A rare earth modified tungsten hard alloy and a preparation method and application thereof

Abstract

The present application relates to tungsten hard alloy technical field, especially to a kind of rare earth modified tungsten hard alloy and its preparation method and application.The rare earth modified tungsten hard alloy provided by the present application mainly uses cerium oxide, yttrium oxide and titanium oxide rare earth as modified component, through the preparation of special structure to modified component, so that modified component can synergistically give full play to function, improve the overall modification effect, so that the rare earth modified tungsten hard alloy provided by the present application has high hardness and high toughness.And, by controlling the specific composition and particle size of the composite rare earth particles and the rare earth modified iron powder and other parameters, the synergistic effect between the rare earths can be further improved, and the toughness can be improved under the premise of high hardness.The composite rare earth particles and the rare earth modified iron powder in the present application also have good complex effect, which helps the effective dispersion and particle size control of the overall component, thereby ensuring the balance of hardness and toughness of the rare earth modified tungsten hard alloy.

Description

Technical Field

[0001] This invention relates to the field of tungsten cemented carbide technology, and in particular to a rare earth modified tungsten cemented carbide, its preparation method, and its application. Background Technology

[0002] Tungsten carbide is one of the most commonly used materials in the mechanical and engineering fields. Its performance directly affects the performance of mechanical products (such as parts and high-end equipment) and the feasibility of engineering implementation (such as drilling tools and pressure-bearing equipment).

[0003] Researchers have conducted extensive research on improving the performance of tungsten cemented carbide. For example, researchers have modified adhesives to improve the bonding properties of the various components of tungsten cemented carbide, thereby enhancing its overall performance. Other researchers have increased the hardness of tungsten cemented carbide by introducing high-hardness components (such as titanium carbide and tantalum carbide).

[0004] While the methods described above have improved the performance of tungsten carbide to some extent, much work is still needed to further enhance its properties. For example, the high hardness and high toughness of tungsten carbide are often contradictory; therefore, obtaining a tungsten carbide with both high hardness and high toughness remains a challenge for those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a rare earth modified tungsten cemented carbide, its preparation method and application. The rare earth modified tungsten cemented carbide provided by the present invention has both high hardness and high toughness.

[0006] This invention provides a rare earth-modified tungsten cemented carbide, comprising the following components in parts by weight:

[0007] The mixture comprises 100 parts tungsten carbide, 6-13.5 parts cobalt powder, 22.5-33.5 parts composite rare earth particles, and 7-14 parts rare earth modified iron powder; the composite rare earth particles include cerium oxide (CeO2) and yttrium oxide (Y2O3) coated on the surface of the cerium oxide; the rare earth modified iron powder includes iron powder and titanium oxide (Ti2O3) coated on the surface of the iron powder.

[0008] Preferably, the tungsten carbide has a particle size of 850-1050 nanometers; and the cobalt powder has a particle size of 2-5 micrometers.

[0009] Preferably, the mass ratio of yttrium oxide to cerium oxide in the composite rare earth particles is 100:85~105.

[0010] Preferably, the particle size of the composite rare earth particles is 5 to 9 micrometers.

[0011] Preferably, in the rare earth modified iron powder, the mass ratio of iron powder to titanium oxide is 100:50~75.

[0012] Preferably, the particle size of the rare earth modified iron powder is 3-6 micrometers.

[0013] Preferably, the rare earth modified tungsten cemented carbide further includes one or more of yttrium oxide powder and cerium oxide powder.

[0014] This invention also provides a method for preparing the rare earth-modified tungsten cemented carbide described above, comprising the following steps:

[0015] (1) Yttrium salt, cerium salt, precipitant and water are mixed and co-precipitated and calcined in sequence to obtain composite rare earth particles;

[0016] (2) Titanium salt, iron powder, alkali and water are mixed and subjected to precipitation reaction and heat treatment in sequence to obtain rare earth modified iron powder;

[0017] (3) The composite rare earth particles and rare earth modified iron powder are ground, pressed and sintered with tungsten carbide and cobalt powder in sequence to obtain the rare earth modified tungsten hard alloy.

[0018] There is no requirement for the time order of steps (1) and (2).

[0019] Preferably, the sintering is carried out in a protective atmosphere; the sintering temperature is 1250~1550 degrees Celsius, and the holding time is 2~5 hours.

[0020] The present invention also provides the application of the rare earth modified tungsten cemented carbide described in the above-described scheme or the rare earth modified tungsten cemented carbide obtained by the preparation method described in the above-described scheme in the mechanical or engineering fields.

[0021] This invention provides a rare-earth modified tungsten cemented carbide. The rare-earth modified tungsten cemented carbide provided by this invention mainly utilizes cerium oxide, yttrium oxide, and titanium oxide as modifying components. Through the preparation of a special structure (composite rare-earth particles and rare-earth modified iron powder) for the modifying components, the components can synergistically exert their effects, improving the overall modification effect. This results in a rare-earth modified tungsten cemented carbide that possesses both high hardness and high toughness. Furthermore, by controlling the specific composition and particle size parameters of the composite rare-earth particles and rare-earth modified iron powder, this invention can further enhance the synergistic effect between rare earth elements, ensuring high hardness while improving toughness. The composite rare-earth particles and rare-earth modified iron powder in this invention also have a good composite effect, contributing to the effective dispersion of the overall components and particle size control, avoiding the generation of ultra-large particle size components, thereby ensuring a balance between hardness and toughness in the rare-earth modified tungsten cemented carbide. In addition, the rare-earth modified tungsten cemented carbide provided by this invention has good processing performance, facilitating its application in various scenarios.

[0022] This invention also provides a method for preparing the rare-earth modified tungsten cemented carbide described above. The preparation method provided by this invention is simple in steps, convenient to operate, safe and stable, and cost-controllable, making it suitable for large-scale industrial production.

[0023] This invention also provides applications of the rare-earth modified tungsten cemented carbide described in the above-described scheme or the rare-earth modified tungsten cemented carbide prepared by the above-described scheme in the mechanical or engineering fields. The rare-earth modified tungsten cemented carbide provided by this invention has both good hardness and toughness, and can better meet the performance requirements of the mechanical or engineering fields. Specifically, it can be used in high-end equipment manufacturing, resource exploration, or tunnel construction and other application scenarios, with broad application prospects. Detailed Implementation

[0024] This invention provides a rare earth-modified tungsten cemented carbide, comprising the following components in parts by weight:

[0025] The mixture comprises 100 parts tungsten carbide, 6-13.5 parts cobalt powder, 22.5-33.5 parts composite rare earth particles, and 7-14 parts rare earth modified iron powder; the composite rare earth particles include cerium oxide and yttrium oxide coated on the surface of the cerium oxide; the rare earth modified iron powder includes iron powder and titanium oxide coated on the surface of the iron powder.

[0026] The rare earth modified tungsten cemented carbide provided by the present invention comprises 100 parts by weight of tungsten carbide. In the present invention, the particle size of the tungsten carbide is preferably 850-1050 nanometers, more preferably 900-1000 nanometers.

[0027] Based on the mass fraction of tungsten carbide, the rare earth modified tungsten cemented carbide provided by the present invention includes 6 to 13.5 parts of cobalt powder, preferably 8.5 to 11 parts, more preferably 9 to 10 parts, and even more preferably 9.5 parts.

[0028] In this invention, the particle size of the cobalt powder is preferably 2 to 5 micrometers, more preferably 3 to 4 micrometers.

[0029] Based on the mass fraction of tungsten carbide, the rare earth modified tungsten cemented carbide provided by the present invention comprises 22.5 to 33.5 parts of composite rare earth particles, preferably 23 to 31 parts, more preferably 24.5 to 28 parts, and even more preferably 26 parts.

[0030] In this invention, the composite rare earth particles include cerium oxide and yttrium oxide coated on the surface of the cerium oxide; the mass ratio of yttrium oxide to cerium oxide is preferably 100:85~105, more preferably 100:95~100, and even more preferably 100:98.

[0031] In this invention, the particle size of the composite rare earth particles is preferably 5-9 micrometers, more preferably 6-8 micrometers, and even more preferably 7 micrometers.

[0032] Based on the mass fraction of tungsten carbide, the rare earth modified tungsten cemented carbide provided by the present invention comprises 7 to 14 parts of rare earth modified iron powder, preferably 8.5 to 12.5 parts, more preferably 9 to 11 parts, and even more preferably 10 parts.

[0033] In this invention, the rare earth modified iron powder includes iron powder and titanium oxide coated on the surface of the iron powder; the mass ratio of the iron powder to titanium oxide is preferably 100:50~75, more preferably 100:55~70, and even more preferably 100:60~65.

[0034] In this invention, the particle size of the rare earth modified iron powder is preferably 3-6 micrometers, more preferably 4-5 micrometers.

[0035] In this invention, the rare-earth modified tungsten cemented carbide preferably further includes one or more of yttrium oxide powder and cerium oxide powder. This invention does not have special requirements on the particle size and amount of the yttrium oxide powder and cerium oxide powder; commonly used particle sizes and amounts in the art are sufficient. The rare-earth modified tungsten cemented carbide provided by this invention can further improve its overall performance through the use of yttrium oxide powder or cerium oxide powder.

[0036] This invention also provides a method for preparing the rare earth-modified tungsten cemented carbide described above, comprising the following steps:

[0037] (1) Yttrium salt, cerium salt, precipitant and water are mixed and co-precipitated and calcined in sequence to obtain composite rare earth particles;

[0038] (2) Titanium salt, iron powder, alkali and water are mixed and subjected to precipitation reaction and heat treatment in sequence to obtain rare earth modified iron powder;

[0039] (3) The composite rare earth particles and rare earth modified iron powder are ground, pressed and sintered with tungsten carbide and cobalt powder in sequence to obtain the rare earth modified tungsten hard alloy.

[0040] There is no requirement for the time order of steps (1) and (2).

[0041] This invention involves mixing yttrium salt, cerium salt, a precipitant, and water (referred to as the first mixture), followed by sequential co-precipitation and calcination to obtain composite rare earth particles. In this invention, the yttrium salt is preferably yttrium chloride; and the yttrium chloride is preferably yttrium chloride hexahydrate (YCl3·6H2O).

[0042] In this invention, the cerium salt is preferably cerium nitrate; the cerium nitrate is preferably cerium nitrate hexahydrate (Ce(NO3)3·6H2O).

[0043] In this invention, the molar ratio of yttrium salt to cerium salt is preferably 44~45:48~62, more preferably 44.5:49~61.

[0044] In this invention, the precipitant preferably includes ammonia; the concentration of the ammonia is preferably 10-20 wt%.

[0045] In this invention, the first mixing preferably includes the following steps: mixing cerium salt, yttrium salt and water to obtain a mixed salt solution, and then adding a precipitant dropwise to the mixed salt solution.

[0046] In this invention, the dripping rate is preferably 30-60 drops / minute, more preferably 40-50 drops / minute.

[0047] In this invention, the amount of precipitant is preferably based on the pH value of the system being 9 or higher, and more preferably 9 to 10.

[0048] In this invention, the ratio of the total mass of the yttrium salt and cerium salt to the mass of water is preferably 150-170:100, more preferably 155-165:100, and even more preferably 160:100.

[0049] In this invention, the co-precipitation temperature is preferably 30-40 degrees Celsius, and the co-precipitation time is preferably 1-6 hours, more preferably 2-5 hours.

[0050] In this invention, the co-precipitation process preferably further includes aging, centrifuging, washing, and drying the resulting product in sequence; the aging temperature is preferably 30-40 degrees Celsius, and the holding time is preferably 2-5 hours, more preferably 3-4 hours; the washing detergent is preferably water; the drying temperature is preferably 70-80 degrees Celsius, and the holding time is preferably 1-3 hours.

[0051] In this invention, the calcination temperature is preferably 850-1000 degrees Celsius, more preferably 900-950 degrees Celsius, and the holding time is preferably 80-150 minutes, more preferably 100-120 minutes; the calcination is preferably carried out under oxygen-containing conditions; the oxygen-containing conditions are preferably air.

[0052] In this invention, the calcination process preferably includes cooling the resulting product in the furnace.

[0053] This invention involves mixing titanium salt, iron powder, alkali, and water, followed by a precipitation reaction and heat treatment, to obtain rare earth modified iron powder. In this invention, the titanium salt is preferably titanium tetrachloride (TiCl4).

[0054] In this invention, the molar ratio of iron powder to titanium salt is preferably 178~179:52~80, and more preferably 178~179:57~70.

[0055] In this invention, the alkali is preferably ammonia water; the concentration of the ammonia water is preferably 10~20wt%.

[0056] In this invention, the mass ratio of the titanium salt to the alkali is preferably 100:10~15, more preferably 100:12.

[0057] In this invention, the mass ratio of the titanium salt to water is preferably 16-20:100, and more preferably 18:100.

[0058] In this invention, the temperature of the precipitation reaction is preferably 40-60 degrees Celsius, more preferably 50 degrees Celsius, and the holding time is preferably 1-3 hours, more preferably 2 hours; the precipitation reaction is preferably carried out under stirring conditions; the stirring speed is preferably 50-80 rpm, more preferably 60-70 rpm.

[0059] In this invention, the heat treatment is preferably carried out in a protective atmosphere; the protective atmosphere is preferably nitrogen; the temperature of the heat treatment is preferably 200-300 degrees Celsius, more preferably 240 degrees Celsius, and the holding time is preferably 2-4 hours, more preferably 3 hours.

[0060] After obtaining composite rare earth particles and rare earth modified iron powder, the present invention grinds, presses and sintersects the composite rare earth particles and rare earth modified iron powder with tungsten carbide and cobalt powder in sequence to obtain the rare earth modified tungsten cemented carbide.

[0061] In this invention, the grinding is preferably ball milling; the ball milling speed is preferably 80~100 rpm, more preferably 90 rpm, and the ball milling time is preferably 7~10 hours, more preferably 8 hours.

[0062] In this invention, the pressing pressure is preferably 500-650 MPa, more preferably 550-600 MPa.

[0063] In this invention, the sintering is preferably carried out in a protective atmosphere; the protective atmosphere is preferably nitrogen; the sintering temperature is preferably 1250~1550 degrees Celsius, more preferably 1350 degrees Celsius, and the holding time is preferably 2~5 hours, more preferably 3~4 hours.

[0064] In this invention, the sintering process preferably includes cooling the resulting product in the furnace.

[0065] The present invention also provides the application of the rare earth modified tungsten cemented carbide described in the above-described scheme or the rare earth modified tungsten cemented carbide obtained by the preparation method described in the above-described scheme in the mechanical or engineering fields.

[0066] The rare earth modified tungsten cemented carbide provided by this invention has both good hardness and toughness, which can better meet the performance requirements of the mechanical or engineering fields. Specifically, it can be used in high-end equipment manufacturing, resource exploration or tunnel construction and other application scenarios, with broad application prospects.

[0067] To further illustrate the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments thereof.

[0068] Example 1

[0069] This embodiment prepares a rare earth-modified tungsten cemented carbide with the following specific components:

[0070] 100 kg of tungsten carbide (particle size distribution of 850~1000 nm);

[0071] 6 kg of cobalt powder (particle size distribution of 3-4 micrometers);

[0072] 22.5 kg of composite rare earth particles (particle size distribution of 7-9 micrometers); the composite rare earth particles include cerium oxide and yttrium oxide coated on the surface of cerium oxide, wherein the mass ratio of yttrium oxide to cerium oxide is 100:98;

[0073] 7 kg of rare earth modified iron powder (particle size distribution of 5-6 micrometers); the rare earth modified iron powder includes iron powder and titanium oxide coated on the surface of the iron powder, wherein the mass ratio of iron powder to titanium oxide is 100:70.

[0074] The specific steps for preparing rare-earth modified tungsten cemented carbide in this embodiment are as follows:

[0075] (1) Add 170 kg of yttrium chloride hexahydrate and cerium nitrate hexahydrate (molar ratio of yttrium salt to cerium salt is 44.5:61) to 100 kg of water to obtain a mixed salt solution. Then, add ammonia water (concentration 15wt%) to the prepared mixed salt solution at a dropping rate of 40 drops / min until the pH of the system is 10. After co-precipitation at 40 degrees Celsius for 6 hours, age at 40 degrees Celsius for 5 hours, centrifuge, wash with water, dry at 70 degrees Celsius for 3 hours, calcine at 1000 degrees Celsius in air for 100 minutes, and cool with the furnace to obtain composite rare earth particles.

[0076] (2) Titanium tetrachloride, iron powder, ammonia (concentration 15wt%) and water were mixed evenly according to the molar ratio of iron powder to titanium salt of 178:75, the mass ratio of titanium salt to ammonia water of 100:14 and the mass ratio of titanium salt to water of 20:100. The mixture was stirred at 50 rpm and precipitated at 50 degrees Celsius for 2 hours. The mixture was then heat-treated at 240 degrees Celsius in a nitrogen atmosphere for 3 hours to obtain rare earth modified iron powder.

[0077] (3) According to the above composition, the prepared composite rare earth particles and rare earth modified iron powder are mixed with tungsten carbide and cobalt powder, ball milled at 90 rpm for 8 hours, pressed into shape at 550 MPa, sintered at 1350 degrees Celsius in nitrogen for 4 hours, and cooled with the furnace to obtain rare earth modified tungsten cemented carbide.

[0078] Example 2

[0079] This embodiment prepares a rare earth-modified tungsten cemented carbide with the following specific components:

[0080] 100 kg of tungsten carbide (particle size distribution of 850~1000 nm);

[0081] 8.5 kg of cobalt powder (particle size distribution of 4-5 micrometers);

[0082] 26 kg of composite rare earth particles (particle size distribution of 7-9 micrometers); the composite rare earth particles include cerium oxide and yttrium oxide coated on the surface of cerium oxide, wherein the mass ratio of yttrium oxide to cerium oxide is 100:98;

[0083] 14 kg of rare earth modified iron powder (particle size distribution of 5-6 micrometers); the rare earth modified iron powder includes iron powder and titanium oxide coated on the surface of the iron powder, wherein the mass ratio of iron powder to titanium oxide is 100:65.

[0084] The specific steps for preparing rare-earth modified tungsten cemented carbide in this embodiment are as follows:

[0085] (1) Add 170 kg of yttrium chloride hexahydrate and cerium nitrate hexahydrate (molar ratio of yttrium salt to cerium salt is 44.5:61) to 100 kg of water to obtain a mixed salt solution. Then, add ammonia water (concentration 15wt%) to the prepared mixed salt solution at a dropping rate of 40 drops / min until the pH of the system is 10. After co-precipitation at 40 degrees Celsius for 6 hours, age at 40 degrees Celsius for 5 hours, centrifuge, wash with water, dry at 70 degrees Celsius for 3 hours, calcine at 1000 degrees Celsius in air for 100 minutes, and cool with the furnace to obtain composite rare earth particles.

[0086] (2) Titanium tetrachloride, iron powder, ammonia (concentration 15wt%) and water were mixed. The molar ratio of iron powder to titanium tetrachloride was 178:70, the mass ratio of titanium tetrachloride to ammonia was 100:13, and the mass ratio of titanium tetrachloride to water was 18:100. The mixture was stirred at 50 rpm and precipitated at 50 degrees Celsius for 2 hours. The mixture was then heat-treated at 240 degrees Celsius in a nitrogen atmosphere for 3 hours to obtain rare earth modified iron powder.

[0087] (3) According to the above composition, the prepared composite rare earth particles and rare earth modified iron powder are mixed with tungsten carbide and cobalt powder, ball milled at 90 rpm for 8 hours, pressed into shape at 600 MPa, sintered in nitrogen at 1550 degrees Celsius for 2 hours, and cooled with the furnace to obtain rare earth modified tungsten cemented carbide.

[0088] Example 3

[0089] This embodiment prepares a rare earth-modified tungsten cemented carbide with the following specific components:

[0090] 100 kg of tungsten carbide (particle size distribution of 850~1000 nm);

[0091] 11 kg of cobalt powder (particle size distribution of 3-4 micrometers);

[0092] 23 kg of composite rare earth particles (particle size distribution of 6-8 micrometers); the composite rare earth particles include cerium oxide and yttrium oxide coated on the surface of cerium oxide, wherein the mass ratio of yttrium oxide to cerium oxide is 100:98.

[0093] 12.5 kg of rare earth modified iron powder (particle size distribution of 4-5 micrometers); the rare earth modified iron powder includes iron powder and titanium oxide coated on the surface of the iron powder, wherein the mass ratio of iron powder to titanium oxide is 100:60.

[0094] The specific steps for preparing rare-earth modified tungsten cemented carbide in this embodiment are as follows:

[0095] (1) Add 170 kg of yttrium chloride hexahydrate and cerium nitrate hexahydrate (molar ratio of yttrium salt to cerium salt is 44.5:61) to 100 kg of water to obtain a mixed salt solution. Then, add ammonia water (concentration 15wt%) to the prepared mixed salt solution at a dropping rate of 60 drops / min until the pH of the system is 10. After co-precipitation at 40 degrees Celsius for 2 hours, age at 40 degrees Celsius for 3 hours, centrifuge, wash with water, dry at 70 degrees Celsius for 3 hours, calcine in air at 850 degrees Celsius for 150 minutes, and cool with the furnace to obtain composite rare earth particles.

[0096] (2) Titanium tetrachloride, iron powder, ammonia (concentration 15wt%) and water were mixed. The molar ratio of iron powder to titanium tetrachloride was 179:65, the mass ratio of titanium tetrachloride to ammonia was 100:12, and the mass ratio of titanium tetrachloride to water was 16:100. The mixture was stirred at 60 rpm and precipitated at 60 degrees Celsius for 1 hour. The mixture was then heat-treated at 200 degrees Celsius in a nitrogen atmosphere for 3 hours to obtain rare earth modified iron powder.

[0097] (3) According to the above composition, the prepared composite rare earth particles and rare earth modified iron powder are mixed with tungsten carbide and cobalt powder, ball milled at 100 rpm for 7 hours, pressed into shape at 650 MPa, sintered in nitrogen at 1250 degrees Celsius for 5 hours, and cooled in the furnace to obtain rare earth modified tungsten cemented carbide.

[0098] Example 4

[0099] This embodiment prepares a rare earth-modified tungsten cemented carbide with the following specific components:

[0100] 100 kg of tungsten carbide (particle size distribution of 900~1050 nm);

[0101] 13.5 kg of cobalt powder (particle size distribution of 3-4 micrometers);

[0102] 24.5 kg of composite rare earth particles (particle size distribution of 6-8 micrometers); the composite rare earth particles include cerium oxide and yttrium oxide coated on the surface of cerium oxide, wherein the mass ratio of yttrium oxide to cerium oxide is 100:85.

[0103] 10 kg of rare earth modified iron powder (particle size distribution of 4-5 micrometers); the rare earth modified iron powder includes iron powder and titanium oxide coated on the surface of the iron powder, wherein the mass ratio of iron powder to titanium oxide is 100:60.

[0104] The specific steps for preparing rare-earth modified tungsten cemented carbide in this embodiment are as follows:

[0105] (1) Add 170 kg of yttrium chloride hexahydrate and cerium nitrate hexahydrate (molar ratio of yttrium salt to cerium salt is 44.5:61) to 100 kg of water to obtain a mixed salt solution. Then, add ammonia water (concentration 15wt%) to the prepared mixed salt solution at a dropping rate of 50 drops / min until the pH of the system is 9. After co-precipitation at 30 degrees Celsius for 6 hours, age at 30 degrees Celsius for 5 hours, centrifuge, wash with water, dry at 80 degrees Celsius for 1 hour, calcine at 900 degrees Celsius in air for 100 minutes, and cool with the furnace to obtain composite rare earth particles.

[0106] (2) Titanium tetrachloride, iron powder, ammonia (concentration 15wt%) and water were mixed. The molar ratio of iron powder to titanium tetrachloride was 179:65, the mass ratio of titanium tetrachloride to ammonia was 100:12, and the mass ratio of titanium tetrachloride to water was 16:100. The mixture was stirred at 60 rpm and precipitated at 60 degrees Celsius for 1 hour. The mixture was then heat-treated at 200 degrees Celsius in a nitrogen atmosphere for 3 hours to obtain rare earth modified iron powder.

[0107] (3) According to the above composition, the prepared composite rare earth particles and rare earth modified iron powder are mixed with tungsten carbide and cobalt powder, ball milled at 100 rpm for 7 hours, pressed into shape at 500 MPa, sintered at 1350 degrees Celsius in nitrogen for 3 hours, and cooled with the furnace to obtain rare earth modified tungsten cemented carbide.

[0108] Example 5

[0109] This embodiment prepares a rare earth-modified tungsten cemented carbide with the following specific components:

[0110] 100 kg of tungsten carbide (particle size distribution of 900~1050 nm);

[0111] 9 kg of cobalt powder (particle size distribution of 3-4 micrometers);

[0112] 33.5 kg of composite rare earth particles (particle size distribution of 6-8 micrometers); the composite rare earth particles include cerium oxide and yttrium oxide coated on the surface of cerium oxide, wherein the mass ratio of yttrium oxide to cerium oxide is 100:85.

[0113] 11 kg of rare earth modified iron powder (particle size distribution of 4-5 micrometers); the rare earth modified iron powder includes iron powder and titanium oxide coated on the surface of the iron powder, wherein the mass ratio of iron powder to titanium oxide is 100:55.

[0114] The specific steps for preparing rare-earth modified tungsten cemented carbide in this embodiment are as follows:

[0115] (1) Add 170 kg of yttrium chloride hexahydrate and cerium nitrate hexahydrate (molar ratio of yttrium salt to cerium salt is 44.5:61) to 100 kg of water to obtain a mixed salt solution. Then, add ammonia water (concentration 15wt%) to the prepared mixed salt solution at a dropping rate of 50 drops / min until the pH of the system is 9. After co-precipitation at 30 degrees Celsius for 6 hours, age at 30 degrees Celsius for 5 hours, centrifuge, wash with water, dry at 80 degrees Celsius for 1 hour, calcine at 900 degrees Celsius in air for 100 minutes, and cool with the furnace to obtain composite rare earth particles.

[0116] (2) Titanium tetrachloride, iron powder, ammonia (concentration 15wt%) and water were mixed. The molar ratio of iron powder to titanium tetrachloride was 179:60, the mass ratio of titanium tetrachloride to ammonia was 100:12, and the mass ratio of titanium tetrachloride to water was 16:100. The mixture was stirred at 60 rpm and precipitated at 60 degrees Celsius for 1 hour. The mixture was then heat-treated at 200 degrees Celsius in a nitrogen atmosphere for 3 hours to obtain rare earth modified iron powder.

[0117] (3) According to the above composition, the prepared composite rare earth particles and rare earth modified iron powder are mixed with tungsten carbide and cobalt powder, ball milled at 80 rpm for 8 hours, pressed into shape at 550 MPa, sintered in nitrogen at 1350 degrees Celsius for 3 hours, and cooled in the furnace to obtain rare earth modified tungsten cemented carbide.

[0118] Example 6

[0119] This embodiment prepares a rare earth-modified tungsten cemented carbide with the following specific components:

[0120] 100 kg of tungsten carbide (particle size distribution of 900~1050 nm);

[0121] 9.5 kg of cobalt powder (particle size distribution of 2-3 micrometers);

[0122] 31 kg of composite rare earth particles (particle size distribution of 5-7 micrometers); the composite rare earth particles include cerium oxide and yttrium oxide coated on the surface of cerium oxide, wherein the mass ratio of yttrium oxide to cerium oxide is 100:105.

[0123] 9 kg of rare earth modified iron powder (particle size distribution of 3-4 micrometers); the rare earth modified iron powder includes iron powder and titanium oxide coated on the surface of the iron powder, wherein the mass ratio of iron powder to titanium oxide is 100:75.

[0124] The specific steps for preparing rare-earth modified tungsten cemented carbide in this embodiment are as follows:

[0125] (1) Add 15 kg of yttrium chloride hexahydrate and cerium nitrate hexahydrate (molar ratio of yttrium salt to cerium salt is 44.5:49) to 10 kg of water to obtain a mixed salt solution. Then, add ammonia water (concentration 15wt%) to the prepared mixed salt solution at a dropping rate of 40 drops / min until the pH of the system is 9. After co-precipitation at 35 degrees Celsius for 4 hours, age at 35 degrees Celsius for 3 hours, centrifuge, wash with water, dry at 80 degrees Celsius for 1 hour, calcine in air at 950 degrees Celsius for 120 minutes, and cool with the furnace to obtain composite rare earth particles.

[0126] (2) Titanium tetrachloride, iron powder, ammonia (concentration 15wt%) and water were mixed evenly according to the following conditions: the molar ratio of iron powder to titanium salt was 178:78, the mass ratio of titanium salt to ammonia was 100:15, and the mass ratio of titanium salt to water was 20:100. The mixture was stirred at 50 rpm and precipitated at 50 degrees Celsius for 1.5 hours. The mixture was then heat-treated at 240 degrees Celsius in a nitrogen atmosphere for 3 hours to obtain rare earth modified iron powder.

[0127] (3) According to the above composition, the prepared composite rare earth particles and rare earth modified iron powder are mixed with tungsten carbide and cobalt powder, ball milled at 90 rpm for 8 hours, pressed into shape at 600 MPa, sintered at 1350 degrees Celsius in nitrogen for 3 hours, and cooled with the furnace to obtain rare earth modified tungsten cemented carbide.

[0128] Example 7

[0129] This embodiment prepares a rare earth-modified tungsten cemented carbide with the following specific components:

[0130] 100 kg of tungsten carbide (particle size distribution of 900~1050 nm);

[0131] 10 kg of cobalt powder (particle size distribution of 2-3 micrometers);

[0132] 28 kg of composite rare earth particles (particle size distribution of 5-7 micrometers); the composite rare earth particles include cerium oxide and yttrium oxide coated on the surface of cerium oxide, wherein the mass ratio of yttrium oxide to cerium oxide is 100:105.

[0133] 8.5 kg of rare earth modified iron powder (particle size distribution of 3-4 micrometers); the rare earth modified iron powder includes iron powder and titanium oxide coated on the surface of the iron powder, wherein the mass ratio of iron powder to titanium oxide is 100:75.

[0134] The specific steps for preparing rare-earth modified tungsten cemented carbide in this embodiment are as follows:

[0135] (1) Add 15 kg of yttrium chloride hexahydrate and cerium nitrate hexahydrate (molar ratio of yttrium salt to cerium salt is 44.5:49) to 10 kg of water to obtain a mixed salt solution. Then, add ammonia water (concentration 15wt%) to the prepared mixed salt solution at a dropping rate of 40 drops / min until the pH of the system is 9. After co-precipitation at 35 degrees Celsius for 4 hours, age at 35 degrees Celsius for 3 hours, centrifuge, wash with water, dry at 80 degrees Celsius for 1 hour, calcine in air at 950 degrees Celsius for 120 minutes, and cool with the furnace to obtain composite rare earth particles.

[0136] (2) Titanium tetrachloride, iron powder, ammonia (concentration 15wt%) and water were mixed evenly according to the following conditions: the molar ratio of iron powder to titanium salt was 178:78, the mass ratio of titanium salt to ammonia was 100:15, and the mass ratio of titanium salt to water was 20:100. The mixture was stirred at 50 rpm and precipitated at 50 degrees Celsius for 1.5 hours. The mixture was then heat-treated at 240 degrees Celsius in a nitrogen atmosphere for 3 hours to obtain rare earth modified iron powder.

[0137] (3) According to the above composition, the prepared composite rare earth particles and rare earth modified iron powder are mixed with tungsten carbide and cobalt powder, ball milled at 90 rpm for 8 hours, pressed into shape at 600 MPa, sintered at 1350 degrees Celsius in nitrogen for 3 hours, and cooled with the furnace to obtain rare earth modified tungsten cemented carbide.

[0138] Example 8

[0139] This embodiment prepares a rare earth-modified tungsten cemented carbide with the following specific components:

[0140] 100 kg of tungsten carbide (particle size distribution of 900~1050 nm);

[0141] 7 kg of cobalt powder (particle size distribution of 2-3 micrometers);

[0142] 31 kg of composite rare earth particles (particle size distribution of 5-7 micrometers); the composite rare earth particles include cerium oxide and yttrium oxide coated on the surface of cerium oxide, wherein the mass ratio of yttrium oxide to cerium oxide is 100:105.

[0143] 11 kg of rare earth modified iron powder (particle size distribution of 3-4 micrometers); the rare earth modified iron powder includes iron powder and titanium oxide coated on the surface of the iron powder, wherein the mass ratio of iron powder to titanium oxide is 100:50.

[0144] The specific steps for preparing rare-earth modified tungsten cemented carbide in this embodiment are as follows:

[0145] (1) Add 15 kg of yttrium chloride hexahydrate and cerium nitrate hexahydrate (molar ratio of yttrium salt to cerium salt is 44.5:49) to 10 kg of water to obtain a mixed salt solution. Then, add ammonia water (concentration 15wt%) to the prepared mixed salt solution at a dropping rate of 40 drops / min until the pH of the system is 9. After co-precipitation at 35 degrees Celsius for 4 hours, age at 35 degrees Celsius for 3 hours, centrifuge, wash with water, dry at 80 degrees Celsius for 1 hour, calcine in air at 950 degrees Celsius for 120 minutes, and cool with the furnace to obtain composite rare earth particles.

[0146] (2) Titanium tetrachloride, iron powder, ammonia (concentration 15wt%) and water were mixed evenly according to the molar ratio of iron powder to titanium salt of 178:52, the mass ratio of titanium salt to ammonia water of 100:13 and the mass ratio of titanium salt to water of 16:100. The mixture was stirred at 60 rpm and precipitated at 60 degrees Celsius for 3 hours. The mixture was then heat-treated at 300 degrees Celsius in a nitrogen atmosphere for 3 hours to obtain rare earth modified iron powder.

[0147] (3) According to the above composition, the prepared composite rare earth particles and rare earth modified iron powder are mixed with tungsten carbide and cobalt powder, ball milled at 90 rpm for 8 hours, pressed into shape at 600 MPa, sintered at 1350 degrees Celsius in nitrogen for 3 hours, and cooled with the furnace to obtain rare earth modified tungsten cemented carbide.

[0148] Comparative Example 1

[0149] The preparation method of this comparative example is the same as that of Example 1, except that the composite rare earth particles are replaced with an equal mass of rare earth modified iron powder.

[0150] Comparative Example 2

[0151] The preparation method of this comparative example is the same as that of Example 1, except that rare earth modified iron powder is replaced with an equal mass of composite rare earth particles.

[0152] Comparative Example 3

[0153] The preparation method of this comparative example is the same as that of Example 1, except that the composite rare earth particles are replaced with an equal amount of cerium oxide particles of the same size.

[0154] Comparative Example 4

[0155] The preparation method of this comparative example is the same as that of Example 1, except that the composite rare earth particles are replaced with an equal amount of yttrium oxide particles of equal size.

[0156] Comparative Example 5

[0157] The preparation method of this comparative example is the same as that of Example 1, except that rare earth modified iron powder is replaced with iron powder of equal mass and particle size.

[0158] Comparative Example 6

[0159] The preparation method of this comparative example is the same as that of Example 1, except that rare earth modified iron powder is replaced with titanium oxide powder of equal mass and particle size.

[0160] Test Example 1

[0161] The hardness and toughness properties of the rare earth modified tungsten cemented carbides prepared in Examples 1-8 and Comparative Examples 1-6 were tested. Vickers hardness was tested according to standard GB / T 7997, fracture toughness was tested using the single-sided notched beam method, and impact toughness was tested according to standard GB / T 1817. The results are shown in Table 1.

[0162] Table 1 Performance test results of Test Example 1

[0163]

[0164] As shown in Table 1, the rare earth-modified tungsten cemented carbide prepared in the embodiments of the present invention maintains a hardness of 1903 kg / mm². 2Based on the above, toughness indicators such as fracture toughness and impact toughness are significantly improved, achieving a combination of high hardness and high toughness, resulting in better overall performance. This can better meet the performance requirements of mechanical and engineering fields, while keeping costs under control and yielding significant economic and social benefits.

[0165] The embodiments of the present invention have been described above; however, these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. All other embodiments obtained by those skilled in the art based on the above embodiments of the present invention without inventive effort are within the protection scope of the present invention.

Claims

1. A rare-earth modified tungsten cemented carbide, characterized in that, The components include the following parts by mass: 100 parts tungsten carbide, 6-13.5 parts cobalt powder, 22.5-33.5 parts composite rare earth particles and 7-14 parts modified iron powder; The composite rare earth particles include cerium oxide and yttrium oxide coated on the surface of the cerium oxide; The modified iron powder includes iron powder and titanium oxide coated on the surface of the iron powder; The tungsten carbide has a particle size of 850~1050 nanometers; The cobalt powder has a particle size of 2-5 micrometers; The particle size of the composite rare earth particles is 5-9 micrometers; The modified iron powder has a particle size of 3-6 micrometers.

2. The rare earth modified tungsten cemented carbide according to claim 1, characterized in that, In the composite rare earth particles, the mass ratio of yttrium oxide to cerium oxide is 100:85~105.

3. The rare earth modified tungsten cemented carbide according to claim 1, characterized in that, In the modified iron powder, the mass ratio of iron powder to titanium oxide is 100:50~75.

4. The rare earth modified tungsten cemented carbide according to claim 1, characterized in that, The rare earth modified tungsten cemented carbide also includes one or both of yttrium oxide powder and cerium oxide powder.

5. The method for preparing the rare earth modified tungsten cemented carbide according to any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Yttrium salt, cerium salt, precipitant and water are mixed and co-precipitated and calcined in sequence to obtain composite rare earth particles; (2) Titanium salt, iron powder, alkali and water are mixed and subjected to precipitation reaction and heat treatment in sequence to obtain modified iron powder; (3) The composite rare earth particles and modified iron powder are ground, pressed and sintered with tungsten carbide and cobalt powder in sequence to obtain the rare earth modified tungsten hard alloy. There is no requirement for the time order of steps (1) and (2).

6. The preparation method according to claim 5, characterized in that, The sintering is carried out in a protective atmosphere; The sintering temperature is 1250~1550 degrees Celsius, and the holding time is 2~5 hours.

7. The application of the rare earth modified tungsten cemented carbide according to any one of claims 1 to 4 in the field of engineering.

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