Decobalt pdc ceramic self-lubricating layer filling method under extreme pressure driving

Abstract

The application discloses a decobalt PDC ceramic self-lubricating layer filling method under extreme pressure driving, and belongs to the technical field of inorganic non-metal material preparation. The method comprises the following steps: wrapping a self-lubricating powder layer on the outer part of a processed and formed decobalt PDC, and then wrapping the self-lubricating powder layer with a metal wrapping body; high-temperature and high-pressure treatment is conducted on the metal wrapping body or high-pressure treatment is conducted on the metal wrapping body; the processed sample is taken out, the metal wrapping body and residual self-lubricating block outside the sample are removed, and a decobalt PDC self-lubricating ceramic containing a lubricating layer is obtained. The PDC self-lubricating ceramic prepared by adopting the method has the same mechanical property as the decobalt PDC ceramic, and the wear resistance is obviously improved compared with the non-lubricating layer.

Description

Technical Field

[0001] This invention relates to the field of inorganic non-metallic material preparation technology, and more specifically to a method for filling a cobalt-free PDC ceramic self-lubricating layer under extreme pressure. Background Technology

[0002] Currently, PDC (polycrystalline diamond composite) drill bits are widely used in oil and gas drilling projects, accounting for over 90% of the total footage in global oil and gas drilling. Their market share exceeds 80% and continues to grow. The two most important characteristics of PDC drill bits are drilling efficiency and service life. Excessive wear of the cutting teeth reduces the depth of cut, hindering rock breaking and lowering rock-breaking efficiency. Regarding drill bit life, drill bit costs account for one-third of drilling costs; therefore, improving the wear resistance of PDC drill bits and extending their service life is a pressing issue. Currently, there are two ways to improve the wear resistance of PDC drill bits: increasing the hardness of the PDC material and improving the lubrication environment of the drill bit. However, the optimization of the PDC microstructure has almost reached its limit, while the cost of producing binder-free polycrystalline diamond would increase dramatically. Furthermore, the lubrication efficiency provided by the drilling fluid is insufficient. As drilling depth increases, the rheological properties, leaching properties, and chemical stability of the drilling fluid change, leading to blockage and significantly affecting drilling efficiency.

[0003] Self-lubricating ceramics are hard materials designed for the extreme conditions of high-speed drilling. They can autonomously release self-lubricating particles to the friction interface during friction, increasing lubrication efficiency to 100% and effectively improving the wear resistance of ceramics. However, current methods for preparing self-lubricating ceramics involve co-sintering the ceramic matrix and lubricating phase powder. Since the lubricating phase is a soft phase, this leads to a significant reduction in the mechanical properties of PDC (Polydioxanone Dioxide). Therefore, how to impart self-lubricating properties to PDC while maintaining its mechanical properties is a problem that urgently needs to be solved.

[0004] Studies have shown that preparing self-lubricating PDC materials with excellent wear resistance requires meeting conditions such as high hardness, high toughness, high density, and good high-temperature stability, which presents a significant engineering challenge.

[0005] Therefore, how to develop a method for filling cobalt-free PDC ceramic self-lubricating layers under extreme pressure is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a method for filling a cobalt-free PDC ceramic self-lubricating layer under extreme pressure.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for filling a cobalt-free PDC ceramic self-lubricating layer under extreme pressure, comprising the following steps:

[0009] (1) Wrap a layer of self-lubricating powder around the processed cobalt-free PDC, and then wrap it with a metal encapsulation body;

[0010] The self-lubricating powder mentioned above is a metal powder. The metal inclusions are treated with high temperature and high pressure. The specific steps are as follows: first, pressurize to the set pressure, then heat to the melting point of the metal powder under the set pressure, keep warm, stop heating, continue to keep pressure for a period of time, and then slowly reduce the pressure.

[0011] Alternatively, the self-lubricating powder mentioned above is a non-metallic powder. The metal encapsulation is subjected to high-pressure treatment. The specific steps are: first, pressurize to the set pressure, maintain the pressure for a period of time, and then slowly reduce the pressure.

[0012] (2) Take out the sample after step (1), remove the metal inclusions and residual self-lubricating blocks outside the sample, and obtain the decobalt-free PDC self-lubricating ceramic containing the lubricating layer.

[0013] Furthermore, in step (1), the pressure is set to 5.5 GPa.

[0014] Furthermore, in step (1), the self-lubricating powder is MoS2, WS2, Cu or Al powder, and the particle size of the self-lubricating powder is 10nm-10μm.

[0015] Furthermore, the metal inclusions in step (1) are Mo, Zr, or Ta.

[0016] Furthermore, in step (1), the thickness of the self-lubricating powder layer is 0.5 mm or more.

[0017] Further, in step (1), the above self-lubricating powder is a metal powder, which is sintered under high temperature and high pressure. The pressure increase rate and pressure decrease rate are 5GPa / min. The temperature is increased to the melting point of the metal powder at 5.5GPa, the heating rate is 100℃ / min, the holding time is 5min, the heating is stopped, the pressure is held for another 5min, and then the pressure is slowly reduced to 0GPa.

[0018] Alternatively, the self-lubricating powder mentioned above is a non-metallic powder, subjected to high pressure treatment, with a pressure increase rate and a pressure decrease rate of 5 GPa / min, a holding time of 5 min, and then slowly reduced to 0 GPa.

[0019] The beneficial effects of the present invention are as follows: The present invention uses extreme temperature and pressure loads to fill solid / liquid self-lubricating particles into the micropores inside the PDC along the cobalt-free PDC pores. The particle size of the self-lubricating particles is much larger than the pore size inside the PDC micropores.

[0020] The PDC self-lubricating ceramic prepared by the method of the present invention has the same mechanical properties as the cobalt-free PDC;

[0021] The wear resistance of the cobalt-free PDC self-lubricating ceramic prepared by the method of the present invention is significantly improved compared with that of the non-lubricating layer. Attached Figure Description

[0022] Figure 1 This is a scanning electron microscope (SEM) image of the cobalt-free PDC-MoS2 self-lubricating ceramic from Example 1.

[0023] Figure 2 This is a scanning electron microscope (SEM) image of the cobalt-free PDC-Cu self-lubricating ceramic from Example 2.

[0024] Figure 3 This is a scanning electron microscope (SEM) image of the cobalt-free PDC-Al self-lubricating ceramic from Example 3. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] A method for filling cobalt-free PDC ceramic self-lubricating layers under extreme pressure includes the following steps:

[0028] (1) Preparation of cobalt-free PDC ceramics: 10g of ferric chloride and 100mL of 6mol / L hydrochloric acid were mixed to prepare a cobalt-free reagent. Co-containing PDC ceramics were immersed in the cobalt-free reagent at a temperature of 200℃ for 20h to obtain cobalt-free PDC ceramic materials.

[0029] (2) The cobalt-free PDC ceramic is coated with a layer of self-lubricating powder MoS2 powder with a particle size of 1μm and a layer thickness of 1mm. Then it is coated with a metal inclusion body with Mo as the material. The sample with the metal inclusion body is loaded into the high-pressure unit and then subjected to high-pressure treatment. The specific steps are as follows: first, the pressure is increased to the set pressure of 5.5GPa at a rate of 5GPa / min, and the pressure is held for 5min before slowly decreasing the pressure to 0GPa at a rate of 5GPa / min.

[0030] (3) Take out the sample after high pressure treatment in step (2), remove the metal inclusions and residual self-lubricating blocks that wrap around the sample, and obtain PDC-MoS2 ceramic containing a lubricating layer.

[0031] The thickness of the ceramic lubricating layer was 1 μm; the Vickers hardness of the PDC-MoS2 ceramic was measured to be 98.5 ± 1.1 GPa; the nanoindentation hardness of the PDC-MoS2 lubricating layer was measured to be 105 GPa; the hardness of the cobalt-depleted PDC remained unchanged before and after the lubricating layer was filled.

[0032] The wear resistance of cobalt-free PDC and PDC-MoS2 ceramic was measured by rubbing against a cemented carbide ball (YG6) (pressure 10N, friction time 15min, rotation speed 400rpm). The wear rate of PDC was 150×10⁻⁶. -8 mm 3 / Nm, the wear rate of PDC-MoS2 is 20×10 - 8 mm 3 / Nm, the wear resistance of the decobalt-free PDC after high-pressure filling of the lubricating layer is significantly improved compared with that before filling.

[0033] Example 2

[0034] A method for filling cobalt-free PDC self-lubricating layers under extreme pressure includes the following steps:

[0035] (1) Preparation of cobalt-free PDC ceramics: 10g of ferric chloride and 100mL of 6mol / L hydrochloric acid were mixed to prepare a cobalt-free reagent. Co-containing PDC ceramics were immersed in the cobalt-free reagent at a temperature of 200℃ for 20h to obtain cobalt-free PDC ceramic materials.

[0036] (2) The cobalt-free PDC gap ceramic is coated with a layer of self-lubricating powder Cu powder with a particle size of 1 μm and a layer thickness of 1 mm. Then it is coated with a metal inclusion body, which is Ta. The raw material with the metal inclusion body is loaded into the high-pressure sintering unit and then subjected to high temperature and high pressure treatment. The specific steps are as follows: First, the pressure is increased to the set pressure of 5.5 GPa at a rate of 5 GPa / min. Then the temperature is increased to the melting point of Cu at 5.5 GPa, which is 1400℃ at a rate of 100℃ / min. The temperature is held for 30 min. Then the heating is stopped and the pressure is held for 5 min before slowly reducing the pressure to 0 GPa at a rate of 5 GPa / min.

[0037] (3) Take out the sample after the high temperature and high pressure treatment in step (2), remove the metal inclusions and residual self-lubricating blocks that wrap the sample, and obtain PDC-Cu ceramic containing a lubricating layer.

[0038] The thickness of the PDC lubricating layer was 1 μm; the Vickers hardness of the PDC-Cu ceramic was measured to be 97.3 ± 1.1 GPa; the nanoindentation hardness of the PDC-Cu lubricating layer was measured to be 103 GPa; the hardness of the cobalt-free PDC remained unchanged before and after the lubricating layer was filled.

[0039] The wear resistance of cobalt-free PDC and PDC-MoS2 ceramic was measured by rubbing against a cemented carbide ball (YG6) (pressure 10N, friction time 15min, rotation speed 400rpm). The wear rate of PDC was 143×10⁻⁶. -8 mm 3 / Nm, the wear rate of PDC-Cu is 40×10 -8 mm 3 / Nm, the wear resistance of the decobalt-free PDC after high-pressure filling of the lubricating layer is significantly improved compared with that before filling.

[0040] Example 3

[0041] A method for filling cobalt-free PDC self-lubricating layers under extreme pressure includes the following steps:

[0042] (1) Preparation of cobalt-free PDC ceramics: 10g of ferric chloride and 100mL of 6mol / L hydrochloric acid were mixed to prepare a cobalt-free reagent. Co-containing PDC ceramics were immersed in the cobalt-free reagent at a temperature of 200℃ for 20h to obtain cobalt-free PDC ceramic materials.

[0043] (2) WC-based porous ceramics are coated with a layer of self-lubricating powder Al powder with a particle size of 1 μm and a layer thickness of 1 mm. Then, they are coated with a metal inclusion body made of Zr. The raw material with the metal inclusion body is loaded into a high-pressure sintering unit and then subjected to high temperature and high pressure treatment. The specific steps are as follows: First, the pressure is increased to the set pressure of 5.5 GPa at a rate of 5 GPa / min. Then, the temperature is increased to the melting point of Al at 5.5 GPa, which is 800 °C, at a rate of 100 °C / min. The temperature is held for 30 min. Then, the heating is stopped and the pressure is held for 5 min before slowly reducing the pressure to 0 GPa at a rate of 5 GPa / min.

[0044] (3) Take out the sample after high pressure treatment in step (2), remove the metal inclusions and residual self-lubricating blocks that wrap the sample, and obtain PDC-Al ceramic containing a lubricating layer.

[0045] The thickness of the PDC lubricating layer was 1 μm; the Vickers hardness of the PDC-Al ceramic was measured to be 92.3 ± 1.1 GPa; the nanoindentation hardness of the PDC-Al lubricating layer was measured to be 99 GPa; the hardness of the cobalt-depleted PDC remained unchanged before and after the lubricating layer was filled.

[0046] The wear resistance of cobalt-free PDC and PDC-MoS2 ceramic was measured by rubbing against a cemented carbide ball (YG6) (pressure 10N, friction time 15min, rotation speed 400rpm). The wear rate of PDC was 162×10⁻⁶. -8 mm 3 / Nm, the wear rate of PDC-Al is 13×10 -8 mm 3 / Nm, the wear resistance of the decobalt-free PDC after high-pressure filling of the lubricating layer is significantly improved compared with that before filling.

[0047] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for filling a cobalt-free PDC ceramic self-lubricating layer under extreme pressure, characterized in that, Includes the following steps: (1) The cobalt-free PDC ceramic is coated with a layer of self-lubricating powder and then wrapped with a metal encapsulation. The self-lubricating powder is a metal powder. The metal inclusion is treated with high temperature and high pressure. The specific steps are: first, pressurize to the set pressure, then heat to the melting point of the metal powder under the set pressure, keep warm, stop heating, continue to keep pressure for a period of time, and then slowly reduce the pressure. Alternatively, the self-lubricating powder is a non-metallic powder, and the metal encapsulation is subjected to high pressure treatment. The specific steps are: first, pressurize to the set pressure, maintain the pressure for a period of time, and then slowly reduce the pressure. (2) Take out the sample after step (1), remove the metal inclusions and residual self-lubricating blocks outside the sample, and obtain the decobalt-free PDC self-lubricating ceramic containing the lubricating layer; In step (1), the pressure is set to 5.5 GPa; The self-lubricating powder is MoS2, WS2, Cu or Al powder, and the particle size of the self-lubricating powder is 10 nm-10 μm; The metal inclusions are Mo or Zr; The thickness of the self-lubricating powder layer is 0.5 mm or more.

2. The method of claim 1, wherein the method is a method of filling a decobalt PDC ceramic self-lubricating layer under extreme pressure driving, characterized by, In step (1), the self-lubricating powder is a metal powder, which is sintered under high temperature and high pressure. The pressure increase rate and pressure decrease rate are 5 GPa / min. The temperature is increased to the melting point of the metal powder at 5.5 GPa, the heating rate is 100℃ / min, the holding time is 5 min, the heating is stopped, the pressure is held for another 5 min, and then the pressure is slowly reduced to 0 GPa. Alternatively, the self-lubricating powder is a non-metallic powder, subjected to high pressure treatment, with a pressurization rate and a depressurization rate of 5 GPa / min, a holding time of 5 min, and then slowly depressurized to 0 GPa.

Images