materials in percentage by weight: ti₃SiC₂2.0% of powder, 88% of tungsten carbide powder and 10% of cobalt powder; the grain diameters are respectively 3 mu m, 1 mu m and 1 mu m, and the prepared wear-resistant WC-Co-Ti₃SiC₂Cemented carbide is noted WC-Co-2.0% Ti₃SiC₂。

Example 3

The hard alloy comprises the following raw materials in percentage by weight: ti₃SiC₂5% of powder, 85% of tungsten carbide powder and 10% of cobalt powder; the grain diameters are respectively 3 μm, 1 μm and 1 μm;

mixing the hard alloy raw material with 2 wt% of polyethylene glycol, and carrying out ball milling for 60 hours, wherein the ball milling medium is absolute ethyl alcohol, and the ball-to-material ratio is 10:1, rotating the main shaft of a ball mill at 275r/min, drying the obtained ball-milled material in a vacuum rotary evaporator at 80 ℃ for 6h to obtain mixed powder, pressing the mixed powder at the pressure of 300MPa for 1min to obtain a molded green body; loading the shaped green bodyPutting into a vacuum high-temperature atmosphere furnace, and keeping the vacuum degree at 10E^-2～10E^-3Heating the mixture to 1250 ℃ from room temperature at a heating rate of 7 ℃/min under the Pa condition, introducing argon (the flow is 5-10 slm), continuously heating the mixture to 1400 ℃ at a heating rate of 3 ℃/min, carrying out vacuum liquid phase sintering for 1h, then cooling the mixture to 1100 ℃, stopping introducing the argon, and cooling the mixture to room temperature along with the furnace to obtain the wear-resistant WC-Co-Ti-alloy powder₃SiC₂Cemented carbide, written as WC-Co-5.0% Ti₃SiC₂。

Comparative example 1

Ti in example 1₃SiC₂The powder is completely replaced by WC powder, and other parameters and steps are the same as those of the embodiment 1, so that the WC-Co hard alloy material is prepared and recorded as WC-Co.

Performance testing

1) XRD characterization was performed on the cemented carbide prepared in examples 1-3 and comparative example 1, and the results are shown in FIG. 1. As can be seen from FIG. 1, WC, Co and Ti mainly exist in the hard alloy prepared in the embodiments 1-3 of the invention₃SiC₂Phase (1); WSi can be seen in the spectrum of example 3₂Presence of phase, evidence of Ti₃SiC₂A part of Ti after the content is increased₃SiC₂And (5) decomposing.

2) The relation test of the friction coefficient and the time is carried out on the hard alloy prepared in the embodiment 1-3 and the comparative example 1 by a ball disc method, and the result is shown in figure 2; as can be seen from FIG. 2, Ti was added₃SiC₂The wear-in period of the cemented carbide of (a) is significantly shorter than that of the non-added one and its coefficient of friction is significantly lower than that of the non-added one. This indicates that Ti is added₃SiC₂The hard alloy can obtain certain antifriction capability.

3) The mechanical properties of the hard alloys prepared in examples 1 to 3 and comparative example 1 were measured by vickers hardness measurement, and the results are shown in table 1.

TABLE 1 Performance parameters of cemented carbides prepared in examples 1-3 and comparative example 1

As can be seen from Table 1, WC-Co-Ti prepared according to the present invention₃SiC₂The hardness of the cemented carbide was significantly greater than the WC-Co cemented carbide of comparative example 1.

4) The hard alloys prepared in examples 1 to 3 and comparative example 1 were subjected to wear performance tests using a ball-and-disc method under room temperature, dry and atmospheric conditions with a reciprocating length of 5mm and a reciprocating speed of 500r/min, and the results are shown in table 2.

TABLE 2 average coefficient of friction and wear rate of cemented carbide prepared in examples 1-3 and comparative example 1

As can be seen from FIG. 2 and Table 2, WC-Co-Ti prepared according to the present invention₃SiC₂The coefficient of friction of the cemented carbide was significantly lower than that of the WC-Co cemented carbide of comparative example 1, and the wear rate was significantly lower than that of the WC-Co cemented carbide.

Furthermore, it can be presumed from the results shown in FIG. 2 that 5 wt% Ti was added₃SiC₂In the cemented carbide of₂Phase, this may be WC-Co-Ti with reduced toughness and higher coefficient of friction than the other examples₃SiC₂The reason for cemented carbide.

As can be seen from the above examples, the present invention provides a wear-resistant WC-Co-Ti₃SiC₂Hard alloy and preparation method thereof, WC-Co-Ti prepared by the invention₃SiC₂The hard alloy has a hardness of 16-20 GPa and a fracture toughness of 6-9 MPa.m^1/2. With no addition of Ti₃SiC₂Compared with WC-Co hard alloy, the friction coefficient is reduced by nearly 27.44%, and the wear resistance is improved by nearly 87.01%. Therefore, the hard alloy prepared by the invention has the advantages of high hardness, good wear resistance and the like. The invention has the advantages of relatively simple raw material preparation, process and equipment and low manufacturing cost.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.