High-entropy carbide-high-entropy carbonitride ceramic cutter as well as preparation method and application thereof

Abstract

The invention belongs to the field of ceramic cutters, and discloses a high-entropy carbide-high-entropy carbonitride ceramic cutter as well as a preparation method and application thereof. The ceramic cutting tool comprises a tool nose high-entropy carbide (Ti0. 2Zr0. 2Nb0. 2Ta0. 2W0. 2) C and a rear tool face high-entropy carbonitride (Ti0. 2Zr0. 2Nb0. 2Ta0. 2W0. 2) CxN1-x (x is more than or equal to 0.1 and less than or equal to 0.9), the preparation method comprises the following steps of: pressurizing carbide mixed powder of TiC, ZrC, NbC, TaC and WC and carbonitride mixed powder of TiC, ZrC, NbC, TaC, WC, TiN, ZrN, NbN, TaN, WN and Ni powder to 30-50 MPa in a vacuum environment, and carrying out spark plasma sintering at 1600-1800 DEG C to obtain the TiC / NbC / TaC / WC composite material. The tool nose of the ceramic tool has high hardness, the rear tool face has high toughness and wear resistance, and the ceramic tool can be applied to continuous cutting of high-hardness materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic cutting tools, and more specifically, relates to a high entropy carbide cutting tool-a high entropy carbonitride ceramic cutting tool and a preparation method and application thereof. Background Art

[0002] High entropy ceramics are a new material design theory that has emerged in recent years. It is currently a hot topic in the field of material research. Its concept was originally developed from high entropy alloys. High entropy ceramics are generally multi-component single-phase solid solutions composed of four or more cations in equal or nearly equal amounts. Due to its unique "high entropy effect", high entropy ceramics have high strength, hardness, excellent wear resistance, excellent high temperature strength, good structural stability, good corrosion resistance and oxidation resistance compared to the single-phase materials they are composed of. Due to the increase in components, the combination space for exploring and discovering new materials has greatly increased. Due to the increase in components, the configuration entropy of high entropy ceramics increases, resulting in a decrease in its Gibbs free energy, making the ceramic system more stable and its performance showing excellent stability. In addition, since various atoms are randomly distributed in the lattice lattice, the environment and position around each atom are different, which makes the lattice more lattice distortion and defects inside the lattice, making it difficult to slip and improving performance.

[0003] High entropy carbide materials have excellent mechanical properties and are suitable for use in the tool field. However, due to their low toughness, the back face of the tool wears faster during turning. For high entropy carbonitride materials, the introduction of nitrogen improves the configuration entropy of the material and the stability of the high entropy material system, thereby improving the toughness of the material and having better wear resistance. If the excellent properties of the above two high entropy materials can be combined, it is expected that high entropy ceramic tools can achieve high-speed and long-life cutting of high-hardness, high-cutting temperature, and easy-to-bond materials such as gray cast iron and ductile iron. Therefore, it is urgent to design and develop a cutting tool that has the characteristics of both high entropy carbide and high entropy carbonitride ceramics. Summary of the invention

[0004] In order to solve the above-mentioned deficiencies and shortcomings of the prior art, the purpose of the present invention is to provide a high entropy carbide-high entropy carbonitride ceramic tool. The ceramic tool has a high entropy carbide as the blade tip and a carbonitride ceramic as the back face. The components of the high entropy carbide ceramic are (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )C, high entropy carbonitride ceramics are based on (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )Cx N 1-x (0.1≤x≤0.9) high entropy carbonitride is used as the main phase, and a small amount of metal powder (Co, Ni, Mo) is added as the reinforcement phase. The tool tip has a higher hardness than high entropy carbonitride, and the back face has a higher toughness than high entropy carbide.

[0005] Another object of the present invention is to provide a method for preparing the ceramic tool having the high entropy carbide tip-high entropy carbonitride flank structure. The method places the high entropy carbide and the high entropy carbonitride in different areas for sintering.

[0006] Another object of the present invention is to provide an application of a ceramic tool with a high entropy carbide tip-high entropy carbonitride flank structure. The tool can be used for high-speed cutting of gray cast iron and ductile iron.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A ceramic tool with a high entropy carbide tip and a high entropy carbonitride back face structure includes a tip high entropy carbide phase (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )C and high entropy carbonitride phase (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )C x N 1-x , 0.1≤x≤0.9.

[0009] Preferably, the ceramic tool is prepared by ball-milling and mixing TiC, ZrC, NbC, TaC and WC in equal molar ratios to obtain a carbide mixed powder, and ball-milling and mixing TiC, ZrC, NbC, TaC, WC, TiN, ZrN, NbN, TaN, WN and a sintering aid Ni powder to obtain a carbonitride mixed powder; then the carbonitride mixed powder and the carbide mixed powder are successively placed in a graphite mold, maintained at a pressure of 1 to 3 T for 1 to 3 minutes, pressurized to 30 to 50 MPa in a vacuum environment, and spark plasma sintering is performed at 1600 to 1800°C to obtain the ceramic tool.

[0010] Preferably, the density of the ceramic tool is above 98%, the Vickers hardness of the high entropy carbide phase is 26-29 GPa, and the fracture toughness is 4-6 MPa·m 1 / 2 The Vickers hardness of the high entropy carbonitride phase is 23-25 ​​GPa, and the fracture toughness is 7-9 MPa·m 1 / 2 .

[0011] Preferably, the sintering aid Ni powder is 5-10 vol% of the carbonitride mixed powder.

[0012] The method for preparing the ceramic tool with a high entropy carbide tip-high entropy carbonitride flank structure comprises the following specific steps:

[0013] S1. TiC, ZrC, NbC, TaC and WC are mixed in equal molar ratios, anhydrous ethanol is used as solvent, Si3N4 is used as ball milling medium, and then the mixture is ball milled and dried to obtain a carbide mixed powder, whose molecular formula is (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )C;

[0014] S2. TiC, ZrC, NbC, TaC, WC, TiN, ZrN, NbN, TaN, WN and Ni powder are mixed, anhydrous ethanol is used as solvent, Si3N4 is used as ball milling medium, and the mixture is ball milled and dried to obtain a carbonitride mixed powder, whose molecular formula is (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )C x N 1-x , 0.1≤x≤0.9;

[0015] S3. Place the carbonitride mixed powder into a graphite mold with a cross-groove pressure column, maintain the pressure at 1 to 3T for 1 to 3min, then replace the cross-groove pressure column with a round-bottom pressure column and place the carbide mixed powder into a graphite mold, maintain the pressure at 1 to 3T for 1 to 3min, pressurize at 30 to 50MPa in a vacuum environment, and perform spark plasma sintering at 1600 to 1800°C to obtain a high-entropy carbide-high-entropy carbonitride composite ceramic;

[0016] S4. Processing high entropy carbide-high entropy carbonitride composite ceramics, using high entropy carbide as the tool tip and high entropy carbonitride as the back face, to obtain a high entropy carbide-high entropy carbonitride ceramic tool.

[0017] Preferably, the heating rate of the spark plasma sintering in step S3 is 50-150° C. / min; and the time of the spark plasma sintering is 10-20 min.

[0018] Preferably, in step S4, the width of the area where the high entropy carbide tip is located is 1.7-1.9 cm.

[0019] The ceramic tool with the high entropy carbide tip-high entropy carbonitride flank face structure is used in high-speed cutting of grey cast iron or ductile iron.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention combines high entropy carbide with high entropy carbonitride ceramics to prepare a ceramic tool with a high entropy carbide tip-high entropy carbonitride flank structure. The high entropy carbide as the tip has a higher hardness than the high entropy carbonitride ceramic, and the high entropy carbonitride as the flank has a higher fracture toughness than the high entropy carbide, thereby improving the cutting life of the tool.

[0022] 2. The Vickers hardness of the tip of the ceramic tool of the present invention is 26 to 29 GPa, and the fracture toughness is 4 to 6 MPa·m 1 / 2 The Vickers hardness of the back face is 23-25GPa, and the fracture toughness is 7-9MPa·m 1 / 2 The ceramic tool can be used for continuous cutting of high-hardness materials such as gray cast iron and ductile iron.

[0023] 3. The present invention combines high entropy carbide with high entropy carbonitride ceramics. Due to the consistent transition metal components, high entropy carbide and high entropy carbonitride diffuse with each other on the bonding surface to form a stable structure, thereby further improving the strength of the bonding surface. The metal added to the high entropy carbonitride reaches the melting point to form a liquid phase, which promotes the high entropy carbide and accelerates the densification process, so that the tool has stronger cutting performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A graphite mold designed according to the scheme of the present invention.

[0025] Figure 2 It is a schematic diagram of the high entropy carbide-high entropy carbonitride blank of the present invention.

[0026] Figure 3 It is a schematic diagram of a ceramic tool having a high entropy carbide tip-high entropy carbonitride flank structure of the present invention. DETAILED DESCRIPTION

[0027] The content of the present invention is further described below in conjunction with specific examples, but it should not be construed as limiting the present invention. If not specifically indicated, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0028] Example 1

[0029] 1. TiC (purity 99.9%, particle size 1 μm), ZrC (purity 99.9%, particle size 1 μm), NbC (purity 99.9%, particle size 1 μm), TaC (purity 99.9%, particle size 1 μm) and WC (purity 99.9%, particle size 1 μm) in equal molar ratio were planetarily ball milled at a speed of 300 r / min for 6 h using anhydrous ethanol as solvent and Si3N4 as ball milling medium, and then dried and sieved to obtain a carbide mixed powder.

[0030] 2. Mix equal molar ratios of TiC (purity 99.9%, particle size 1 μm), ZrC (purity 99.9%, particle size 1 μm), NbC (purity 99.9%, particle size 1 μm), TaC (purity 99.9%, particle size 1 μm), WC (purity 99.9%, particle size 1 μm), TiN (purity 99.9%, particle size 1 μm), ZrN (purity 99.9%, particle size 1 μm), N bN (purity of 99.9%, particle size of 1 μm), TaN (purity of 99.9%, particle size of 1 μm) and WN (purity of 99.9%, particle size of 1 μm) were mixed, and then 10 vol% of Ni (purity of 99.9%, particle size of 1 μm) was added, and anhydrous ethanol was used as solvent and Si3N4 was used as ball milling medium. Planetary ball milling was performed at a speed of 300 r / min for 6 hours, and after drying and sieving, a carbonitride mixed powder was obtained;

[0031] 3. Place the carbonitride mixed powder into a graphite mold with a cross-groove pressure column ( Figure 1 As shown), the pressure of 1T is maintained for 2 minutes, and then the cross-groove pressure column is replaced with a round-bottom pressure column and the carbide mixed powder is placed into the graphite mold, and the pressure of 1T is maintained for 2 minutes to obtain a blank ( Figure 2 As shown), the graphite mold is placed in an SPS sintering furnace, and under vacuum, the axial pressure is 30MPa, and the temperature is raised to 1800℃ at a rate of 100℃ / min and kept for 10min to obtain a high entropy carbide-high entropy carbonitride composite ceramic, whose molecular formula is (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )C-(Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )C 0.75 N 0.25 .

[0032] 4. Processing the high entropy carbide-high entropy carbonitride composite ceramics, using the high entropy carbide as the tool tip and the high entropy carbonitride as the back face, and processing the high entropy carbide-high entropy carbonitride ceramics into ceramic tools, such as Figure 3 shown.

[0033] The density of the ceramic tool with high entropy carbide tip-high entropy carbonitride flank structure is 98.8%, the Vickers hardness of the tool tip is 28.2GPa, and the fracture toughness is 5.2MPa·m 1 / 2 The Vickers hardness of the back face is 24.7GPa, and the fracture toughness is 8.2MPa·m 1 / 2 , cutting life is 2015s.

[0034] Example 2

[0035] The difference from Example 1 is that the axial pressure is 50 MPa in step 3. The density of the ceramic tool in this example is 99.1%, the Vickers hardness of the tool tip is 27.4 GPa, and the fracture toughness is 4.6 MPa·m 1 / 2 The Vickers hardness of the back face is 24.2GPa, and the fracture toughness is 7.8MPa·m 1 / 2 , cutting life is 1910s.

[0036] Example 3

[0037] The difference from Example 1 is that the holding time in step 3 is 15 minutes. The density of the ceramic tool in this example is 98.4%, the Vickers hardness of the tool tip is 26.3 GPa, and the fracture toughness is 4.5 MPa·m 1 / 2 The Vickers hardness of the back face is 23.7GPa, and the fracture toughness is 7.4MPa·m 1 / 2 , cutting life is 1890s.

[0038] Example 4

[0039] The difference from Example 1 is that the sintering temperature in step 3 is 1700° C. The density of the ceramic tool in this example is 98.2%, the Vickers hardness of the tool tip is 26.1 GPa, and the fracture toughness is 4.1 MPa·m 1 / 2 The Vickers hardness of the back face is 23.1GPa, and the fracture toughness is 7.2MPa·m 1 / 2 , cutting life is 1820s.

[0040] The density of the ceramic tool of the present invention is above 98%, the Vickers hardness of the tool tip is 26-29 GPa, and the fracture toughness is 4-6 MPa·m 1 / 2 The Vickers hardness of the back face is 23-25GPa, and the fracture toughness is 7-9MPa·m 1 / 2 The cutting life is 1820 seconds or more, preferably 1820 to 2015 seconds.

[0041] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A high entropy carbide-high entropy carbonitride ceramic tool, characterized in that: The ceramic tool comprises a tip high entropy carbide phase (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )C and high entropy carbonitride phase (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )C x N 1-x , 0.1≤x≤0.

9.

2. The high entropy carbide-high entropy carbonitride ceramic tool according to claim 1, characterized in that: The ceramic tool is prepared by ball-milling and mixing TiC, ZrC, NbC, TaC and WC in equal molar ratios to obtain a carbide mixed powder, and ball-milling and mixing TiC, ZrC, NbC, TaC, WC, TiN, ZrN, NbN, TaN, WN and sintering aid Ni powder to obtain a carbonitride mixed powder; then the carbonitride mixed powder and the carbide mixed powder are successively placed in a graphite mold, maintained at a pressure of 1 to 3T for 1 to 3 minutes, pressurized to 30 to 50MPa in a vacuum environment, and spark plasma sintered at 1600 to 1800°C to obtain the ceramic tool.

3. The high entropy carbide-high entropy carbonitride ceramic tool according to claim 1 or 2, characterized in that: The density of the ceramic tool is above 98%, the Vickers hardness of the high entropy carbide phase is 26-29GPa, and the fracture toughness is 4-6MPa·m 1 / 2 The high entropy carbonitride phase has a Vickers hardness of 23 to 25 GPa and a fracture toughness of 7 to 9 MPa·m 1 / 2 .

4. The high entropy carbide-high entropy carbonitride ceramic tool according to claim 2, characterized in that: The sintering aid Ni powder is 5-10 vol% of the carbonitride mixed powder.

5. The method for preparing a high entropy carbide-high entropy carbonitride ceramic tool according to any one of claims 1 to 4, characterized in that: The specific steps include: S1. TiC, ZrC, NbC, TaC and WC are mixed in equal molar ratios, anhydrous ethanol is used as solvent, Si3N4 is used as ball milling medium, and then the mixture is ball milled and dried to obtain a carbide mixed powder, whose molecular formula is (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )C; S2. TiC, ZrC, NbC, TaC, WC, TiN, ZrN, NbN, TaN, WN and Ni powder are mixed, anhydrous ethanol is used as solvent, Si3N4 is used as ball milling medium, and the mixture is ball milled and dried to obtain a carbonitride mixed powder, whose molecular formula is (Ti 0.2 Zr 0.2 Nb 0.2 Ta 0.2 W 0.2 )C x N 1-x , 0.1≤x≤0.9; S3. Place the carbonitride mixed powder into a graphite mold with a cross-groove pressure column, maintain the pressure at 1 to 3T for 1 to 3min, then replace the cross-groove pressure column with a round-bottom pressure column and place the carbide mixed powder into a graphite mold, maintain the pressure at 1 to 3T for 1 to 3min, pressurize at 30 to 50MPa in a vacuum environment, and perform spark plasma sintering at 1600 to 1800°C to obtain a high-entropy carbide-high-entropy carbonitride composite ceramic; S4. Processing high entropy carbide-high entropy carbonitride composite ceramics, using high entropy carbide as the tool tip and high entropy carbonitride as the back face, to obtain a high entropy carbide-high entropy carbonitride ceramic tool.

6. The method for preparing a high entropy carbide-high entropy carbonitride ceramic tool according to claim 5, characterized in that: The heating rate of the spark plasma sintering in step S3 is 50-150° C. / min; the time of the spark plasma sintering is 10-20 min.

7. Use of the high entropy carbide-high entropy carbonitride ceramic tool according to any one of claims 1 to 4 in high-speed cutting of gray cast iron or ductile iron.

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