Plasma mass spectrometer sampling cone with automatic cooling function and preparation method thereof

Abstract

The invention discloses a plasma mass spectrometer sampling cone with an autonomous cooling function, the plasma mass spectrometer sampling cone comprises a sealing surface, a cone body is arranged on the sealing surface, and a spiral cooling flow channel is arranged in the cone body, in addition, the invention further discloses a preparation method of the plasma mass spectrometer sampling cone with the autonomous cooling function. Comprising the following steps: 1, processing a cooling runner core body; 2, pressing and forming; 3, high-temperature sintering; 4, shape processing; and 5, machining the inner surface of the runner. According to the design principle of active cooling, the optimal structural form is determined, the spiral cooling flow channel is designed, effective control over the service temperature of the sampling cone in the operation process is achieved, temperature impact on the sampling cone in the ionization process is eliminated, the strength and corrosion resistance of the sampling cone in the service process are improved, and the service life of the sampling cone is prolonged. The preparation process is simple, the assembly form of an existing sampling cone is not changed, the service life of the sampling cone is far longer than that of an existing structure, and the sampling cone has wide application prospects in inductively coupled plasma mass spectrometers and other devices.

Description

Technical Field

[0001] This invention belongs to the technical field of sampling cones for plasma mass spectrometers, specifically relating to a sampling cone for plasma mass spectrometers with self-cooling function and its preparation method. Background Technology

[0002] Inductively coupled plasma mass spectrometry (ICP-MS) boasts advantages such as high sensitivity, low inter-element interference, good precision, and ease of operation. In recent years, it has been widely used both domestically and internationally in trace element detection in industries such as environmental geology and non-ferrous metals. In ICP-MS, the sampling cone is one of the core components. Its function is to extract ions from the plasma; that is, after the sample is ionized, the sampling cone captures these ions and transports them to the intercepting cone.

[0003] The existing sampling cone is formed by fixing a cone body to a base. The cone body is essentially a conical cylinder with different taper on its outer and inner surfaces (i.e., the wall thickness gradually decreases from bottom to top). The front section has a conical hole with a diameter of 0.8–2 mm, and its surface is nearly mirror-like. However, during long-term operation, the cone temperature continuously rises. Metal oxides and carbides generated by high-temperature ionization accumulate on the sampling cone surface, constantly eroding and corroding the front end of the conical hole, leading to deformation and dimensional changes in the hole, severely affecting the equipment's detection performance. Furthermore, the continuous rise and fluctuation of the cone temperature during long-term operation exacerbates the evaporation of the sample, resulting in significant signal fluctuations in the sample detection and thus uncontrollable changes in the detection results.

[0004] To address the aforementioned issues, existing solutions typically include the following aspects: 1) Periodic cleaning of the sampling cone, i.e., removing deposits from the cone orifice and body using physical or chemical methods to restore the cone's size and surface condition. However, this method requires disassembling and reassembling the instrument, which is time-consuming and laborious, and does not solve the problem of detection signal fluctuations caused by cone temperature changes. 2) Improving the cone material, i.e., using new erosion-resistant, corrosion-resistant, and high-strength materials to reduce changes in the cone's shape and surface condition caused by long-term use. This method increases the cost of the cone and also does not solve the problem of detection signal fluctuations caused by cone temperature changes. 3) Installing heat dissipation columns and cooling pipes on the outside of the cone to reduce or control the cone temperature. This method solves the cone temperature fluctuation to some extent, but the structure is complex, disassembly is difficult, and the external cooling water volume control needs to be matched with the ionization process to ensure that the sampling cone temperature remains balanced.

[0005] Therefore, there is a need to provide a sampling cone for a plasma mass spectrometer with self-cooling function and its preparation method. Summary of the Invention

[0006] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a sampling cone for a plasma mass spectrometer with an independent cooling function. This sampling cone, through the design of a spiral cooling channel, reduces and controls the operating temperature of the sampling cone while further improving its strength, erosion resistance, and corrosion resistance during service. This effectively reduces sampling cone failure caused by deformation or dimensional changes in the cone tip, and lowers the frequency of equipment maintenance and parts replacement.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a sampling cone for a plasma mass spectrometer with self-cooling function, characterized in that the sampling cone includes a sealing surface, a cone body is provided on the sealing surface, a spiral cooling channel is provided inside the cone body, the roughness Ra of the inner surface of the cooling channel is ≤2μm, and the distance between the cooling channel and the cone hole at the top of the cone body is not greater than 0.4mm.

[0008] The above-mentioned sampling cone for a plasma mass spectrometer with self-cooling function is characterized in that the cross-sectional area of ​​the cooling channel in the longitudinal section of the cone is 35% to 55% of the cross-sectional area of ​​the cone, and the cone is also provided with a cooling medium inlet and a cooling medium outlet that are respectively connected to both ends of the cooling channel.

[0009] The sampling cone for a plasma mass spectrometer with self-cooling function described above is characterized in that the spacing between adjacent channels in the spiral cooling channel is 2mm to 3mm.

[0010] The sampling cone for a plasma mass spectrometer with self-cooling function described above is characterized in that the sampling cone is made of stainless steel, nickel, nickel alloy, platinum, or platinum alloy.

[0011] In addition, the present invention also provides a method for preparing a sampling cone for a plasma mass spectrometer with self-cooling function, characterized in that the method includes the following steps: Step 1: Machining the cooling channel core: Machining the low-melting-point material according to the external dimensions of the spiral cooling channel to obtain the cooling channel core; Step 2, pressing and forming: The cooling channel core obtained in Step 1 is loaded into the sampling cone pressing mold, and metal powder is continuously added under vibration, and then pressed and formed to obtain the blank. Step 3, High-temperature sintering: The billet obtained in step 2 is continuously subjected to core removal sintering and densification sintering to obtain sintered billet; Step 4, Shape Processing: The sintered billet obtained in Step 3 is surface-processed to obtain a surface-processed billet; Step 5, Inner Surface Machining of the Flow Channel: The cooling flow channel of the surface-machined blank obtained in Step 4 is polished with an abrasive to obtain a sampling cone for plasma mass spectrometer with self-cooling function.

[0012] This invention first processes a cooling channel core, then prepares a blank containing the cooling channel core in metal powder by pressing, achieving preliminary shaping. Next, the core is removed by core extraction sintering, forming a spiral cooling channel within the blank. This is followed by densification sintering for final shaping, and finally, the cooling channel is polished with an abrasive. This process achieves the fabrication of a sampling cone for a plasma mass spectrometer with self-cooling capabilities. The process is simple, low-cost, and easy to promote and use.

[0013] The above method is characterized in that the low-melting-point material in step one is paraffin wax, polyurethane, lead, or aluminum; the processing is digital additive manufacturing; and the surface roughness Ra of the cooling channel core is ≤1.6μm. This invention controls the material of the cooling channel core, ensuring that these raw materials are easy to process into cooling channel cores and have low melting points, facilitating subsequent extraction; and also reducing costs, thus ensuring controllable production costs for the sampling cone. The use of digital additive manufacturing guarantees the structural integrity and high precision of the cooling channel core, ensuring the integrity of the cooling channel structure in the sampling cone. By controlling the surface roughness of the cooling channel core, the roughness of the inner surface of the cooling channel in the blank is controlled, ensuring the surface roughness of the cooling channel in the sampling cone and preventing deficiencies caused by excessive surface roughness that would prevent subsequent internal processing from meeting design requirements, thus ensuring the smooth flow of the cooling medium.

[0014] The method described above is characterized in that the particle size of the metal powder in step two is -300 to +500 mesh; the pressing is performed by molding or cold isostatic pressing, with a pressure of 250 MPa to 350 MPa. This invention ensures the dimensional stability and strength of the sampling cone by controlling the particle size of the metal powder and the pressing method and pressure.

[0015] The above method is characterized in that, in step three, the heating rate for core removal sintering is 1℃ / min~3℃ / min, the temperature is 300℃~500℃, and the holding time is 30min~120min; the heating rate for densification sintering is 5℃ / min~15℃ / min, the temperature is 1200℃~1350℃, and the holding time is 120min~180min. This invention, by controlling the parameters of core removal sintering, ensures the retention of the blank's external dimensions after core removal, while also ensuring that the low-melting-point core does not leave residual contamination inside the cone; by controlling the parameters of densification sintering, it ensures the density, strength, and external dimensions of the sintered blank, thus achieving the desired shape.

[0016] The above method is characterized in that the surface roughness Ra of the surface-processed blank in step four is ≤0.6μm, and its external dimensions meet the requirements for use with the sampling cone. This invention controls the surface roughness and external dimensions of the surface-processed blank to ensure it meets the requirements for use with the sampling cone.

[0017] The above method is characterized in that the abrasive in step five is synthetic diamond with an average particle size of 200nm~300nm; the abrasive flow pressure during the grinding process is 30MPa~45MPa, the flow rate is 500L / min~800L / min, the grinding time is 4h~8h, and the surface roughness Ra of the inner surface of the cooling channel after grinding is ≤2μm. This invention ensures that the surface roughness of the inner channel after processing meets the requirements of the sampling cone design by controlling the abrasive particle size; it ensures the high efficiency and reliability of the inner channel processing by controlling the process parameters during processing; and it ensures the smooth flow of the subsequent cooling medium by controlling the surface roughness of the inner surface of the cooling channel after grinding.

[0018] Compared with the prior art, the present invention has the following advantages: 1. This invention is based on an in-depth study and analysis of the working principle of existing plasma mass spectrometers and the failure mechanism of their sampling cones. According to the design principle of active cooling, a sampling cone with autonomous cooling function is proposed. With the support of a large amount of experimental data, the optimal internal structure of the sampling cone has been determined. The spiral cooling channel achieves efficient and precise temperature control of the sampling cone during equipment operation without changing the existing cone shape and assembly form. It effectively solves the problem of changes in the concentration of the analyte caused by the rise in internal temperature of the sampling cone due to ionization heat, and ensures the constant temperature of the test environment and the accuracy and repeatability of the test results.

[0019] 2. The spiral cooling channel design of this invention reduces and controls the operating temperature of the sampling cone, while further improving the strength, erosion resistance and corrosion resistance of the sampling cone during service. It effectively reduces sampling cone failure caused by deformation and size change of the cone hole at the front end of the sampling cone, and reduces the frequency of equipment maintenance and replacement of parts.

[0020] 3. The preparation method of the present invention adopts near-net-shape powder metallurgy and uses materials that are easily extracted at low temperature as cores to directly prepare sampling cone structures with complex internal flow channels in one step. It is simple to operate, low in cost, wide in application, easy to operate, and has a high yield. It is especially suitable for the technical upgrading and transformation of existing large-scale production lines and can significantly improve the added value of products without changing the existing core equipment.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the sampling cone for the plasma mass spectrometer with self-cooling function of the present invention.

[0023] Figure 2 This is a partial cross-sectional view of a single flow channel inside the sampling cone of the plasma mass spectrometer with self-cooling function according to the present invention.

[0024] Figure 3 This is a partial cross-sectional view of the internal flow channels of the sampling cone for the plasma mass spectrometer with self-cooling function of the present invention.

[0025] Figure 4 This is a partial cross-sectional view of the top flow channel of the sampling cone for the plasma mass spectrometer with self-cooling function of the present invention.

[0026] Figure 5 The temperature change curves of the sampling cone for the plasma mass spectrometer with self-cooling function prepared in Example 2 of the present invention and the traditional sampling cone during actual operation are shown.

[0027] Explanation of reference numerals in the attached figures: Detailed Implementation

[0028] The sampling cone for a plasma mass spectrometer with self-cooling function of the present invention is described in detail through Example 1.

[0029] Example 1 like Figures 1-4 As shown, the sampling cone for the plasma mass spectrometer with self-cooling function in this embodiment includes a sealing surface 1, a cone 2 is provided on the sealing surface 1, a spiral cooling channel 3 is provided inside the cone 2, the roughness Ra of the inner surface of the cooling channel 3 is ≤2μm, and the distance between the cooling channel 3 and the cone hole 4 at the top of the cone 2 is not greater than 0.4mm.

[0030] It should be noted that, based on an in-depth analysis of the working principle of existing plasma mass spectrometers and the failure mechanism of their sampling cones, this embodiment proposes a sampling cone with autonomous cooling function according to the design principle of active cooling. Furthermore, with the support of a large amount of experimental data, the optimal internal structure of the sampling cone has been determined. The plasma mass spectrometer sampling cone with autonomous cooling function consists of three parts: a sealing surface 1, a cone 2, and a spiral cooling channel 3 that controls the temperature of the cone 2. Without changing the original external dimensions of the sampling cone, the cooling structure is integrated through structural optimization design, ensuring that the temperature of the sampling cone remains constant during long-term operation.

[0031] It should be noted that in this embodiment, the sealing surface 1 and the cone body 2 of the sampling cone are integrally formed, and the external structure is completely consistent with that of a conventional sampling cone, which will not cause inconvenience to the operator. The sealing surface is used for assembly with the main body of the equipment. By designing a smooth spiral cooling channel 3 inside the cone body 2, the heat of the sampling cone is completely carried away by the flow of the cooling medium, realizing efficient temperature control of the sampling cone during operation and solving the problem of fluctuation of the measured signal caused by excessive temperature of the sampling cone. At the same time, after reducing the temperature of the sampling cone, the problems of oxide and carbide adhesion and erosion corrosion of the sampling cone are also greatly improved. This sampling cone has the advantages of simple structure, low cost, convenient disassembly, and constant internal temperature of the system during the test, and has broad application prospects in instruments such as inductively coupled plasma mass spectrometers.

[0032] It should be noted that controlling the roughness Ra of the inner surface of the cooling channel 3 to be ≤2μm maximizes the heat exchange efficiency between the cooling medium and the cone 2, ensuring that the cooling medium flow rate is minimized while achieving cooling of the cone 2. Controlling the distance between the cooling channel 3 and the cone hole 4 at the top of the cone 2 to be no more than 0.4mm actually controls the distance between the uppermost part of the spiral cooling channel 3 and the cone hole 4, ensuring that the leading edge of the cone hole 4 of the cone 2 can also be effectively cooled.

[0033] In this embodiment, the cross-sectional area of ​​the cooling channel 3 in the longitudinal section of the cone 2 is 35% to 55% of the cross-sectional area of ​​the cone 2. The cone 2 is also provided with a cooling medium inlet and a cooling medium outlet that are respectively connected to both ends of the cooling channel 3. By controlling the cross-sectional area of ​​the cooling channel 3, that is, controlling the proportion of the cooling channel 3 in the cone 2, not only is the flow rate of the cooling medium guaranteed, but the overall strength of the cone 2 is also guaranteed. In the experiment, it was found that when the cross-sectional area of ​​the cooling channel 3 is less than 35% of the cross-sectional area of ​​the cone 2, the pressure required by the cooling medium exceeds the requirements of conventional conveying devices, resulting in the sampling cone temperature being unable to be accurately controlled; when the cross-sectional area of ​​the cooling channel 3 is greater than 55% of the cross-sectional area of ​​the cone 2, the overall strength and rigidity of the cone 2 are significantly weakened, and it cannot meet the usage requirements. By setting the cooling medium inlet and the cooling medium outlet, it is convenient to continuously introduce the cooling medium into the cooling channel 3, so as to remove the heat of the sampling cone in time, ensuring the constant temperature of the test environment and the accuracy and repeatability of the test results.

[0034] It should be noted that, as Figure 1As shown, the wall thickness of cone 2 gradually decreases from sealing surface 1 to cone hole 4. Therefore, the cross-sectional area of ​​cooling channel 3 also gradually decreases as the wall thickness decreases. Overall, the cross-sectional area of ​​cooling channel 3 in the longitudinal section of cone 2 is 35%~55% of the cross-sectional area of ​​cone 2. In addition, since the cooling channels 3 are equally spaced, the cross-sectional area of ​​each cooling channel 3 is also 35%~55% of the cross-sectional area of ​​cone 2 at that location. The cross-sectional area of ​​cooling channel 3, i.e., the blank part, is 35%~55% of the cross-sectional area of ​​cone 2, i.e., the shaded part. Figure 2 This ensures optimal cooling performance and structural strength of the flow channel.

[0035] In this embodiment, the spacing between adjacent channels in the spiral cooling channel 3 is 2mm to 3mm. By controlling the distribution and spacing of the cooling channels 3, efficient control of the overall effect is achieved. This prevents the problem that when the channel spacing is less than 2mm, the thermal conductivity of the cooling medium far exceeds the maximum temperature that the sampling cone can reach, resulting in wasted cooling capacity and significantly increasing the processing difficulty of the sampling cone. It also prevents the problem that when the channel spacing is greater than 3mm, the thermal conductivity of the cooling medium cannot ensure precise temperature control of the sampling cone, leading to fluctuations in the measured signal.

[0036] It should be noted that, as Figure 3 and 4 As shown, the distance between the uppermost spiral cooling channel 3 and the cone hole 4 at the top of the cone 2 is no more than 0.4 mm, which is... Figure 4 The L in the middle is no greater than 0.4mm, achieving effective cooling of the leading edge of the conical hole 4, which is the highest temperature point in the entire cone 2. The cooling channels 3 below are arranged downwards at intervals of 2mm to 3mm until they fill the cone 2. Figure 3 H in the figure is 2mm~3mm.

[0037] In this embodiment, the sampling cone is made of stainless steel, nickel, nickel alloy, platinum, or platinum alloy. By controlling the material of the sampling cone, it is easier to process the cone and the material selectivity is enhanced, making it suitable for various working conditions.

[0038] The preparation method of a sampling cone for a plasma mass spectrometer with self-cooling function according to the present invention is described in detail through Examples 2 to 6.

[0039] Example 2 This embodiment includes the following steps: Step 1: Machining the cooling channel core: The polyurethane is digitally additively manufactured according to the outer dimensions of the spiral cooling channel to obtain a cooling channel core with a roughness Ra=1.2μm; Step 2, pressing and forming: The cooling channel core obtained in Step 1 is loaded into the sampling cone pressing mold, and 316L powder of -300 mesh to +500 mesh is continuously added under vibration. Then, the mold is pressed at a pressure of 250MPa and held for 2 minutes to obtain the blank. Step 3, High-temperature sintering: The billet obtained in Step 2 is heated from room temperature to 450°C at a heating rate of 1°C / min, held for 120 min for core removal sintering, and then heated to 1250°C at a rate of 10°C / min, held for 120 min for densification sintering to obtain sintered billet. Step 4, Shape Machining: The sintered blank obtained in Step 3 is surface machined to obtain a surface roughness Ra=0.6μm and a shape that meets the requirements of the sampling cone. Step 5, Inner Surface Machining of the Channel: The cooling channel of the surface-machined blank obtained in Step 4 is fed into synthetic diamond with an average particle size of 220nm at a flow pressure of 30MPa and a flow rate of 560L / min for 4 hours to obtain a sampling cone for plasma mass spectrometry with an inner surface roughness Ra=2μm and self-cooling function.

[0040] Upon testing, the sampling cone for plasma mass spectrometer with self-cooling function prepared in this embodiment has a cooling channel distance of 0.32 mm from the top cone hole, a cross-sectional area of ​​45.3% of the cone cross-sectional area, a spiral distribution of the cooling channel inside the cone, and a channel spacing of 2.7 mm.

[0041] The plasma mass spectrometer with self-cooling function prepared in this embodiment was installed in the equipment using a sampling cone for batch testing. To more accurately test the temperature change at the tip of the sampling cone, a temperature measuring device was used to monitor the temperature change at the tip of the sampling cone. Figure 5 As shown, traditional sampling cones, lacking active cooling technology, maintain a temperature close to room temperature during standby. However, once the sample enters the device and begins ionization, the cone temperature rapidly rises, exceeding 550°C. This temperature fluctuation during ionization causes significant stress on the cone. In contrast, the self-cooling sampling cone of this embodiment maintains a surface temperature below 100°C throughout the test, effectively verifying the effectiveness of active cooling and completely eliminating the thermal shock. Testing shows that the self-cooling sampling cone of this embodiment has a lifespan more than three times that of traditional sampling cones.

[0042] Example 3 This embodiment includes the following steps: Step 1: Machining the cooling channel core: Lead is digitally additively manufactured according to the outer dimensions of the spiral cooling channel to obtain a cooling channel core with a roughness Ra=1.0μm; Step 2, pressing and forming: The cooling channel core obtained in Step 1 is loaded into the sampling cone pressing mold, and nickel powder of -300 mesh to +500 mesh is continuously added under vibration. Then, cold isostatic pressing is performed with a pressure of 300MPa and held for 2 minutes to obtain the billet. Step 3, High-temperature sintering: The billet obtained in Step 2 is heated from room temperature to 330°C at a heating rate of 2°C / min, held at this temperature for 100 min for core removal sintering, and then heated to 1200°C at a rate of 5°C / min, held at this temperature for 140 min for densification sintering to obtain the sintered billet. Step 4, Shape Processing: The sintered blank obtained in Step 3 is surface processed to obtain a surface roughness Ra=0.5μm and a shape that meets the requirements of the sampling cone. Step 5, Inner Surface Machining of the Channel: The cooling channel of the surface-machined blank obtained in Step 4 is fed into synthetic diamond with an average particle size of 200 nm at a flow pressure of 45 MPa and a flow rate of 580 L / min for 6 hours to obtain a sampling cone for plasma mass spectrometry with an inner surface roughness Ra=1.6 μm and an autonomous cooling function.

[0043] Testing revealed that in the self-cooling plasma mass spectrometer sampling cone prepared in this embodiment, the distance between the cooling channel and the top cone orifice is 0.31 mm, the cross-sectional area of ​​the cooling channel is 49.1% of the cross-sectional area of ​​the cone, the cooling channel is spiral-shaped inside the cone, and the channel spacing is 2.2 mm. Tests showed that the self-cooling plasma mass spectrometer sampling cone prepared in this embodiment has a lifespan more than four times that of traditional sampling cones.

[0044] Example 4 This embodiment includes the following steps: Step 1: Machining the cooling channel core: Aluminum is digitally additively manufactured according to the outer dimensions of the spiral cooling channel to obtain a cooling channel core with a roughness Ra=0.8μm; Step 2, pressing and forming: The cooling channel core obtained in Step 1 is loaded into the sampling cone pressing mold, and platinum powder of -300 mesh to +500 mesh is continuously added under vibration. Then, the mold is pressed at a pressure of 350MPa and held for 2 minutes to obtain the blank. Step 3, High-temperature sintering: The billet obtained in Step 2 is heated from room temperature to 500°C at a heating rate of 3°C / min and held for 80 min to remove the core and sinter. Then, the temperature is increased to 1350°C at a rate of 15°C / min and held for 160 min to densify and sinter, thus obtaining the sintered billet. Step 4, Shape Machining: The sintered blank obtained in Step 3 is surface machined to obtain a surface roughness Ra=0.6μm and a shape that meets the requirements of the sampling cone. Step 5, Inner Surface Machining of the Channel: The cooling channel of the surface-machined blank obtained in Step 4 is fed into synthetic diamond with an average particle size of 250 nm at a flow pressure of 40 MPa and a flow rate of 680 L / min for 7 hours to obtain a sampling cone for plasma mass spectrometry with an inner surface roughness of Ra=1.2 μm and an independent cooling function.

[0045] Testing revealed that in the self-cooling plasma mass spectrometer sampling cone prepared in this embodiment, the distance between the cooling channel and the top cone orifice is 0.28 mm, the cross-sectional area of ​​the cooling channel is 51% of the cross-sectional area of ​​the cone, the cooling channel is spiral-shaped inside the cone, and the channel spacing is 2.3 mm. Tests showed that the self-cooling plasma mass spectrometer sampling cone prepared in this embodiment has a lifespan more than four times that of traditional sampling cones.

[0046] Example 5 This embodiment includes the following steps: Step 1: Machining the cooling channel core: Aluminum is digitally additively manufactured according to the outer dimensions of the spiral cooling channel to obtain a cooling channel core with a roughness Ra=0.9μm; Step 2, pressing and forming: The cooling channel core obtained in Step 1 is loaded into the sampling cone pressing mold, and nickel alloy powder of -300 mesh to +500 mesh is continuously added under vibration. Then, cold isostatic pressing is performed at a pressing pressure of 320MPa and held for 2 minutes to obtain the billet. Step 3, High-temperature sintering: The billet obtained in Step 2 is heated from room temperature to 300°C at a heating rate of 1°C / min, held at that temperature for 30 min to remove the core and sinter. Then, the temperature is increased to 1300°C at a rate of 12°C / min, held at that temperature for 160 min to densify and sinter, to obtain the sintered billet. Step 4, Shape Machining: The sintered blank obtained in Step 3 is surface machined to obtain a surface roughness Ra=0.6μm and a shape that meets the requirements of the sampling cone. Step 5, Inner Surface Machining of the Channel: The cooling channel of the surface-machined blank obtained in Step 4 is fed into artificial diamond with an average particle size of 300 nm at a flow pressure of 35 MPa and a flow rate of 500 L / min for 8 hours to obtain a sampling cone for plasma mass spectrometry with an inner surface roughness Ra=1.2 μm and an independent cooling function.

[0047] Testing revealed that in the plasma mass spectrometer sampling cone with self-cooling function prepared in this embodiment, the distance between the cooling channel and the top cone hole is 0.30 mm, the cross-sectional area of ​​the cooling channel is 55% of the cross-sectional area of ​​the cone, the cooling channel is spiral-shaped inside the cone, and the channel spacing is 2.0 mm. Tests showed that the lifespan of the plasma mass spectrometer sampling cone with self-cooling function prepared in this embodiment is more than four times that of traditional sampling cones.

[0048] Example 6 This embodiment includes the following steps: Step 1: Machining the cooling channel core: The paraffin wax is digitally additively manufactured according to the outer dimensions of the spiral cooling channel to obtain a cooling channel core with a roughness Ra=1.0μm; Step 2, pressing and forming: The cooling channel core obtained in Step 1 is loaded into the sampling cone pressing mold, and platinum alloy powder of -300 mesh to +500 mesh is continuously added under vibration. Then, the pressing and forming pressure is 340MPa for molding and held for 2 minutes to obtain the blank. Step 3, High-temperature sintering: The billet obtained in Step 2 is heated from room temperature to 500°C at a heating rate of 1°C / min, held at that temperature for 90 min to remove the core and sinter. Then, the temperature is increased to 1300°C at a rate of 8°C / min, held at that temperature for 180 min to densify and sinter, to obtain the sintered billet. Step 4, Shape Machining: The sintered blank obtained in Step 3 is surface machined to obtain a surface roughness Ra=0.6μm and a shape that meets the requirements of the sampling cone. Step 5, Inner Surface Machining of the Channel: The cooling channel of the surface-machined blank obtained in Step 4 is fed into synthetic diamond with an average particle size of 240 nm at a flow pressure of 40 MPa and a flow rate of 800 L / min for grinding for 5 hours, resulting in a sampling cone for plasma mass spectrometry with an inner surface roughness of Ra=1.2 μm and an independent cooling function.

[0049] Testing revealed that in the self-cooling plasma mass spectrometer sampling cone prepared in this embodiment, the distance between the cooling channel and the top cone orifice is 0.29 mm, the cross-sectional area of ​​the cooling channel is 35% of the cross-sectional area of ​​the cone, the cooling channel is spiral-shaped inside the cone, and the channel spacing is 3.0 mm. Tests showed that the self-cooling plasma mass spectrometer sampling cone prepared in this embodiment has a lifespan more than four times that of traditional sampling cones.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, or variations made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A sampling cone for a plasma mass spectrometer with self-cooling function, characterized in that, The sampling cone includes a sealing surface (1), on which a cone (2) is provided. A spiral cooling channel (3) is provided inside the cone (2). The roughness Ra of the inner surface of the cooling channel (3) is ≤2μm. The distance between the cooling channel (3) and the cone hole (4) at the top of the cone (2) is not greater than 0.4mm.

2. The sampling cone for a plasma mass spectrometer with self-cooling function according to claim 1, characterized in that, The cross-sectional area of ​​the cooling channel (3) in the longitudinal section of the cone (2) is 35% to 55% of the cross-sectional area of ​​the cone (2). The cone (2) is also provided with a cooling medium inlet and a cooling medium outlet that are respectively connected to both ends of the cooling channel (3).

3. A sampling cone for a plasma mass spectrometer with self-cooling function according to claim 1, characterized in that, The spacing between adjacent channels in the spiral cooling channel (3) is 2mm to 3mm.

4. A sampling cone for a plasma mass spectrometer with self-cooling function according to claim 1, characterized in that, The sampling cone is made of stainless steel, nickel, nickel alloy, platinum, or platinum alloy.

5. A method for preparing a sampling cone for a plasma mass spectrometer with self-cooling function as described in any one of claims 1 to 4, characterized in that, The method includes the following steps: Step 1: Machining the cooling channel core: Machining the low-melting-point material according to the external dimensions of the spiral cooling channel to obtain the cooling channel core; Step 2, pressing and forming: The cooling channel core obtained in Step 1 is loaded into the sampling cone pressing mold, and metal powder is continuously added under vibration, and then pressed and formed to obtain the blank. Step 3, High-temperature sintering: The billet obtained in step 2 is continuously subjected to core removal sintering and densification sintering to obtain sintered billet; Step 4, Shape Processing: The sintered billet obtained in Step 3 is surface-processed to obtain a surface-processed billet; Step 5, Inner Surface Machining of the Flow Channel: The cooling flow channel of the surface-machined blank obtained in Step 4 is polished with an abrasive to obtain a sampling cone for plasma mass spectrometer with self-cooling function.

6. The method according to claim 5, characterized in that, The low-melting-point material mentioned in step one is paraffin wax, polyurethane, lead, or aluminum; the processing is digital additive manufacturing, and the surface roughness Ra of the cooling channel core is ≤1.6μm.

7. The method according to claim 5, characterized in that, The particle size of the metal powder in step two is -300 to +500 mesh; the pressing is performed by molding or cold isostatic pressing, with a pressure of 250 MPa to 350 MPa.

8. The method according to claim 5, characterized in that, In step three, the heating rate for core removal sintering is 1℃ / min to 3℃ / min, the temperature is 300℃ to 500℃, and the holding time is 30min to 120min; the heating rate for densification sintering is 5℃ / min to 15℃ / min, the temperature is 1200℃ to 1350℃, and the holding time is 120min to 180min.

9. The method according to claim 5, characterized in that, The surface roughness Ra of the surface-processed blank in step four is ≤0.6μm, and its external dimensions meet the requirements for use with the sampling cone.

10. The method according to claim 5, characterized in that, The abrasive used in step five is synthetic diamond with an average particle size of 200nm~300nm. During the polishing process, the flow pressure of the abrasive is 30MPa~45MPa, the flow rate is 500L / min~800L / min, the polishing time is 4h~8h, and the roughness Ra of the inner surface of the cooling channel after polishing is ≤2μm.

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