A polycrystalline diamond composite sheet vacuum packaging flow blocker and flow block structure

Abstract

The present invention relates to a polycrystalline diamond composite sheet vacuum packaging flow blocker and flow blocker structure, so that the molten solder liquid or metal gas inside the metal cup is blocked by the flow blocker and stays in the space between the metal cap cup and the flow blocker, and does not enter the polycrystalline diamond composite sheet synthesis area. The polycrystalline diamond micropowder and the alloy matrix are not affected by the molten solder liquid and trace metal gas in the flow blocker, and are in a vacuum sealed environment, so that the molten solder liquid and the trace metal gas generated by the solder during melting are prevented from flowing and diffusing to the polycrystalline diamond composite sheet synthesis area, thereby improving the stability and yield rate of the polycrystalline diamond composite sheet.

Description

Technical Field

[0001] The invention relates to the technical field of superhard material synthesis, and more specifically to a polycrystalline diamond composite sheet vacuum packaging flow blocker and a flow blocker structure. Background Art

[0002] Polycrystalline diamond composite sheets are made of polycrystalline diamond powder and cemented carbide matrix sintered under ultra-high temperature and high pressure conditions. They have the high hardness, high wear resistance and thermal conductivity of diamond, as well as the strength and impact toughness of cemented carbide. They are ideal materials for manufacturing cutting tools, drilling bits and other wear-resistant tools. When preparing polycrystalline diamond composite sheets, metal cups are first assembled, then subjected to high-temperature vacuum purification, and then assembled into synthetic blocks, which are sintered at high temperature and high pressure, and finally processed into products that meet the requirements.

[0003] During the high-temperature vacuum purification process, the vacuum is first drawn, and then the temperature in the vacuum furnace is increased after the vacuum is drawn to melt the solder for welding, thereby forming a seal for the metal cup assembly. However, the molten solder flows downward under the action of gravity. If it enters the alloy matrix or polycrystalline diamond powder, it will directly destroy the synthesis environment of the composite sheet. Furthermore, the solder will produce trace amounts of gaseous metal under the action of high temperature, which will remain in the metal cup after welding. The gaseous metal diffuses in the metal cup. If it enters the alloy matrix and polycrystalline diamond powder, it will also affect the synthesis of the polycrystalline diamond composite sheet. In short, if the molten solder liquid inside the metal cup and the metal gas generated at high temperature flow into the synthesis area of ​​the polycrystalline diamond composite sheet, the stability of the polycrystalline diamond composite sheet will be directly reduced, and the yield rate will be reduced. Summary of the invention

[0004] In view of the problems existing in the above-mentioned prior art, the present invention provides a polycrystalline diamond composite sheet vacuum packaging flow blocker and flow blocker structure, so that the molten solder liquid or metal gas inside the metal cup is blocked by the flow blocker and stays in the space between the metal cap cup and the flow blocker, and does not enter the polycrystalline diamond composite sheet synthesis area. The polycrystalline diamond micropowder and the alloy matrix are not affected by the molten solder liquid and trace metal gas in the flow blocker and are in a vacuum sealed environment.

[0005] The present invention provides the following technical solution: a polycrystalline diamond composite sheet vacuum packaging flow barrier, which is a granular material with a particle size of less than or equal to 20 meshes and does not react with metal niobium and metal niobium alloys and the cemented carbide of the polycrystalline diamond composite sheet.

[0006] The particles are refractory oxide particles with a melting temperature greater than 1300°C.

[0007] The refractory oxides are silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, and manganese oxide.

[0008] The particulate matter is at least one of oxide particles or glass particles, wherein the melting temperature of at least one oxide particle or glass particle is 200°C-1000°C; the oxide particles with a melting temperature of 200°C-1000°C are: potassium oxide, cesium oxide, lead oxide, bismuth oxide, antimony oxide; the glass particles with a melting temperature of 200°C-1000°C are: lead glass, frosted glass, embossed glass, and heat-bent glass.

[0009] A polycrystalline diamond composite sheet vacuum packaging flow-blocking structure comprises a metal bottom cup and a metal cap cup. Polycrystalline diamond micropowder, a cemented carbide matrix, a first insulating layer, and a flow blocker between the periphery of the first insulating layer and the cup wall of the metal bottom cup are sequentially placed in the metal bottom cup. The flow blocker is in the shape of a closed circular ring.

[0010] A second insulating layer is arranged on the upper part of the flow blocker. The flow blocker is arranged between the periphery of the second insulating layer and the cup wall of the metal bottom cup, and the shape of the flow blocker is a closed circular ring. The first insulating layer and the second insulating layer are single substances, mixtures, alloys or alloy mixtures of metal niobium, iron, titanium, tantalum, manganese and cobalt. The mouth of the metal bottom cup is an inward folded edge, and a welding agent is arranged between the upper part of the folded edge and the metal cap cup. The welding agent (8) is a single substance of copper, silver, gold, tin, zinc, phosphorus, aluminum, cadmium, or an alloy of copper, nickel, manganese, cobalt, silver, gold, rhodium, palladium, titanium, tin, zinc, niobium, phosphorus, boron, aluminum, cadmium, tantalum, silicon and chromium with a melting point of 700°C-1300°C.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1. When the flow blocker is refractory oxide particles at a high temperature of 1300°C, the refractory oxide particles in close contact can completely prevent the molten solder liquid from flowing to the synthesis area of ​​the polycrystalline diamond composite sheet, ensuring that the synthesis environment of the composite sheet is not affected by the molten solder liquid, thereby improving the stability and yield of the polycrystalline diamond composite sheet.

[0013] 2. When the flow blocker is oxide particles or glass particles, at a high temperature of 1300°C, the particles with a low melting point melt first to form a molten state, or the molten glass and / or oxides cover the solid particles with a melting temperature greater than 1300°C to form a mixed molten state. At this time, the flow blocker can block the gap between the cup wall and the cemented carbide substrate. When vacuuming, air overflows from between the cup wall and the cemented carbide substrate and encounters the molten or mixed molten flow blocker. Since the flow blocker is in a soft molten or mixed molten state, the air will push away the molten or mixed molten flow blocker, making the air between the diamond particles When the vacuum is completed, the molten or mixed molten flow blocker is in a vacuum. Due to the flow tendency of the molten or mixed molten flow blocker, the molten or mixed molten flow blocker will fill the gap between the cup wall and the cemented carbide substrate. When welding, the excess molten welding agent and the trace metal gas generated by the welding agent generate a small positive pressure. The small positive pressure makes the molten or mixed molten flow blocker further fill the gap between the cup wall and the cemented carbide substrate, preventing the excess molten welding agent and the trace metal gas generated by the welding agent from entering the composite sheet synthesis area. This flow blocker can prevent the welding agent from melting liquid and the trace metal gas generated by the welding agent during melting from flowing and diffusing to the polycrystalline diamond composite sheet synthesis area, with better barrier effect, thereby improving the stability and yield rate of the polycrystalline diamond composite sheet.

[0014] 3. The preparation method of the flow-blocking agent is simple, low-cost, and saves product processing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the vacuum packaging flow-blocking structure of the present invention.

[0016] Figure 2 It is a partial enlarged view of the vacuum packaging flow-blocking structure of the present invention.

[0017] Figure 3 It is a partial enlarged view of another vacuum packaging flow-blocking structure of the present invention.

[0018] Among them, 1 is a metal bottom cup; 2 is a metal cap cup; 3 is polycrystalline diamond powder; 4 is a cemented carbide substrate; 5 is a first insulating layer; 6 is a flow blocker; 7 is a second insulating layer; 8 is a welding agent; and 9 is a folded edge. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0020] like Figure 1As shown, a polycrystalline diamond composite sheet vacuum packaging flow barrier, the polycrystalline diamond composite sheet vacuum packaging flow barrier is a particle with a particle size of less than or equal to 20 meshes that does not react with metal niobium and metal niobium alloys and the cemented carbide of the polycrystalline diamond composite sheet. The mesh number is expressed in the Chinese standard as the number of mesh holes per square centimeter area, and is expressed in the international standard as the number of mesh holes per inch. It is also expressed in the size of each mesh hole (mm). In this application, the Taylor standard sieve system is used as the standard, and a particle size of less than or equal to 20 meshes is equivalent to a particle size of less than or equal to 0.850mm. The larger the mesh number, the finer the material particle size; the smaller the mesh number, the larger the material particle size.

[0021] The particles are refractory oxide particles with a melting temperature greater than 1300°C.

[0022] The refractory oxides are silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, and manganese oxide. In general production and processing, the flow inhibitor is prepared into a paste by adding a dispersant to the refractory oxides, which is convenient for forming and applying.

[0023] The particles are at least one of oxide particles or glass particles, wherein the melting temperature of at least one oxide particle or glass particle is 200°C-1000°C; oxide particles with a melting temperature of 200°C-1000°C are: potassium oxide, cesium oxide, lead oxide, bismuth oxide, antimony oxide; glass particles with a melting temperature of 200°C-1000°C are: lead glass, frosted glass, embossed glass, and hot-bent glass. Ordinary glass can generally soften at 600°C-900°C.

[0024] A polycrystalline diamond composite sheet vacuum packaging flow-blocking structure comprises a metal bottom cup 1 and a metal cap cup 2. Polycrystalline diamond powder 3, a cemented carbide substrate 4, a first insulating layer 5 are sequentially placed in the metal bottom cup, and a flow blocker 6 is placed between the periphery of the first insulating layer 5 and the cup wall of the metal bottom cup 1. The flow blocker 6 is in the shape of a closed circular ring.

[0025] The metal bottom cup and the metal cap cup are used in pairs. The metal cup is generally made of niobium (Nb) or tantalum (Ta). In this embodiment, a niobium cup is selected. Niobium and tantalum are both high melting point metals. Niobium is a shiny gray metal with a melting point of 2468°C, and tantalum is a steel gray metal with a melting point of 2996°C. The metal cup is generally cylindrical, and in special cases, it is a special-shaped structure. The main characteristics of niobium are good heat resistance, good thermal conductivity, light weight, thin metal cup wall thickness, and good ductility. Therefore, it is easy to bend at the mouth of the metal bottom cup. The edge sealing machine provides very little force to achieve the bending requirements, and will not deform the cup wall of the metal bottom cup, ensuring the shape and size requirements of the polycrystalline diamond composite sheet.

[0026] A second insulating layer 7 is disposed on the upper portion of the flow blocker 6 .

[0027] The second insulating layer 7 is surrounded by the wall of the metal bottom cup 1 and is provided with a flow blocker 6. The flow blocker 6 is in the shape of a closed circular ring. The double-layer flow blocker makes the sealing effect better and more reliable. The first insulating layer 5 and the second insulating layer 7 are single substances, mixtures, alloys or alloy mixtures of metal niobium, iron, titanium, tantalum, manganese and cobalt. As an insulating layer, the flow blocker is mainly used to seal and isolate to prevent the molten welding agent or the trace metal gas generated by the welding agent at high temperature from flowing to the cemented carbide substrate or the diamond powder layer, so as to ensure the normal synthesis of the polycrystalline diamond composite sheet. Therefore, the selected metal material should have a high melting point, good thermal conductivity, certain strength and plasticity, and be resistant to high temperature and high pressure. Secondly, the thickness should be relatively thin, generally 0.3 mm.

[0028] The mouth of the metal bottom cup 1 is an inwardly folded edge 9 , and welding agent 8 is provided between the upper part of the folded edge 9 and the metal cap cup 2 .

[0029] The solder 8 is a single substance of copper, silver, gold, tin, zinc, phosphorus, aluminum, cadmium, or an alloy of copper, nickel, manganese, cobalt, silver, gold, rhodium, palladium, titanium, tin, zinc, niobium, phosphorus, boron, aluminum, cadmium, tantalum, silicon, and chromium with a melting point of 700°C-1300°C. In this embodiment, the solder is made of copper alloy, which has good thermal conductivity and does not affect the temperature uniformity of the synthesis field. It melts at about 1100°C, has good plasticity, and has a good sealing effect. The solder is set in a ring shape and is located at the upper part of the folded edge, which saves solder material and reduces processing costs.

[0030] Assembly process: take a set of metal base cup and metal cap cup, set welding agent at the bottom of the metal cap cup, first fill the metal base cup with polycrystalline diamond powder, flatten it with a T-shaped hammer, then put in the carbide substrate and the first insulating layer, and then apply a layer of flow barrier between the edge of the first insulating layer and the inner wall of the metal base cup to form a closed circular ring, then put in the second insulating layer, and apply another layer of flow barrier between the edge of the second insulating layer and the inner wall of the metal base cup, and finally use a sealing machine to bend the cup mouth of the metal base cup inward to form a folded edge; cover the metal cap cup with welding agent on the metal base cup to complete the assembly, and the assembly is ready to enter the high-temperature vacuum purification treatment stage.

[0031] High-temperature vacuum purification treatment: Place the assembly steadily in a vacuum furnace and perform vacuum treatment first. After vacuuming, apply high temperature (1000℃-1300℃) to melt the solder on the metal cap cup to form a closed space in the metal cup.

[0032] When evacuating, the air pressure outside the baffle (towards the mouth of the metal bottom cup) is lower than the air pressure inside the baffle (towards the bottom of the metal bottom cup), forming a pressure difference. Under the pressure inside the baffle, the paste-like baffle changes slightly in shape when under pressure, forming a tiny gap between it and the inner wall of the metal bottom cup. The air between the polycrystalline diamond micropowder and the air between the cemented carbide matrix and the inner wall of the metal bottom cup are drawn out under pressure through the tiny gap between the baffle and the inner wall. The air between the two insulating layers is also drawn out from the tiny gap formed between the baffle and the second insulating layer under pressure (there is a gap between the bent part and the upper surface of the second insulating layer, which does not hinder the air from flowing out). All the air in the metal cup is drawn out through the gap between the metal cap cup and the metal bottom cup, forming a completely vacuum environment inside the cup.

[0033] When all the air is exhausted, the furnace starts to heat up, and the solder reaches a molten state at high temperature to form a seal. Different flow barriers inside the metal cup have different barrier effects. When the flow barrier is refractory oxide particles at a high temperature of 1300°C, the refractory oxide particles in close contact can completely prevent the molten solder liquid from flowing to the synthesis area of ​​the polycrystalline diamond composite sheet, ensuring that the synthesis environment of the composite sheet is not affected by the molten solder liquid, thereby improving the stability and yield of the polycrystalline diamond composite sheet. When the flow barrier is oxide particles or glass particles, at a high temperature of 1300°C, the particles with a low melting point melt first to form a liquid state, and then cover the solid particles with a melting temperature greater than 1300°C to form a viscous state. Due to the support of the particles, the flow barrier only undergoes a slight change in overall shape under pressure, and fits on the inner wall of the metal bottom cup to form a seal, and does not flow into the synthesis area of ​​the composite sheet. This flow blocker can prevent both the molten liquid of the solder and the trace metal gas generated by the solder during melting from flowing to the synthesis area of ​​the polycrystalline diamond composite sheet, thereby achieving a better barrier effect and improving the stability and yield rate of the polycrystalline diamond composite sheet.

[0034] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A polycrystalline diamond composite vacuum packaging flow-blocking structure, comprising a metal bottom cup (1) and a metal cap cup (2), characterized in that: Polycrystalline diamond micropowder (3), a hard alloy matrix (4), a first insulating layer (5), and a flow blocker (6) are placed in sequence in the metal bottom cup (1). The flow blocker (6) is in the shape of a closed circular ring. The flow blocker (6) is at least one of oxide particles or glass particles, wherein the melting temperature of at least one of the oxide particles or glass particles is 200°C-1000°C. At a high temperature of 1300°C, particles with a low melting point melt first to form a liquid state, and then cover solid particles with a melting temperature greater than 1300°C to form a viscous state. Due to the support of the particles, the flow blocker (6) only undergoes a slight change in overall shape under the action of pressure, and is attached to the inner wall of the metal bottom cup (1) to form a seal, and does not flow into the composite sheet synthesis area. The flow blocker (6) can prevent the molten liquid of the solder and the trace metal gas generated by the solder during melting from flowing to the polycrystalline diamond composite sheet synthesis area.

2. The polycrystalline diamond composite vacuum package flow-blocking structure according to claim 1, characterized in that: A second insulating layer (7) is provided on the upper part of the flow blocker (6).

3. The polycrystalline diamond composite vacuum package flow-blocking structure according to claim 2, characterized in that: A flow blocker (6) is provided between the periphery of the second insulating layer (7) and the cup wall of the metal bottom cup (1), and the flow blocker (6) is in the shape of a closed circular ring.

4. The polycrystalline diamond composite vacuum package flow-blocking structure according to claim 3, characterized in that: The first insulating layer (5) and the second insulating layer (7) are single substances, mixtures, alloys or alloy mixtures of metals such as niobium, iron, titanium, tantalum, manganese and cobalt.

5. The polycrystalline diamond composite vacuum package flow-blocking structure according to claim 4, characterized in that: The mouth of the metal bottom cup (1) is an inwardly folded edge (9), and welding agent (8) is provided between the upper part of the folded edge (9) and the metal cap cup (2).

6. The polycrystalline diamond composite vacuum package flow-blocking structure according to claim 5, characterized in that: The solder (8) is a single substance of copper, silver, gold, tin, zinc, phosphorus, aluminum, cadmium, or an alloy of copper, nickel, manganese, cobalt, silver, gold, rhodium, palladium, titanium, tin, zinc, niobium, phosphorus, boron, aluminum, cadmium, tantalum, silicon, and chromium with a melting point of 700° C. to 1300° C.

Images