Ti(C,N)-based superhard metal composite material and preparation method thereof

Abstract

The disclosure relates to a method for preparing Ti(C,N)-based superhard metal composite materials, with Ti(C,N) powder and (W,Mo,Ta)(C,N) powder as main raw materials and Co powder as binding phase for preparation, thereby obtaining a material in which a microstructure is a double-core rim structure that has both a black core rim and a white core rim. The material has a complete and evenly distributed double-core rim structure. In the condition that the ensured hardness of the material is not reduced and even slightly increased, the toughness of the material is significantly improved, wherein the fracture toughness of the material is in the range of 11.3 to 12.5 MPa.Math.m.sup.1/2.

Claims

1. A preparation method of Ti(C,N)-based superhard metal composite material, wherein Ti(C,N) powder and (W, Mo, Ta)(C,N) powder are adopted as main raw materials, the (W, Mo, Ta)(C,N) powder is added into the Ti(C,N) powder, and a Co powder is adopted as a binding phase, then molding and sintering are performed for preparation, thereby obtaining a double-core rim structure having a microstructure with black core rim and white core rim both; wherein mass fractions of the Ti (C, N) powder, the (W, Mo, Ta) (C, N) powder and the Co powder are 40-50%, 40-50%, 10-20%, respectively; the Ti (C, N) powder, the (W, Mo, Ta) (C, N) powder and the Co powder all have a fineness of 0.5 to 3 μm; specific steps are as follows: weigh the Ti(C,N) powder and the (W, Mo, Ta) (C, N) powder and mix them with the Co powder based on a proportion described above, and then add a paraffin wax, thereafter high-energy ball milling, drying, sieving, press-forming, sintering are performed; the sintering is carried out in sequence based on the following conditions: carried out in a solid phase at 1150° C., maintain the temperature for 60 to 80 minutes, sintering is carried out in a liquid phase at 1400° C. to 1450° C., maintain the temperature for 60 to 80 minutes, then fill in with nitrogen at 7 to 10 MPa, then maintain the temperature for 60 to 90 minutes, maintain a nitrogen atmosphere and then cool to room temperature.

2. The preparation method of the Ti(C,N)-based superhard metal composite material according to claim 1, wherein an amount of the paraffin wax to be added is calculated based on 3 to 5% of a total mass of the mixed powder consisting of the Ti(C,N) powder, the (W, Mo, Ta) (C, N) powder and the Co powder; the high-energy ball milling is performed by using a planetary ball mill, a ball-to-material ratio is 3 to 6:1, a rotation speed is 300 to 500 r/min, and the ball milling is performed for 48 to 90 hours; the sieving is performed by using a 60 mesh sieve; the press-forming is performed by using a hydraulic press specifically, and a pressing force is 200 to 230 KN.

3. The preparation method of the Ti(C,N)-based superhard metal composite material according to claim 2, wherein the (W, Mo, Ta) (C, N) powder is prepared and obtained according to the following steps: based on an amount with mass fractions of 20-30%, 20-30%, 10-15% and 25-50%, respectively, weigh the WO.sub.3, MoO.sub.3, Ta.sub.2O.sub.5, and the carbon black having a purity of >99.9% and an average particle size of 10 to 50 μm for batching, then add PEG-4000 polyethylene glycol, and use a planetary ball mill for ball milling, and a slurry is spray dried and then put into a graphite boat, and a carbothermal nitridation reduction reaction is performed in a vacuum tube furnace, wherein N.sub.2 atmosphere is adopted, and finally (W, Mo, Ta) (C,N) powder is obtained.

4. The preparation method of the Ti(C,N)-based superhard metal composite material according to claim 3, wherein the (W, Mo, Ta) (C, N) powder is prepared and obtained according to the following steps: based on the amount with mass fractions of 20-30%, 20-30%, 10-15% and 25-50%, respectively, weigh the WO.sub.3, MoO.sub.3, Ta.sub.2O.sub.5, and the carbon black having the purity of >99.9% and the average particle size of 10 to 50 μm for batching to obtain the four-component mixed material, then add the PEG-4000 polyethylene glycol which accounts for 4 to 10% of a total mass of the four-component mixed material, and use a planetary ball mill for ball milling, wherein a ball milling medium is n-hexane and a milling ball is a zirconia ball of 5 to 7 mm, a ball material mass ratio is 8 to 10:1, a rotation speed is 200 to 300 r/min, and the ball milling is performed for 4 to 6 hours, after the ball milling is performed, the slurry is spray dried and then put into the graphite boat, and the carbothermal nitridation reduction reaction is performed in the vacuum tube furnace, wherein N.sub.2 atmosphere is adopted, a flow rate is 500 to 600 ml/min, a pressure in the furnace is 0.1 to 0.2 MPa, a reduction temperature is 1300° C. to 1600° C., a reduction time is 3 to 4 hours, and finally (W, Mo, Ta) (C,N) powder is obtained.

5. A preparation method of Ti(C,N)-based superhard metal composite material, wherein the method adopts the following raw materials and is performed according to the following steps: (1) based on an amount with mass fractions of 20-30%, 20-30%, 10-15% and 25-50%, respectively, weigh WO.sub.3, MoO.sub.3, Ta.sub.2O.sub.5, and carbon black having a purity of >99.9% and an average particle size of 10 to 50 μm for batching to obtain a four-component mixed material; then add PEG-4000 polyethylene glycol which accounts for 4 to 10% of a total mass of the four-component mixed material, and use a planetary ball mill for ball milling, wherein a ball milling medium is n-hexane and a milling ball is a zirconia ball of 5 to 7 mm, a ball material mass ratio is 8 to 10:1, a rotation speed is 200 to 300 r/min, and the ball milling is performed for 4 to 6 hours, after the ball milling is performed, a slurry is spray dried and then put into a graphite boat, and a carbothermal nitridation reduction reaction is performed in a vacuum tube furnace, wherein N.sub.2 atmosphere is adopted, a flow rate is 500 to 600 ml/min, a pressure in a furnace is 0.1 to 0.2 MPa, a reduction temperature is 1300° C. to 1600° C., a reduction time is 3 to 4 hours, and finally (W, Mo, Ta) (C,N) powder is obtained; (2) based on an amount with mass fractions of 40-50%, 40-50%, and 10-20%, respectively, weigh the Ti(C,N) powder and the (W, Mo, Ta) (C, N) powder with fineness of 0.5 to 3 μm and mix them with a Co powder, and then add a paraffin wax which accounts for 3 to 5% of a total mass of the mixed powder consisting of the Ti (C, N) powder, the (W, Mo, Ta) (C, N) powder and the Co powder, thereafter the high-energy ball milling is performed by using the planetary ball mill, wherein the ball-to-material ratio is 3 to 6:1, the rotation speed is 300 to 500 r/min, and the ball milling is performed for 48 to 90 hours, after drying, sieving is performed by using a 60 mesh sieve, then press-forming is performed by using a hydraulic press, and a pressing force is 200 to 230 KN, then sintering is carried out in a solid phase at 1150° C., maintain the temperature for 60 to 80 minutes, sintering is carried out in a liquid phase at 1400° C. to 1450° C., maintain the temperature for 60 to 80 minutes, then fill in with nitrogen at 7 to 10 MPa, then maintain the temperature for 60 to 90 minutes, maintain a nitrogen atmosphere and then cool to room temperature.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an SEM morphology and energy spectrum of (Ta, Mo, W) (C, N) solid solution powder prepared in Example 1 of the disclosure.

(2) FIG. 2 is a microstructure diagram, wherein a and b of FIG. 2 are the microstructure diagrams of the Ti(C,N)-based superhard metal composite material prepared in Example 1 of the disclosure with different measurement sizes, and c of FIG. 2 is the microstructure diagram of the conventional Ti (C, N) material (that is, without addition of (W, Mo, Ta) (C, N) powder).

(3) FIG. 3 shows a comparison of mechanical properties of the Ti(C,N)-based superhard metal composite material prepared in Example 1 of the disclosure and the conventional Ti (C, N) material (that is, without addition of (W, Mo, Ta) (C, N) powder).

(4) FIG. 4 is a microstructure diagram of the Ti(C,N)-based superhard composite material prepared by the related art.

DESCRIPTION OF THE EMBODIMENTS

(5) The technical solutions in the disclosure will be described clearly and thoroughly in combination with the embodiments of the disclosure. Obviously, the following embodiments are only a part of the embodiments, rather than all the embodiments, of the disclosure.

Example 1

(6) A preparation method of Ti(C,N)-based superhard metal composite material, which is carried out according to the following steps in sequence:

(7) (1) Based on an amount with mass fractions of 20%, 20%, 10%, and 50%, respectively, weigh the WO.sub.3, MoO.sub.3, Ta.sub.2O.sub.5, and the carbon black having a purity of >99.9% and an average particle size of 10 to 50 μm for batching to obtain a four-component mixed material. The mixed material is placed in a zirconia ceramic tank. Then add PEG-4000 polyethylene glycol which accounts for 4% of the total mass of the above four-component mixed material, and use a planetary ball mill for ball milling, wherein the ball milling medium is n-hexane and the milling ball is a zirconia ball of 5 mm, the ball material mass ratio is 10:1, the rotation speed is 200 r/min, the ball milling is performed for 4 hours. After the ball milling is performed, the slurry is spray dried and then put into the graphite boat, and the carbothermal nitridation reduction reaction is performed in the vacuum tube furnace, wherein N.sub.2 atmosphere is adopted, the flow rate is 600 ml/min, the pressure in the furnace is 0.2 MPa, the reduction temperature is 1500° C., the reduction time is 3 hours, and finally the (W, Mo, Ta) (C,N) powder is obtained.

(8) (2) Based on an amount with mass fractions of 40%, 47%, and 13%, respectively, weigh the Ti(C.sub.0.5,N.sub.0.5) powder and the (W, Mo, Ta) (C, N) powder with fineness of 0.5 to 3 μm and mix them with the Co powder, and then add the paraffin wax which accounts for 5% of the total mass of the mixed powder consisting of the Ti (C.sub.0.5,N.sub.0.5) powder, the (W, Mo, Ta) (C, N) powder and the Co powder. Thereafter, the high-energy ball milling is performed by using a planetary ball mill, wherein a ball-to-material ratio is 6:1, a rotation speed is 500 r/min, and the ball milling is performed for 48 hours. After drying, sieving is performed by using a 60 mesh sieve. Then press-forming is performed by using a hydraulic press, and the pressing force is 200 KN. Then sintering is carried out in solid phase at 1150° C., maintain the temperature for 60 minutes, sintering is carried out in liquid phase at 1450° C., maintain the temperature for 80 minutes, then fill in with nitrogen at 10 MPa, then maintain the temperature for 90 minutes, maintain a nitrogen atmosphere and then cool to room temperature in a natural condition.

(9) In this Example 1, specifically a YXQM-4L planetary ball mill is used for high-energy ball milling; a JEOL-6490LV scanning electron microscope manufactured by Japanese company is used to observe the morphology and grain size of the sample; a D/MAX2500VL/PC X-ray diffractometer is used for object imaging analysis (Cu K.sub.α, λ=0.154 nm, scanning speed is 0.05°/s); a AR-600 Rockwell hardness tester is used to measure hardness, a HV-10 Vickers hardness tester is used to test the Vickers hardness of the material, and Shetty fracture toughness calculation formula (see Formula 1 below) is used to calculate the fracture toughness value.
KIC=0.0889(HV.Math.P/4L)½(MPa.Math.m.sup.1/2).  Formula 1:

(10) As can be seen from FIG. 1, the particle size of the (W, Mo, Ta) (C, N) powder is 0.4 to 1.5 μm, and the powder is spherical and the surface thereof is smooth. The energy spectrum of the powder shows that the powder consists of 5 elements including W, Mo, Ta, C and N, indicating that the reaction product is (Ta, Mo, W) (C, N) phase.

(11) According to b of FIG. 2, it can be seen that the microstructure of the Ti(C,N)-based superhard metal composite material as the product of the disclosure exhibits a double-core rim structure with clear black core-white inner rim-gray outer rim/white core-gray rim.

(12) According to FIG. 3, it can be seen that the Ti(C,N)-based superhard metal composite material sample prepared as the product of the disclosure has significantly increased strength and toughness compared to the conventional superhard metal composite materials, which shows that the superhard metal composite material with double-core rim structure has improved material properties.

Example 2

(13) A preparation method of Ti(C,N)-based superhard metal composite material, which is carried out according to the following steps in sequence:

(14) (1) Based on an amount with mass fractions of 25%, 23%, 15%, and 37%, respectively, weigh the WO.sub.3, MoO.sub.3, Ta.sub.2O.sub.5, and the carbon black having a purity of >99.9% and an average particle size of 10 to 50 μm for batching to obtain a four-component mixed material. The mixed material is placed in a zirconia ceramic tank. Then add PEG-4000 polyethylene glycol which accounts for 8% of the total mass of the above four-component mixed material, and use a planetary ball mill for ball milling, wherein the ball milling medium is n-hexane and the milling ball is a zirconia ball of 7 mm, the ball material mass ratio is 8:1, the rotation speed is 300 r/min, the ball milling is performed for 6 hours. After the ball milling is performed, the slurry is spray dried and then put into the graphite boat, and the carbothermal nitridation reduction reaction is performed in the vacuum tube furnace, wherein N.sub.2 atmosphere is adopted, the flow rate is 500 ml/min, the pressure in the furnace is 0.15 MPa, the reduction temperature is 1600° C., the reduction time is 3.5 hours, and finally the (W, Mo, Ta) (C,N) powder is obtained.

(15) (2) Based on an amount with mass fractions of 45%, 40%, and 15%, respectively, weigh the Ti(C.sub.0.7,N.sub.0.3) powder and the (W, Mo, Ta) (C, N) powder with fineness of 0.5 to 3 μm and mix them with the Co powder, and then add the paraffin wax which accounts for 3% of the total mass of the mixed powder consisting of the Ti (C.sub.0.7,N.sub.0.3) powder, the (W, Mo, Ta) (C, N) powder and the Co powder. Thereafter, the high-energy ball milling is performed by using a planetary ball mill, wherein a ball-to-material ratio is 4:1, a rotation speed is 400 r/min, and the ball milling is performed for 60 hours. After drying, sieving is performed by using a 60 mesh sieve. Then press-forming is performed by using a hydraulic press, and the pressing force is 230 KN. Then sintering is carried out in solid phase at 1150° C., maintain the temperature for 80 minutes, sintering is carried out in liquid phase at 1400° C., maintain the temperature for 70 minutes, then fill in with nitrogen at 8 MPa, then maintain the temperature for 80 minutes, maintain a nitrogen atmosphere and then cool to room temperature in a natural condition. At this stage, the sintering is completed.

(16) Through the same detection method and equipment as adopted in Example 1, it can be obtained that the microstructure of the Ti(C,N)-based superhard metal composite material prepared as the product in this example exhibits a double-core rim structure with clear black core-gray rim/white core-gray rim.

Example 3

(17) A preparation method of Ti(C,N)-based superhard metal composite material, which is carried out according to the following steps in sequence:

(18) (1) Based on an amount with mass fractions of 30%, 20%, 10%, and 40%, respectively, weigh the WO.sub.3, MoO.sub.3, Ta.sub.2O.sub.5, and the carbon black having a purity of >99.9% and an average particle size of 10 to 50 μm for batching to obtain a four-component mixed material. The mixed material is placed in a zirconia ceramic tank. Then add PEG-4000 polyethylene glycol which accounts for 10% of the total mass of the above four-component mixed material, and use a planetary ball mill for ball milling, wherein the ball milling medium is n-hexane and the milling ball is a zirconia ball of 6 mm, the ball material mass ratio is 9:1, the rotation speed is 250 r/min, the ball milling is performed for 4.5 hours. After the ball milling is performed, the slurry is spray dried and then put into the graphite boat, and the carbothermal nitridation reduction reaction is performed in the vacuum tube furnace, wherein N.sub.2 atmosphere is adopted, the flow rate is 560 ml/min, the pressure in the furnace is 0.1 MPa, the reduction temperature is 1400° C., the reduction time is 4 hours, and finally the (W, Mo, Ta) (C,N) powder is obtained.

(19) (2) Based on an amount with mass fractions of 40%, 40%, and 20%, respectively, weigh the Ti(C.sub.0.6,N.sub.0.4) powder and the (W, Mo, Ta) (C, N) powder with fineness of 0.5 to 3 μm and mix them with the Co powder, and then add the paraffin wax which accounts for 5% of the total mass of the mixed powder consisting of the Ti (C.sub.0.6,N.sub.0.4) powder, the (W, Mo, Ta) (C, N) powder and the Co powder. Thereafter, the high-energy ball milling is performed by using a planetary ball mill, wherein a ball-to-material ratio is 3:1, a rotation speed is 500 r/min, and the ball milling is performed for 90 hours. After drying, sieving is performed by using a 60 mesh sieve. Then press-forming is performed by using a hydraulic press, and the pressing force is 200 KN. Then sintering is carried out in solid phase at 1150° C., maintain the temperature for 70 minutes, sintering is carried out in liquid phase at 1450° C., maintain the temperature for 60 minutes, then fill in with nitrogen at 10 MPa, then maintain the temperature for 90 minutes, maintain a nitrogen atmosphere and then cool to room temperature in a natural condition. At this stage, the sintering is completed.

(20) Through the same detection method and equipment as adopted in Example 1, it can be obtained that the microstructure of the Ti(C,N)-based superhard metal composite material prepared as the product in this example exhibits a double-core rim structure with clear black core-white rim/white core-gray rim.