Preparation method of ultra-precise platinum-iridium C-type ring for development

Abstract

The invention relates to the technical field of metal material processing, in particular to a preparation method of an ultra-precision platinum-iridium C-type ring for development. The method comprises the steps that firstly, a pipe blank is prepared, then laser is used for conducting segmented cutting on the surface of a platinum-iridium alloy pipe to form grooves, after cutting is completed, heat treatment is conducted on the whole pipe at the low temperature, then cutting of the C-shaped ring is completed, and finally plasma polishing is used for removing surface impurities and burrs to obtain a C-shaped ring finished product. The invention overcomes the defects that in the prior art, the C-shaped ring can be prepared and processed only by depending on equipment, meanwhile, the opening of a C-shaped port caused by stress release after heat treatment is avoided, the problems that burrs generated after cutting are not easy to remove, the production efficiency is low and the like are solved, and provides the C-shaped ring which is simple in processing, high in efficiency, suitable for large-scale batch production and low in production cost. And the prepared platinum-iridium ultra-precise C-shaped ring for development is excellent in surface quality and accurate in size precision.

Description

Technical Field

[0001] The invention relates to the technical field of metal material processing, and in particular to a method for preparing an ultra-precision platinum-iridium C-type ring for development. Background Art

[0002] In the market, the demand for biomedical materials is huge and the profit margin is high. Implant-grade biomedical materials are becoming a pillar industry of the world economy.

[0003] Among them, platinum-iridium alloy has excellent physical and chemical properties: such as good biocompatibility and corrosion resistance, which can reduce the risk of rejection and corrosion of implants in the human body; such as high strength and high ductility, which can make it easy to process into various complex shapes; such as being able to effectively absorb and convert radiation energy such as X-rays, and having excellent development properties. Platinum-iridium alloy can meet the diverse needs of medical device design, and is therefore widely used in implant-grade biomedical devices.

[0004] Among them, the annual demand for platinum-iridium C-rings is huge, and they are widely used at the distal end of interventional catheters for radiographic positioning. During complex medical surgeries, such as cardiovascular or neurological surgery, doctors need to accurately position and operate the catheter. Due to its high density and excellent radiation absorption capacity, platinum-iridium C-rings can be clearly visualized under X-rays or other imaging equipment, helping doctors to more accurately identify the location of the catheter and perform delicate surgical operations.

[0005] However, there are still some problems in the current processing of platinum-iridium C-type rings: on the one hand, in published patents such as Chinese patent CN111112494A, the production of platinum-iridium C-type rings requires a fixed device, and the production size is limited. Therefore, C-type rings of different sizes require corresponding devices, which is costly; on the other hand, when producing platinum-iridium C-type rings, the C-type rings are prone to the problem of opening of the C-type ports, and the C-type rings after cutting are prone to burrs on the cut edges, which are difficult to remove, thus affecting subsequent use. Summary of the invention

[0006] Therefore, in order to solve the above problems in the prior art, the present invention proposes a method for preparing an ultra-precision platinum-iridium C-shaped ring for development that does not rely on specific equipment, has a stable C-shaped port and a smooth surface. The specific scheme is as follows:

[0007] A method for preparing an ultra-precision platinum-iridium C-shaped ring for development comprises the following steps:

[0008] Step 1: Peel the platinum-iridium alloy rod and drill a hole to prepare a platinum-iridium tube billet, insert the air-dried platinum-iridium tube billet into a rolling mill mandrel and cold-roll it to 6 mm or less, then perform multiple cold drawing, remove the mandrel, and obtain an ultra-fine platinum-iridium tube with an inner diameter of less than 0.61 mm and a wall thickness of less than 0.05 mm; specifically, the mandrel and roller of the rolling mill are made of M42 high-speed steel or W 18 Cr4V tungsten high speed steel;

[0009] Step 2: Use two femtosecond or picosecond lasers to cut the ultra-fine platinum-iridium tube multiple times, the lasers cut along two straight lines parallel to the axial direction of the ultra-fine platinum-iridium tube respectively, the angles between the two straight line endpoints of the same longitudinal section and the center of the longitudinal section are greater than 10°, the length of each cutting is 15-50 cm, and then cut at both ends of the two parallel cutting lines to obtain a platinum-iridium tube with multiple long grooves, and the spacing between two adjacent grooves is the same;

[0010] Step 3: Under an inert gas protective atmosphere, the platinum-iridium tube in step 2 is subjected to low-temperature annealing treatment, wherein the annealing temperature is 300-400° C. and the time is 10-15 min to obtain a treated platinum-iridium tube;

[0011] Step 4: cutting the treated platinum-iridium tube in step 3 to obtain a C-shaped ring;

[0012] Step 5: Plasma cleaning the C-ring in step 4;

[0013] Step 6: Clamp the C-type ring cleaned in step 5 onto a special fixture, immerse it in a polishing liquid, and pass direct current to perform plasma polishing on the C-type ring. The polishing liquid includes 0.5%-4% sulfate by mass and 0.1%-2% complexing agent. The temperature of the polishing liquid is controlled at 70-100° C. After polishing, dry the C-type platinum-iridium ring. Preferably, the solvent of the polishing liquid is water, and the drying time in the oven is 5-30 minutes.

[0014] Furthermore, the ultrafine platinum-iridium tube obtained in step 1 has an inner diameter of 0.2-0.6 mm and a wall thickness of 0.01-0.04 mm.

[0015] Furthermore, in step 1, the rolling rate of cold rolling is 200mm / min-300mm / min, the rolling mill feed speed is 2mm-5mm / time, and the processing rate of each rolling pass is 10-15%.

[0016] Furthermore, the distance between the groove opened in step 2 and the end of the ultra-fine platinum-iridium tube and between two adjacent grooves is 2-5 cm.

[0017] Furthermore, in step 2, the angles between the two straight line endpoints of the same longitudinal section and the center of the longitudinal section are 30°-120°.

[0018] Furthermore, the cutting method in step 4 is femtosecond laser cutting or picosecond laser cutting, the cutting direction is perpendicular to the tube cutting, and the interval between two cuttings is less than 1 mm.

[0019] Furthermore, the process conditions of plasma cleaning in step 5 are: when the vacuum degree is less than 10 -2 After filling with argon-hydrogen mixed gas with a purity of 99.99%, the flow rate is 5-15SCCM, the vacuum degree range is 5-10Pa after filling with argon-hydrogen mixed gas, and the cleaning time is 400-600s.

[0020] Furthermore, the sulfate in step 6 is a mixture of one or more of ammonium sulfate, sodium sulfate and zinc sulfate.

[0021] Furthermore, the complexing agent in step 6 is a mixture of one or more of tetrasodium ethylenediaminetetraacetate, citric acid, and succinic acid.

[0022] Furthermore, the voltage of the direct current in step 6 is 260-300V, and the current density is 60-90A / dm 2 .

[0023] The beneficial effects of the present invention are:

[0024] (1) The present invention uses a femtosecond or picosecond laser to cut a C-shaped opening on the surface of a platinum-iridium tube, thereby avoiding the problem that a specific device is required to make a C-shaped ring. In addition, the relative positions of two laser beams can be simply adjusted to achieve precise cutting of C-shaped rings of different specifications and sizes. The method is simple, feasible, and can be flexibly applied to different industrial needs.

[0025] (2) The present invention performs low-temperature annealing on a single platinum-iridium tube having a 15-50 cm long groove every 2-5 cm, and then cuts it: on the one hand, the whole platinum-iridium tube is heat-treated before cutting, which can avoid the deformation problem of the C-shaped port opening due to stress release after heat treatment in the process of cutting first and then heat-treating; on the other hand, annealing at low temperature can eliminate the stress generated during the processing and ensure the strength of the C-shaped platinum-iridium ring, thereby ensuring the performance of the product;

[0026] (3) The present invention adopts femtosecond cutting, which can avoid the common problems of thermal damage, deformation and burrs in traditional laser cutting. The cut ports are flush and have high dimensional accuracy.

[0027] (4) The present invention can activate the surface of the platinum-iridium C-type ring, increase the surface wettability, and improve the adhesion by plasma cleaning the C-type platinum-iridium ring after filling with argon-hydrogen mixed gas, so that the surface performance can be greatly improved, which is helpful for subsequent processing and application; at the same time, the plasma cleaning process does not use chemical reagents, so it will not cause secondary pollution, the cleaning equipment has strong repeatability, the required equipment and operating costs are relatively low, and the operation is flexible and simple, and it can achieve the cleaning of the entire metal surface or certain parts and complex structures;

[0028] (5) The present invention can effectively remove burrs and surface oxides generated after C-ring cutting by plasma polishing in a sulfate polishing liquid, and the surface of the polished product has no lines, the transition of the surface edges and corners is smooth and uniform, and the yield rate is high, so that high-quality ultra-precision C-rings can be produced. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail by specific embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] Embodiment 1:

[0031] This embodiment provides a method for preparing an ultra-precision platinum-iridium C-shaped ring for development, to prepare a C-shaped ring with dimensions of 0.6 mm inner diameter, 0.03 mm wall thickness, and 0.2 mm length, specifically comprising the following steps:

[0032] (1) a platinum-iridium alloy rod with an inner diameter of 20 mm is peeled and drilled to prepare a platinum-iridium tube billet, the air-dried tube billet is inserted into a rolling mill mandrel, the platinum-iridium tube billet is rolled to 6 mm using a rolling mill with a feed speed of 4 mm / time and a rolling speed of 200 mm / min, and then the platinum-iridium tube billet is inserted into a tube drawing die for multi-pass cold drawing, wherein the pass processing rate is 10%, and the mandrel is removed to finally obtain an ultra-fine platinum-iridium tube with an inner diameter of 0.6 mm and a wall thickness of 0.03 mm;

[0033] (2) Determine two straight lines parallel to the axial direction of the ultra-fine platinum-iridium tube on the surface of the ultra-fine platinum-iridium tube, wherein the angle between the two straight line endpoints of the same longitudinal section and the center of the longitudinal section is 70°, and then cut the platinum-iridium tube along the two straight lines 3 cm away from the incision at one end using a 1030 nm laser picosecond laser, with a cutting length of 16 cm, and then cut at both ends of the two parallel cutting lines, and then cut a groove of about 16 cm in length after an interval of 3 cm, and repeat the operation until the entire tube is cut, to obtain a platinum-iridium tube with a 16 cm long groove every 3 cm;

[0034] (3) The platinum-iridium tube with a 16 cm groove was placed in an annealing furnace filled with argon gas for heat treatment at a temperature of 400° C. for 15 min.

[0035] (4) using a 1030 nm laser picosecond laser to vertically cut the heat-treated platinum-iridium tube, with a cutting distance of 0.2 mm, to finally obtain a C-shaped ring with an inner diameter of 0.6 mm, a wall thickness of 0.03 mm, a length of 0.2±0.01 mm, and a port angle of 70°;

[0036] (5) Place the C-shaped ring obtained in step 4 in a plasma cleaning chamber and evacuate the plasma cleaning chamber. When the vacuum degree is less than 10 -2 After 100 Pa, fill with argon-hydrogen mixed gas with a purity of 99.99% to a vacuum degree of 10Pa, with a flow rate of 15SCCM, and clean for 400s to remove impurities remaining on the surface of the C-type platinum-iridium ring obtained in step 4;

[0037] (6) The cleaned C-shaped ring is placed on a hanger as an anode and immersed in a polishing liquid prepared with a low concentration of neutral salt for polishing, wherein the polishing liquid contains 0.5% (mass fraction) ammonium sulfate, 0.5% (mass fraction) complexing agent tetrasodium ethylenediaminetetraacetate, the solvent is water, the temperature is 100° C., the input voltage is 260 V, and the current density is 60 A / dm 2 The C-ring is plasma polished with direct current, and the polished C-ring is placed in a 50°C oven and baked for 30 minutes to obtain an ultra-precision platinum-iridium C-ring with a smooth surface, no burrs, no cracks, and no depressions.

[0038] Embodiment 2:

[0039] This embodiment provides a method for preparing an ultra-precision platinum-iridium C-shaped ring for development, to prepare a C-shaped ring with dimensions of 0.2 mm inner diameter, 0.03 mm wall thickness, and 0.2 mm length, specifically comprising the following steps:

[0040] (1) a platinum-iridium alloy rod with an inner diameter of 15 mm is peeled and drilled to prepare a platinum-iridium tube billet, the air-dried tube billet is inserted into a rolling mill mandrel, the platinum-iridium tube billet is rolled to 6 mm using a rolling mill with a feed speed of 5 mm / time and a rolling speed of 300 mm / min, and then the platinum-iridium tube billet is inserted into a tube drawing die for multi-pass cold drawing, wherein the pass processing rate is 15%, and the mandrel is removed to finally obtain an ultra-fine platinum-iridium tube with an inner diameter of 0.2 mm and a wall thickness of 0.03 mm;

[0041] (2) Determine two straight lines parallel to the ultra-fine platinum-iridium tube on the surface of the tube, wherein the angle between the two straight line endpoints of the same longitudinal section and the center of the longitudinal section is 100°, and then cut the platinum-iridium tube along the two straight lines 2 cm away from the incision at one end using a 1030 nm laser picosecond laser, with a cutting length of 22 cm, and then cut at both ends of the two parallel cutting lines, and then cut a groove of about 22 cm in length after an interval of 2 cm, and repeat the operation until the entire tube is cut, to obtain a platinum-iridium tube with a 22 cm long groove every 2 cm;

[0042] (3) The platinum-iridium tube with a 22 cm groove was placed in an annealing furnace filled with argon gas for heat treatment at 300° C. for 10 min.

[0043] (4) using a 1030 nm laser picosecond laser to vertically cut the heat-treated platinum-iridium tube at a cutting distance of 0.2 mm, and finally obtaining a C-shaped ring with an inner diameter of 0.2 mm, a wall thickness of 0.03 mm, a length of 0.2±0.01 mm, and a port angle of 100°;

[0044] (5) Place the C-shaped ring obtained in step 4 in a plasma cleaning chamber and evacuate the plasma cleaning chamber. When the vacuum degree is less than 10 -2 After 30 ℃, fill with argon-hydrogen mixed gas with a purity of 99.99% to a vacuum degree of 5 Pa, with a flow rate of 5 SCCM, and clean for 600 s to remove impurities remaining on the surface of the C-type platinum-iridium ring obtained in step 4;

[0045] (6) The cleaned C-shaped ring is placed on a hanger as an anode and immersed in a polishing liquid prepared with a low concentration of neutral salt for polishing. The polishing liquid contains 4% sodium sulfate, 2% complexing agent citric acid, the solvent is water, the temperature is 70°C, the voltage is 300V, and the current density is 90A / dm 2 The C-ring is plasma polished with direct current, and the polished C-ring is placed in a 50°C oven and baked for 30 minutes to obtain an ultra-precision platinum-iridium C-ring with a smooth surface, no burrs, no cracks, and no depressions.

[0046] Embodiment 3:

[0047] This embodiment provides a method for preparing an ultra-precision platinum-iridium C-shaped ring for development, to prepare a C-shaped ring with dimensions of 0.2 mm inner diameter, 0.03 mm wall thickness, and 0.2 mm length, specifically comprising the following steps:

[0048] (1) a platinum-iridium alloy rod with an inner diameter of 30 mm is peeled and drilled to prepare a platinum-iridium tube billet, the air-dried tube billet is inserted into a rolling mill mandrel, the platinum-iridium tube billet is rolled to 6 mm using a rolling mill with a feed speed of 5 mm / time and a rolling speed of 300 mm / min, and then the platinum-iridium tube billet is inserted into a tube drawing die for multi-pass cold drawing, wherein the pass processing rate is 15%, and the mandrel is removed to finally obtain an ultra-fine platinum-iridium tube with an inner diameter of 0.2 mm and a wall thickness of 0.03 mm;

[0049] (2) Determine two straight lines parallel to the ultra-fine platinum-iridium tube on the surface of the tube, wherein the angle between the two straight line endpoints of the same longitudinal section and the center of the longitudinal section is 60°, and then cut the platinum-iridium tube along the two straight lines 2 cm away from the incision at one end using a 1030 nm laser picosecond laser, with a cutting length of about 15 cm, and then cut at both ends of the two parallel cutting lines, and then cut a groove of about 15 cm in length after an interval of 2 cm, and repeat the operation until the entire tube is cut, to obtain a platinum-iridium tube with a 15 cm long groove every 2 cm;

[0050] (3) The platinum-iridium tube with a 15 cm groove was placed in an annealing furnace filled with argon gas for heat treatment at 300° C. for 10 min.

[0051] (4) using a laser picosecond with a laser of 1030 nm to cut the heat-treated platinum-iridium tube perpendicular to the platinum-iridium tube, with a cutting distance of 0.2 mm, and finally obtaining a C-shaped ring with an inner diameter of 0.2 mm, a wall thickness of 0.03 mm, a length of 0.2±0.01 mm, and a port angle of 60°;

[0052] (5) Place the C-shaped ring obtained in step 4 in a plasma cleaning chamber and evacuate the plasma cleaning chamber. When the vacuum degree is less than 10 -2 After 1000 s, fill with argon-hydrogen mixed gas with a purity of 99.99% to a vacuum degree of 8 Pa at a flow rate of 10 SCCM, and clean for 500 s to remove impurities remaining on the surface of the C-type platinum-iridium ring obtained in step 4;

[0053] (6) The cleaned C-shaped ring is placed on a hanger as an anode and immersed in a polishing liquid prepared with a low concentration of neutral salt for polishing. The polishing liquid contains 2% zinc sulfate, 1% complexing agent succinic acid, and the solvent is water. The temperature is 80°C, the voltage is 280V, and the current density is 70A / dm 2 The C-ring is plasma polished with direct current, and the polished C-ring is placed in a 50°C oven and baked for 30 minutes to obtain an ultra-precision platinum-iridium C-ring with a smooth surface, no burrs, no cracks, and no depressions.

[0054] Some exemplary embodiments of the present invention are described above. It can be understood that the above embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention. The features in these embodiments can be recombined in a suitable manner, and the scheme obtained thereby is still within the protection scope required by the present invention. Based on the above embodiments, all other embodiments obtained by those skilled in the art without making creative work, that is, all modifications, equivalent substitutions and improvements made within the spirit and principles of this application, fall within the protection scope required by the present invention.

Claims

1. A method for preparing an ultra-precision platinum-iridium C-type ring for development, characterized in that: The following steps are involved: Step 1: Peeling the platinum-iridium alloy rod and drilling a hole to prepare a platinum-iridium tube blank, inserting the platinum-iridium tube blank into a rolling mill mandrel and cold-rolling the tube blank to 6 mm or less, and then performing multiple cold drawing, removing the mandrel, and obtaining an ultra-fine platinum-iridium tube with an inner diameter of less than 0.61 mm and a wall thickness of less than 0.05 mm; Step 2: Use two femtosecond or picosecond lasers to cut the ultra-fine platinum-iridium tube multiple times, the lasers cut along two straight lines parallel to the axial direction of the ultra-fine platinum-iridium tube respectively, the angles between the two straight line endpoints of the same longitudinal section and the center of the longitudinal section are greater than 10°, the length of each cutting is 15-50 cm, and then cut at both ends of the two parallel cutting lines to obtain a platinum-iridium tube with multiple long grooves, and the spacing between two adjacent grooves is the same; Step 3: Under an inert gas protective atmosphere, the platinum-iridium tube in step 2 is subjected to low-temperature annealing treatment, wherein the annealing temperature is 300-400° C. and the time is 10-15 min to obtain a treated platinum-iridium tube; Step 4: cutting the treated platinum-iridium tube in step 3 to obtain a C-shaped ring; Step 5: Plasma cleaning the C-ring in step 4; Step 6: Immerse the C-type ring cleaned in step 5 in a polishing solution, and pass direct current to perform plasma polishing on the C-type ring. The polishing solution includes 0.5%-4% sulfate by mass and 0.1%-2% complexing agent. The temperature of the polishing solution is controlled at 70-100°C. After polishing, dry the ring to obtain a C-type platinum-iridium ring.

2. The method for preparing an ultra-precision platinum-iridium C-shaped ring for development according to claim 1, characterized in that: The ultra-fine platinum-iridium tube obtained in step 1 has an inner diameter of 0.2-0.6 mm and a wall thickness of 0.01-0.04 mm.

3. The method for preparing an ultra-precision platinum-iridium C-shaped ring for development according to claim 1, characterized in that: In step 1, the cold rolling rate is 200 mm / min-300 mm / min, the rolling mill feed speed is 2 mm-5 mm / time, and the processing rate per rolling pass is 10-15%.

4. The method for preparing an ultra-precision platinum-iridium C-shaped ring for development according to claim 1, characterized in that: The distance between the groove opened in step 2 and the end of the ultra-fine platinum-iridium tube and between two adjacent grooves is 2-5 cm.

5. The method for preparing an ultra-precision platinum-iridium C-shaped ring for development according to claim 1, characterized in that: In step 2, the angles between the two straight line endpoints of the same longitudinal section and the center of the longitudinal section are 30°-120°.

6. The method for preparing an ultra-precision platinum-iridium C-shaped ring for development according to claim 1, characterized in that: The cutting method in step 4 is femtosecond laser or picosecond laser cutting, the cutting direction is perpendicular to the tube, and the interval between two cuts is less than 1 mm.

7. The method for preparing an ultra-precision platinum-iridium C-shaped ring for development according to claim 1, characterized in that: The process conditions of plasma cleaning in step 5 are: when the vacuum degree is less than 10 -2 Pa, fill in with argon-hydrogen mixed gas with a purity of 99.99% at a flow rate of 5-15 SCCM. After filling with argon-hydrogen mixed gas, the vacuum degree is 5-10 Pa, and the cleaning time is 400-600s.

8. The method for preparing an ultra-precision platinum-iridium C-shaped ring for development according to claim 1, characterized in that: The sulfate in step 6 is a mixture of one or more of ammonium sulfate, sodium sulfate and zinc sulfate.

9. The method for preparing an ultra-precision platinum-iridium C-shaped ring for development according to claim 1, characterized in that: The complexing agent in step 6 is a mixture of one or more of tetrasodium ethylenediaminetetraacetate, citric acid and succinic acid.

10. The method for preparing an ultra-precision platinum-iridium C-shaped ring for development according to claim 1, characterized in that: The voltage of the DC power in step 6 is 260-300V, and the current density is 60-90A / dm 2 .