ANTIBACTERIAL AND ANTIVIRAL COPPER-CONTAINING STAINLESS STEEL, AND PREPARATION METHOD THEREFOR AND USE THEREOF

Abstract

The present invention provides an antibacterial and antiviral copper-containing stainless steel, and a preparation method for and the use of a stainless-steel conforming to the composition thereof. The copper-containing stainless steel comprises a stainless steel matrix and a copper-rich phase evenly distributed in the stainless steel matrix, wherein the copper content of the copper-containing stainless steel is 6-30 wt %. The preparation method therefor comprises the manufacturing of a small stainless steel product mainly using powder metallurgy technology, and the manufacturing of a large stainless steel sheet, bar or pipe mainly using a composite process without significant thermal deformation. Compared with a traditional antibacterial stainless steel, the composition design of the present invention contains sufficient copper-rich precipitated phases, such that the antibacterial and antiviral copper-containing stainless steel of the present invention can achieve both a good killing effect on bacteria and a virus killing capacity comparable with that of pure copper, can be used for preparing the integral body or the whole of parts such as cutters, elevator buttons, railings, handrails, door handles and cups, and can effectively kill bacteria and viruses existing on the surfaces thereof.

Claims

1. An antibacterial and antiviral copper-bearing stainless steel, the copper-bearing stainless steel comprising a stainless steel matrix and a copper-rich phase uniformly distributed in the stainless steel matrix, wherein the copper content of the copper-bearing stainless steel is 6-30 wt %.

2. The antibacterial and antiviral copper-bearing stainless steel according to claim 1, wherein the copper-bearing stainless steel comprises the following composition in mass percentages: Cu: 6-30 wt %; Ag: 0-1 wt %; Zn: 0-1.5 wt %; Cr: 11-30 wt %; Mn: 0-20 wt %; Ni: 0-18 wt %; Co: 0-8 wt %; Al: 0-5 wt %; Ti: 0-5 wt %; Mo: 0-4 wt %; V: 0-3 wt %; C1 wt %, with the remainder being iron and unavoidable impurities.

3. The antibacterial and antiviral copper-bearing stainless steel according to claim 1, wherein the copper-bearing stainless steel may further contain one or more elements selected from the group consisting of Nb, Si, Zr, N and B, wherein Si2 wt %, and the total content of the other alloying elements is 3 wt %.

4. The antibacterial and antiviral copper-bearing stainless steel according to claim 1, wherein the copper content of the copper-bearing stainless steel is 8-20 wt %, more preferably 10-15 wt %.

5. A preparation method of the antibacterial and antiviral copper-bearing stainless steel according to claim 1, the preparation method including: formulating a raw material powder according to the composition of the antibacterial and antiviral copper-bearing stainless steel, wherein the raw material powder comprise 6-30 wt % of copper powder; and molding the raw material powder into a stainless steel product by using a powder metallurgy method.

6. The preparation method according to claim 5, wherein the molding includes metal injection molding technology, powder pressing sintering technology, and/or hot pressing sintering technology.

7. The preparation method according to claim 5, wherein the preparation method includes the following steps: (1) weighing the raw material powder according to the composition of the antibacterial and antiviral copper-bearing stainless steel; (2) mixing the raw material powder from step (1) with a binder evenly and then granulating to obtain a feed; (3) injection molding the feed material obtained in step (2) to obtain a green body; (4) degreasing and sintering the green body obtained in step (3) to obtain a copper-bearing stainless steel product; (5) subjecting the copper-bearing stainless steel product obtained in step (4) to solid solution and aging treatments to obtain the antibacterial and antiviral copper-bearing stainless steel.

8. A preparation method of the antibacterial and antiviral copper-bearing stainless steel according to claim 1, the preparation method including: formulating a raw material powder according to the composition of the antibacterial and antiviral copper-bearing stainless steel, wherein the raw material powder comprises 6-30 wt % of copper powder; pre-molding the raw material powder to obtain a green body; sintering the green body to obtain a preliminarily dense sintered part; completely densifying the sintered part by one or more methods selected from extrusion, cold rolling and hot isostatic pressing to obtain the antibacterial and antiviral copper-bearing stainless steel product.

9. The preparation method according to claim 8, wherein the preparation method includes the following steps: (1) weighing the raw material powder according to the composition of the copper-bearing stainless steel; (2) pouring the raw material powder from step (1) into a powder rolling mill to make a green body; (3) subjecting the green body obtained in step (2) to sintering treatment to obtain a preliminarily dense sintered part; (4) subjecting the sintered part obtained in step (3) to cold rolling so as to completely densify it and obtain a copper-bearing stainless steel material; (5) subjecting the copper-bearing stainless steel material obtained in step (4) to solid solution and aging treatments.

10. A stainless steel appliance, the stainless steel appliance including a medical appliance or an appliance for living or public place, wherein the stainless steel appliance comprises the antibacterial and antiviral stainless steel of claim 1, preferably, the stainless steel appliance includes a knife, elevator button, door handle, railing and handrail, as a whole or a component thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0061] FIG. 1 is an SEM image of the stainless steel containing 10 wt % of copper prepared by the method of Example 2 of the present invention.

[0062] FIG. 2 is an SEM image of the stainless steel containing 20 wt % of copper prepared by the method of Example 2 of the present invention.

[0063] FIG. 3 is a photograph of the stainless steel discs containing 10 wt % of copper prepared by the method of Example 2 of the present invention.

[0064] FIG. 4 is a photograph of the elevator buttons made of the stainless steel containing 20 wt % of copper prepared using the method of Example 2 of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

[0065] The present invention is further described in detail below in combination with the specific embodiments, wherein the given examples are for illustrative purposes only, and are not intended to limit the scope of the invention.

Example 1

[0066] This example is used to illustrate a method of preparing a stainless steel disc with a high copper content using powder metallurgy technology. The preparation method includes the following steps: [0067] (1) On the basis of the composition of 304 stainless steel, 304-10 wt % Cu pre-alloyed powder with an additional 10 wt % copper added was prepared. [0068] (2) The 304-10 wt % Cu pre-alloyed powder from step (1) was pressed into a green disc through cold press molding. [0069] (3) The green disc obtained in step (2) was placed into an atmosphere sintering furnace, with argon gas being a protective gas, and held at 1350 C. for 2 hours to complete the sintering process to obtain a stainless steel disc. [0070] (4) The stainless steel disc obtained in step (3) was held at 1100 C. for 1 hour and then quenched, and subsequently an aging treatment was performed at 700 C. for 6 hours to obtain an antibacterial and antiviral copper-bearing stainless steel disc of the present invention.

Example 2

[0071] This example is used to illustrate a method of preparing a stainless steel disc with a high copper content using powder metallurgy technology. The preparation method includes the following steps: [0072] (1) On the basis of the composition of 316L stainless steel, 10 wt % copper powder was added to a 316L pre-alloyed powder, and the two powders were mixed evenly to obtain a 316L-10 wt % copper mixed powder. [0073] (2) The 316L-10 wt % copper mixed powder obtained in step (1) was pressed into a green disc through cold press molding. [0074] (3) The green disc obtained in step (2) was placed into an atmosphere sintering furnace, with argon gas being a protective gas, and held at 1350 C. for 2 hours to complete the sintering process to obtain a stainless steel disc. [0075] (4) The stainless steel disc obtained in step (3) was held at 1100 C. for 1 hour and then quenched, and subsequently an aging treatment was performed at 700 C. for 6 hours to obtain an antibacterial and antiviral copper-bearing stainless steel disc of the present invention.

Example 3

[0076] This example is used to illustrate a method of preparing a stainless steel disc with a high copper content using powder metallurgy technology. The preparation method includes the following steps: [0077] (1) Based on mass parts, 20 parts chromium powder, 17 parts nickel powder, 10 parts copper, 3.5 parts molybdenum powder, 1.6 parts manganese, and 0.75 parts silicon, with the remainder being iron powder (100 parts in total), were taken and t mixed evenly. [0078] (2) The mixed powder from step (1) was mixed with 13 wt % polymer binder (the main components of which are polyformaldehyde, polyethylene and a small amount of paraffin), and a feed for metal injection molding was obtained through mixing and granulation. [0079] (3) By an injection molding machine, the feed from step (2) was injection molded into a green body of elevator buttons. [0080] (4) The green body of elevator buttons obtained in step (3) was degreased to remove the polymer binder. [0081] (5) The sample obtained in step (4) was sintered under an argon protective atmosphere, and held at 1350 C. for 2 hours to complete the sintering to obtain sintered parts of elevator button. [0082] (6) The sintered parts of elevator button obtained in step (5) was held at 1100 C. for 1 hour and then quenched, and subsequently an aging treatment was performed at 700 C. for 6 hours to obtain stainless steel elevator buttons with antibacterial and antiviral effects.

Example 4

[0083] This example is used to illustrate a method of preparing a large copper-bearing stainless steel product as described in the present invention. The preparation method includes the following steps: [0084] (1) On the basis of the composition of 304 stainless steel, a 304-10 wt % Cu pre-alloyed powder with an additional 10 wt % copper added was prepared. [0085] (2) The spacing and power of a powder rolling mill were adjusted, and the 304-10 wt % Cu pre-alloyed powder from step (1) was poured into the powder rolling mill to obtain a green body of stainless steel sheet. [0086] (3) The green body of sheet obtained in step (2) was placed into an atmosphere sintering furnace, with argon gas being a protective gas, and held at 1350 C. for 2 hours to obtain a basically densified sintered part. [0087] (4) The sintered part obtained in step (3) was subjected to a cold rolling treatment so as to completely densify the sheet. [0088] (5) The stainless steel sheet obtained in step (4) was held at 1050 C. for 30 minutes and then quenched, and subsequently an aging treatment was performed at 700 C. for 6 hours to obtain a stainless steel sheet with antibacterial and antiviral effects of the present invention.

Example 5

[0089] This example is used to illustrate a preparation method of a large copper-bearing stainless steel product as described in the present invention. The preparation method includes the following steps: [0090] (1) On the basis of the composition of 304 stainless steel, a 304-10 wt % Cu pre-alloyed powder with an additional 10 wt % copper added was prepared. [0091] (2) The 304-10 wt % Cu pre-alloyed powder from step (1) was poured into a rubber mold for bar, and the mold was placed into a cold isostatic press. The pressure was set to 180 MPa and the pressure was maintained for 5 minutes to obtain a green body of stainless steel bar. [0092] (3) The green body of bar obtained in step (2) was placed into a vacuum sintering furnace and held at 1350 C. for 2 hours to obtain a basically densified sintered part. [0093] (4) The bar sintered part obtained in step (3) was subjected to an extrusion treatment so that the sintered part was completely densified during the extrusion, and simultaneously a stainless steel bar with a corresponding size was obtained. [0094] (5) The stainless steel bar obtained in step (4) was held at 1050 C. for 30 minutes and then quenched, and subsequently an aging treatment was performed at 700 C. for 6 hours to obtain a stainless steel bar with antibacterial and antiviral effects of the present invention.

Product Characterization

[0095] FIG. 1 is an SEM image of the stainless steel containing 10 wt % copper prepared by the method of Example 2 of the present invention, in which, the white particles are the copper-rich phases in the matrix. FIG. 2 is an SEM image of the stainless steel containing 20 wt % copper prepared by the method of Example 2 of the present invention, in which the white particles are the copper-rich phases in the matrix. From FIGS. 1 and 2, it can be seen that the copper-rich phases are essentially uniformly distributed in the stainless steel matrix.

[0096] FIG. 3 is a photograph of the stainless steel discs containing 10 wt % copper prepared by the method of Example 2 of the present invention. FIG. 4 is a photograph of the elevator buttons made of the stainless steel containing 20 wt % copper prepared using the method of Example 2 of the present invention. As can be seen from FIGS. 3 and 4, the antibacterial and antiviral copper-bearing stainless steel material of the present invention has a surface which is silvery white in color and smooth and clean. In contrast, 316L stainless steel containing 10 wt % copper which was prepared using existing casting, hot forging, and hot rolling methods, caused fissures or cracks occurring on the surface of cast large stainless steel material during the hot forging or hot rolling process, and directly lead to material breakage in the severe cases. Therefore, the preparation method of the present invention has solved the copper brittleness problem.

The Antibacterial and Antiviral Performance Test

[0097] In accordance with JIS Z2801 2010 standard, E. coli was cultured on the surface of the disc obtained in Example 2 at 37 C. for 24 hours. The surface was washed with phosphate buffer solution (PBS), and the resulting bacterial solution was put and cultured on a counting plate for 24 hours. After counting, it was found that there were many bacterial colonies on an ordinary stainless steel as the control group, but almost no bacterial colonies appeared on the copper-bearing stainless steel as the experimental group. Therefore, after calculation, the antibacterial rate of this stainless steel disc can reach above 99%.

[0098] In addition, the experiments, in which a certain amount of novel coronavirus was added dropwise onto the sample surfaces and the stability and decay rate of the novel coronavirus on the surfaces of ordinary 316L stainless steel, 316L stainless steel containing 5 wt % copper, 316L stainless steel containing 10 wt % copper as obtained in Example 2 and pure copper were tested over different time periods. The experiments show that the stainless steel obtained by the present invention can effectively shorten the survival time of 2019-nCov virus on its surface. Compared with the surfaces of ordinary stainless steel and 5 wt % copper-containing stainless steel on which a large number of viruses still survived after 24 h, the number of novel coronavirus on the surface of the stainless steel obtained by the present invention had been greatly reduced after only 3 hrs, and completely inactivated after 24 hrs.

[0099] The above are only the specific embodiments of the present invention. However, the protection scope of the present invention is not limited thereto. Any stainless steel having a chemical composition falling within the scope of the present invention should fall within the protection scope of the present invention. Those skilled in the art should understood that any changes or substitutions within the technical scope as disclosed in the present invention that can be easily conceived of by those skilled in the art fall within the protection scope and the scope of disclosure of the present invention.