阅读说明：本技术 一种医用生物可降解锌合金材料及其制备方法 (Medical biodegradable zinc alloy material and preparation method thereof ) 是由 王红星 张炎 吴灿辉 李�雨 韩程澄 卞连森 赵崔贵 许殷泽 周一文 程军权 于 2021-09-29 设计创作，主要内容包括：本发明涉及一种医用生物可降解锌合金材料及其制备方法,由Zn、Cu、Li组成Zn合金体系,各组分质量百分比为：Cu为1～4％,Li为0.2～0.8％,余量为Zn。经300℃、保温6小时固溶处理后,拉伸强度为343MPa,延伸率高达24.2%。自腐蚀电位为-1.29V,自腐蚀电流密度为19.769×10～(-6)A/cm～(2)。本发明制备的锌合金避免了不利元素的引入,具有良好的力学性能,合适的降解速率,可以满足植入体对生物可降解锌合金材料的腐蚀性能和力学性能的要求。(The invention relates to a medical biodegradable zinc alloy material and a preparation method thereof, wherein a Zn alloy system is composed of Zn, Cu and Li, and the mass percent of each component is as follows: 1 to 4% of Cu, 0.2 to 0.8% of Li and the balance of Zn. After solution treatment at 300 ℃ for 6 hours, the tensile strength is 343MPa, and the elongation is as high as 24.2%. The self-etching potential is-1.29V, and the self-etching current density is 19.769 × 10 ‑6 A/cm 2 . The zinc alloy prepared by the invention avoids the introduction of adverse elements, has good mechanical property and proper degradation rate, and can meet the requirement of an implant on biodegradable zincThe corrosion performance and the mechanical property of the alloy material.)

1. A medical biodegradable zinc alloy material is characterized in that: the Zn alloy system consists of Zn, Cu and Li in percentage by mass: 1 to 4% of Cu, 0.2 to 0.8% of Li and the balance of Zn.

2. The medical biodegradable zinc alloy material according to claim 1, characterized in that: the alloy comprises the following components in percentage by mass: 97.2% of Zn, 2% of Cu and 0.8% of Li.

3. A preparation method of a medical biodegradable zinc alloy material is characterized by sequentially comprising the following steps:

(1) preparing an as-cast alloy, namely taking purple Cu, purple copper foil, pure Li and pure Zn as raw materials for preparing the biological zinc alloy;

(1-1) firstly adding pure Zn into a clean graphite crucible and putting the crucible into a hearth of a power frequency induction furnace, setting the temperature to be 540 ℃, adding purple Cu after most of Zn is molten, then adding a surface covering agent which is a mixture of NaCl, NaF and KF =1:5:4 in mass ratio, heating to 650 ℃, and stirring a metal liquid after Cu is completely molten;

(1-2) after Cu is completely dissolved, cooling to 580 ℃, pressing pure Li hermetically wrapped by a red copper foil into the liquid metal by using a bell jar, and rotating the bell jar to stir the metal liquid;

(1-3) after the alloy is melted, cooling to 550 ℃, standing for 3-5 minutes, taking out the crucible from a power frequency furnace hearth, and pulling out slag; pouring the mixture into a metal mold with the mold temperature of room temperature to prepare as-cast Zn alloy;

(2) solution treatment and/or aging treatment:

the solid solution treatment comprises the steps of (1) preserving heat of the as-cast Zn alloy obtained in the step (1) at 300-360 ℃ for 3-12 hours, and cooling with water;

and (2) the aging treatment is to keep the temperature of the as-cast Zn alloy obtained in the step (1) or the Zn alloy subjected to the solution treatment at 220-280 ℃ for 6-24 hours, and air-cool the alloy.

4. The preparation method of the medical biological zinc alloy material according to claim 3, characterized in that: the temperature of the solid solution treatment is 300-320 ℃, and the heat preservation time of the solid solution treatment is 3-6 hours.

5. The preparation method of the medical biological zinc alloy material according to claim 3, characterized in that: the aging treatment temperature is 260-280 ℃, and the heat preservation time is 6-12 hours.

Technical Field

The invention relates to a medical alloy and a preparation method thereof, in particular to an alloy used in the field of biodegradable implant materials and a preparation method thereof.

Background

In the biomedical metal material, except for the Fe-based alloy and the titanium alloy which are clinically applied at present, the Mg alloy has good mechanical property, biocompatibility and in-vivo degradation property of the biomaterial by virtue of excellent comprehensive properties, and is expected to be used as a biological alternative material of implants such as bones, vascular stents, dental implants and the like.

But the biological Mg alloy has a fast degradation rate, and before the biological function of the biological Mg alloy is realized, the Mg alloy implant is degraded and loses the supporting function; the biological Fe-based alloy is an inert material, is hardly degraded in vivo, needs a secondary operation to take out the implant, and increases the pain and economic burden of patients. Therefore, the existing biological metal material cannot well meet the requirement of human body implantation.

Zn is one of essential nutrient elements for human body, has good biocompatibility, and the degradation rate of Zn is between Mg-based alloy and Fe-based alloy, which is close to the requirement of human body implant. However, pure Zn has low hardness and poor strength, and is difficult to meet the requirements of biological implants on mechanical properties. By adopting an alloying technology, trace human body nutrient elements are added into pure Zn, the tissue morphology and the size of the pure Zn are improved, the mechanical property of the zinc alloy is improved through solid solution strengthening and second phase analysis, and the degradation rate is adjusted by changing the structure and the relative content of the zinc alloy so as to meet the clinical application. At present, the defects that the biodegradable metal material is single in molding shape and the degradation rate and the mechanical property cannot be matched very well exist.

The Chinese patent 2019110996172 'a degradable medical Zn alloy material and a preparation method thereof' is an invention patent in the prior period of the applicant, and a Zn alloy system is formed by Zn, Sn, Mg, Cu, Ag, Zr, Ca, Sr, Gd, Nd, Y and Mn.

Disclosure of Invention

Aiming at the defects of the existing biological material, the invention provides a medical biodegradable zinc alloy material and a preparation method thereof, wherein the zinc alloy material has high strength and plasticity and adjustable degradation rate, the elongation is as high as 6.05-24.2%, and the excellent elongation is beneficial to deformation processing.

The invention relates to a medical biodegradable zinc alloy material, which consists of Zn, Li and Cu to form a Zn alloy system, wherein the mass percentages of the components are as follows: 1 to 4% of Cu, 0.2 to 0.8% of Li and the balance of Zn.

Preferably, the zinc alloy material of the invention comprises the following components: 97.2% of Zn, 2% of Cu and 0.8% of Li.

The invention also discloses a preparation method of the medical biodegradable zinc alloy material, which comprises two parts of alloy component smelting and heat treatment. The method comprises the following steps:

(1) preparing an as-cast alloy, namely taking purple Cu, purple copper foil, pure Li and pure Zn as raw materials for preparing the biological zinc alloy;

(1-1) firstly adding pure Zn into a clean graphite crucible and putting the crucible into a hearth of a power frequency induction furnace, setting the temperature to be 540 ℃, adding purple Cu after most of Zn is molten, then adding a surface covering agent which is a mixture of NaCl, NaF and KF =1:5:4 in mass ratio, heating to 650 ℃, and stirring a metal liquid after Cu is completely molten;

(1-2) after Cu is completely dissolved, cooling to 580 ℃, pressing pure Li hermetically wrapped by a red copper foil into the liquid metal by using a bell jar, and rotating the bell jar to stir the metal liquid;

and (1-3) after the alloy is melted, cooling to 550 ℃, standing for 3-5 minutes, taking out the crucible from the power frequency furnace, and pulling out slag. Pouring the mixture into a metal mold with the mold temperature of room temperature to prepare as-cast Zn alloy;

(2) solution treatment and/or aging treatment:

the solid solution treatment comprises the steps of (1) preserving heat of the as-cast Zn alloy obtained in the step (1) at 300-360 ℃ for 3-12 hours, and cooling with water;

and (2) the aging treatment is to keep the temperature of the as-cast Zn alloy obtained in the step (1) or the Zn alloy subjected to the solution treatment at 220-280 ℃ for 6-24 hours, and air-cool the alloy.

Preferably, the temperature of the solution treatment is 300-320 ℃, and the heat preservation time of the solution treatment is 3-6 hours.

Preferably, the temperature of the aging treatment is 260-280 ℃, and the heat preservation time is 6-12 hours.

Drawings

FIG. 1 is a metallographic photograph of an as-cast Zn-2Cu-0.8Li alloy.

FIG. 2 is a metallographic photograph of Zn-2Cu-0.8Li after heat-preservation for 6 hours at 300 ℃.

FIG. 3 is a graph showing the tensile strength at a tensile rate of 1 mm/min of a zinc alloy after heat-preservation for 6 hours at 300 ℃ in the presence of Zn-2Cu-0.8 Li.

FIG. 4 is an electrochemical polarization curve of Zn-2Cu-0.8Li in 3.5% NaCl solution at 300 deg.C after 6 hr solution treatment.

Detailed Description

The invention is further illustrated by the following examples.

The alloy raw materials adopted by the embodiment of the invention have the purity of Cu more than or equal to 99.99%, the purity of Li more than or equal to 99.99%, the purity of Al more than or equal to 99.95% and the purity of Zn more than or equal to 99.95%.

Example 1

The alloy is prepared according to the components of Zn-2Cu-0.8Li (mass fraction), namely the mass percentages of Zn 97.2%, Cu 2% and Li 0.8%.

When smelting, firstly adding pure Zn into a clean graphite crucible and putting the graphite crucible into a hearth of a power frequency induction furnace, setting the temperature to be 540 ℃, adding purple Cu after most of Zn is molten, then adding a surface covering agent which is a mixture of NaCl, NaF and KF =1:5:4 in mass ratio, heating to 650 ℃, and stirring molten metal after Cu is completely molten; cooling to 580 ℃, pressing pure Li hermetically wrapped by the purple copper foil into the liquid metal by using a bell jar, and simultaneously rotating the bell jar to stir the molten metal; and after the Li is completely melted, reducing the temperature to 550 ℃, standing for 3-5 minutes, taking out the crucible from the hearth, and pulling out the slag. Pouring the mixture into a metal mold with the mold temperature of room temperature to prepare the as-cast Zn alloy.

The cast alloy has tensile strength of 380MPa at room temperature, elongation of 2.34%, electrochemical polarization test self-corrosion potential of-1.288V and self-corrosion current of 21.369X 10 in 3.5 wt% NaCl solution^-6A/cm²。

And (3) preserving the temperature of the obtained as-cast Zn alloy at 300 ℃ for 6 hours, carrying out solid solution treatment, and cooling with water. The alloy has tensile strength of 343MPa at room temperature, elongation of 24.2%, self-corrosion potential of-1.292V and self-corrosion current of 19.769X 10 in 3.5 wt% NaCl solution^-6A/cm²。

Example 2

An as-cast Zn alloy was prepared using the same alloy composition and procedure as in example 1, and then the obtained as-cast Zn alloy was subjected to solution treatment at 320 ℃ for 6 hours, and water-cooled.

The alloy has room temperature tensile strength of 445 MPa, elongation of 11.32%, self-corrosion potential of-1.274V and self-corrosion current of 20.606X 10 in 3.5 wt% NaCl solution^-6A/cm²。

Example 3

The same alloy composition and procedure as in example 1 were used to prepare an as-cast Zn alloy, which was then subjected to aging treatment at 280 c for 12 hours and air-cooled.

The alloy has a tensile strength of 340 MPa at room temperature, an elongation of 13.16%, a self-corrosion potential of-1.289V and a self-corrosion current of 15.382 multiplied by 10 in 3.5% (mass percent) NaCl solution^-6A/cm²。

Example 4

An as-cast Zn alloy was prepared by the same alloy composition and procedure as in example 1, and then the obtained as-cast Zn alloy was heat-preserved at 240 ℃ for 6 hours for aging treatment and air-cooled.

The alloy has room temperature tensile strength of 520MPa, elongation of 7.85%, self-corrosion potential of-1.264V and self-corrosion current of 14.791X 10 in 3.5 wt% NaCl solution^-6A/cm²。

Example 5

The same alloy composition and procedure as in example 1 were used to prepare an as-cast Zn alloy, which was then subjected to aging treatment at 260 ℃ for 12 hours and air-cooled.

The alloy has tensile strength of 437 MPa at room temperature, elongation of 11.5%, self-corrosion potential of-1.275V and self-corrosion current of 26.363X 10 in 3.5 wt% NaCl solution^-6A/cm²。

Example 6

The same alloy composition and procedure as in example 1 were used to prepare an as-cast Zn alloy, and the obtained as-cast Zn alloy was first subjected to solution treatment at 360 ℃ for 12 hours and water-cooled.

The alloy has tensile strength of 394 MPa at room temperature, elongation of 6.5%, self-corrosion potential of-1.279V and self-corrosion current of 36.361X 10 in 3.5 wt% NaCl solution^-6A/cm²。

Example 7

An as-cast Zn alloy was prepared using the same alloy composition and procedure as in example 1, and then the obtained as-cast Zn alloy was subjected to solution treatment by holding at 300 ℃ for 6 hours, followed by aging treatment by holding at 260 ℃ for 12 hours.

The alloy has tensile strength of 364 MPa at room temperature, elongation of 10.46% and elongation of 3.5% (mass percentage)In NaCl solution, the self-corrosion potential is-1.268V, and the self-corrosion current is 17.101X 10^-6A/cm²。

Comparative example 1

The alloy is prepared according to the components of Zn-1.25Cu-2Al (mass fraction), namely the mass percentages of Zn 96.75%, Cu 1.25% and Al 2.0% respectively.

When smelting, firstly adding pure Zn into a clean graphite crucible and putting the graphite crucible into a hearth of a power frequency induction furnace, setting the temperature to be 540 ℃, adding purple Cu after most of Zn is molten, then adding a surface covering agent which is a mixture of NaCl, NaF and KF =1:5:4 in mass ratio, heating to 650 ℃, and stirring molten metal after Cu is completely molten; keeping the temperature at 650 ℃, pressing the aluminum block into the liquid metal by using a bell jar, and simultaneously rotating the bell jar to stir the molten metal; and after the Al is completely dissolved and cleaned, cooling to 550 ℃, standing for 3-5 minutes, taking out the crucible from the hearth, and pulling out the slag. Pouring the mixture into a metal mold with the mold temperature of room temperature to prepare the as-cast Zn alloy.

The cast alloy has tensile strength of 232 MPa at room temperature, elongation of 0.93%, electrochemical polarization test self-corrosion potential of-1.229V and self-corrosion current of 9.506 x 10 in 3.5 wt% NaCl solution^-6A/cm²。

And (3) preserving the temperature of the obtained as-cast Zn alloy at 300 ℃ for 6 hours, carrying out solid solution treatment, and cooling with water. The alloy has room temperature tensile strength of 213 MPa, elongation of 1.45%, self-corrosion potential of-1.252V and self-corrosion current of 17.372X 10-6A/cm in 3.5 wt% NaCl solution²。

Comparative example 2

The alloy is prepared according to the components of Zn-2Cu-1Al (mass fraction), namely the mass percentages of Zn 97%, Cu 2% and Al 1%.

When smelting, firstly adding pure Zn into a clean graphite crucible and putting the graphite crucible into a hearth of a power frequency induction furnace, setting the temperature to be 540 ℃, adding purple Cu after most of Zn is molten, then adding a surface covering agent which is a mixture of NaCl, NaF and KF =1:5:4 in mass ratio, heating to 650 ℃, and stirring molten metal after Cu is completely molten; keeping the temperature at 650 ℃, pressing the aluminum block into the liquid metal by using a bell jar, and simultaneously rotating the bell jar to stir the molten metal; and after the Al is completely dissolved and cleaned, cooling to 550 ℃, standing for 3-5 minutes, taking out the crucible from the hearth, and pulling out the slag. Pouring the mixture into a metal mold with the mold temperature of room temperature to prepare the as-cast Zn alloy.

The cast alloy has tensile strength of 173 MPa at room temperature, elongation of 1.51%, electrochemical polarization test self-corrosion potential of-1.239V and self-corrosion current of 13.645X 10 in 3.5 wt% NaCl solution^-6A/cm²。

And preserving the temperature of the obtained as-cast Zn alloy at 260 ℃ for 12 hours for aging treatment, and cooling in air. The alloy has room temperature tensile strength of 183 MPa, elongation of 2.02%, self-corrosion potential of-1.286V and self-corrosion current of 22.387X 10 in 3.5 wt% NaCl solution^-6A/cm²。

Comparative example 3

The alloy is prepared according to the components of Zn-1.25Cu-5Al (mass fraction), namely the mass percentages of Zn 93.75%, Cu 1.25% and Al 5% respectively.

When smelting, firstly adding pure Zn into a clean graphite crucible and putting the graphite crucible into a hearth of a power frequency induction furnace, setting the temperature to be 540 ℃, adding purple Cu after most of Zn is molten, then adding a surface covering agent which is a mixture of NaCl, NaF and KF =1:5:4 in mass ratio, heating to 650 ℃, and stirring molten metal after Cu is completely molten; keeping the temperature at 650 ℃, pressing the aluminum block into the liquid metal by using a bell jar, and simultaneously rotating the bell jar to stir the molten metal; and after the Al is completely dissolved and cleaned, cooling to 550 ℃, standing for 3-5 minutes, taking out the crucible from the hearth, and pulling out the slag. Pouring the mixture into a metal mold with the mold temperature of room temperature to prepare the as-cast Zn alloy.

The cast alloy has tensile strength of 287 MPa at room temperature, elongation of 1.13%, electrochemical polarization test self-corrosion potential of-1.205V and self-corrosion current of 1.336 × 10 in 3.5 wt% NaCl solution^-6A/cm²。

And preserving the temperature of the obtained as-cast Zn alloy at 260 ℃ for 12 hours for aging treatment, and cooling in air. The alloy has room temperature tensile strength of 253 MPa, elongation of 2.72 percent and self-corrosion potential of-1.2 percent in 3.5 percent (mass percent) NaCl solution13V, self-corrosion current of 6.546X 10^-6A/cm²。

Comparative example 4

The alloy is prepared according to the components of Zn-2Cu-5Al (mass fraction), namely the mass percentages of Zn 93.0%, Cu 2% and Al 5%.

When smelting, firstly adding pure Zn into a clean graphite crucible and putting the graphite crucible into a hearth of a power frequency induction furnace, setting the temperature to be 540 ℃, adding purple Cu after most of Zn is molten, then adding a surface covering agent which is a mixture of NaCl, NaF and KF =1:5:4 in mass ratio, heating to 650 ℃, and stirring molten metal after Cu is completely molten; keeping the temperature at 650 ℃, pressing the aluminum block into the liquid metal by using a bell jar, and simultaneously rotating the bell jar to stir the molten metal; and after the Al is completely dissolved and cleaned, cooling to 550 ℃, standing for 3-5 minutes, taking out the crucible from the hearth, and pulling out the slag. Pouring the mixture into a metal mold with the mold temperature of room temperature to prepare the as-cast Zn alloy.

The cast alloy has tensile strength of 302 MPa at room temperature, elongation of 0.83%, electrochemical polarization test self-corrosion potential of-1.208V and self-corrosion current of 3.776 x 10 in 3.5 wt% NaCl solution^-6A/cm²。

And (3) preserving the temperature of the obtained as-cast Zn alloy at 340 ℃ for 6 hours, carrying out solid solution treatment, and cooling with water. The alloy has tensile strength at room temperature of 273 MPa, elongation of 2.68%, self-corrosion potential of-1.462V and self-corrosion current of 35.481X 10 in 3.5 wt% NaCl solution^-6A/cm²。

Comparative example 5

The alloy is prepared according to the components of Zn-4Cu-1Al (mass fraction), namely the mass percentages of Zn 95.0%, Cu 4% and Al 1%.

When smelting, firstly adding pure Zn into a clean graphite crucible and putting the graphite crucible into a hearth of a power frequency induction furnace, setting the temperature to be 540 ℃, adding purple Cu after most of Zn is molten, then adding a surface covering agent which is a mixture of NaCl, NaF and KF =1:5:4 in mass ratio, heating to 650 ℃, and stirring molten metal after Cu is completely molten; keeping the temperature at 650 ℃, pressing the aluminum block into the liquid metal by using a bell jar, and simultaneously rotating the bell jar to stir the molten metal; and after the Al is completely dissolved and cleaned, cooling to 550 ℃, standing for 3-5 minutes, taking out the crucible from the hearth, and pulling out the slag. Pouring the mixture into a metal mold with the mold temperature of room temperature to prepare the as-cast Zn alloy.

The cast alloy has a tensile strength of 302 MPa at room temperature, an elongation of 1.58%, a self-corrosion potential of-1.217V and a self-corrosion current of 18.923 x 10 in 3.5% (mass percent) NaCl solution in an electrochemical polarization test^-6A/cm²。

And (3) preserving the temperature of the obtained as-cast Zn alloy at 320 ℃ for 6 hours, carrying out solid solution treatment, and cooling with water. The alloy has tensile strength of 336 MPa at room temperature, elongation of 2.48%, self-corrosion potential of-1.219V and self-corrosion current of 22.321X 10 in 3.5 wt% NaCl solution^-6A/cm²。

Example 8

The alloy is prepared according to the components of Zn-3Cu-0.8 Li (mass fraction), namely the mass percentages of Zn 96.2%, Cu3% and Li 0.8%.

When smelting, firstly adding pure Zn into a clean graphite crucible and putting the graphite crucible into a hearth of a power frequency induction furnace, setting the temperature to be 540 ℃, adding purple Cu after most of Zn is molten, then adding a surface covering agent which is a mixture of NaCl, NaF and KF =1:5:4 in mass ratio, heating to 650 ℃, and stirring molten metal after Cu is completely molten; cooling to 580 ℃, pressing pure Li hermetically wrapped by the purple copper foil into the liquid metal by using a bell jar, and simultaneously rotating the bell jar to stir the molten metal; and after the Li is completely melted, reducing the temperature to 550 ℃, standing for 3-5 minutes, taking out the crucible from the hearth, and pulling out the slag. Pouring the mixture into a metal mold with the mold temperature of room temperature to prepare the as-cast Zn alloy. And (3) preserving the temperature of the obtained as-cast Zn alloy at 280 ℃ for 12 hours, carrying out aging treatment, and cooling in air.

The alloy has tensile strength at room temperature of 338 MPa, elongation of 6.05%, self-corrosion potential of-1.321V and self-corrosion current of 56.479X 10 in 3.5 wt% NaCl solution^-6A/cm²。

Example 9

The same alloy composition and procedure as in example 6 were used to prepare an as-cast Zn alloy, which was then subjected to aging treatment at 220 ℃ for 24 hours and air-cooled.

The alloy has tensile strength of 302 MPa at room temperature, elongation of 8.48%, self-corrosion potential of-1.249V and self-corrosion current of 23.442X 10 in 3.5 wt% NaCl solution^-6A/cm²。

Example 10

The alloy is prepared according to the components of Zn-4Cu-0.2 Li (mass fraction), namely the mass percentages of Zn 95.8%, Cu 4% and Li 0.2% respectively.

When smelting, firstly adding pure Zn into a clean graphite crucible and putting the graphite crucible into a hearth of a power frequency induction furnace, setting the temperature to be 540 ℃, adding purple Cu after most of Zn is molten, then adding a surface covering agent which is a mixture of NaCl, NaF and KF =1:5:4 in mass ratio, heating to 650 ℃, and stirring molten metal after Cu is completely molten; cooling to 580 ℃, pressing pure Li hermetically wrapped by the purple copper foil into the liquid metal by using a bell jar, and simultaneously rotating the bell jar to stir the molten metal; and after the Li is completely melted, reducing the temperature to 550 ℃, standing for 3-5 minutes, taking out the crucible from the hearth, and pulling out the slag. Pouring the mixture into a metal mold with the mold temperature of room temperature to prepare the as-cast Zn alloy.

The cast alloy has room temperature tensile strength of 348MPa, elongation of 1.68%, electrochemical polarization test self-corrosion potential of-1.298V and self-corrosion current of 20.369X 10 in 3.5 wt% NaCl solution^-6A/cm²。

And (3) preserving the temperature of the obtained as-cast Zn alloy at 300 ℃ for 6 hours, carrying out solid solution treatment, and cooling with water. The alloy has tensile strength at room temperature of 333 MPa, elongation of 8.3%, self-corrosion potential of-1.29V and self-corrosion current of 26.546X 10 in 3.5% (mass percent) NaCl solution^-6A/cm²。

Example 11

The alloy is prepared according to the components of Zn-1.0Cu-0.8 Li (mass fraction), namely the mass percentages of Zn 98.2%, Cu 1% and Li 0.8%.

When smelting, firstly adding pure Zn into a clean graphite crucible and putting the graphite crucible into a hearth of a power frequency induction furnace, setting the temperature to be 540 ℃, adding purple Cu after most of Zn is molten, then adding a surface covering agent which is a mixture of NaCl, NaF and KF =1:5:4 in mass ratio, heating to 650 ℃, and stirring molten metal after Cu is completely molten; cooling to 580 ℃, pressing pure Li hermetically wrapped by the purple copper foil into the liquid metal by using a bell jar, and simultaneously rotating the bell jar to stir the molten metal; and after the Li is completely melted, reducing the temperature to 550 ℃, standing for 3-5 minutes, taking out the crucible from the hearth, and pulling out the slag. Pouring the mixture into a metal mold with the mold temperature of room temperature to prepare the as-cast Zn alloy.

The cast alloy has room temperature tensile strength of 328MPa and elongation of 1.87%, and has electrochemical polarization test self-corrosion potential of-1.236V and self-corrosion current of 17.223X 10 in 3.5 wt% NaCl solution^-6A/cm²。

And preserving the temperature of the obtained as-cast Zn alloy at 270 ℃ for 12 hours for aging treatment, and cooling in air. The alloy has tensile strength of 313 MPa at room temperature, elongation of 7.43%, self-corrosion potential of-1.278V and self-corrosion current of 20.386 x 10 in 3.5 wt% NaCl solution^-6A/cm²。

Comparative example 6

The alloy is prepared according to the components of Zn-2Cu-1.0Al-0.5 Li (mass fraction), namely the mass percentages of Zn 96.5%, Cu 2%, Al 1.0% and Li 0.5%.

When smelting, firstly adding pure Zn into a clean graphite crucible and putting the graphite crucible into a hearth of a power frequency induction furnace, setting the temperature to be 540 ℃, adding purple Cu after most of Zn is molten, then adding a surface covering agent which is a mixture of NaCl, NaF and KF =1:5:4 in mass ratio, heating to 650 ℃, and stirring molten metal after Cu is completely molten; keeping the temperature at 650 ℃, pressing the aluminum block into the liquid metal by using a bell jar, and simultaneously rotating the bell jar to stir the molten metal; cooling to 580 ℃, pressing pure Li hermetically wrapped by the purple copper foil into the liquid metal by using a bell jar, and simultaneously rotating the bell jar to stir the molten metal; and after the Li is melted, reducing the temperature to 550 ℃, standing for 3-5 minutes, taking out the crucible from the hearth, and pulling out the slag. Pouring the mixture into a metal mold with the mold temperature of room temperature to prepare the as-cast Zn alloy.

The tensile strength of the as-cast alloy at room temperature is 288 MPa, the elongation is 0.53 percent and is 3.5 percent (mass percent) of NaIn Cl solution, the self-corrosion potential is-1.288V and the self-corrosion current is 30.762X 10 in electrochemical polarization test^-6A/cm²。

And (3) preserving the temperature of the obtained as-cast Zn alloy at 360 ℃ for 6 hours, carrying out solid solution treatment, and cooling with water. The alloy has tensile strength of 322 MPa at room temperature, elongation of 0.81%, self-corrosion potential of-1.282V and self-corrosion current of 45.234 x 10 in 3.5 wt% NaCl solution^-6A/cm²。

The present invention is not limited to the above embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts according to the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.