CN107815618A - A kind of amorphous Biological magnesium alloy and preparation method thereof - Google Patents

Abstract

The invention relates to an amorphous bio-magnesium alloy and a preparation method thereof, belonging to the technical field of design and manufacture of bio-magnesium alloys. The amorphous biological magnesium alloy includes the following components in terms of mass percentage: 75-82% magnesium, 15-20% zinc, and 3-5% neodymium. The preparation method is as follows: take magnesium powder, zinc powder and neodymium powder according to the designed composition, and ball mill at 240-360r/min for at least 2 hours under a protective atmosphere to obtain a mixed powder; then, under a protective atmosphere, adopt a selective laser melting process Obtain magnesium-zinc-neodymium amorphous bio-magnesium alloy; during selective laser melting, control the cooling rate of molten pool to 10 ⁵ ‑10 ¹⁰ K/s, control laser power to 200‑400W, and scan rate to 2‑5m/s , the control spot diameter is 50 μm. The invention prepares the bio-magnesium alloy with an amorphous structure through relatively simple steps, improves the corrosion resistance of the bio-magnesium alloy, and promotes its application in the field of tissue repair.

Description

A kind of amorphous bio-magnesium alloy and preparation method thereof

technical field

The invention relates to an amorphous bio-magnesium alloy and a preparation method thereof, belonging to the technical field of design and manufacture of bio-magnesium alloys.

Background technique

Biomagnesium alloys are considered as potential bone repair materials due to their natural degradability, matching mechanical properties and good biocompatibility. However, at present, the degradation rate of conventional bio-magnesium alloys in the human environment is too fast, so that its mechanical strength rapidly decays after implantation in the body, and its structural support is lost prematurely; on the other hand, too fast degradation of magnesium alloys can also lead to The local pH is elevated, which is also not conducive to the growth of new bone tissue. Therefore, improving the corrosion resistance of bio-magnesium alloys is an urgent problem to be solved.

Amorphous magnesium alloys have no grain boundaries and a highly uniform single-phase structure, which can well inhibit the corrosion of micro-batteries caused by different local chemical compositions of conventional magnesium alloys, so it has shown great potential in improving the corrosion resistance of biological magnesium alloys. Advantage. In general, obtaining an amorphous structure requires a specific alloy system and a high cooling rate. Specifically, the alloy system usually requires three or more components, and the atomic size difference between the components is greater than 10% and has a negative heat of mixing; and a higher cooling rate can keep the atoms in the solidification process of the alloy. Disordered arrangement in liquid state, thus promoting the formation of amorphous structure.

At present, scholars at home and abroad have carried out a series of studies on magnesium-based amorphous alloy systems, and obtained a variety of amorphous alloy systems, such as Mg _58.5 Cu _30.5 Y ₁₁ , Mg ₆₅ Ni ₂₀ Nd ₁₅ and Mg ₅₄ Cu _26.5 Ag _8.5 Gd ₁₁ , etc. . However, there are few studies on the amorphous alloy system of bio-magnesium alloys. The above-mentioned systems contain a large amount of alloying elements with biotoxicity, and there will be unpredictable risks if they are applied to human tissue repair. Commonly used preparation methods include mold casting and quick quenching. The mold casting method is to melt the magnesium alloy and press it into the metal mold cavity, and use the characteristics of fast heat conduction of the metal mold to obtain a relatively fast cooling rate, thereby obtaining an amorphous magnesium alloy; The rapid quenching method is to spray molten magnesium alloy into a quartz glass tube with a smaller diameter, and then put it into water to quench to obtain amorphous magnesium alloy. However, the size and shape of the mold cavity in the die casting method will limit the size and shape of the formed alloy, and the cooling rate of the rapid quenching method is low, which is not suitable for the magnesium alloy system with weak glass transition ability.

In the prior art, there is no relevant record about the preparation of amorphous bio-magnesium alloy by selective laser melting process.

Contents of the invention

The invention aims at the problem of poor corrosion resistance of conventional bio-magnesium alloys, and proposes an amorphous bio-magnesium alloy and a preparation method thereof, thereby improving its corrosion resistance.

An amorphous biomagnesium alloy of the present invention comprises the following components in terms of mass percentage:

Magnesium 75-82%, preferably 77-80%, more preferably 78%;

Zinc 15-20%, preferably 17-19%, more preferably 19%;

Neodymium 3-5%, preferably 3-4%, more preferably 3%.

The invention relates to an amorphous bio-magnesium alloy. The surface of the amorphous bio-magnesium alloy is further provided with a neodymium oxide film.

A kind of preparation method of amorphous magnesium alloy of the present invention comprises the following steps:

step one

According to the design composition, take magnesium powder, zinc powder and neodymium powder with a particle size range of 10-50 μm, and ball mill at 240-360r/min, preferably 360r/min, for at least 2h, preferably 3-4h, and further It is preferably 4h to obtain a mixed powder with a particle size of 10-50 μm;

step two

Using the mixed powder obtained in step 1 as the raw material, under a protective atmosphere, the magnesium-zinc-neodymium amorphous bio-magnesium alloy is obtained by selective laser melting process; during selective laser melting, the cooling rate of the molten pool is controlled to be 10 ⁵ -10 ¹⁰ K/s, preferably 10 ¹⁰ K/s, the control laser power is 200-500W, the scan rate is 2-5m/s, and the control spot diameter is 50μm.

The invention relates to a method for preparing an amorphous bio-magnesium alloy, wherein the protective atmosphere is high-purity argon. The high-purity argon gas is argon gas with a purity greater than or equal to 99.999%.

The invention utilizes the selective laser melting process to quickly scan the above-mentioned mixed powder to form a molten pool, and utilizes the cooling rate of up to 10 ¹⁰ K/s in the range of laser nanoseconds to realize interfaceless heat conduction and rapid solidification, thereby obtaining magnesium-zinc-neodymium non-metallic Crystal biomagnesium alloy.

The surface of the magnesium-zinc-neodymium amorphous bio-magnesium alloy designed and prepared by the invention has a highly uniform neodymium oxide film closely combined with the substrate, which can further improve the corrosion resistance of the bio-magnesium alloy. In the present invention, the amount of neodymium must be strictly controlled, because the rare earth metal element neodymium has high activity, adding too high content of neodymium will lead to its agglomeration, thereby reducing the performance of the magnesium alloy. If the amount added is too low, its anti-corrosion performance and the degree of amorphization of the finished product cannot be guaranteed.

Compared with prior art, the present invention has the following advantages:

(1) The developed magnesium-zinc-neodymium alloy system can not only obtain amorphous bio-magnesium alloy, but also has excellent biocompatibility and can be used for human tissue repair.

(2) The present invention cleverly utilizes the characteristic of high-energy rapid cooling of selective laser melting technology, and under the synergistic effect of an appropriate amount of large atomic diameter (relative to Mg), the formation of the amorphous structure of the bio-magnesium alloy is promoted.

(3) The selective laser melting technology used in the present invention, as an additive manufacturing method, can form amorphous bio-magnesium alloys of arbitrary complex shapes.

(4) An appropriate amount of alloying element neodymium forms a highly uniform neodymium oxide film on the surface of the bio-magnesium alloy that is closely combined with the substrate, and further improves the corrosion resistance of the bio-magnesium alloy through passivation.

Detailed ways

The specific implementation mode of the present invention is set forth below by two examples:

Example 1

Using magnesium, zinc and neodymium powders as raw materials, weigh 0.78g magnesium powder, 0.19g zinc powder and 0.03g neodymium powder according to the mass ratio of 78:19:3, ball mill under the protection of 99.999% high-purity argon, and the ball mill speed is 360r /min, and the ball milling time is 4h. After ball milling, a uniformly dispersed magnesium-zinc-neodymium mixed powder is obtained. ^Magnesium- Zn-Nd amorphous biomagnesium alloy.

Phase detection found that the as-prepared Mg-Zn-Nd alloy had diffuse diffuse reflection peaks, revealing its amorphous structure; electrochemical analysis found that compared with conventional Mg-Zn-Nd alloys, the Mg-Zn-Nd alloy with amorphous structure The corrosion potential of the neodymium alloy in the simulated body fluid was positively shifted, and the corrosion current density was 2μA/cm ² ; the corrosion surface was observed under the electron microscope to be smooth, with few corrosion products and no obvious corrosion pits; Dense neodymium oxide passivation film, thus improving its corrosion resistance. The corrosion rate is 0.10mm/year, and the ultimate tensile strength is 350MPa.

Example 2

Using magnesium, zinc and neodymium powders as raw materials, weigh 0.8g magnesium powder, 0.17g zinc powder and 0.03g neodymium powder according to the mass ratio of 80:17:3, ball mill under the protection of 99.999% high-purity argon gas, and the speed of the ball mill is 300r /min, and the ball milling time is 2h. After ball milling, a uniformly dispersed magnesium-zinc-neodymium mixed powder is obtained. ^Magnesium- Zn-Nd amorphous biomagnesium alloy.

Phase detection found that the as-prepared Mg-Zn-Nd alloy had diffuse diffuse reflection peaks, revealing its amorphous structure; electrochemical analysis found that compared with conventional Mg-Zn-Nd alloys, the Mg-Zn-Nd alloy with amorphous structure The corrosion current density of neodymium alloy in simulated body fluid was 7μA/cm ² ; the corrosion surface was observed under the electron microscope to be flat; at the same time, it was found that a dense neodymium oxide passivation film was formed on the surface of the magnesium-zinc-neodymium amorphous alloy. The corrosion rate is 0.17mm/year, and the ultimate tensile strength is 320MPa.

Comparative example 1

Other conditions are all consistent with embodiment 1, and difference is: by the mass ratio of 80:19:1, weigh 0.8g magnesium powder, 0.19g zinc powder and 0.01g neodymium powder, obtain product, adopt phase detection to find obvious Mg, MgZn characteristic peaks. The corrosion current density of the obtained product is 36.1μA/cm ² , the corrosion rate is 1.66mm/year, and the ultimate tensile strength is 212MPa.

Comparative example 2

Other conditions are the same as in Example 1, except that the scan speed is 2 m/s (the cooling rate of the molten pool is 10 ⁴ K/s), and the obtained product has obvious Mg and MgZn characteristic peaks by phase detection. The corrosion current density of the obtained product is 26.8μA/cm ² , the corrosion rate is 1.33mm/year, and the ultimate tensile strength is 234MPa.

Comparative example 3

Other conditions are consistent with Example 1, the difference is: the scanning speed is 0.1m/s (the cooling rate of the molten pool is 10 ² K/s), the product is obtained, and the phase detection is used to find that there are obvious MgZn and MgZnNd characteristic peaks . The corrosion current density of the obtained product is 28.4μA/cm ² , the corrosion rate is 1.48mm/year, and the ultimate tensile strength is 258MPa.

It can be seen from Example 1 and Comparative Example that the components and preparation process of the present invention are an organic whole, and when any one or several key parameters are not within the protection scope of the present invention, its effect will be significantly reduced. Through the internal comparison of Example 1 and Example 2 of the present invention, it is found that the preferred solution of the present invention has played an unexpected effect.

Claims (6)

1. A kind of 1. amorphous Biological magnesium alloy, it is characterised in that；The amorphous Biological magnesium alloy includes following by percentage to the quality Component：

   Magnesium 75-82%；

   Zinc 15-20%；

   Neodymium 3-5%.
2. A kind of 2. amorphous Biological magnesium alloy according to claim 1, it is characterised in that；The amorphous Biological magnesium alloy is with matter Amount percentages include following components：

   Magnesium 77-80%；

   Zinc 17-19%；

   Neodymium 3-4%.
3. A kind of 3. amorphous Biological magnesium alloy according to claim 2, it is characterised in that；The amorphous Biological magnesium alloy is with matter Amount percentages include following components：

   Magnesium 78%；

   Zinc 19%；

   Neodymium 3%.
4. A kind of 4. amorphous Biological magnesium alloy according to claim 1, it is characterised in that；The amorphous Biological magnesium alloy surface Also carry one layer of neodymia film.
5. A kind of 5. preparation method of the amorphous Biological magnesium alloy as described in claim 1-4 any one, it is characterised in that；Including under State step：

   Step 1

   Match somebody with somebody magnesium powder, zinc powder and the neodymium powder for taking particle size range to be 10-50 μm by design component, under protective atmosphere, in 240-360r/ Min ball millings at least 2h, obtain the mixed-powder that particle diameter is 10-50 μm；

   Step 2

   Using mixed-powder obtained by step 1 as raw material, under protective atmosphere, using selective laser melting technique obtain magnesium-zinc- Neodymium amorphous Biological magnesium alloy；During selective laser melting, the cooldown rate for controlling molten bath is 10⁵-10¹⁰K/s, control laser power For 200-500W, sweep speed 2-5m/s, it is 50 μm to control spot diameter.
6. A kind of 6. preparation method of amorphous Biological magnesium alloy according to claim 5, it is characterised in that：The protective atmosphere For high-purity argon gas；The purity of the high-purity argon gas is more than or equal to 99.999%.