Tantalum coating applied to heart occluder and preparation method thereof

Abstract

The invention relates to the technical field of medical implant materials, discloses a tantalum coating applied to a heart occluder and a preparation method of the tantalum coating, and solves the problems that the use process of an existing tantalum coating preparation method is mostly realized through chemical vapor deposition, the method is only suitable for a plate-shaped workpiece with a simple structure, and the use cost is low. And the problem that a thin-size pure tantalum coating with uniform components and fine crystal grains cannot be obtained due to too long preparation time possibly occurs.

Description

Technical Field

[0001] The invention relates to the technical field of medical implant materials, in particular to a tantalum coating used for a cardiac occluder and a preparation method thereof. Background Art

[0002] Congenital heart disease refers to anatomical abnormalities caused by formation disorders or abnormal development of the heart and large blood vessels during embryonic development, or failure to close the channels that should close automatically after birth. It is the most common type of congenital malformation, with an incidence of about 0.4% to 1% of newborns. Abnormal hemodynamics in congenital heart disease will increase the burden on the heart, leading to heart failure and inducing arrhythmias; abnormal blood shunting in congenital heart disease will increase abnormal blood flow in the lungs, leading to respiratory infections in children; children with congenital heart disease are significantly slower in development than normal children, and because of the impact of congenital heart disease on the nervous system, they are likely to have intellectual and cognitive impairments. Therefore, the treatment of congenital heart disease has become an important issue of social concern.

[0003] Minimally invasive interventional treatment has developed rapidly and is now very mature. Compared with traditional surgical operations, minimally invasive interventional treatment is a modern high-tech minimally invasive treatment. Through femoral vein puncture, under the guidance of medical imaging equipment, the heart occluder is pushed into the delivery catheter to the site to be occluded for occlusion treatment. Such minimally invasive interventional treatment has the advantages of no surgery, less trauma, fewer complications, faster recovery, better results, a wide range of indications and relatively low surgical costs.

[0004] The existing tantalum coating preparation methods are mostly achieved through chemical vapor deposition during use. This method is only applicable to plate-like workpieces with simple structures, and may fail to obtain a thin-size pure tantalum coating with uniform composition and fine grains due to the long preparation time. Therefore, it is inconvenient to prepare a thin-size and low-diffusion high-performance pure tantalum coating on the surface of a multi-net nickel-titanium alloy substrate.

[0005] In view of the above problems, a tantalum coating for use in a cardiac occluder and a preparation method thereof are proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a tantalum coating for cardiac occluder and a preparation method thereof. The present method is used to work, thereby solving the problem that the existing tantalum coating preparation methods are mostly implemented by chemical vapor deposition during use, which is only applicable to plate-like workpieces with simple structures, and may fail to obtain a thin-size pure tantalum coating with uniform composition and fine grains due to the long preparation time. Therefore, it is inconvenient to prepare a thin-size and low-diffusion high-performance pure tantalum coating on the surface of a multi-net nickel-titanium alloy substrate.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a method for preparing a tantalum coating for a cardiac occluder, comprising the following main steps;

[0008] Step 1: placing the substrate to be coated in the reaction chamber, wherein the material of the cardiac occluder is nickel-titanium alloy;

[0009] Step 2: reacting solid pure tantalum metal with chlorine to obtain tantalum pentachloride gas, and conveying the tantalum pentachloride gas into a waiting reaction chamber for storage by helium gas transport, wherein the waiting reaction chamber contains high-purity helium gas;

[0010] Step 3: placing cupric chloride powder in a quartz tube of a tube furnace, evacuating the quartz tube, introducing nitrogen gas and heating the tube to obtain cupric chloride gas, and introducing the cupric chloride gas into a reaction chamber;

[0011] Step 4: reacting the tantalum pentachloride with hydrogen and the copper chloride gas, and the copper and tantalum elements are attached to the surface of the heart occluder;

[0012] Step 5: After the reaction is completed, the copper chloride gas can be stopped from being introduced, and the temperature of the reaction chamber can be lowered, and then tantalum pentachloride gas and hydrogen gas can be introduced, so that after the copper and tantalum elements are attached to the surface of the substrate, a layer of tantalum elements can also be attached to the outside;

[0013] Step 6: Finally, argon gas is introduced to avoid further reaction, and the reaction chamber is cooled to slowly reduce the temperature, and a tantalum coating can be obtained after cooling;

[0014] The above-mentioned method and steps use chemical vapor deposition to process and manufacture the tantalum coating of the heart occluder, and the step of introducing argon gas not only facilitates the preparation and reaction of tantalum single substance, prevents chemical reaction between tantalum and other single substances during the reaction process, improves production efficiency, but also reduces various physical, chemical and biological reactions of blood to metals, reduces the leakage of metal ions, and thus avoids allergic reactions or thrombosis.

[0015] Preferably, in step one, the ion beam enhanced vapor deposition method is to bombard the titanium evaporated and deposited on the surface of the occluder with an inert gas ion beam at room temperature and vacuum conditions to form a coating on the surface of the occluder; the reaction gas may be nitrogen, carbon or oxygen.

[0016] Preferably, in step 2, the temperature when the solid pure tantalum metal reacts with the chlorine is set to 800 to 1,000 degrees Celsius, the gas flow rate of the chlorine is 200 to 350 milliliters per minute, the reaction vacuum is 15 to 20 Pa, and the gas flow rate of the helium is 600 to 900 milliliters per minute.

[0017] Preferably, in step 3, the reaction temperature of the copper chloride is 1,000 to 1,200 degrees Celsius, and the rate of introduction of copper chloride gas is 20 to 40 milliliters per minute.

[0018] Preferably, in step 4, the time for the tantalum pentachloride to react with the hydrogen gas and the copper chloride gas is controlled to be six to nine hours.

[0019] Preferably, in step 5, the gas flow rate of the hydrogen gas is 400 ml to 550 ml per minute, and the temperature of the reaction chamber is 900 to 1,100 degrees Celsius.

[0020] Preferably, the tantalum coating is based on the tantalum element as a matrix, copper element, and trace amounts of tantalum nitride and copper nitride. The thickness of the tantalum coating is less than ten microns, the purity of the tantalum coating is greater than or equal to ninety-nine percent, and the grain size of the tantalum coating is less than one-quarter of the thickness of the tantalum coating.

[0021] Preferably, the surface of the tantalum coating has a silver-grey metallic luster, the thickness of the interdiffusion zone is less than one-third of the thickness of the tantalum coating, and the tantalum element and its oxide compound exist on the nickel-titanium alloy substrate.

[0022] Preferably, in the chemical vapor deposition process, the tantalum pentachloride is used as a reaction source, hydrogen is used as a reducing gas, helium is used as a carrier gas, the flow ratio of the evaporation rate of the tantalum pentachloride is 50 ml to 100 ml, the reaction temperature is 900 to 1,100 degrees Celsius, the reaction time is shortened to two to four hours, and the pressure of the reaction chamber is greater than 20 Pa.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present application proposes a tantalum coating for cardiac occluder and a preparation method thereof, which solves the problem that the existing tantalum coating preparation methods are mostly implemented by chemical vapor deposition during use. This method is only applicable to plate-like workpieces with simple structures, and may fail to obtain a thin-size pure tantalum coating with uniform composition and fine grains due to the long preparation time. The tantalum coating preparation method adopted by the present invention uses chemically pure tantalum pentachloride as the reaction raw material during the reaction, and uses high-purity hydrogen as the reducing gas and carrier gas to transport the evaporated tantalum pentachloride to a high-temperature deposition area, generate metallic tantalum through a reduction reaction, and deposit it on the surface of the titanium alloy. The step of introducing argon gas not only facilitates the preparation and reaction of tantalum as a single substance, but also prevents the occurrence of tantalum and other single substances during the reaction. The copper-tantalum mixed element is attached with a layer of tantalum to further reduce the harm of the heart occluder to the human body, prevent the occurrence of excessive copper ions and human poisoning, and achieve the effect of evenly attaching a layer of tantalum coating on the outside of the heart occluder, thereby improving the manufacturing effect. The patent foramen ovale occluder is a self-expanding double-disc occluder woven from imported nickel-titanium alloy wires of varying thicknesses. The built-in bluff body is a 100% non-woven polyester sheet. The thin non-woven fabric design can block abnormal blood flow, and also reduce the diameter of the occluder delivery catheter and reduce vascular damage to patients. The upper and lower ends are made of stainless steel, and the suture is polyester. The mechanism of action of the patent foramen ovale occluder is to place a metal grid structure containing fillers at the lesion to mechanically block abnormal blood flow, and induce thrombosis or stimulate the growth of surrounding tissues through the fillers to achieve the purpose of closing the foramen ovale and treating the disease.

[0025] 2. The present application proposes a tantalum coating for cardiac occluders and a preparation method thereof, which solves the problem that the existing tantalum coating has a relatively single content and often lacks a bactericidal function, and is prone to intraoperative and postoperative infections during surgery, which affects its use. The tantalum coating preparation method adopted by the present invention introduces copper chloride gas into the reaction chamber to react with tantalum pentachloride and hydrogen. After the reaction, copper can be attached to the cardiac occluder, and copper metal is simultaneously deposited in the tantalum metal coating. The copper ions have a bactericidal effect, so that the tantalum metal coating has antibacterial properties. The synergistic enhancement of tantalum and copper can solve the infection problem of surgery and improve the human tissue repair effect, avoiding the problem that copper covers tantalum in multi-layer deposition and the synergistic effect of the two metals cannot be exerted. Both tantalum and copper can contact human tissues and cells, which helps the tantalum coating to regulate cell behavior and promote human bone tissue regeneration. The tantalum coating has a certain bactericidal function through the setting of copper, thereby improving the medical hygiene coefficient.

[0026] 3. The present application proposes a tantalum coating for cardiac occluders and a preparation method thereof, which solves the problem that the existing cardiac occluders are easily affected by the gas compounds of the two metals during the simultaneous deposition of the two metal materials, resulting in uneven deposition. The tantalum coating preparation method adopted by the present invention obtains copper chloride gas through a heating step during the process of introducing nitrogen after evacuating the quartz tube. At this time, the copper chloride gas is mixed with nitrogen, so that the copper chloride and tantalum pentachloride gases are in a dynamically stable state. During the deposition process, the surface of the nickel-titanium base material can be deposited into a surface coating with metallic tantalum as the base, composite copper metal, and trace amounts of tantalum nitride and copper nitride, thereby achieving the effect of avoiding the uneven deposition caused by the influence of gas compounds during the simultaneous deposition process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall process structure of the present invention;

[0028] Figure 2 It is a schematic diagram of gas flow and temperature control of the present invention;

[0029] Figure 3 It is a schematic diagram of the cardiac occluder of the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings.

[0032] Combination Figure 1-Figure 3 , a method for preparing a tantalum coating for a cardiac occluder, comprising the following main steps;

[0033] Step 1: placing the substrate to be coated in the reaction chamber, the material of the cardiac occluder is nickel-titanium alloy;

[0034] Step 2: reacting solid pure tantalum metal with chlorine to obtain tantalum pentachloride gas, and conveying the tantalum pentachloride gas into a waiting reaction chamber for storage through helium gas transport, wherein the waiting reaction chamber contains high-purity helium gas;

[0035] Step 3: placing cupric chloride powder in a quartz tube of a tube furnace, evacuating the quartz tube, introducing nitrogen gas and heating the tube to obtain cupric chloride gas, and introducing the cupric chloride gas into the interior of the reaction chamber;

[0036] Step 4: reacting tantalum pentachloride with hydrogen and copper chloride gas, and the copper and tantalum elements are attached to the surface of the heart occluder;

[0037] Step 5: After the reaction is completed, the copper chloride gas can be stopped from being introduced, and the temperature of the reaction chamber can be lowered, and then tantalum pentachloride gas and hydrogen gas can be introduced, so that after the copper and tantalum elements are attached to the surface of the substrate, a layer of tantalum elements can also be attached to the outside;

[0038] Step 6: Finally, argon gas is introduced to avoid further reaction, and the reaction chamber is cooled to slowly reduce the temperature, and a tantalum coating can be obtained after cooling;

[0039] The above-mentioned method and steps use chemical vapor deposition to process and manufacture the tantalum coating of the heart occluder, and the step of introducing argon gas not only facilitates the preparation and reaction of tantalum single substance, prevents chemical reaction between tantalum and other single substances during the reaction process, improves production efficiency, but also reduces various physical, chemical and biological reactions of blood to metals, reduces the leakage of metal ions, and thus avoids allergic reactions or thrombosis.

[0040] In step 1, the ion beam enhanced vapor deposition method is to bombard the titanium evaporated and deposited on the surface of the occluder with an inert gas ion beam at room temperature and vacuum conditions to form a coating on the surface of the occluder; the reaction gas can be nitrogen, carbon or oxygen.

[0041] In step 2, the temperature for the reaction of solid pure tantalum metal and chlorine is set to 800 to 1,000 degrees Celsius, the gas flow rate of the chlorine is 200 to 350 milliliters per minute, the reaction vacuum is 15 to 20 Pa, and the gas flow rate of the helium is 600 to 900 milliliters per minute.

[0042] In step 3, the reaction temperature of copper chloride is 1,000 to 1,200 degrees Celsius, and the introduction rate of copper chloride gas is 20 to 40 milliliters per minute.

[0043] In step 4, the time for the reaction between tantalum pentachloride, hydrogen gas and copper chloride gas is controlled to be six to nine hours.

[0044] In step 5, the gas flow rate of the hydrogen gas is 400 ml to 550 ml per minute, and the temperature of the reaction chamber is 900 to 1,100 degrees Celsius.

[0045] The tantalum coating is based on tantalum as a single substance, copper as a single substance, and trace amounts of tantalum nitride and copper nitride. The thickness of the tantalum coating is less than ten microns, the purity of the tantalum coating is greater than or equal to ninety-nine percent, and the grain size of the tantalum coating is less than one-quarter of the thickness of the tantalum coating.

[0046] The surface of the tantalum coating has a silver-grey metallic luster, the thickness of the interdiffusion zone is less than one-third of the thickness of the tantalum coating, and the tantalum element and its oxide compounds exist on the nickel-titanium alloy substrate.

[0047] In the chemical vapor deposition process, tantalum pentachloride is used as a reaction source, hydrogen is used as a reducing gas, and helium is used as a carrier gas. The flow ratio of the evaporation rate of tantalum pentachloride is 50 ml to 100 ml, the reaction temperature is 900 to 1,100 degrees Celsius, the reaction time is shortened to two to four hours, and the pressure of the reaction chamber is greater than 20 Pa.

[0048] The present invention will be further described below in conjunction with the embodiments.

[0049] Embodiment 1:

[0050] In order to solve the problem that the existing tantalum coating preparation methods are mostly implemented by chemical vapor deposition during use, which is only applicable to plate-like workpieces with simple structures, and may fail to obtain a thin-size pure tantalum coating with uniform composition and fine grains due to the long preparation time, this embodiment discloses the following technical solutions, specifically as follows Figure 1-Figure 3 As shown, the tantalum coating preparation method adopted by the present invention, during the reaction process, the reaction raw material is chemically pure tantalum pentachloride, high-purity hydrogen is used as the reducing gas and carrier gas, the evaporated tantalum pentachloride is transported to the high-temperature deposition area, and metallic tantalum is generated by the reduction reaction and deposited on the surface of the titanium alloy. The step of introducing argon gas not only facilitates the preparation and reaction of tantalum single substance, prevents tantalum from chemically reacting with other single substances during the reaction process, improves production efficiency, reduces various physical, chemical and biological reactions of blood to metals, reduces the leakage of metal ions, thereby avoiding inflammatory reactions or thrombosis, and attaches a layer of tantalum single substance to the outside of the copper-tantalum mixed single substance, so that the harm of the heart occluder to the human body is further reduced, and the situation of human poisoning caused by excessive copper ions is prevented, and the effect of evenly attaching a layer of tantalum coating to the outside of the heart occluder is achieved, thereby improving the manufacturing effect.

[0051] At the same time, in order to solve the problem that the existing tantalum coating has a relatively single content and often lacks a bactericidal function, and is prone to intraoperative and postoperative infections during surgery, which affects its use, the present embodiment also discloses the following scheme: copper chloride gas is introduced into the reaction chamber to react with tantalum pentachloride and hydrogen. After the reaction, copper can be attached to the cardiac occluder, and copper metal is simultaneously deposited in the tantalum metal coating. The copper ions have a bactericidal effect, so that the tantalum metal coating has antibacterial properties. The synergistic enhancement of tantalum and copper can solve the infection problem of surgery and improve the human tissue repair effect, avoiding the problem of copper covering tantalum in multi-layer deposition and failing to exert the synergistic effect of the two metals. Both tantalum and copper can contact human tissues and cells, which helps the tantalum coating to regulate cell behavior and promote human bone tissue regeneration. The tantalum coating can have a certain bactericidal function through the setting of copper, thereby improving the medical hygiene coefficient.

[0052] At the same time, in order to solve the problem that the existing heart occluder is easily affected by the gas compounds of the two metals during the simultaneous deposition of the two metal materials, resulting in uneven deposition, the present embodiment also discloses the following scheme: in the process of introducing nitrogen after evacuating the quartz tube, copper chloride gas is obtained through a heating step. At this time, the copper chloride gas is mixed with nitrogen, so that the copper chloride and tantalum pentachloride gases are in a dynamically stable state. During the deposition process, the surface of the nickel-titanium base material can be deposited into a surface coating with metallic tantalum as the base, composite copper metal, and trace amounts of tantalum nitride and copper nitride, thereby achieving the effect of avoiding the uneven deposition caused by the influence of gas compounds during the simultaneous deposition process.

[0053] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0054] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a tantalum coating for a cardiac occluder, characterized in that: The main steps include: Step 1: placing the substrate to be coated in the reaction chamber, wherein the material of the cardiac occluder is nickel-titanium alloy; Step 2: reacting solid pure tantalum metal with chlorine to obtain tantalum pentachloride gas, and conveying the tantalum pentachloride gas into a waiting reaction chamber for storage by helium gas transport, wherein the waiting reaction chamber contains high-purity helium gas; Step 3: placing cupric chloride powder in a quartz tube of a tube furnace, evacuating the quartz tube, introducing nitrogen gas and heating the tube to obtain cupric chloride gas, and introducing the cupric chloride gas into a reaction chamber; Step 4: reacting the tantalum pentachloride with hydrogen and the copper chloride gas, and the copper and tantalum elements are attached to the surface of the heart occluder; Step 5: After the reaction is completed, the copper chloride gas can be stopped from being introduced, and the temperature of the reaction chamber can be lowered, and then tantalum pentachloride gas and hydrogen gas can be introduced, so that after the copper and tantalum elements are attached to the surface of the substrate, a layer of tantalum elements can also be attached to the outside; Step 6: Finally, argon gas is introduced to avoid further reaction, and the reaction chamber is cooled to slowly reduce the temperature, and a tantalum coating can be obtained after cooling; The above-mentioned method and steps use chemical vapor deposition to process and manufacture the tantalum coating of the heart occluder, and the step of introducing argon gas not only facilitates the preparation and reaction of tantalum single substance, prevents chemical reaction between tantalum and other single substances during the reaction process, improves production efficiency, but also reduces various physical, chemical and biological reactions of blood to metals, reduces the leakage of metal ions, and thus avoids allergic reactions or thrombosis.

2. The method for preparing a tantalum coating for a cardiac occluder according to claim 1, characterized in that: In step one, the ion beam enhanced vapor deposition method is to bombard the titanium evaporated and deposited on the surface of the occluder with an inert gas ion beam at room temperature and vacuum conditions to form a coating on the surface of the occluder; the reaction gas can be nitrogen, carbon or oxygen.

3. The method for preparing a tantalum coating for a cardiac occluder according to claim 1, characterized in that: In step 2, the temperature when the solid pure tantalum metal reacts with the chlorine gas is set to 800 to 1,000 degrees Celsius, the gas flow rate of the chlorine gas is 200 to 350 milliliters per minute, the reaction vacuum is 15 to 20 Pa, and the gas flow rate of the helium gas is 600 to 900 milliliters per minute.

4. The method for preparing a tantalum coating for a cardiac occluder according to claim 1, characterized in that: In step 3, the reaction temperature of the copper chloride is 1,000 to 1,200 degrees Celsius, and the introduction rate of the copper chloride gas is 20 to 40 milliliters per minute.

5. The method for preparing a tantalum coating for a cardiac occluder according to claim 1, characterized in that: In step 4, the time for the tantalum pentachloride to react with the hydrogen gas and the copper chloride gas is controlled to be six to nine hours.

6. The method for preparing a tantalum coating for a cardiac occluder according to claim 1, characterized in that: In step 5, the gas flow rate of the hydrogen gas is 400 ml to 550 ml per minute, and the temperature of the reaction chamber is 900 to 1,100 degrees Celsius.

7. The method for preparing a tantalum coating for a cardiac occluder according to claim 1, characterized in that: In step five, during the chemical vapor deposition process, the tantalum pentachloride is used as a reaction source, hydrogen is used as a reducing gas, helium is used as a carrier gas, the flow ratio of the evaporation rate of the tantalum pentachloride is 50 ml to 100 ml, the reaction temperature is 900 to 1,100 degrees Celsius, the reaction time is shortened to two to four hours, and the pressure of the reaction chamber is greater than 20 Pa.

8. The tantalum coating for a cardiac occluder according to claim 1, characterized in that: The tantalum coating is based on the tantalum element as a matrix, copper element, and trace amounts of tantalum nitride and copper nitride. The thickness of the tantalum coating is less than ten microns, the purity of the tantalum coating is greater than or equal to ninety-nine percent, and the grain size of the tantalum coating is less than one-quarter of the thickness of the tantalum coating.

9. The tantalum coating for a cardiac occluder according to claim 1, characterized in that: The surface of the tantalum coating has a silver-grey metallic luster, the thickness of the interdiffusion zone is less than one-third of the thickness of the tantalum coating, and the tantalum element and its oxide compound exist on the nickel-titanium alloy substrate.

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