阅读说明：本技术 一种类地幔条件烧结聚晶金刚石复合片及其制备方法 (Sintered polycrystalline diamond compact under mantle-like condition and preparation method thereof ) 是由 刘宝昌 陈朝然 于 2020-12-22 设计创作，主要内容包括：本发明公开了一种类地幔条件烧结聚晶金刚石复合片及其制备方法,属于材料学领域,利用镀镍金刚石微粉、金刚石微粉,石墨微晶、肼类化合物、碳酸盐或硅酸盐混合配比制备聚晶金刚石复合片,本发明采用粒径为25μm～30μm的镀镍金刚石微粉为主粒径,优化金刚石微粉、石墨微晶、肼类化合物、碳酸盐及硅酸盐合理添加量,从最佳堆积密度最优配比出发,在类似地幔的高温高压条件下与硬质合金烧结,制得用于钻探领域的类地幔条件烧结聚晶金刚石复合片,提升聚晶金刚石复合片致密性、硬度、耐磨性以及热稳定性。(The invention discloses a kind of mantle condition sintering polycrystalline diamond compact and a preparation method thereof, belonging to the field of materials, wherein the polycrystalline diamond compact is prepared by mixing and proportioning nickel-plated diamond micro powder, graphite microcrystal, hydrazine compound, carbonate or silicate, the invention adopts the nickel-plated diamond micro powder with the particle size of 25-30 mu m as the main particle size, optimizes the reasonable addition amount of the diamond micro powder, the graphite microcrystal, the hydrazine compound, the carbonate and the silicate, and is sintered with hard alloy under the high-temperature and high-pressure condition similar to a mantle from the optimal proportioning of the optimal bulk density to prepare the kind of mantle condition sintering polycrystalline diamond compact for the drilling field, thereby improving the compactness, hardness, wear resistance and thermal stability of the polycrystalline diamond compact.)

1. The utility model provides a mantle-like condition sintering polycrystalline diamond compact, this polycrystalline diamond compact includes polycrystalline diamond layer and hard alloy layer, its characterized in that: the polycrystalline diamond layer is prepared from the following raw materials in percentage by weight: 80-85 wt% of nickel-plated diamond micro powder, 5-8 wt% of diamond micro powder, 1-5 wt% of graphite microcrystal, 0.1-2 wt% of hydrazine compound, 1-4 wt% of carbonate and 1-4 wt% of silicate, wherein the sum of the weight percentages of the components is 100%; the particle size of the nickel-plated diamond micro powder is 25-30 μm; the grain size of the diamond micro powder is 2-15 mu m; the hydrazine compound is one or more of adamantane formyl hydrazine, cyano acetyl hydrazine, adipic acid dihydrazide, carbohydrazide and octanoyl hydrazide; the particle size of the carbonate is 2-16 mu m; the particle size of the silicate is 2-16 mu m.

2. The mantle-like condition sintered polycrystalline diamond compact of claim 1, wherein: the nickel-plated diamond micro powder is obtained by vacuum evaporating nickel on the surface of conventional diamond micro powder to form a nickel plating layer, and the thickness of the nickel plating layer is 100 nm-200 nm.

3. The mantle-like condition sintered polycrystalline diamond compact of claim 1, wherein: the carbonate is one or a mixture of calcium carbonate, magnesium carbonate and lithium carbonate.

4. The mantle-like condition sintered polycrystalline diamond compact of claim 1, wherein: the silicate is calcium silicate, magnesium silicate or a mixture of the two.

5. The mantle-like condition sintered polycrystalline diamond compact of claim 1, wherein: the hard alloy layer is made of tungsten-cobalt alloy, the cobalt content of the hard alloy is 16-18%, the diameter of the hard alloy is 13-19 mm, and the thickness of the hard alloy is 4-18 mm.

6. A method of making the mantle-like sintered polycrystalline diamond compact of claim 1, 2, 3, 4, or 5, wherein: the method comprises the following steps:

step 1, preparing raw materials:

firstly, processing the surface of the diamond micro powder, and removing impurities on the surface of the diamond micro powder for later use;

secondly, placing the hard alloy in an absolute ethyl alcohol environment for ultrasonic treatment for 30min to remove impurities on the surface of the hard alloy for later use;

step 2, weighing 80-85 wt% of nickel-plated diamond micro powder, 5-8 wt% of diamond micro powder, 1-5 wt% of graphite microcrystal, 0.1-2 wt% of hydrazine compound, 1-4 wt% of carbonate and 1-4 wt% of silicate according to weight percentage, adding the components into a ball mill, taking toluene as a lubricant, stopping ball milling after the ball milling is fully mixed, putting the mixed powder into a graphite cup after the toluene is evaporated, then putting the graphite cup with the powder into a vacuum furnace for vacuum heat treatment, wherein the maximum temperature in the vacuum furnace is 1100 ℃, and the vacuum degree is 3 multiplied by 10^-3Pa, obtaining mixed powder, putting the obtained mixed powder and the purified hard alloy into a metal molybdenum container or a metal tantalum container, and performing tabletting treatment to obtain a composite material;

step 3, placing the composite material in a zirconium oxide packaging container along with a metal molybdenum container or a metal tantalum container which is packaged outside the composite material, assembling the zirconium oxide packaging container and the pyrophyllite assembly block to obtain an assembled synthetic block, placing the assembled synthetic block in a cubic press for prepressing, applying pressure to 2 GPa-3 GPa, and maintaining the pressure for 5 min-7 min to obtain a prepressed assembly block; placing the pre-pressed assembly block in a vacuum sintering furnace, vacuumizing until the air pressure in the furnace is 2 multiplied by 10^-3Heating to 600 ℃ below Pa, keeping the temperature for 3-5 min, stopping vacuumizing, filling a mixed gas of hydrogen and nitrogen, uniformly mixing the hydrogen and the nitrogen in a mass ratio of 1:1, keeping the mixture for 1h, and vacuumizing to the pressure of 2 x 10^-3Below Pa, obtaining a composite component;

step 4, placing the composite assembly in a cubic press again, sintering at high temperature and high pressure, and preserving heat for a preset time after sintering to obtain a sintered body;

wherein, during sintering, the pressure is increased to the sintering pressure at the pressure increasing rate of 0.5 GPa/min-1 GPa/min, the sintering pressure is 6.1 GPa-6.8 GPa, the temperature is increased at the temperature increasing rate of 40 ℃/s-60 ℃/s for high-temperature sintering, after the temperature is maintained at 1400 ℃ -1480 ℃ for 80 s-110 s, the temperature is increased to the sintering temperature within 40 s-50 s, the sintering temperature is 1700 ℃ -1800 ℃, the temperature is reduced to 500 ℃ -650 ℃ at the temperature reducing rate of 20 ℃/s-40 ℃/s after the sintering is finished, the temperature is reduced to the room temperature after the temperature is maintained for 5 min-8 min, and the pressure is reduced to the normal pressure at the pressure reducing rate of 0.1 GPa/min-0.8 GPa/min;

and 5, taking out the sintered body obtained in the step 4 from a cubic press, removing a container coated on the surface of the sintered body from a sand blasting machine, and grinding and polishing to obtain the sintered polycrystalline diamond compact under the condition of similar mantle.

7. The method of claim 6, wherein: in the step 1, the surface of the diamond micro powder is treated, and the process of removing impurities on the surface of the diamond micro powder is as follows: firstly, placing diamond micro powder and 35% by mass of concentrated NaOH solution in a beaker, wherein the volume ratio of the diamond micro powder to the 35% by mass of concentrated NaOH solution is 1: 2, preserving the heat for 45min at 600 ℃ in a muffle furnace, and washing the solution to be neutral under the normal temperature condition; then placing aqua regia and the diamond micro powder treated by the concentrated NaOH solution in a magnetic stirrer to heat for 80 min; finally, washing to be neutral under the condition of normal temperature and drying.

8. The method of claim 6, wherein: in the step 2, ball milling is carried out by using a ball-material ratio of 1:1, the rotating speed of the ball mill is 400 r/min-600 r/min, toluene is added every 2 hours in the ball milling process, and the ball milling is stopped after 8 hours.

9. The method of claim 6, wherein: in the step 2, the grinding body adopted by ball milling is composed of tungsten-cobalt alloy balls with the diameter of phi 12mm and tungsten-cobalt alloy balls with the diameter of phi 6mm according to the proportion of 1:1, and mixing the components in a weight ratio.

Technical Field

The invention belongs to the field of materials, and particularly relates to a mantle-like sintered polycrystalline diamond compact and a preparation method thereof.

Background

Diamond is the mineralogical name of diamond, and in industry, diamond is mainly used for manufacturing drill bits for drilling and cutting and grinding tools for machining, is complete in shape and is also used for manufacturing high-grade ornaments such as ornaments, and the price of diamond is very high. The diamond is natural single crystal diamond.

The natural single crystal diamond originates from the deep part of the earth mantle billions of years ago, and according to the diamond-containing rock, the natural single crystal diamond mainly originates from the high-temperature and high-pressure environment with the depth of 120-200 kilometers of the mantle, the pressure of about 4-5 GPa and the temperature of 900-1300 ℃. Certain magma components are captured as inclusions of diamond during the growth process of natural single crystal diamond. Diamond ore is found all over the world, so that the composition of inclusions in natural single crystal diamond is different, the natural single crystal diamond which is found mainly exists in kimberlite or kammy porphyry, and the material environment is a C-H-O fluid or melt environment rich in volatile components, including solid carbon dioxide, carbonate, silicate, graphite, crystal water and other minerals.

The hydrazine compounds are readily soluble in water, soluble in ethanol, and slightly soluble in chloroform and diethyl ether. Is easily decomposed by heating, and the final decomposition product is CH₄，NH₃，CO₂，H₂O, and the like, and other impurities are not introduced, and small molecular compounds are common substance components in the inclusion of the natural monocrystalline diamond, and are also considered as common components in the valance component, so that hydrazine compounds are ideal additives for researching the synthesis of the natural monocrystalline diamond under the coexistence environment of nitrogen, hydrogen and oxygen, such as Guolong lock of Jilin university, research on high-temperature and high-pressure synthesis and annealing of hydrazine organic matter doped diamond large monocrystals (see the national network of knowledge, academic treatise library, Jilin university, 2019), and the preparation of the large monocrystalline diamond by the hydrazine organic matter at high temperature and high pressureArtificial single crystal diamond. The artificial single crystal diamond has slow growth speed and long synthesis time (generally dozens of hours or even hundreds of hours), the manufacturing cost exceeds that of the natural single crystal diamond with the same size, the mass production of large-particle single crystal diamond is still quite difficult, and the anisotropy, the heat resistance, the impact toughness and the wear resistance of the single crystal diamond are all lower than those of polycrystalline diamond and polycrystalline diamond composite sheets, so that the artificial single crystal diamond is extremely limited in the field of tools and cannot meet the requirements of the fields of cutters and drilling.

Polycrystalline diamond is formed by sintering diamond micropowder under high temperature and high pressure. The fine diamond grains in the polycrystalline diamond are randomly arranged in a disordered way, have the same overall isotropy, no cleavage plane, and have excellent qualities of high hardness, high strength, high wear resistance and the like, and the toughness of the polycrystalline diamond is also improved due to the existence of the metal adhesive. The polycrystalline diamond compact is a superhard composite material synthesized by diamond micropowder and a hard alloy substrate under the condition of ultrahigh pressure and high temperature, and has extremely high hardness, impact toughness, thermal stability and wear resistance. The polycrystalline diamond compact has the hardness and the strength of diamond and the toughness and the weldability of a hard alloy matrix material, is an excellent cutting tool and an excellent wear-resistant material, and is widely applied to the fields of machining tools, petroleum, geological drilling and the like.

Disclosure of Invention

The invention aims to provide a polycrystalline diamond compact sintered under a mantle-like condition and a preparation method thereof.

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

the invention provides a kind of mantle condition sintering polycrystalline diamond compact, this polycrystalline diamond compact includes polycrystalline diamond layer and hard alloy layer, characterized by that: the polycrystalline diamond layer is prepared from the following raw materials in percentage by weight: 80-85 wt% of nickel-plated diamond micro powder, 5-8 wt% of diamond micro powder, 1-5 wt% of graphite microcrystal, 0.1-2 wt% of hydrazine compound, 1-4 wt% of carbonate and 1-4 wt% of silicate, wherein the sum of the weight percentages of the components is 100%; the particle size of the nickel-plated diamond micro powder is 25-30 μm; the grain size of the diamond micro powder is 2-15 mu m; the hydrazine compound is one or more of adamantane formyl hydrazine, cyano acetyl hydrazine, adipic acid dihydrazide, carbohydrazide and octanoyl hydrazide; the particle size of the carbonate is 2-16 mu m; the particle size of the silicate is 2-16 mu m.

Further, the nickel-plated diamond micro powder is obtained by performing vacuum evaporation of nickel on the surface of conventional diamond micro powder to form a nickel plating layer, and the thickness of the nickel plating layer is 100 nm-200 nm.

Further, the carbonate is one or a mixture of calcium carbonate, magnesium carbonate and lithium carbonate.

Further, the silicate is calcium silicate, magnesium silicate or a mixture of the two.

Furthermore, the raw material of the hard alloy layer is tungsten-cobalt alloy, the cobalt content of the hard alloy is 16-18%, the diameter of the hard alloy is 13-19 mm, and the thickness of the hard alloy is 4-18 mm.

The invention also provides a method for preparing the polycrystalline diamond compact sintered under the condition similar to the mantle, which is characterized by comprising the following steps: the method comprises the following steps:

step 1, preparing raw materials:

firstly, processing the surface of the diamond micro powder, and removing impurities on the surface of the diamond micro powder for later use;

secondly, placing the hard alloy in an absolute ethyl alcohol environment for ultrasonic treatment for 30min to remove impurities on the surface of the hard alloy for later use;

step 2, weighing 80-85 wt% of nickel-plated diamond micro powder, 5-8 wt% of diamond micro powder, 1-5 wt% of graphite microcrystal, 0.1-2 wt% of hydrazine compound, 1-4 wt% of carbonate and 1-4 wt% of silicate according to weight percentage, adding the components into a ball mill, using toluene as a lubricant, stopping ball milling after fully mixing the components by ball milling, and evaporating the toluene until the toluene is driedThe mixed powder is put into a graphite cup, and then the graphite cup filled with the powder is put into a vacuum furnace for vacuum heat treatment, wherein the maximum temperature in the vacuum furnace is 1100 ℃, and the vacuum degree is 3 multiplied by 10^-3Pa, obtaining mixed powder, putting the obtained mixed powder and the purified hard alloy into a metal molybdenum container or a metal tantalum container, and performing tabletting treatment to obtain a composite material;

step 3, placing the composite material in a zirconium oxide packaging container along with a metal molybdenum container or a metal tantalum container which is packaged outside the composite material, assembling the zirconium oxide packaging container and the pyrophyllite assembly block to obtain an assembled synthetic block, placing the assembled synthetic block in a cubic press for prepressing, applying pressure to 2 GPa-3 GPa, and maintaining the pressure for 5 min-7 min to obtain a prepressed assembly block; placing the pre-pressed assembly block in a vacuum sintering furnace, vacuumizing until the air pressure in the furnace is 2 multiplied by 10^-3Heating to 600 ℃ below Pa, keeping the temperature for 3-5 min, stopping vacuumizing, filling a mixed gas of hydrogen and nitrogen, uniformly mixing the hydrogen and the nitrogen in a mass ratio of 1:1, keeping the mixture for 1h, and vacuumizing to the pressure of 2 x 10^-3Below Pa, obtaining a composite component;

step 4, placing the composite assembly in a cubic press again, sintering at high temperature and high pressure, and preserving heat for a preset time after sintering to obtain a sintered body;

wherein, during sintering, the pressure is increased to the sintering pressure at the pressure increasing rate of 0.5 GPa/min-1 GPa/min, the sintering pressure is 6.1 GPa-6.8 GPa, the temperature is increased at the temperature increasing rate of 40 ℃/s-60 ℃/s for high-temperature sintering, after the temperature is maintained at 1400 ℃ -1480 ℃ for 80 s-110 s, the temperature is increased to the sintering temperature within 40 s-50 s, the sintering temperature is 1700 ℃ -1800 ℃, the temperature is reduced to 500 ℃ -650 ℃ at the temperature reducing rate of 20 ℃/s-40 ℃/s after the sintering is finished, the temperature is reduced to the room temperature after the temperature is maintained for 5 min-8 min, and the pressure is reduced to the normal pressure at the pressure reducing rate of 0.1 GPa/min-0.8 GPa/min;

and 5, taking out the sintered body obtained in the step 4 from a cubic press, removing a container coated on the surface of the sintered body from a sand blasting machine, and grinding and polishing to obtain the sintered polycrystalline diamond compact under the condition of similar mantle.

Further, in the step 1, the surface of the diamond micro powder is treated, and the process of removing impurities on the surface of the diamond micro powder is as follows: firstly, placing diamond micro powder and 35% by mass of concentrated NaOH solution in a beaker, wherein the volume ratio of the diamond micro powder to the 35% by mass of concentrated NaOH solution is 1: 2, preserving the heat for 45min at 600 ℃ in a muffle furnace, and washing the solution to be neutral under the normal temperature condition; then placing aqua regia and the diamond micro powder treated by the concentrated NaOH solution in a magnetic stirrer to heat for 80 min; finally, washing to be neutral under the condition of normal temperature and drying.

Further, in the step 2, ball milling is performed by using a ball-to-material ratio of 1:1, the rotating speed of the ball mill is 400 r/min-600 r/min, toluene is added every 2 hours in the ball milling process, and the ball milling is stopped after 8 hours.

Further, in the step 2, the grinding body used for ball milling is composed of tungsten cobalt alloy balls with the diameter of phi 12mm and tungsten cobalt alloy balls with the diameter of phi 6mm according to the ratio of 1:1, and mixing the components in a weight ratio.

Through the design scheme, the invention can bring the following beneficial effects: the invention provides a mantle-like sintered polycrystalline diamond compact and a preparation method thereof, wherein nickel-plated diamond micro powder with the particle size of 25-30 microns is used as the main particle size, the reasonable addition amounts of the diamond micro powder, graphite microcrystals, hydrazine compounds, carbonates and silicates are optimized, the polycrystalline diamond compact for the drilling field is prepared from the optimal bulk density and optimal proportion under the conditions of high temperature and high pressure, and the compactness, hardness, wear resistance and thermal stability of the polycrystalline diamond compact are improved. Compared with the conventional method for preparing the polycrystalline diamond compact, the heat resistance is improved by 150-200 ℃, the wear resistance is improved by 25-50%, the impact toughness is improved by 65-80%, and the polycrystalline diamond compact is excellent in comprehensive performance. In the drilling process, the high heat resistance can bear the severe high-temperature operation environment of an ultra-deep stratum, the high wear resistance can increase the footage capacity in a stratum with strong abrasiveness, the phenomena of tipping, delaminating and the like of the polycrystalline diamond compact can be reduced due to high impact resistance, the service life of the polycrystalline diamond compact is greatly prolonged, and the high-temperature drilling tool has wide practicability and applicability.

Detailed Description

The utility model provides a mantle-like condition sintering polycrystalline diamond compact, this polycrystalline diamond compact includes polycrystalline diamond layer and hard alloy layer, polycrystalline diamond layer is made by following weight percent's raw materials: 80-85 wt% of nickel-plated diamond micro powder, 5-8 wt% of diamond micro powder, 1-5 wt% of graphite microcrystal, 0.1-2 wt% of hydrazine compound, 1-4 wt% of carbonate and 1-4 wt% of silicate, wherein the sum of the weight percentages of the components is 100%; the particle size of the nickel-plated diamond micro powder is 25-30 microns, the nickel-plated diamond micro powder is obtained by vacuum evaporation of nickel on the surface of conventional diamond micro powder to form a nickel coating, the thickness of the nickel coating is 100-200 nm, on one hand, cracks existing in the conventional diamond micro powder can be filled, the compressive strength of the conventional diamond micro powder is improved, and on the other hand, graphite microcrystals can be promoted to be changed into diamonds; the grain size of the diamond micro powder is 2-15 mu m; the hydrazine compound is one or more of adamantane formyl hydrazine, cyano acetyl hydrazine, adipic acid dihydrazide, carbohydrazide and octanoyl hydrazide; the carbonate is one or a mixture of calcium carbonate, magnesium carbonate and lithium carbonate, and the particle size of the carbonate is 2-16 mu m; the silicate is calcium silicate, magnesium silicate or a mixture of the calcium silicate and the magnesium silicate, and the particle size of the silicate is 2-16 mu m; the hard alloy layer is made of tungsten-cobalt alloy, the cobalt content of the hard alloy is 16-18%, the diameter of the hard alloy is 13-19 mm, and the thickness of the hard alloy is 4-18 mm.

The method for preparing the polycrystalline diamond compact sintered under the condition of the similar mantle comprises the following steps:

step 1, preparing raw materials:

firstly, processing the surface of the diamond micro powder, and removing impurities on the surface of the diamond micro powder for later use;

the specific process is as follows: firstly, placing diamond micro powder and 35% by mass of concentrated NaOH solution in a beaker, wherein the volume ratio of the diamond micro powder to the 35% by mass of concentrated NaOH solution is 1: 2, preserving the heat for 45min at 600 ℃ in a muffle furnace, and washing the solution to be neutral under the normal temperature condition; concentrated hydrochloric acid (HCl) and concentrated nitric acid (HNO) are then added₃) Mixture of aqua regia and concentrated NaOH in a volume ratio of 3:1Heating the diamond micropowder treated by the solution for 80min in a magnetic stirrer, finally washing the diamond micropowder to be neutral at normal temperature, and drying the diamond micropowder for later use;

secondly, placing the hard alloy in an absolute ethyl alcohol environment for ultrasonic treatment for 30min to remove impurities on the surface of the hard alloy for later use;

step 2, weighing 80-85 wt% of nickel-plated diamond micro powder, 5-8 wt% of diamond micro powder, 1-5 wt% of graphite microcrystal, 0.1-2 wt% of hydrazine compound, 1-4 wt% of carbonate and 1-4 wt% of silicate according to the weight percentage, adding the components into a ball mill, using toluene as a lubricant, carrying out ball milling and mixing in the ball mill, wherein the ball milling adopts a ball-to-material ratio of 1:1, the rotating speed of a ball mill is 400 r/min-600 r/min, so that the original powder is mixed more uniformly, toluene is added every 2 hours in the ball milling process, the ball milling is stopped after 8 hours of ball milling, the mixed powder is filled into a graphite cup after the toluene is evaporated, then the graphite cup filled with the powder is placed into a vacuum furnace for vacuum heat treatment, the highest temperature in the vacuum furnace is 1100 ℃, and the vacuum degree is 3 multiplied by 10, and the highest temperature in the vacuum furnace is 1100 ℃, and the vacuum degree is 3 multiplied by 10^-3Pa, removing oxygen, water vapor and the like adsorbed on the surface of the powder, enabling the surface of the powder to have better reaction activity, obtaining mixed powder, putting the obtained mixed powder and the purified hard alloy into a metal molybdenum container or a metal tantalum container, and performing tabletting treatment to obtain a composite material;

the grinding body adopted by ball milling comprises tungsten-cobalt alloy balls with the diameter of phi 12mm and tungsten-cobalt alloy balls with the diameter of phi 6mm according to the weight ratio of 1:1 by weight ratio;

step 3, placing the composite material in a zirconium oxide packaging container along with a metal molybdenum container or a metal tantalum container which is packaged outside the composite material, assembling the zirconium oxide packaging container and the pyrophyllite assembly block to obtain an assembled synthetic block, placing the assembled synthetic block in a cubic press for prepressing, applying pressure to 2 GPa-3 GPa, and maintaining the pressure for 5 min-7 min to obtain a prepressed assembly block; placing the prepressed assembly block in a vacuum sintering furnace for vacuumizing until the air pressure in the furnace is 2 multiplied by 10^-3Raising the temperature to 600 ℃ below Pa, keeping the temperature for 3-5 min, stopping vacuumizing, filling a mixed gas of hydrogen and nitrogen, and adding hydrogen and nitrogenMixing uniformly at a ratio of 1:1, maintaining for 1 hr, and vacuumizing to pressure of 2 × 10^-3Below Pa, obtaining a composite component;

the zirconia wrapping container is of a hollow cylinder structure, the diameter of the zirconia wrapping container is 30mm, the height of the zirconia wrapping container is 30mm, the zirconia wrapping container is processed into 0-3 through holes and used for placing hard alloys with different sizes and synthesizing composite sheets with different sizes, and therefore the composite sheets with the required corresponding sizes are wrapped;

the structure of the assembled synthetic block is an assembly structure commonly used by a cubic press: placing a zirconium oxide wrapping container in a salt pipe, sealing the upper end and the lower end of the salt pipe with salt sheets respectively to form a salt column assembly, then placing the salt column assembly in a graphite pipe, sealing the upper end and the lower end of the graphite pipe with graphite sheets respectively to form a graphite column assembly, finally placing the graphite column assembly in a pyrophyllite assembly block, and sequentially arranging titanium sheets and conductive steel rings at the upper end and the lower end of the graphite column assembly respectively; the pyrophyllite assembly block adopts pyrophyllite as a sealing pressure transmission medium; in the invention, a magnesium oxide sheet and a salt sheet are arranged in the middle of a zirconium oxide wrapping container and used as the partition and heat preservation functions among corresponding composite sheets;

step 4, placing the composite assembly in a cubic press again, sintering at high temperature and high pressure, and preserving heat for a preset time after sintering to obtain a sintered body;

wherein, during sintering, the pressure is increased to the sintering pressure at the pressure increasing rate of 0.5 GPa/min-1 GPa/min, the sintering pressure is 6.1 GPa-6.8 GPa, the temperature is increased at the temperature increasing rate of 40 ℃/s-60 ℃/s for high-temperature sintering, after the temperature is maintained at 1400 ℃ -1480 ℃ for 80 s-110 s, the temperature is increased to the sintering temperature within 40 s-50 s, the sintering temperature is 1700 ℃ -1800 ℃, the temperature is reduced to 500 ℃ -650 ℃ at the temperature reducing rate of 20 ℃/s-40 ℃/s after the sintering is finished, the temperature is reduced to the room temperature after the temperature is maintained for 5 min-8 min, and the pressure is reduced to the normal pressure at the pressure reducing rate of 0.1 GPa/min-0.8 GPa/min;

and 5, taking out the sintered body obtained in the step 4 from a cubic press, removing a container coated on the surface of the sintered body from a sand blasting machine, and grinding and polishing to obtain the sintered polycrystalline diamond compact under the condition of similar mantle.

The environment of the mantle-like melt is created by using the hydrazine compound, the carbonate and the silicate, the graphite microcrystals are uniformly dispersed in the nickel-plated diamond and the gaps of the diamond under the action of high temperature and high pressure of the cubic press, the polycrystalline diamond is better formed under the catalytic action of nickel on the surface of the nickel-plated diamond and cobalt in the hard alloy, and the comprehensive properties of compactness, heat resistance, wear resistance, impact toughness and the like of the polycrystalline diamond compact are improved.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention are clearly and completely described below. It is to be understood that the embodiments described are only some embodiments of the invention, and not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without any creative work belong to the protection scope of the present invention. Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs.

Example 1

A preparation method of a polycrystalline diamond compact sintered under a mantle-like condition comprises the following steps:

step 1, preparing raw materials:

according to the weight percentage, 80 wt% of nickel-plated diamond micro powder, 8 wt% of diamond micro powder, 5 wt% of graphite microcrystal, 0.1 wt% of cyanoacethydrazide, 2.9 wt% of calcium carbonate and 4 wt% of magnesium silicate are respectively weighed, the mass of a mixed material formed by the nickel-plated diamond micro powder, the graphite microcrystal, the cyanoacethydrazide, the calcium carbonate and the magnesium silicate is 4 g-8 g, the mixed material is uniformly mixed in a ball mill, the ball milling adopts a ball-to-material ratio of 1:1, a ball milling medium is toluene, the using amount is 10mL, the rotating speed of the ball mill is 600r/min, a part of toluene is added every 2h in the ball milling process, and the; opening the ball mill, evaporating toluene to dry, placing the mixed powder into a graphite cup, placing the graphite cup containing the powder into a vacuum furnace for vacuum heat treatment to remove oxygen, water vapor and the like adsorbed on the surface of the powder and enable the surface of the powder to have better reaction activity to obtain mixed powder, heating the mixed powder to obtain the mixed powderDuring the period, the temperature in the vacuum furnace is 1000 ℃, and the vacuum degree is 3 multiplied by 10^-3Pa; weighing 1-4 g of mixed powder subjected to vacuum heat treatment and hard alloy, putting the mixed powder and the hard alloy into a metal molybdenum container, and putting the metal molybdenum container into a mold for prepressing molding, wherein the prepressing pressure is 10MPa, and the pressure maintaining time is 60s, so as to obtain a composite material;

step 2, a high-temperature high-pressure assembly sintering process:

placing the composite material in a zirconium oxide wrapping container along with a metal molybdenum container wrapped outside the composite material, assembling the zirconium oxide wrapping container and the pyrophyllite assembly block to obtain an assembled synthetic block, placing the assembled synthetic block in a cubic press for prepressing, applying pressure to 2 GPa-3 GPa, and maintaining the pressure for 5 min-7 min to obtain a prepressed assembly block; placing the prepressed assembly block in a vacuum sintering furnace for vacuumizing until the air pressure in the furnace is 2 multiplied by 10^-3Heating to 600 deg.C below Pa, keeping the temperature for 3min, stopping vacuumizing, introducing mixed gas of hydrogen and nitrogen at a ratio of 1:1, maintaining for 1 hr, and vacuumizing to pressure of 2 × 10^-3Below Pa, obtaining a composite component;

placing the composite assembly in a 6 x 1200MN cubic press, boosting the pressure to a sintering pressure of 6.1GPa at a boosting rate of 1GPa/min, heating at a heating rate of 45 ℃/s for high-temperature sintering, keeping the temperature at 1450 ℃ for 100s, then heating to a sintering temperature of 1700 ℃ within 50s, cooling to 650 ℃ at 32 ℃/s after sintering, cooling to room temperature after keeping the temperature for 6min, reducing to normal pressure at a decompression rate of 0.6GPa/min, removing a metal molybdenum container wrapped outside a compact sample by a sand blasting machine to obtain a polycrystalline diamond compact, and observing the surface of the sintered compact uniformly sintered by a stereoscopic microscope without defects such as points, cracks and the like;

step 3, grinding and polishing the polycrystalline diamond compact obtained in the step 2 to obtain a sintered polycrystalline diamond compact under a mantle-like condition;

the performance indexes of the sintered polycrystalline diamond compact with the similar mantle condition prepared in the embodiment are detected as follows: the abrasion ratio is 39.2 ten thousand, and the impact toughness is 1212J; thermal stability initial oxidation temperature 925 ℃.

Example 2

A preparation method of a polycrystalline diamond compact sintered under a mantle-like condition comprises the following steps:

step 1, preparing raw materials:

the preparation method comprises the following steps of weighing 85 wt% of nickel-plated diamond micro powder, 5 wt% of diamond micro powder, 3 wt% of graphite microcrystal, 2 wt% of carbohydrazide, 1 wt% of lithium carbonate and 4 wt% of calcium silicate according to the weight percentage, wherein the mass of a mixed material consisting of the nickel-plated diamond micro powder, the graphite microcrystal, the carbohydrazide, the lithium carbonate and the calcium silicate is 4 g-8 g, uniformly mixing the materials in a ball mill, wherein the ball-to-material ratio of the ball mill is 1:1, a ball milling medium is toluene, the using amount is 10mL, the rotating speed of the ball mill is 600r/min, a part of toluene is added every 2 hours in the ball milling process, and the ball milling is stopped after 8 hours; opening the ball mill, evaporating toluene to dry, placing the mixed powder into a graphite cup, placing the graphite cup containing the powder into a vacuum furnace for vacuum heat treatment to remove oxygen, water vapor and the like adsorbed on the surface of the powder and enable the surface of the powder to have better reaction activity to obtain mixed powder, wherein the temperature in the vacuum furnace is 1100 ℃ during heating, and the vacuum degree is 3 multiplied by 10^-3Pa; weighing 1-4 g of mixed powder subjected to vacuum heat treatment and hard alloy, putting the mixed powder and the hard alloy into a metal molybdenum container, and putting the metal molybdenum container into a mold for prepressing molding, wherein the prepressing pressure is 10MPa, and the pressure maintaining time is 60s, so as to obtain a composite material;

step 2, a high-temperature high-pressure assembly sintering process:

placing the composite material in a zirconium oxide wrapping container along with a metal molybdenum container wrapped outside the composite material, assembling the zirconium oxide wrapping container and the pyrophyllite assembly block to obtain an assembled synthetic block, placing the assembled synthetic block in a cubic press for prepressing, applying pressure to 2 GPa-3 GPa, and maintaining the pressure for 5 min-7 min to obtain a prepressed assembly block; placing the prepressed assembly block in a vacuum sintering furnace for vacuumizing until the air pressure in the furnace is 2 multiplied by 10^-3Heating to 600 deg.C below Pa, keeping the temperature for 5min, stopping vacuumizing, introducing mixed gas of hydrogen and nitrogen at a ratio of 1:1, maintaining for 1 hr, and vacuumizing to pressure of 2 × 10^-3Below Pa, obtaining a composite component;

placing the composite component in a 6 x 1200MN cubic press, increasing the pressure to 6.2GPa at the pressure increasing rate of 0.5GPa/min, increasing the temperature at the temperature increasing rate of 50 ℃/s for high-temperature sintering, keeping the temperature at 1400 ℃ for 80s, increasing the temperature to 1750 ℃ within 50s, reducing the temperature to 600 ℃ at 35 ℃/s after sintering, keeping the temperature for 6min, reducing the temperature to room temperature, and reducing the pressure to normal pressure at the pressure reducing rate of 0.8 GPa/min. Removing the metal molybdenum container wrapped outside the sample of the composite sheet from the sand blasting machine to obtain the polycrystalline diamond composite sheet, and performing primary observation on a stereoscopic microscope to ensure that the surface of a sintered body is uniformly sintered and has no defects such as pits, cracks and the like;

step 3, grinding and polishing the polycrystalline diamond compact obtained in the step 2 to obtain a sintered polycrystalline diamond compact under a mantle-like condition;

the performance indexes of the sintered polycrystalline diamond compact with the similar mantle condition prepared in the embodiment are detected as follows: the abrasion ratio is 41.6 ten thousand, and the impact toughness is 1324J; thermal stability initial oxidation temperature 937 ℃.

Example 3

A preparation method of a polycrystalline diamond compact sintered under a mantle-like condition comprises the following steps:

step 1, preparing raw materials:

the method comprises the following steps of weighing 85 wt% of nickel-plated diamond micro powder, 7.5 wt% of diamond micro powder, 2 wt% of graphite microcrystal, 0.5 wt% of adamantane formyl hydrazine, 2.5 wt% of calcium carbonate and 2.5 wt% of calcium silicate according to the weight percentage, uniformly mixing the nickel-plated diamond micro powder, the graphite microcrystal, the adamantane formyl hydrazine, the calcium carbonate and the calcium silicate under a ball mill, wherein the ball mill adopts a ball-to-material ratio of 1:1, a ball milling medium is toluene, the using amount of the toluene is 10mL, the rotating speed of the ball mill is 600r/min, adding a part of toluene every 2 hours in the ball milling process, and stopping ball milling for 8 hours; opening the ball mill, evaporating toluene to dry, placing the mixed powder into a graphite cup, placing the graphite cup containing the powder into a vacuum furnace for vacuum heat treatment to remove oxygen, water vapor and the like adsorbed on the surface of the powder and enable the surface of the powder to have better reaction activity to obtain mixed powder, wherein the temperature in the vacuum furnace is 1100 ℃ during heating, and the vacuum degree is 3 multiplied by 10^-3Pa; weighing 1-4 g of mixed powder subjected to vacuum heat treatment and hard alloy, putting the mixed powder and the hard alloy into a metal molybdenum container, and putting the metal molybdenum container into a mold for prepressing molding, wherein the prepressing pressure is 10MPa, and the pressure maintaining time is 60s, so as to obtain a composite material;

step 2, a high-temperature high-pressure assembly sintering process:

placing the composite material in a zirconium oxide wrapping container along with a metal molybdenum container wrapped outside the composite material, assembling the zirconium oxide wrapping container and the pyrophyllite assembly block to obtain an assembled synthetic block, placing the assembled synthetic block in a cubic press for prepressing, applying pressure to 2 GPa-3 GPa, and maintaining the pressure for 5 min-7 min to obtain a prepressed assembly block; placing the prepressed assembly block in a vacuum sintering furnace for vacuumizing until the air pressure in the furnace is 2 multiplied by 10^-3Heating to 600 deg.C below Pa, keeping the temperature for 3min, stopping vacuumizing, introducing mixed gas of hydrogen and nitrogen at a ratio of 1:1, maintaining for 1 hr, and vacuumizing to pressure of 2 × 10^-3Below Pa, obtaining a composite component;

placing the composite component in a 6 x 1200MN cubic press, increasing the pressure to 6.3GPa at the pressure increasing rate of 0.8GPa/min, increasing the temperature at the temperature increasing rate of 45 ℃/s for high-temperature sintering, keeping the temperature at 1420 ℃ for 100s, increasing the temperature to 1780 ℃ within 45s, reducing the temperature to 550 ℃ at 40 ℃/s after sintering, keeping the temperature for 7min, reducing the temperature to room temperature, and reducing the pressure to normal pressure at the pressure reducing rate of 0.8 GPa/min; removing the metal molybdenum container wrapped outside the sample of the composite sheet from the sand blasting machine to obtain the polycrystalline diamond composite sheet, and performing primary observation on a stereoscopic microscope to ensure that the surface of a sintered body is uniformly sintered and has no defects such as pits, cracks and the like;

step 3, grinding and polishing the polycrystalline diamond compact obtained in the step 2 to obtain the mantle-like sintered polycrystalline diamond compact;

the performance indexes of the composite sheet prepared in the embodiment are detected as follows: the abrasion ratio is 41.5 ten thousand, and the impact toughness is 1216J; thermal stability initial oxidation temperature 942 ℃.

Example 4

A preparation method of a polycrystalline diamond compact sintered under a mantle-like condition comprises the following steps:

step 1, preparing raw materials:

weighing 83 wt% of nickel-plated diamond micro powder, 7 wt% of diamond micro powder, 4 wt% of graphite microcrystal, 1 wt% of adipic dihydrazide, 4 wt% of magnesium carbonate and 1 wt% of magnesium silicate according to the weight percentage, uniformly mixing the nickel-plated diamond micro powder, the graphite microcrystal, the adipic dihydrazide, the magnesium carbonate and the magnesium silicate under a ball mill, wherein the ball-milling adopts a ball-to-material ratio of 1:1, a ball-milling medium is toluene, the using amount of the toluene is 10mL, the rotating speed of the ball mill is 600r/min, adding a part of toluene every 2h in the ball-milling process, and stopping ball-milling after 8 h; opening the ball mill, evaporating toluene to dry, placing the mixed powder into a graphite cup, placing the graphite cup containing the powder into a vacuum furnace for vacuum heat treatment to remove oxygen, water vapor and the like adsorbed on the surface of the powder and enable the surface of the powder to have better reaction activity to obtain mixed powder, wherein the temperature in the vacuum furnace is 1050 ℃ during heating, and the vacuum degree is 3 multiplied by 10^-3Pa; weighing 1-4 g of mixed powder subjected to vacuum heat treatment and hard alloy, putting the mixed powder and the hard alloy into a metal tantalum container, putting the metal tantalum container into a mold, and performing pre-pressing molding, wherein the pre-pressing pressure is 10MPa, and the pressure maintaining time is 60s, so as to obtain a composite material;

step 2, a high-temperature high-pressure assembly sintering process:

placing the composite material in a zirconium oxide wrapping container along with a metal tantalum container wrapped outside the composite material, assembling the zirconium oxide wrapping container and the pyrophyllite assembly block to obtain an assembled synthetic block, placing the assembled synthetic block in a cubic press for prepressing, applying pressure to 2 GPa-3 GPa, and maintaining the pressure for 5 min-7 min to obtain a prepressed assembly block; placing the prepressed assembly block in a vacuum sintering furnace for vacuumizing until the air pressure in the furnace is 2 multiplied by 10^-3Heating to 600 deg.C below Pa, keeping the temperature for 3min, stopping vacuumizing, introducing mixed gas of hydrogen and nitrogen at a ratio of 1:1, maintaining for 1 hr, and vacuumizing to pressure of 2 × 10^-3Below Pa, obtaining a composite component;

placing the composite component in a 6 x 1200MN cubic press, boosting the pressure to 6.6GPa at the boosting rate of 1GPa/min, heating at the heating rate of 55 ℃/s for high-temperature sintering, keeping the temperature at 1480 ℃ for 110s, then increasing the temperature to 1800 ℃ within 45s, cooling to 500 ℃ at 30 ℃/s after sintering, keeping the temperature for 5min, then cooling to room temperature, and reducing the pressure to normal pressure at the pressure reduction rate of 0.1 GPa/min; removing the metal tantalum container wrapped outside the sample of the composite sheet by using a sand blasting machine to obtain a polycrystalline diamond composite sheet, and performing primary observation on the polycrystalline diamond composite sheet by using a stereoscopic microscope to ensure that the surface of a sintered body is uniformly sintered and has no defects such as pits, cracks and the like;

step 3, grinding and polishing the polycrystalline diamond compact obtained in the step 2 to obtain the mantle-like sintered polycrystalline diamond compact;

the performance indexes of the composite sheet prepared in the embodiment are detected: the abrasion ratio is 42.1 ten thousand, and the impact toughness is 1424J; thermal stability initial oxidation temperature 928 ℃.

The sintered polycrystalline diamond compact with the mantle-like condition prepared in the above examples 1 to 4 was subjected to wear resistance, impact toughness, and thermal stability tests under the same test conditions, and the measurement methods all adopted conventional measurement means in the field, and the wear resistance test was performed by using JB/T3235-2013 "method for measuring the wear ratio of artificial diamond sintered body", and the impact toughness test was performed by using a drop hammer impact method (that is, a 1.5kg impact hammer freely drops at a height of 10cm, and the corner of the sample is impacted by the energy, and when a microcrack appears on the surface of the sample, the impact toughness value was obtained). The thermal stability test adopts a TG-DSC differential thermogravimetric analyzer, the set condition is air heating, and the heating rate is 20 ℃/min.

The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Those skilled in the art can make numerous possible variations and modifications to the present teachings, or modify equivalents thereof, without departing from the scope thereof, by applying the methods and techniques disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiment example according to the technical essence of the present invention are still within the protection scope of the technical solution of the present invention, unless the technical essence of the present invention departs from the content of the technical solution of the present invention.