Indicating structure for internal temperature of polycrystalline diamond synthesis cavity

Abstract

The invention discloses a polycrystalline diamond synthesis cavity internal temperature indication structure which is located at any position in a synthesis cavity and comprises double-layer carbon paper sheets arranged up and down, a metal layer located in the middle of the double-layer carbon paper sheets and an insulation penetration body arranged on the periphery of the double-layer carbon paper sheets. And a heating body is arranged on the outer side of the insulating permeation body and is a constituent part of the synthesis cavity. When the temperature in the cavity reaches the melting point of the metal ring, the metal ring melts, penetrates through the insulating penetrating body and is in contact with and attached to the inner wall of the heating body to form a new conductive structure, so that the resistance in the cavity is sharply reduced, and the current is intuitively increased to a certain degree within a certain period of time; therefore, it can be determined that the temperature in the cavity reaches or is slightly higher than the melting point of the metal ring, thereby reflecting the temperature reference in the cavity. The heating process can be correspondingly adjusted according to the heating time required for reaching the temperature reference.

Description

Technical Field

[0001] The invention relates to the field of diamond and cemented carbide composite materials, and in particular to a structure for indicating the internal temperature of a cavity and regulating the temperature field during the process of synthesizing a polycrystalline diamond composite sheet by a high-temperature and high-pressure method. Background Art

[0002] Polycrystalline diamond composite sheet is a superhard material composed of diamond and cemented carbide matrix. It has the high hardness and high wear resistance of diamond and the strength and impact toughness of cemented carbide. It is an ideal material for manufacturing drilling bits, cutting tools and other wear-resistant tools. It is widely used in oil and gas extraction, mechanical processing and other fields.

[0003] At present, the domestic main method of synthesizing polycrystalline diamond composite sheets is to use a six-sided top press through a high temperature and high pressure method. During the synthesis process, temperature is the most important factor affecting the synthesis performance of polycrystalline diamond composite sheets. The temperature changes in the synthesis chamber and the balance of the temperature field are crucial to the final synthesis quality. However, since the synthetic raw materials, including diamond micropowder, cemented carbide matrix and other basic components, are relatively hard, they have almost no fluidity under high temperature and high pressure, and the internal shear stress is very strong. The success rate of conventional temperature measurement methods is low. In the actual production process, it is often necessary to rely on experience or multiple trials and errors to judge the approximate temperature in the chamber, which is very unfavorable for production synthesis, especially when testing new products. In addition, the cost of platinum-rhodium wire used for conventional thermocouple temperature measurement is not cheap, which undoubtedly increases the production cost of enterprises.

[0004] Therefore, it is extremely necessary to provide a structure specifically suitable for indicating the temperature inside the cavity and adjusting the temperature field during the synthesis process of polycrystalline diamond composite sheets. Summary of the invention

[0005] Based on the need to measure the temperature change inside the cavity during the synthesis of polycrystalline diamond composite sheets by the high temperature and high pressure method, and the actual situation that the conventional temperature measurement method has a low success rate and high cost due to the large shear stress, the present invention provides an indication structure for the temperature inside the polycrystalline diamond synthesis cavity, which can efficiently and conveniently provide a reference feedback on the temperature change in the cavity under high temperature and high pressure, and the process can be adjusted accordingly according to the time of the temperature reference feedback.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: A temperature indicating structure inside a polycrystalline diamond synthesis cavity, the indicating structure is located at any position inside the synthesis cavity, and comprises a double-layer carbon paper sheet arranged on the upper and lower sides, a metal layer located in the middle of the double-layer carbon paper sheet, and an insulating permeable body arranged on the outer circumference of the double-layer carbon paper sheet; the outer side of the insulating permeable body is a heating body, and the heating body is a component of the synthesis cavity; When the temperature inside the synthetic cavity reaches the melting point of the metal layer, the metal layer melts and contacts and adheres to the inner wall of the heating body through the insulating permeable body, forming a new conductive structure, causing the internal resistance of the cavity to drop sharply. This is intuitively manifested as the current rising to a certain level within a certain period of time. Based on this, it can be judged that the temperature in the cavity at this time has reached or is slightly higher than the melting point of the metal layer, thereby reflecting the temperature benchmark in the cavity.

[0007] Furthermore, the insulating permeable body is a salt tube; when the temperature in the synthesis cavity reaches the melting point of the metal layer, the metal layer melts and contacts and adheres to the inner wall of the heating body through the molten salt tube.

[0008] Furthermore, the longitudinal length of the salt pipe matches that of the heating body.

[0009] Furthermore, the indicating structure is located in the middle of the synthetic cavity, and the double-layer carbon paper sheet and the middle metal layer correspond to the middle of the heating body.

[0010] Furthermore, the metal layer is a metal disc or a metal ring.

[0011] Furthermore, the material of the metal layer is selected from metal materials with different melting points according to the temperature reference required for feedback.

[0012] Furthermore, the outer circle of the metal layer is arranged close to the salt pipe.

[0013] Furthermore, the thickness of the metal layer is 0.1-0.5 mm, and the thickness of each layer of carbon paper is 0.2-1 mm.

[0014] Furthermore, the thickness of the metal ring is 0.2 mm, and the thickness of each layer of carbon paper is 0.4 mm.

[0015] Furthermore, the composition of the synthetic cavity is as follows: The synthetic cavity is composed of a conductive medium, a sealing material, an end surface heating element and a pressure transmission medium from outside to inside in the longitudinal direction; The synthetic cavity is provided with sealing material and heating element from outside to inside in the transverse direction; The synthesis chamber is used to place samples.

[0016] Beneficial effects of the present invention: The present invention creatively designs an indicator structure suitable for the temperature inside a polycrystalline diamond synthesis cavity. The indicator structure consists of a double-layer carbon paper sheet, an intermediate metal layer, and an insulating permeable body on the outer circumference. When the metal layer melts at high temperature, it penetrates through the insulating permeable body and adheres to the heating body, resulting in a decrease in heating resistance, which is intuitively displayed as a drastic change in the current signal. A benchmark feedback can be efficiently and conveniently performed on the temperature inside the cavity under high temperature and high pressure. According to the heating time required to reach the temperature benchmark, corresponding adjustments can be made to the heating process.

[0017] At the same time, the indicator structure can effectively balance the temperature field, improve temperature distribution, reduce thermal stress, and improve the comprehensive performance of the composite sheet. For common high-temperature and high-pressure synthesis cavities, since the temperature in the middle of the cavity heating body is generally higher than that at both ends in the indirect heating method, the temperature field distribution in the cavity is uneven, which is usually not conducive to high-temperature and high-pressure synthesis. When the above-mentioned indicator structure is placed in the middle of the heating body, since the heat generated by the heating body is proportional to the resistance, the reduction in resistance will cause the heat generated in the middle of the heating body to decrease, and the temperature will decrease, thereby balancing the temperature field inside the high-temperature and high-pressure cavity, making the radial temperature uniformity in the cavity better, and improving the product performance at the edge of the composite sheet.

[0018] In addition, the metal used in the metal layer is not fixed and can be replaced by other low melting point metals according to the temperature reference of the required feedback.

[0019] The insulating permeable body of the present invention is a salt tube, which satisfies both insulation and metal layer melting and penetration. When the temperature in the synthesis cavity reaches the melting point of the metal layer, the metal layer melts and contacts and adheres to the inner wall of the heating body through the molten salt tube.

[0020] Compared with the common thermocouple temperature measurement, the present invention has low cost and balanced temperature field, improves the quality function of composite sheet products, has strong practicality, and can be used for batch use in production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the indication structure of the present invention; Figure 2 This is a schematic diagram of the assembly structure of the present invention applied to a synthesis cavity; Figure 3 It is the power curve diagram for synthesis of the present invention.

[0022] In the figure: 1-conductive medium; 2-sealing material; 3-end surface heating element; 4-pressure transmission medium; 5, 9-samples; 6-heating element; 7-carbon paper sheet; 8-salt tube; 10-metal ring.

[0023] The drawings are only used for illustrative purposes and should not be construed as limitations on this patent. In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0025] Embodiment 1: like Figure 1 to Figure 2As shown, this embodiment provides an indicating structure for the internal temperature of a polycrystalline diamond synthesis cavity, the indicating structure comprising a double-layer carbon paper sheet 7 arranged on the upper and lower sides, a metal layer located in the middle of the double-layer carbon paper sheet 7, and an insulating permeable body arranged on the outer circumference of the double-layer carbon paper sheet 7.

[0026] The selection of the insulating penetrating body should satisfy both the insulation and the metal layer melting and penetrating functions. In this embodiment, the insulating penetrating body is selected from the salt pipe 8 .

[0027] In this embodiment, the metal layer is in the form of a metal ring 10, and the outer circle of the metal ring 10 is arranged close to the salt pipe 8. The outer side of the salt pipe 8 is a heating body 6, which is a component of the high temperature and high pressure synthesis cavity.

[0028] In this embodiment, the longitudinal length of the salt pipe 8 is equal to that of the heating body 6. In other embodiments, the longitudinal length of the salt pipe 8 can be selected as needed.

[0029] In this embodiment, the thickness of the metal ring 10 is 0.1-0.5 mm, and the thickness of each layer of carbon paper is 0.2-1 mm.

[0030] Under the premise of not affecting the internal design of the cavity, the indicating structure is independently placed in the middle position of the high-temperature and high-pressure synthesis cavity, and the double-layer carbon paper sheet 7 and the middle metal ring 10 correspond to the middle position of the heating body 6.

[0031] The composition of the high temperature and high pressure synthesis chamber is as follows: The high-temperature and high-pressure synthesis cavity is composed of a conductive medium 1, a sealing material 2, an end surface heating element 3 and a pressure transmission medium 4 from the outside to the inside along the longitudinal direction.

[0032] The high-temperature and high-pressure synthesis cavity is composed of a sealing material 2 and a heating element (carbon tube) 6 from outside to inside in the horizontal direction.

[0033] The high temperature and high pressure synthesis chamber is used to place samples 5 and 9, which are arranged on the upper and lower sides of the chamber respectively. The samples are products that require high temperature and high pressure, such as diamond, PCD, etc.

[0034] The heating body 6 is energized by indirect heating. When the temperature in the cavity reaches the melting point of the metal ring 10, the metal ring 10 melts and contacts and adheres to the inner wall of the heating body 6 through the molten salt tube 8, forming a new conductive structure, causing the resistance inside the cavity to drop sharply. This is intuitively manifested as the current rising to a certain level within a certain period of time. Based on this, it can be judged that the temperature in the cavity at this time reaches or is slightly higher than the melting point of the metal ring, thereby reflecting the temperature reference in the cavity. According to the heating time required to reach the temperature reference, the heating process can be adjusted accordingly.

[0035] The metal used for the metal ring 10 is not fixed and can be replaced by other (low) melting point metals according to the temperature reference required for feedback.

[0036] For common high-temperature and high-pressure synthesis cavities, since the temperature in the middle of the cavity heating body 6 is generally higher than that at both ends in the indirect heating method, the temperature field distribution in the cavity is uneven, which is usually not conducive to high-temperature and high-pressure synthesis. When the indicating structure is placed in the middle of the heating body 6, since the heating value of the heating body is proportional to the resistance, the reduction in resistance will cause the heat generation in the middle position of the heating body 6 to decrease, and the temperature will decrease, thereby balancing the temperature field inside the high-temperature and high-pressure cavity, making the radial temperature uniformity in the cavity better, and improving the product performance at the edge of the composite sheet.

[0037] The working principle of the present invention is described in detail below in conjunction with specific experimental examples.

[0038] In this experimental example, copper is used as the material of the metal ring 10, with a thickness of 0.2 mm and a ring width of 1 / 3 of the radius. The thickness of the two layers of carbon paper 7 is 0.4 mm. The thickness of the salt tube 8 is 1.5 mm. The above-mentioned indicator structure is placed in the middle of the heating body 6, and the indicator structure and the high-temperature and high-pressure synthesis cavity assembly structure are as shown in FIG. Figure 1 and 2 shown.

[0039] During the high-temperature and high-pressure synthesis process, the power of the six-sided top press was set as follows: the initial power increased from 0 to W1 within T1 seconds, the power remained unchanged for T2 seconds for high-temperature sintering, and then the power was reduced to W2 within T3 seconds before stopping heating.

[0040] like Figure 3 As shown, during the heating stage when the starting power rises from 0 to W1, the cavity temperature gradually increases. When the melting point of copper is reached, the copper ring melts at high temperature, penetrates through the salt tube and adheres to the heating body, resulting in a decrease in heating resistance, which is intuitively displayed as a drastic change in the current signal (the current fluctuation amplitude exceeds 3% within 10 seconds), thereby efficiently and conveniently providing a benchmark feedback for the temperature in the cavity under high temperature and high pressure. According to the heating time required to reach this state, the heating process can be adjusted accordingly. At the same time, since the heat generated by the heating body is proportional to the resistance, the reduction in resistance will lead to a decrease in heat generation and temperature reduction at the middle position of the heating body, thereby balancing the temperature field inside the high temperature and high pressure cavity. This makes the temperature uniformity in the cavity better and improves the performance consistency of the composite sheet product. Compared with the normal structure, the wear range of the polycrystalline diamond composite sheet produced under this structure is reduced from 10% to 5% in the same cavity.

[0041] Compared with the common thermocouple temperature measurement, the present invention can effectively avoid the burden on enterprise production caused by the low success rate of the conventional thermocouple temperature measurement method and the high cost of the platinum-rhodium wire used for temperature measurement. The solution of the present invention is low in cost and has the function of balancing the temperature field, improving the quality of the composite sheet product, and is highly practical, and can be used for batch use in production.

[0042] Embodiment 2: The difference between this embodiment and the first embodiment is that the metal layer in this embodiment is in the form of a metal disc, and the outer circle of the metal disc is arranged close to the salt pipe 8.

[0043] Embodiment three: The difference between this embodiment and the first embodiment is that the indicating structure in this embodiment can be located at any position in the synthesis cavity to indicate the temperature of a specific point.

[0044] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

[0045] If the words "first", "second", etc. are used in this document to limit components, those skilled in the art should know that the use of "first" and "second" is only to facilitate the description of the present invention and simplify the description. Unless otherwise stated, the above words have no special meaning.

[0046] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0047] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A structure for indicating the internal temperature of a polycrystalline diamond synthesis chamber, characterized in that: The indicating structure is located at any position in the synthesis cavity, and includes a double-layer carbon paper sheet arranged on the upper and lower sides, a metal layer located in the middle of the double-layer carbon paper sheet, and an insulating permeable body arranged on the outer circumference of the double-layer carbon paper sheet; the outer side of the insulating permeable body is a heating body, and the heating body is a component of the synthesis cavity; When the temperature inside the synthetic cavity reaches the melting point of the metal layer, the metal layer melts and contacts and adheres to the inner wall of the heating body through the insulating permeable body, forming a new conductive structure, causing the internal resistance of the cavity to drop sharply. This is intuitively manifested as the current rising to a certain level within a certain period of time. Based on this, it can be judged that the temperature in the cavity at this time has reached or is slightly higher than the melting point of the metal layer, thereby reflecting the temperature benchmark in the cavity.

2. The structure for indicating the internal temperature of a polycrystalline diamond synthesis chamber according to claim 1, characterized in that: The insulating permeable body is a salt tube; when the temperature in the synthesis cavity reaches the melting point of the metal layer, the metal layer melts and penetrates the molten salt tube to contact and adhere to the inner wall of the heating body.

3. The structure for indicating the internal temperature of a polycrystalline diamond synthesis chamber according to claim 2, characterized in that: The longitudinal length of the salt tube matches that of the heating body.

4. The internal temperature indicator structure of the polycrystalline diamond synthesis chamber according to any one of claims 1 to 3, characterized in that: The indicating structure is located in the middle of the synthesis cavity, and the double-layer carbon paper sheet and the metal layer in the middle correspond to the middle of the heating body.

5. The structure for indicating the internal temperature of a polycrystalline diamond synthesis chamber according to any one of claims 1 to 3, characterized in that: The metal layer is a metal disc or a metal ring.

6. The structure for indicating the internal temperature of a polycrystalline diamond synthesis chamber according to claim 5, characterized in that: The material of the metal layer is selected by selecting metal materials with different melting points according to the temperature reference required for feedback.

7. The structure for indicating the internal temperature of a polycrystalline diamond synthesis chamber according to claim 5, characterized in that: The outer circle of the metal layer is arranged close to the salt pipe.

8. The structure for indicating the internal temperature of a polycrystalline diamond synthesis chamber according to any one of claims 1 to 3, characterized in that: The thickness of the metal layer is 0.1-0.5 mm, and the thickness of each layer of carbon paper is 0.2-1 mm.

9. The structure for indicating the internal temperature of a polycrystalline diamond synthesis chamber according to claim 8, characterized in that: The thickness of the metal ring is 0.2 mm, and the thickness of each layer of carbon paper is 0.4 mm.

10. The structure for indicating the internal temperature of a polycrystalline diamond synthesis chamber according to any one of claims 1 to 3, characterized in that: The composition of the synthetic cavity is as follows: The synthetic cavity is composed of a conductive medium, a sealing material, an end surface heating element and a pressure transmission medium from outside to inside along the longitudinal direction; The synthetic cavity is provided with sealing material and heating element from outside to inside in the transverse direction; The synthesis chamber is used to place samples.

Images