阅读说明：本技术 一种超硬材料聚晶复合片的制备方法 (Preparation method of superhard material polycrystalline compact ) 是由 陈家荣 陈超 莫培程 贾光 林峰 于 2019-11-28 设计创作，主要内容包括：本发明公开了一种超硬材料聚晶复合片的制备方法,包括以下步骤：1)根据所要制备的超硬材料聚晶复合片的聚晶层的配方称取超硬磨料和粘结剂,混匀后先在氢气中还原,再置于真空中高温净化,得到聚晶层混合粉料；2)获得硬质合金基体；3)取聚晶层混合粉料置于金属杯中,铺平、压实,放入硬质合金基体,压实；重复放入聚晶层混合粉料,铺平、压实后再放入硬质合金基体并压实的操作,直至金属杯填满；4)将装满物料的金属杯在氢气中还原,再在真空中高温净化,取出后在金属杯上加盖；5)将加盖后的金属杯置于保温传压介质中进行高温高压合成,取出后除去金属杯,分切后得到多个超硬材料聚晶复合片。本发明所述方法工艺简单,成本低且效率高。(The invention discloses a preparation method of a superhard material polycrystalline compact, which comprises the following steps: 1) weighing a superhard abrasive and a binder according to a formula of a polycrystalline layer of the superhard material polycrystalline composite sheet to be prepared, uniformly mixing, reducing in hydrogen, and then purifying at high temperature in vacuum to obtain polycrystalline layer mixed powder; 2) obtaining a hard alloy matrix; 3) putting the mixed powder of the polycrystalline layer into a metal cup, paving and compacting, putting a hard alloy matrix into the metal cup, and compacting; repeatedly putting mixed powder of polycrystalline layers, paving and compacting, and then putting a hard alloy matrix and compacting until the metal cup is filled; 4) reducing the metal cup filled with the materials in hydrogen, purifying at high temperature in vacuum, taking out and covering the metal cup; 5) and (3) placing the metal cup after being covered in a heat-preservation pressure-transmission medium for high-temperature high-pressure synthesis, taking out the metal cup, removing the metal cup, and cutting to obtain a plurality of polycrystalline superhard material composite sheets. The method has the advantages of simple process, low cost and high efficiency.)

1. A preparation method of a polycrystalline compact made of superhard material comprises the following steps:

1) weighing a superhard abrasive and a binder according to a formula of a polycrystalline layer of the superhard material polycrystalline composite sheet to be prepared, uniformly mixing, then placing in a hydrogen atmosphere for reduction, then placing in a vacuum condition for high-temperature purification, and cooling to obtain polycrystalline layer mixed powder for later use;

2) obtaining a hard alloy matrix matched with the polycrystalline layer mixed powder;

3) putting the mixed powder of the polycrystalline layer in a metal cup, paving and compacting, then putting a hard alloy matrix, and compacting; repeatedly putting mixed powder of polycrystalline layers, paving and compacting, and then putting a hard alloy matrix and compacting until the metal cup is filled;

4) reducing the metal cup filled with the materials in a hydrogen atmosphere, then purifying at high temperature under a vacuum condition, cooling, taking out, and covering the metal cup;

5) and (3) placing the metal cups with the covers in a heat-preservation pressure-transmission medium, performing high-temperature and high-pressure synthesis, taking out the metal cups, removing the metal cups, and slitting to obtain a plurality of polycrystalline superhard material composite sheets.

2. The method of claim 1, wherein: the superhard abrasive is one or the combination of more than two of cubic boron nitride, diamond and titanium diboride.

3. The method of claim 1, wherein: the binder is one or the combination of more than two of iron, cobalt and nickel.

4. The method of claim 1, wherein: the reduction is carried out at the temperature of 450-900 ℃, and the reduction time is 1-3 h.

5. According to claimThe method of claim 1, wherein: the high-temperature purification is carried out under the vacuum degree of 10 ^-2-10 ^{- 4}Pa, temperature of 600-1200 ℃, and purification time of 1-3 h.

6. The method of claim 1, wherein: the process conditions of the high-temperature high-pressure synthesis are as follows: the pressure is 4.5-5.5GPa, the temperature is 1400-1750 ℃ and the time is 150-800 s.

Technical Field

The invention relates to a preparation method of a superhard composite material, in particular to a preparation method of a superhard material polycrystalline compact.

Background

The superhard polycrystalline composite sheet is a tool or abrasive tool material formed by polymerizing superhard abrasive particles on the surface of a hard alloy substrate. At present, polycrystalline cubic boron nitride composite sheets, polycrystalline diamond composite sheets, polycrystalline drilling spherical teeth made of superhard materials and the like are mainly applied to superhard material engineering technologies. The polycrystalline cubic boron nitride composite sheet is a symbiotic synthetic material with cubic boron nitride particles in a metal array in a disordered orientation and extremely tough manner, and the cubic boron nitride material is obtained at high temperature and high pressure. Sintering is controlled in the thermally stable region of cubic boron nitride, with hard, disordered structures forming between the grains. The blank has a layer of hard alloy substrate, and cubic boron nitride and hard alloy are joined into a whole through a transition layer. In fact, it is a composite material of cubic boron nitride polycrystal and cemented carbide, usually in the shape of a circular disk, and is therefore often called a cubic boron nitride compact. The polycrystalline diamond compact is a composite material consisting of diamond and a hard alloy matrix, has the characteristics of high hardness and good wear resistance, is widely applied to industries such as petroleum drilling, geological exploration, coal field drilling and production drill bits, machining cutters and the like, and is mainly used for cutting aluminum alloy, copper alloy, titanium alloy and the like in machining.

The existing preparation of the superhard material polycrystalline compact is a process of one cup of the superhard material polycrystalline compact, and the process efficiency is low; on the other hand, the synthesis number of the press machine (usually a cubic tripod press) and the heat-preservation pressure-transmission medium (usually a pyrophyllite block) is limited, and each composite sheet is synthesized by one time of high-temperature high-pressure pressing, the pyrophyllite and the heat-preservation material inside the pyrophyllite are all non-repeatable materials which are disposable, and the synthesis cost is high. Due to the reasons, the manufacturing cost of the composite sheet is high, and further popularization and application of the composite sheet are limited.

Disclosure of Invention

The invention aims to provide a preparation method of a superhard material polycrystalline compact with low cost, simple process and high efficiency.

The preparation method of the superhard material polycrystalline compact comprises the following steps:

1) weighing a superhard abrasive and a binder according to a formula of a polycrystalline layer of the superhard material polycrystalline composite sheet to be prepared, uniformly mixing, then placing in a hydrogen atmosphere for reduction, then placing in a vacuum condition for high-temperature purification, and cooling to obtain polycrystalline layer mixed powder for later use;

2) obtaining a hard alloy matrix matched with the polycrystalline layer mixed powder;

3) putting the mixed powder of the polycrystalline layer in a metal cup, paving and compacting, then putting a hard alloy matrix, and compacting; repeatedly putting mixed powder of polycrystalline layers, paving and compacting, and then putting a hard alloy matrix and compacting until the metal cup is filled;

4) reducing the metal cup filled with the materials in a hydrogen atmosphere, then purifying at high temperature under a vacuum condition, cooling, taking out, and covering the metal cup;

5) and (3) placing the metal cups with the covers in a heat-preservation pressure-transmission medium, performing high-temperature and high-pressure synthesis, taking out the metal cups, removing the metal cups, and slitting to obtain a plurality of polycrystalline superhard material composite sheets.

In the step 1) of the preparation method, the formula of the diamond polycrystalline layer is the same as that of the prior art, and the preferable formula comprises the following components in percentage by mass: 0.1-15% of adhesive and the balance of super-hard abrasive. The selection of the adhesive and the super-hard abrasive is the same as that of the prior art, and specifically, the adhesive can be one or the combination of more than two of iron, cobalt and nickel, or ceramic adhesive such as alumina; the superhard abrasive material can be one or a combination of more than two of cubic boron nitride, diamond and titanium diboride, so that the superhard material polycrystalline compact in the invention refers to a polycrystalline diamond compact or a polycrystalline cubic boron nitride compact. The binder and the superabrasive material are both present in powder form and their particle size is selected as in the prior art, wherein the binder preferably has a particle size of 0.1-10 μm and the superabrasive material preferably has a particle size of 0.5-30 μm.

In steps 1) and 4) of the preparation method, the reduction and dehydrogenation treatment is the same as the prior art, preferably, the reduction is carried out at the temperature of 450-900 ℃, and the reduction time is 1-3 h; the high-temperature purification is carried out under the vacuum degree of 10 ^-2-10 ^{- 4}Pa and the temperature of 600-1200 ℃, and the purification time is usually 1-3 h.

In step 2) of the above preparation method, the hard alloy matrix and the polycrystalline layer mixed powder in step 1) are matched according to materials known by those skilled in the art. Specifically, the hard alloy matrix is the conventional alloy of tungsten carbide and cobalt, the alloy of tungsten carbide and titanium or the alloy formula of tungsten carbide and nickel. In this step, the cemented carbide substrate is obtained by a conventional method, such as preparing according to a conventional method (weighing the components according to the formula, mixing, forming and sintering), or directly purchasing a conventional cemented carbide substrate such as YG16, YG16C, YG12, YG12C, YG10, YG10C or YG8 on the market. The thickness of the hard alloy matrix is the conventional thickness of the matrix in the existing composite sheet, and the diameter of the hard alloy matrix is matched with the size of the inner diameter of a metal cup which is subsequently used for containing polycrystalline layer mixed powder and the hard alloy matrix.

In step 3) of the above preparation method, the metal cup of the present invention is a cup conventionally used for containing powder in the prior art, such as a cup made of ductile materials, such as a molybdenum cup, a niobium cup, a zirconium cup or a stainless steel cup with a cover. In the step, the filling thickness of the mixed powder of the polycrystalline layer is the conventional thickness of the polycrystalline layer in the prior art. After all operations of filling and compacting the polycrystalline layer mixed powder and the hard alloy matrix are completed, the metal cup is preferably placed in a cold-pressing die for compaction and then subjected to subsequent reduction operation.

In step 5) of the above preparation method, the heat-insulating pressure-transmitting medium and the subsequent high-temperature high-pressure synthesis are the same as those in the prior art, specifically, the heat-insulating pressure-transmitting medium is usually pyrophyllite, and the process conditions of the high-temperature high-pressure synthesis are preferably as follows: the pressure is 4.5-5.5GPa, the temperature is 1400-1750 ℃ and the time is 150-800 s. After the high-temperature and high-pressure synthesis is completed, the metal cup is taken out of the heat-preservation pressure-transmission medium and placed into a centerless grinding machine, the metal cup is ground to expose alternate polycrystalline layers and hard alloy matrix layers, and then the metal cup is placed on a wire cut electric discharge machine to be positioned and cut from the hard alloy matrix layers, so that a plurality of polycrystalline composite sheets made of the superhard materials are obtained.

Compared with the prior art, the polycrystalline layer mixed powder and the hard alloy matrix are filled, leveled and compacted for multiple times in one metal cup, and a plurality of polycrystalline composite sheets of superhard materials can be obtained by adopting one-time high-temperature and high-pressure synthesis operation and then slitting.

Detailed Description

The present invention will be better understood from the following detailed description of specific examples, which should not be construed as limiting the scope of the present invention.

Diamond powder and cubic boron nitride powder described in the following examples were subjected to conventional chemical acid-base purification treatment.