阅读说明：本技术 一种3d打印金属钽后处理及高温真空烧结降低氧含量的方法 (Method for reducing oxygen content through 3D printing metal tantalum post-treatment and high-temperature vacuum sintering ) 是由 唐建中 郭凯旋 王国华 姜常在 周立波 于 2019-06-05 设计创作，主要内容包括：本发明属于增材制造技术领域,提供一种3D打印多孔钽后处理及高温真空烧结降低氧含量的方法。具体为：将3D打印钽制品从基板上取下,清除粘附在3D打印钽制品上多余钽粉,干燥后,把钽制品置入高温真空烧结处理真空炉中进行多段升温-保温的高温真空烧结处理工艺,具体为先升温至1500～2600℃,保温5～450min,所述升温-保温的段数为1段至任意段数,每段所述温度不同,升温-保温热处理后停电降温至小于50℃,然后停止抽真空,开炉取出3D打印多孔钽植入体。本发明创造性的利用高温真空烧结处理的方法降低激光3D打印钽制品中的氧含量,使其达到300ppm甚至100ppm以下,从而减低了原料3D打印钽粉氧含量的要求,大幅降低3D打印原料及制品的成本。(The invention belongs to the technical field of additive manufacturing, and provides a method for reducing oxygen content through 3D printing porous tantalum post-treatment and high-temperature vacuum sintering. The method specifically comprises the following steps: taking the 3D printed tantalum product off the substrate, removing redundant tantalum powder adhered to the 3D printed tantalum product, drying, putting the tantalum product into a high-temperature vacuum sintering treatment vacuum furnace to perform a multi-stage heating-heat preservation high-temperature vacuum sintering treatment process, specifically, heating to 1500-2600 ℃, preserving heat for 5-450 min, wherein the number of heating-heat preservation stages is 1 to any number of stages, the temperature of each stage is different, stopping power cut and cooling to less than 50 ℃ after heating-heat preservation treatment, then stopping vacuumizing, opening the furnace, and taking out the 3D printed porous tantalum implant. The invention creatively utilizes the high-temperature vacuum sintering treatment method to reduce the oxygen content in the laser 3D printing tantalum product to be 300ppm even less than 100ppm, thereby reducing the requirement of the oxygen content of the raw material 3D printing tantalum powder and greatly reducing the cost of the 3D printing raw material and the product.)

1. A method for reducing oxygen content through 3D printing metal tantalum post-treatment and high-temperature vacuum sintering is characterized in that a 3D printing tantalum product is taken down from a printed substrate, redundant tantalum powder adhered to the 3D printing tantalum product is removed and dried, the 3D printing tantalum product is placed into a high-temperature vacuum sintering vacuum furnace, a multi-section heating-heat preservation high-temperature vacuum sintering heat treatment process is carried out at 1500-2600 ℃, the number of sections of heating-heat preservation is 1 to any number, the heat preservation time in each section of heating-heat preservation is 5-450 min, power is cut down to be less than 50 ℃ after the last section of heating-heat preservation heat treatment is completed, then vacuumizing is stopped, the furnace is opened, a 3D printing implant is taken out,

wherein: in the whole heat treatment process, the vacuum degree of the high-temperature vacuum sintering heat treatment vacuum furnace is kept at 1 multiplied by 10^-1Pa～1×10^-5Pa。

2. The method for reducing the oxygen content through 3D printing metal tantalum post-treatment and high-temperature vacuum sintering according to claim 1, wherein the number of the stages of the heating-heat-preservation high-temperature vacuum sintering heat treatment process is three stages of heating-heat preservation.

3. The method for reducing the oxygen content through 3D printing metal tantalum post-treatment and high-temperature vacuum sintering according to claim 2, wherein the three-stage heating-maintaining temperature comprises the following steps: a first stage: heating to 1500 ℃, and keeping the temperature for 0.5-2 h; and a second stage: heating to 1650 ℃, and keeping the temperature for 0.5-2 h; a third stage: heating to 1800 ℃ and preserving heat for 0.5-4 h.

4. The method for reducing oxygen content in 3D printed metal tantalum post-treatment and high-temperature vacuum sintering according to claim 1, wherein in the heat treatment process, the temperature rise rate is 10-100 ℃/min.

5. The method for reducing oxygen content in 3D printed metal tantalum post-treatment and high-temperature vacuum sintering according to claim 4, wherein the temperature rise rate is 20-40 ℃/min.

6. The method for reducing the oxygen content through the 3D printing metal tantalum post-treatment and the high-temperature vacuum sintering according to claim 1, wherein the heat treatment vacuum furnace is a metal furnace; the plate or rod made of molybdenum, tantalum or tungsten is preferably used as a heating body, and the molybdenum, tantalum or tungsten plate is used as a heat-insulating screen.

7. The method for reducing oxygen content in 3D printed metal tantalum post-treatment and high-temperature vacuum sintering according to claim 1, wherein the vacuum degree of the vacuum furnace for the high-temperature vacuum sintering heat treatment is maintained to be at least 5 x 10 during the whole process of the high-temperature vacuum sintering heat treatment^-3Pa。

8. The method for reducing oxygen content through 3D printing metal tantalum post-treatment and high-temperature vacuum sintering according to any one of claims 1 to 7, characterized in that the method for removing excessive tantalum powder adhered to the 3D printing tantalum product is adopted, and comprises the following specific steps:

s1, blowing off tantalum powder adhered to the 3D printed tantalum product by using compressed air;

s2, removing the overstrain excessive tantalum powder adhered to the 3D printed tantalum product after the step S1 by using a sand blasting method;

s3, tapping by using a mallet or a hand within a distance of 100-150 mm to remove tantalum powder still adhered to the interior of the 3D printed tantalum product after the step S2;

s4, carrying out non-powder-falling inspection on the 3D printed tantalum product obtained by processing in S3, and specifically comprising the following steps: the 3D printed tantalum product is continuously dropped to a hardwood table surface paved with white paper at a height of more than or equal to 200mm for 3 times, and powder which does not drop on the white paper is regarded as not-dropping powder and is qualified through inspection;

s5, placing the 3D printed tantalum product which is processed in the step S4 and is not subjected to powder dropping and qualified in inspection into an ultrasonic cleaning machine, and performing ultrasonic vibration cleaning in deionized water.

9. The method for reducing oxygen content in 3D printed metal tantalum post-treatment and high-temperature vacuum sintering according to claim 8, wherein the sand for sand blasting in step S2 is tantalum powder of 50-150 μm, and the pressure of the air flow for sand blasting is 0.2-0.7 MPa.

10. The method for reducing oxygen content through 3D printing metal tantalum post-treatment and high-temperature vacuum sintering according to claims 1-9, wherein the metal tantalum product is one or more of a laser 3D printing porous tantalum test piece, a laser 3D printing porous tantalum human body implant prosthesis, a non-human body implanted tantalum metal 3D printing product, an electron beam 3D printing porous tantalum test piece, a porous tantalum human body implant prosthesis, or a non-human body implanted tantalum metal 3D printing product.

Technical Field

The invention belongs to the technical field of additive manufacturing, and further relates to a method for reducing oxygen content through 3D printing metal tantalum post-treatment and high-temperature vacuum sintering.

Background

The metal tantalum has excellent biocompatibility and excellent bone conduction, bone induction and bacteriostasis performance, is the metal with the best affinity with human bodies at present, and has been applied for decades. To solve the problem that the traditional processing is difficult due to the high melting point of tantalum metal, the company describes a process method for laser 3D printing of tantalum metal in an issued patent of 'manufacturing method for additive materials of tantalum, niobium or alloy thereof' (patent number ZL 201610322433.8). The patent provides a large-scale, low-cost and simple-process manufacturing method for niobium or tantalum or an alloy additive thereof, but in the practical production and application process of the process method, the problem of overhigh oxygen content in the 3D printed metal tantalum is obvious and needs to be solved urgently.

The industrial application usually employs 1000-1200 ℃ to perform vacuum heat treatment to eliminate the stress of tantalum products, and the oxygen content of tantalum metal products is increased during the vacuum heat treatment. Meanwhile, laser 3D printing is performed in an argon environment, and because the argon environment inevitably contains oxygen (usually 1000ppm) and tantalum is a metal which is very easy to oxidize at high temperature, even if 3D printing tantalum powder raw materials with the oxygen content lower than 300ppm are adopted, the oxygen content of the printed product is increased. It is difficult to achieve the 300ppm oxygen content index of medical tantalum metal products. Therefore, many people pursue to control and reduce the oxygen content of the laser printing raw material tantalum powder to be below 200ppm, so that the production difficulty of the laser printing raw material tantalum powder is increased, the production efficiency of the tantalum powder product is low, and the cost is greatly increased.

Disclosure of Invention

Aiming at the problems in the background art, the invention provides a method for reducing the oxygen content through post-treatment and high-temperature vacuum sintering of 3D printed metal tantalum, which reduces the oxygen content of a 3D printed product by using an ultrahigh-temperature heat treatment method to enable the oxygen content to reach 300ppm or even less than 100ppm, thereby reducing the requirement on the oxygen content of raw material 3D printed tantalum powder and greatly reducing the cost of the raw material and the product for 3D printing.

The purpose of the invention is realized by the following technical scheme:

a method for reducing oxygen content through 3D printing metal tantalum post-treatment and high-temperature vacuum sintering is characterized in that a 3D printing tantalum product is taken down from a printed substrate, redundant tantalum powder adhered to the 3D printing tantalum product is removed and dried, the 3D printing tantalum product is placed into a heat treatment vacuum furnace, a multi-section heating-heat preservation heat treatment process is carried out at 1500-2600 ℃, the number of sections of heating-heat preservation is 1 to any number, the heating-heat preservation time of each section is 5-450 min, power is cut down and the temperature is reduced to be less than 50 ℃ after the last section of heating-heat preservation high-temperature vacuum sintering heat treatment is completed, then vacuumizing is stopped, the furnace is opened, a 3D printing implant is taken out,

wherein: in the whole process of the high-temperature vacuum sintering heat treatment process, the vacuum degree of the high-temperature vacuum sintering heat treatment vacuum furnace is kept at 1 multiplied by 10^-1Pa～1×10^-5Pa。

In the process, tantalum in the metal tantalum product is oxidized with oxygen at the temperature of 400 ℃ to increase the oxygen content, and even under the normal heat treatment vacuum state, the treatment temperature is 900-1200 ℃, and the oxygen content is increased. Therefore, the invention creatively sets the temperature to be higher than 1500 ℃ in a vacuum state, oxygen and tantalum in the tantalum product form tantalum suboxide at the time, the suboxide is gasified and volatilized at more than 1500 ℃, and the gas of the suboxide can be continuously pumped away by vacuumizing, so that the oxygen content of the tantalum product is reduced.

As one of the preferable schemes, the number of the sections of heating and heat preservation is set to be three sections; further preferably, the three segments are respectively: a first stage: heating to 1500 ℃, and keeping the temperature for 0.5-2 h; and a second stage: heating to 1650 ℃, and keeping the temperature for 0.5-2 h; a third stage: heating to 1800 ℃ and preserving heat for 0.5-4 h.

As one of the preferable schemes, in the heat treatment process, the heating rate is 10-100 ℃/min; further preferably 20 to 40 ℃/min.

As one preferable scheme, the high-temperature vacuum sintering heat treatment vacuum furnace used by the invention is a metal furnace; it is further preferred that molybdenum or tantalum or tungsten plate/rod is used as the heating element in the metal furnace, and molybdenum or tantalum or tungsten plate is the screen of heat preservation.

As one preferable scheme, the vacuum degree of the vacuum furnace for the high-temperature vacuum sintering heat treatment is kept at least 5 x 10 in the whole process of the high-temperature vacuum sintering heat treatment process^-3Pa。

As one of the preferable schemes, the invention adopts the following method to remove the redundant tantalum powder adhered on the 3D printed tantalum product, and the specific steps are as follows:

s1, blowing off tantalum powder adhered to the 3D printed tantalum product by using compressed air;

s2, removing the overstrain excessive tantalum powder adhered to the 3D printed tantalum product after the step S1 by using a sand blasting method;

s3, manually carrying out 3D printing on the tantalum product, and manually tapping by using a mallet or within a distance of 100-150 mm to remove tantalum powder still adhered to the inside of the 3D printed tantalum product after the step S2;

s4, carrying out non-powder-falling inspection on the 3D printed tantalum product obtained by processing in S3, and specifically comprising the following steps: the 3D printed tantalum product is continuously dropped to a hardwood table surface paved with white paper at a height of more than or equal to 200mm for 3 times, and powder which does not drop on the white paper is regarded as not-dropping powder and is qualified through inspection;

s5, placing the 3D printed tantalum product which is processed in the step S4 and is not subjected to powder dropping and qualified in inspection into an ultrasonic cleaning machine, and performing ultrasonic vibration cleaning in deionized water.

Further preferably, the sand for blasting in step S2 is tantalum powder of 50 to 150um, and the air pressure for blasting is 0.2 to 0.7 MPa.

The method is particularly suitable for laser 3D printing of porous tantalum test pieces, laser 3D printing of porous tantalum human body implanted prostheses, non-human body implanted tantalum metal 3D printed products, electron beam 3D printing of porous tantalum test pieces, porous tantalum human body implanted prostheses or non-human body implanted tantalum metal 3D printed products.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention creatively utilizes the method of carrying out multi-section high-temperature-heat-preservation high-temperature vacuum sintering heat treatment at 1500-2600 ℃ by using the vacuum reaction furnace to reduce the oxygen content in the tantalum product printed by the laser 3D to be 300ppm or even less than 100ppm, reduces the requirement of the oxygen content of the tantalum powder printed by the raw material 3D, greatly reduces the cost of the raw material and the product printed by the 3D, and further improves the production efficiency.

(2) The invention creatively adopts a mallet or a hand to continuously tap within a distance of 100-150 mm, and can effectively remove tantalum powder in the 3D printed porous tantalum implant;

(3) the invention creatively invents a method for 'no powder falling inspection': the laser 3D printing porous tantalum implant product is continuously and freely dropped for 3 times at a height of more than or equal to 200mm to a hardwood table surface paved with white paper, and powder which does not drop on the white paper is regarded as qualified by 'no powder drop inspection'. The method is effective, applicable and simple.

Drawings

FIG. 1 is a graph of mechanical test samples of porous tantalum with different structural sizes printed by laser 3D in example 1.

FIG. 2 is a graph of mechanical test samples of porous tantalum with different structural sizes, which are laser 3D printed in example 2.

FIG. 3 is a photograph of an implanted prosthesis according to example 3 after annealing.

Detailed Description

In order to facilitate an understanding of the invention, the invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the specific embodiments below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.