KR20110053998A - White-colored copper alloy with reduced nickel content - Google Patents

Abstract

The present invention relates to a white copper alloy comprising up to 30% zinc, up to 20% manganese, up to 5% nickel and residual copper. The alloy may have 6% to 25% zinc, 4% to 17% manganese, 0.1% to 3.5% nickel and the balance copper. The remaining amount of copper in the alloy is further (1) Sn, Si, Co, Ti, Cr, Fe, Mg, Zr and Ag, at least 0.5%, and (2) P, B, Ca, It may contain at least one of at least 0.1% of the group consisting of Ge, Se, and Te. The alloy may also contain up to 0.3 wt% Zr. The alloy may have an electrical conductivity greater than 2.5% IACS in an eddy current gauge that excites a frequency in the range of 60 kHz to 480 kHz.

Description

White copper alloy with reduced nickel content {WHITE-COLORED COPPER ALLOY WITH REDUCED NICKEL CONTENT}

The present invention is directed to US Provisional Application No. 61 / 095,719, filed Sep. 10, 2008, and "Reduced Nickel Content, filed September 10, 2008." US Provisional Application No. 61 / 095,733 entitled " Improved White Copper Alloy with "

Field of invention

The present invention relates to white or silver copper-based alloys having a reduced nickel content compared to standard alloys of similar color.

Copper-based alloys are widely used because of their combination of ease of manufacture, corrosion resistance, electrical and thermal conductivity, and availability in a wide range of attractive colors. It is a preferred material worldwide for use as a common coin, in many cases as part of a multilayer composite system. In addition, recent studies have shown that copper and copper alloy surfaces can be made antimicrobial (inactivating various microorganisms in less than two hours).

Copper itself is red, but the addition of most alloying elements gives it a somewhat reddish or yellowish color. Such colors are typically well known by descriptive names (brassy, golden, bronze, etc.). Alloys with white color (reflecting all light wavelengths more uniformly) are also available, but it is generally difficult to achieve good white without strong red or yellow overtones, especially after the material has discolored or partially oxidized. Whiter alloys are generally achieved by adding more nickel (cupronickel and nickel silver). Unfortunately, nickel is more expensive than most other alloying elements and appears to be a major contributor to the increased case of allergic contact dermatitis when used in contact with human skin and other tissues. It is an object of the present invention to provide a copper alloy having good whiteness using a reduced nickel content.

Alloys consisting predominantly of copper and nickel (with minor additions of other elements) are known as copper or copper-nickel. As the nickel content increases, the color changes from dynamic to light red / purple (10% Ni (C706)) to fairly pure white (25% Ni (C713)). Such white copper-nickel is widely used in US commonly used coins as a material for 5 cent coins and as an outer layer of a three layer composite for 10 cent, 25 cent and 50 cent coins. The alloy is attractive and durable but expensive due to its high Ni content (since Ni is typically more than twice that of copper). The high cost of C713 is partly due to the use of composite coins in the United States. By replacing with a less expensive copper core surrounded by silver C713, the desired appearance can be achieved at lower cost. Another alternative to the high cost of white copper-nickel is to replace some of the copper in the alloy with zinc for silver color to form an alloy known as "positive silver". Zn, although less effective than nickel as a bleach for copper alloys, reduces the need for Ni and is less dense and less expensive than Cu or Ni. Copper alloys of high (more than 20%) manganese content are also reliably white, but due to the difficulties of high temperature operation and very low electrical and thermal conductivity, they are mainly used as castings (where the copper alloys are more Advantageous with low melting point and increased flowability).

By replacing most nickel with a combination of Zn and Mn in white copper alloys, lower cost alloys are possible with similar appearance and other new properties. Other white copper-based alloys similar in surface area to the proposed alloys have been disclosed in the past, but none of them fit the composition range of the present invention as described below.

Various copper-nickel and silver silver with somewhat white color have been provided by various copper alloy manufacturers. Only two of the 41 wrought copper-nickel alloys (C71640 and C72420) listed in the Copper Development Association (CDA) database have Mn content greater than 1%, both of which are less than 1% Zn content. Only four of the 25 forging quantities listed (Cu-Zn-Ni alloy) have a minimum Mn content, and Pb is added to all of them to improve the machining properties. The copper-aluminum alloy (aluminum bronze) contains Zn or Mn but will not contain both. There are only two forged Cu—Zn-Mn alloys listed in the CDA database (C66900 and C66950), both of which contain no nickel. The first contains 0.25% maximum Fe (as impurity) and 0.20% maximum other impurities (no other additives). The latter (Wieland Alloy FX9) contains 14-15% Zn, 14-15% Mn, 1.0-1.5% Al, and the balance Cu.

Casting alloys listed in the CDA database show a similar trend: alloys containing more than 1% of both Mn and Zn also contain at least 0.5% Al. One exception to this is an alloy, also known as "Bronwite" (C99750), containing 17-23% Mn, 17-23% Zn, at least 0.5% Pb, and at most 5% Ni. Bronwite is very white, very fluid, and has a relatively low melting point, which makes it very suitable for small, thin and delicate castings (e.g., imitation jewels), but with current Restrictions on Hazardous Substances (RoHS) and consumer safety It contains enough Pb to cause regulatory problems.

Numerous nickel-free white alloys have been disclosed in the past. Willland Alloy FX9 (C66950) was mentioned above. YKK Corporation of Tokyo, Japan holds numerous patents for nickel-free alloys. U.S. Patent 5,997,663 discloses: (1) 70 to 85% Cu, 5 to 22% Zn, 7 to 15% Mn and 0 to 4% Al or Sn, or a combination of Al and Sn (white); And (2) 70 to 85% Cu, 10 to 25% Zn, 0 to 7% Mn, and 0 to 3% Al or Sn, or a combination of Al and Sn (obvious yellow). . The second Y-KK patent (US Pat. No. 6,340,446) contains 0.5 to 5% Zn, 7 to 17% Mn, 0.5 to 4% Al and the balance copper and is also one of Cr, Si, and / or Ti. The nickel-free alloy which can contain 0.3 or less of the above is disclosed. The third patent (European Patent No. 1 306 453) comprises 0.5 to 30% Zn and 1 to 7% Ti, and optionally up to 4% of a combination of one or more of Al, Sn, Mg, and / or Mn. Nickel white alloys are taught.

Another European patent (European Patent No. 0 685 564) generally contains less copper (50-70% Cu) and more Mn (8-25% Mn), and a balance of zinc than the Waikei patent. And nickel-free alloys are disclosed. Most of the nickel-free white alloys described above are intended to meet EU regulations that limit Ni in jewelry, eyewear and similar items that are "direct and prolonged contact with human skin" by completely removing Ni (allergy and Because of sensitivity-related issues), it is generally intended for use as a cast or wire product.

The alloy disclosed in US Pat. No. 6,432,556 to Brauer et al. Contains 5-10% Mn, 10-14% Zn, 3.5-4.5% Ni, less than 0.07% Al, and the balance Cu. The alloy content of US Pat. No. 6,432,556 is a substitute for the standard alloy C713 (75 Cu-25 Ni) (both in mono and clad form) for use in US distribution coins, in particular Susan B. Anthony ; SBA) Specially balanced to provide both a "gold visual appearance" and electrical conductivity suitable for use as a yellow alloy substitute for coins, and outer cladding layers in both current coins of the Sakhazawea Dollar and US President Dollar series. It is used as. Berwick's related prior art (US Pat. No. 2,445,868), assigned to Olin Inc., cited in US Pat. No. 6,432,556, has a minimum amount of 5% Ni and essentially other additives. It teaches a quaternary (quadruid) alloy of roughly Cu-Zn-Ni-Mn type without silver.

Another substantially nickel-free alloy is disclosed in US Pat. No. 3,778,237 to Shapiro et al., In particular as a substrate for silver-plated products (eg, flat cutlery or concave cutlery in the food industry). This alloy consists of 8-16% Mn, 20-31% Zn and the balance Cu, and a small amount of other elements (Al, Fe, Sn, Si, Co, Mg, Mo, Ni, P, As, Sb) Is added. Nickel is allowed up to 0.3%, but preferably Ni is not added. Goldman et al. US Pat. No. 3,778,236 is a patent on alloys containing 0.5 to 5% Ni, limited as a substrate for silver-plated products. Other nickel-free Cu-Mn-Zn alloys are disclosed in Reichenecker, U.S. Patent No. 2,772,962 (molded electro-resistive alloy) and U.S. Patent No. 2,479,596, such as Anderson and Jillson. have.

U.S. Pat. do.

It is an object of at least one embodiment of the present invention to provide a copper based alloy having a reduced nickel content compared to a conventional copper alloy having a white or silver appearance, and a similar appearance. Another object of at least one embodiment of the present invention is that the alloy of the present invention exhibit at least the same discoloration resistance as other copper alloys of similar color. Another object of at least one embodiment of the invention is that the alloy of the invention (when repeatedly in contact with human skin) exhibits at least the same color resistance as other copper alloys of similar color. Another object of at least one embodiment of the present invention is that the alloy of the present invention exhibits electrical conductivity substantially similar to that of stainless steel or similar to the alloy currently used in circulation coins. Another object of at least one embodiment of the present invention is that the bacteria exposed on the uncoated surface of the alloy of the present invention exhibit an inactivation rate equal to or better than the data published for copper-based alloys of similar color. The alloys of the present invention exhibit antimicrobial activity to such an extent that they exhibit significantly better deactivation rates compared to similarly colored stainless steels.

The above objects, features and advantages will become more apparent from the following specification and the accompanying drawings.

(1) A feature of at least one embodiment of the present invention is that the claimed copper-based alloy has a white or silver appearance suitable for the manufacture of various types of decorative products, in particular (but not limited to) hardware of builders and builders. . It can also be used in monolithic form or as part of a complex system with other materials, wherein the discoloration resistance, antimicrobial and other properties of the alloys of the present invention are characterized by the new material system having properties specifically tailored to the particular application. Enable manufacturing.

(2) Another feature of at least one embodiment of the present invention is that the alloy contains both zinc and manganese and contains reduced levels of nickel as compared to conventional white copper-based alloys.

(3) Another feature of at least one embodiment of the present invention is that iron may be used in place of or in addition to nickel for improved color and discoloration and color resistance compared to nickel or iron free alloys. Is there.

(4) Another feature of at least one embodiment of the present invention is that the alloy has a white visual appearance and has electrical conductivity similar to that of CDA alloy C713 used in US commonly used coins.

(5) Another feature of at least one embodiment of the present invention is that the alloy has a similar appearance to stainless steel and also exhibits the same electrical conductivity as stainless steel.

An advantage of at least one embodiment of the present invention is that the white copper-based alloy of the present invention has antimicrobial properties. The rate of inactivation of bacteria lying on the surface composed of the alloy of at least one embodiment of the invention is superior to other copper-based alloys of similar color, and also in commercial two-component alloys of copper and the components of the proposed alloys. It is better than can be expected from the speed found.

According to the invention, a white copper alloy is provided comprising up to 30% zinc, up to 20% manganese, up to 5% nickel and the balance copper. The alloy more preferably contains 6% to 25% zinc, 4% to 17% manganese, 0.1% to 3.5% nickel and the balance copper. The remaining amount of copper in the alloy is further (1) Sn, Si, Co, Ti, Cr, Fe, Mg, Zr and Ag, at least 0.5%, and (2) P, B, Ca, It may contain at least one of at least 0.1% of the group consisting of Ge, Se, and Te. The alloy preferably contains 12% to 20% Zn, 10% to 17% Mn, and 0.5% to 3.5% Ni. It more preferably contains 13% to 16% Zn, 14% to 17% Mn, and 1.5% to 2.5% Ni. It may also contain up to 0.3 wt% Zr.

According to the present invention there is also provided a white copper alloy comprising up to 30% by weight of zinc, up to 20% by weight of manganese, up to 4% by weight of iron and a balance of copper. The alloy more preferably contains 6% to 25% zinc, 4% to 17% manganese, 0.1% to 2.5% iron and the balance copper. The remaining amount of copper in the alloy is further (1) Sn, Si, Co, Ti, Cr, Ni, Mg, Zr and Ag of at least 0.5%, and (2) P, B, Ca It may contain at least one of at least 0.1% of the group consisting of, Ge, Se and Te. The alloy preferably contains only Ni as an impurity (ie less than about 0.1%) and consists of 12% to 20% Zn, 10% to 17% Mn, and 0.5% to 2.5% Fe. It more preferably contains 15% to 18% Zn, 14% to 17% Mn, and 0.5% to 1.5% Fe.

According to the present invention, there is also provided a white copper alloy comprising up to 30% zinc, up to 20% manganese, up to 6% nickel, up to 4% iron and the balance copper. The alloy more preferably contains 6% to 25% zinc, 4% to 17% manganese, 0.1% to 5% nickel, 0.05% to 2.5% iron and the balance copper. The remaining amount of copper in the alloy may further include (1) Sn, Si, Co, Ti, Cr, Mg, Zr and Ag, at least 0.5%, and (2) P, B, Ca, Ge, It may contain at least one of at least 0.1% of the group consisting of Se and Te. The alloy preferably contains 12% to 20% Zn, 10% to 17% Mn, 0.5% to 3.5% Ni, and 0.1% to 1% Fe. It more preferably contains 13% to 16% Zn, 14% to 17% Mn, 1.5% to 2.5% Ni, and 0.2% to 0.6% Fe. The alloy may further contain up to 1.0% Al.

Furthermore, according to the present invention, it comprises 30 wt% or less zinc, 20 wt% or less manganese, 10 wt% or less nickel, 4% or less iron, 1% or less Zr, and the balance copper, from 60 kHz to A white copper alloy is provided with an electrical conductivity above 2.5% IACS in an eddy current gauge that excites a frequency in the 480 kHz range. The alloy more preferably contains 6% to 25% zinc, 4% to 17% manganese, 0.1% to 9% nickel, up to 2.5% iron, up to 0.5% Zr and residual copper. The remaining amount of copper in the alloy is further (1) Sn, Si, Co, Ti, Cr, Mg, and Ag, at least 0.5% or less of the group consisting of, and (2) P, B, Ca, Ge, Se And at least one of 0.1% or less of the group consisting of Te. The alloy preferably contains 10% to 18% Zn, 4% to 7% Mn, 4% to 9% Ni, and 0.05% to 0.2% Zr. It more preferably contains 12% to 16% Zn, 4% to 6% Mn, 5% to 9% Ni, and 0.05% to 0.15% Zr, these combinations of 4% IACS to 7% IACS Has electrical conductivity.

1 graphically depicts CIELAB color chart characteristics for lightness, hue and chromaticity as known in the prior art.
FIG. 2 shows the inventive alloys and comparative alloys plotted on a two-dimensional CIELAB color chart illustrating the desired color range.
Figure 3 shows the same data as Figure 2, but focuses on the desired "white visual appearance" range.
4 shows the antibacterial effect of the alloy of the present invention.

Justice

For the purposes of the appended claims, the following definitions may apply.

All compositions are given in weight percent. Compositions listed as Cu-18Zn-17Ni will refer to nominal 18% by weight Zn, 17% by weight Ni and the balance of copper and inevitable impurities. Other compositions listed in similar form may be understood similarly to this example.

A “copper based alloy” herein is defined as an alloy having at least 50 wt.% Cu and one or more elemental components, or a multicomponent alloy with a percentage of Cu greater than any other component.

As used herein, “white visual appearance” refers to a CIE 1976 L ^* a ^* b ^* (CIELAB) scale (when measured with a spectrophotometer in the form of d / 8 sphere (including specular reflection) using D65 illumination and 10 ° observer). Will be defined to satisfy -2 <a ^* <3 and -2 <b ^* <10 in the phase.

As used herein, "effectively antimicrobial" may be defined as 99.9% of bacteria in suspension placed on an uncoated surface are inactivated within 120 minutes of exposure.

“Time to complete inactivation” herein can be defined as the time from when bacteria are placed on a surface until 99.9% of the bacteria are inactivated.

As used herein, "chromic resistance" refers to the color change ΔE _CMC (ASTM D2244-07, 2 to 3) between the initial color and the final color after 30 days exposure in air at 20-25 ° C. without contact with human skin or body fluids. May be defined as less than one).

"Temperature resistance to temperature increase" is defined herein as the color change ΔE _CMC (as defined in ASTM D2244-07, pages 2 to 3) between the initial color and the final color after 24 hours of exposure to 150 ° C. air. Can be.

Determining the color (of alloy or other material) can be performed by spectroscopy or other objective means. Equipment such as X-Rite, Inc. (Grand Rapids, Mich.) Or Hunter Associates Laboratory, Inc. (Levi, VA, USA) The equipment provided by Stone Material quantifies the color according to two chromatic attributes of "hue" and "chromatic", and brightness characteristics known as "value". "Hue" is color perception (recognizes the color of an object as red, green, yellow, blue, etc.). "Chroma" is the color depth (intensity or saturation) in the gray to pure hue range. A "value" is a measure of the brightness of a color tone, ranging from pure white to pure black. The combination of these values gives a specific position in the color space of the polar coordinate system, in which the hue represents the color tone (angular position), the chromaticity represents the intensity (radial position), and the value represents the brightness (vertical) Direction position).

An alternative way of specifying the color is by CIELAB scale. CIE stands for International Commission on Illumination, and LAB stands for L ^* , a ^*, and b ^* coordinates of the scale. Thus, CIELAB is an abbreviation for CIE 1976 L ^* a ^* b ^* color scale. On this scale, hue is expressed in terms of color pairs, where + a ^* is red, -a ^* is green, + b ^* is yellow, and -b ^* is blue. Chromaticity (intensity or saturation) is expressed as a value from the center of the coordinate system for the total intensity of the color components at ± 60 (0 is gray). Higher values of any component mean darker colors, and lower values mean that the substance being measured is close to colorless. Brightness values L ^{* range} from 0 (pure black) to 100 (pure white). Again, certain combinations of L ^* , a ^*, and b ^* values represent particular locations, specific colors, saturation, and brightness in the color space.

Colors of all alloys were analyzed using SP-62 spectrophotometer manufactured by X-Light Inc. (Grand Rapids, Mich.). Analysis conditions were in the form of d / 8 spheres using D65 illumination and 10 ° observer. All color measurements were reported on a CIE 1976 L ^* a ^* b ^* (CIELAB) scale. For initial color measurements, samples with the same surface finish [6-18 Ra (measure of surface roughness)] were prepared and washed to effect surface oxides (which affect both initial color measurements and subsequent analysis of atmospheric discoloration resistance). ) Can be removed. The chemical components and colors of the alloys according to the invention are presented in Table 1 below with data of comparative copper alloys and selected stainless steels. Alloys according to the invention are listed in the table below as I1, I2, I3 and the like. Comparative copper alloys are listed as C1, C2, C3 and the like. Comparative alloys not based on copper (carbon steel and stainless steel, zinc and aluminum alloys, pure metals other than copper, etc.) are listed as S1, S2, S3, and the like.

TABLE 1

Chemical composition and original (intrinsic metal) color

One of the difficulties in producing a "white" copper-based alloy is to determine exactly what "white" means. Many early uses of these alloys have been low cost alloys for coins, flat tableware and concave tableware, so the desired color was similar to the color of silver for sterling and coinage. More recently, "white" copper alloys have been considered as replacements for stainless steel or brushed nickel finishes for builders' hardware and construction applications, to enable the antimicrobial properties of copper alloys with a similar appearance to the modern appearance of stainless steels. . Many conventional "white" copper alloys have been analyzed for color along with other alloys that exhibit a slightly but clearly reddish or yellowish color overtone. In addition, stainless and carbon steels were analyzed with pure nickel, zinc and tin (eg, which can be found on the surface of white plated products). By comparing these materials, the practical limits on CIELAB values of white alloys were determined. Substances with measurements of both a ^* and b ^* close to zero appear almost colorless, and therefore whiter than materials with higher values of a ^* or b ^* at the same total brightness (L ^* ) values. . Brightness values (L ^* ) of copper alloys typically range from 75 to 86 for oxide free surfaces having surface roughnesses of 6 to 18 Ra, which are light yellow cartridge brasses (alloy C2, Cu-30Zn) to red This is true for all copper alloys ranging from pure copper (alloy C1) to very white copper-nickel (alloy C5) used in US circulation coins.

In order to determine the desired white color, the upper limit of a ^* is defined herein as the point at which the visual appearance of the copper alloy is no longer mainly white but is initially white with a clear red tint. This white to red transition is defined by the a ^* value of alloy C31 (Cu-15Ni). Alloy 31 has an a ^* value of 2.9. Commercially available copper alloys (alloy C4, Cu-10Ni-1Fe) for comparison have a significant red color and have an a ^* value of 3.7. For the purposes of the present invention, it is appropriate to consider alloys having an a ^* value of less than 3 and a b ^* value (on CIELAB scale) suitable to be white.

For copper alloys with a white visual appearance, the upper limit of b ^* is defined as the point at which the copper alloy is no longer predominantly white but is initially yellow (or white with a yellow tint). This conversion from white to yellow is defined by the b ^* value of comparative alloy C3 (Cu-12Zn-7Mn-4Ni). This is a patented alloy with a “gold visual appearance” (as discussed in US Pat. No. 6,432,556 Bl to Brow et al.) And exhibits a color that is closer to 18K gold than the white of alloy C5, particularly used in US commonly used coins. It is formulated so that The alloy has a measured b ^* value of 10.2. 10 is set to an upper limit of b ^* so that only alloys that are less yellow than alloy C3 are acceptable.

The lower limits of a ^* and b ^* are set based on the color of pure zinc (alloy C35, a ^* −1.7, b ^* −1.9). Pure zinc is subjectively white, but faintly blue and green overtones are observed on freshly cleaned and prepared surfaces. Therefore, to include zinc in the white alloy zone, the lower limits of both a ^* and b ^* are set to −2. The copper alloys measured in this study all have CIELAB values of a ^* > -1.5 and b ^* > 1.5.

In order to be considered white, the copper alloy must satisfy the restrictions listed above for both a ^* and b ^* , ie a ^* is preferably from about −2 to about +3, and b ^* is preferred. Preferably from about −2 to about +10. More preferably, a ^* is about −2 to about +2, while b ^* is about −2 to about +8. Most preferably, a ^* is about −2 to about +1, while b ^* is about −2 to about +7. Alloys that satisfy one of these but not both are not considered white. For example, alloy C2 (Cu-30Zn) has CIELAB a ^* , b ^* values of (−1.5, 21.5). This falls within the a ^* range of white (slightly red), but exceeds the maximum allowable b ^* considered white, so alloy C2 is a yellow copper alloy. A further example is alloy C4 (Cu-10Ni-1Fe) with CIELAB a ^* , b ^* values of (3.7, 8.2). Its b ^* value falls within the white range (slightly yellow), but it exceeds the acceptable a ^* value and is therefore visually red. Moreover, although end values within the ranges discussed above or ranges having these end values are not specifically disclosed, ranges having such end values are also contemplated. For example, the range of a ^* values can range from -1.9, -1.8, -1.7, and the like to +2.7, +2.8, and +2.9, and the upper limit is from +2.9, +2.8, +2.7, and the like. 1.7, -1.8, and -1.9. Similar end values for the b ^* values are also considered. It is also contemplated to combine any range for a ^* and any range for b ^* . For example, the range of a ^* values can range from -2 to +2, and the range of b ^* values can range from -2 to about +10.

The present invention includes alloys having up to 30 weight percent zinc, up to 20 weight percent manganese, up to 5 weight percent nickel and the balance copper. The alloy more preferably contains 6% to 25% zinc, 4% to 17% manganese, 0.1% to 3.5% nickel and the balance copper. Remaining copper in the alloy is further (1) Sn, Si, Co, Ti, Cr, Fe, Mg, Zr and Ag at least one 0.5% or less; And (2) at least one of 0.1% or less of one or more of the group consisting of P, B, Ca, Ge, Se, and Te. The alloy preferably contains 12% to 20% Zn, 10% to 17% Mn, and 0.5% to 3.5% Ni. It more preferably contains 13% to 16% Zn, 14% to 17% Mn, and 1.5% to 2.5% Ni. The alloy may also contain up to 0.3 wt.% Zn. In the most preferred embodiment, the alloy of this composition is also a white copper-based alloy, ie it is CIELAB wherein a ^* is preferably from about −2 to about +3 and b ^* is preferably from about −2 to about +10 Has a value. More preferably, a ^* is about -2 to about +2, while b ^* is about -2 to about +8. Most preferably, a ^* is about −2 to about +1, while b ^* is about −2 to about +7. It is contemplated that the compositions discussed above may be combined with each range of CIELAB values discussed above.

The present invention includes alloys having up to 30 weight percent zinc, up to 20 weight percent manganese, up to 4 weight percent iron and the balance copper. The alloy more preferably contains 6% to 25% zinc, 4% to 17% manganese, 0.1% to 2.5% iron and the balance copper. The remaining amount of copper in the alloy may further include (1) at least 0.5% of at least one of the group consisting of Sn, Si, Co, Ti, Cr, Ni, Mg, Zr and Ag; And (2) at least one of 0.1% or less of one or more of the group consisting of P, B, Ca, Ge, Se, and Te. The alloy preferably contains only Ni as an impurity (ie less than about 0.1%) and has 12% to 20% Zn, 10% to 17% Mn, and 0.5% to 2.5% Fe. The alloy more preferably contains 15% to 18% Zn, 14% to 17% Mn, and 0.5% to 1.5% Fe. In the most preferred embodiment, the alloy of this composition is also a white copper-based alloy, ie it is CIELAB wherein a ^* is preferably from about −2 to about +3 and b ^* is preferably from about −2 to about +10 Has a value. More preferably, a ^* is about -2 to about +2, while b ^* is about -2 to about +8. Most preferably, a ^* is about −2 to about +1, while b ^* is about −2 to about +7. It is contemplated that the compositions discussed above may be combined with each range of CIELAB values discussed above.

The present invention includes alloys having up to 30 weight percent zinc, up to 20 weight percent manganese, up to 6 weight percent nickel, up to 4 weight percent iron and the balance copper. The alloy more preferably contains 6% to 25% zinc, 4% to 17% manganese, 0.1% to 5% nickel, 0.05% to 2.5% iron and the balance copper. The remaining amount of copper in the alloy is further (1) Sn, Si, Co, Ti, Cr, Mg, Zr and Ag, at least 0.5% or less of the group consisting of; And (2) at least one of 0.1% or less of one or more of the group consisting of P, B, Ca, Ge, Se, and Te. The alloy preferably contains 12% to 20% Zn, 10% to 17% Mn, 0.5% to 3.5% Ni, and 0.1% to 1% Fe. The alloy more preferably contains 13% to 16% Zn, 14% to 17% Mn, 1.5% to 2.5% Ni, and 0.2% to 0.6% Fe. The alloy may further contain up to 1.0% Al. In the most preferred embodiment, the alloy of this composition is also a white copper-based alloy, ie it is CIELAB wherein a ^* is preferably from about −2 to about +3 and b ^* is preferably from about −2 to about +10 Has a value. More preferably, a ^* is about -2 to about +2, while b ^* is about -2 to about +8. Most preferably, a ^* is about −2 to about +1, while b ^* is about −2 to about +7. It is contemplated that the compositions discussed above may be combined with each range of CIELAB values discussed above.

In another embodiment of the invention, the alloy has an electrical conductivity of greater than 2.5% IACS in an eddy current gauge that excites a frequency in the range of 60 kHz to 480 kHz, 30 wt% or less zinc, 20 wt% or less Manganese, up to 10 wt% nickel, up to 4 wt% iron, up to 1 wt% Zr, and an alloy with a balance of copper. The alloy more preferably has 6% to 25% zinc, 4% to 17% manganese, 0.1% to 9% nickel, up to 2.5% iron, up to 0.5% Zr and residual copper. The balance of copper in the alloy is further (1) at least 0.5% of at least one of the group consisting of Sn, Si, Co, Ti, Cr, Mg, and Ag; And (2) at least one of 0.1% or less of one or more of the group consisting of P, B, Ca, Ge, Se, and Te. The alloy preferably contains 10% to 18% Zn, 4% to 7% Mn, 4% to 9% Ni, and 0.05% to 0.2% Zr. The alloy preferably contains 12% to 16% Zn, 4% to 6% Mn, 5% to 9% Ni, and 0.05% to 0.15% Zr. In a more preferred embodiment, each of the compositions discussed above also has an electrical conductivity of 4% IACS to 7% IACS. In the most preferred embodiment, the alloy of this composition is also a white copper-based alloy, ie it is CIELAB wherein a ^* is preferably from about −2 to about +3 and b ^* is preferably from about −2 to about +10 Has a value. More preferably, a ^* is about -2 to about +2, while b ^* is about -2 to about +8. Most preferably, a ^* is about −2 to about +1, while b ^* is about −2 to about +7. It is contemplated that the compositions discussed above may be combined with each range of CIELAB values discussed above.

Some specific examples of compositions under consideration include:

(1) 6 to 25% zinc, 4 to 17% manganese, 0.1 to 3.5% nickel and the balance Cu;

(2) Same as above item (1), but at least 0.5% or less of Sn, Si, Co, Ti, Cr, Fe, Mg, Zr and Ag, and 0.1% of P, B, Ca, Ge, Se or Te Below;

(3) the same as the above (1) or (2), except for 0.1 to 2.5% iron;

(4) as in (1) or (2) above, wherein 0.1 to 5% nickel and 0.05 to 2.5% iron;

(5) 12-20% Zn, 10-17% Mn, and 0.5-3.5% Ni and the balance Cu;

(6) 13-16% Zn, 14-17% Mn, and 1.5-2.5% Ni and the balance Cu;

(7) Zr same as above (1) but with 0.3% or less Zr;

(8) 12-20% Zn, 10-17% Mn, and 0.5-2.5% Fe and the balance Cu;

(9) 15-18% Zn, 14-17% Mn, and 0.5-1.5% Fe and the balance Cu;

(10) 13-16% Zn, 14-17% Mn, 1.5-2.5% Ni and 0.2-0.6% Fe and balance Cu;

(11) 6-25% zinc, 4-17% manganese, 0.1-9.0% nickel and the balance Cu;

(12) Zr equivalent to item (11) above but less than or equal to 0.3%;

(13) 10-18% Zn, 4-7% Mn, 4-9% Ni, 0.05-0.20% Zr and balance Cu;

(14) 12-16% Zn, 4-6% Mn, 5-9% Ni, 0.05-0.15% Zr and balance Cu.

All of these examples can be combined with any combination of a ^* and b ^* values and any range of electrical conductivity.

For all components in the composition, end values within the ranges discussed above or ranges having these end values are not specifically disclosed, but ranges having such end values are also contemplated. For example, the range of values for Zn can have lower end values of 6.1%, 6.2%, 6.3%, etc., to 24.7%, 24.8%, and 24.9%, and upper end values of 24.9%, 24.8%, 24.7%, and the like. 6.3%, 6.2% and 6.1%. Similar end values for the range of other components are also considered. It is also contemplated to combine any range specifically disclosed for Zn with any range specifically disclosed for the other components. For example, 6% to 25% zinc can be combined with a range of 10% to 17% Mn, and 0.5% to 3.5% Ni.

A feature of the present invention is an alloy which contains both Zn and Mn and contains lower levels of Ni as compared to conventional "white" copper-based alloys. This is due to the synergistic effect of the alloying elements, where the combination of multiple components gives results that cannot be obtained in a simple two-component alloy.

Nickel is a powerful bleach of copper alloys. The addition of 10% of Ni to Cu (alloy C4) gives a light alloy that still has a reddish purple tinting. Adding 15% or more of Ni to Cu (alloy C31) gives a clear white color, and increasing Ni content to 30% (alloy C6) makes the alloy more colorless. Increased Ni contributes to atmospheric discoloration resistance, inhibiting the formation of black copper oxide. Unfortunately, Ni is also considerably more expensive than Cu (generally two to three times the cost), so it is economically advantageous to produce alloys that are similar in appearance but low in Ni. In addition, the addition of more Ni reduces the antimicrobial effect of the alloy, and therefore Ni must be maintained to match the desired color and discoloration resistance. Nickel is used in jewelry, eyewear and similar items in which the European Union is in "direct and prolonged contact with human skin" {Ammannati, European Patent No. 0 635 564 B1 [Title "Manufacturing direct and prolonged contact products. Copper-zinc-manganese alloys, "metal-contact dermatitis, which led to the enactment of the nickel-free alloy law for".

Manganese is also an effective bleaching agent of copper alloys, but bicomponent alloys are of little commercial importance due to their low strength, difficulty in ingot casting and hot rolling, and low and inconsistent ductility with respect to short range configuration. Adding 12% or more of Mn to Cu can provide a relatively white alloy (alloy C30, [a ^* , b ^* ] = [5.05, 8.27]), but this is where the short-range alignment becomes important in bicomponent alloys. to be. Manganese is typically used at low levels for reinforcement in more complex copper alloys containing Al, Zn, Si, Ni or combinations thereof. In addition, the addition of Mn at such a low level can improve the casting and hot rolling properties of the alloy.

When Zn is added to the copper alloy, the color changes significantly, but this alloy cannot be "white" or colorless. Instead, when the content of Zn increases by about 30%, the Cu—Zn alloy (“brass”) becomes gold to yellow. When Zn exceeds 33%, the alloy becomes red again, forming a new crystal structure. In addition, high-Zn brass exhibits a short range arrangement under certain conditions, which limits ductility and causes property changes in service. Zn may reduce the need for Ni in bleaching copper-based alloys (based on “positive silver” Cu—Ni—Zn alloys). Its appearance is close to a white Cu—Ni alloy and has a slightly mixed yellow due to the Zn content.

The addition of iron to the copper alloy is limited due to its low solubility. There is more than 3.5% miscibility gap of Fe, which prevents the casting of high-Fe alloys. 0.5% to 2.5% of Fe can be retained in solid solution by suitable heat treatment, which is an effective bleach almost equal to Ni at the same level. Fe may also be a strong reinforcing agent and may form precipitates either directly or by reaction with P (phosphorus) in the alloy.

Zinc and aluminum are similar in color to copper alloys, but Al is considerably more effective in achieving gold-yellow color. Adding 6% Al (alloy C32) gives a color similar to Cu-15Zn (alloy C29). Over time, Cu-Al alloys (including alloys with other elements such as Zn, Mn, and Fe) form hard oxide passivation films that are beneficial for discoloration and corrosion resistance. This effect also reduces the antimicrobial effect of the alloy of Cu and Al, so Al must be kept to a minimum for antimicrobial applications. Hot and cold rolling and heat treatment of Al-containing alloys are more complicated than alloys without Al due to their interaction with many other alloying elements.

One of the main objectives of the present invention is to provide a copper alloy with a white visual appearance but with a reduced Ni content. The above description regarding the effect of alloy addition on the color of the copper-based alloy suggests a method of achieving this object. By replacing a portion of Ni with Zn, an alloy with a reduced Ni content can be produced, but its color tends to be yellower compared to Cu-Ni alloys having the same total Cu content. By further replacing some of the remaining Ni with Mn, an alloy with a much lower Ni content while having a substantially white (colorless) appearance is possible. Having a low level of Ni (particularly in the total alloy content) has advantages in helping to maintain the desired white color and also in reducing atmospheric discoloration and coloration due to contact with body fluids from human skin. It was found to have. Thus, copper alloys with a white visual appearance are found by replacing Ni with a combination of Zn and Mn in conventional alloys while maintaining Ni at low levels for improved color and discoloration resistance.

Another feature of the invention is that Fe can be used in place of or in combination with Ni to improve the whitening of the Cu—Zn—Mn alloy. When measuring the color of commercially available Cu—Ni alloys, the whitening of some of these alloys was found to be better than expected from the Ni content alone. The alloys of the present invention have been found to contain significant amounts of Fe added to improve the hot and cold working properties of such alloys. In addition, in the investigation of Cu-Fe alloys, these alloys are still clearly red due to the low total alloy content, but are closer to white (lower on the CIELAB scale than expected for Cu-Zn or Cu-Mn of the same alloy content). a ^* value). On this basis, the inventors have found that up to 2.5% Fe has been added to the alloy of the present invention, which results in improved whitening even up to a total alloy content of more than 30%. It has also been found that the presence of Ni does not interfere with the effect of Fe, either or both of which may be used to improve the whitening of the Cu—Zn—Mn alloy. In addition, the presence of Fe in the solid solution of the alloy (with a certain total alloy content) is advantageous in helping to maintain the desired white color and also in reducing atmospheric discoloration and coloration due to contact with body fluids from human skin. It was found to have (similar to the effect of low levels of Ni on these properties). This effect is also found when Fe or a combination of Fe and Ni is used instead of Ni alone. Thus, copper alloys with a white visual appearance maintain a low level of Ni, Fe, or a combination of Ni and Fe while maintaining a low level of Ni, Fe, or a combination of Ni and Zn, and a combination of Zn and Mn for improved color and discoloration resistance. Is replaced by

An important factor in selecting a copper-based alloy for appearance (eg, hardware of a building or builder) is the stability of the appearance over time. Stainless steel does not change much in appearance when exposed to the atmosphere, because an oxide passivation film is formed that prevents visible discoloration and corrosion and is therefore considered "stainless". Unfortunately, stainless steel is not available for the wide range of colors and tones that can be achieved with copper-based alloys, and stainless steel does not have the antibacterial properties of properly manufactured copper alloys. Traditionally, Ni is added to the copper alloy for improved atmospheric discoloration resistance because Ni forms an oxide passivation layer on the surface of the alloy similarly in terms of the passivation surface of stainless steel. It has been found possible to adjust the chemical composition of white copper alloys with a reduced Ni content in order to provide an alloy with a preferred white appearance, and atmospheric resistance that is substantially the same as conventional high-Ni white copper base alloys.

Discoloration of a copper alloy is a result of the formation of an oxide film with time by reaction with oxygen from the atmosphere. This generally appears as darkening of the surface, but the different colors (and interfacial-layer effects) of the oxides formed from the base material also lead to differences in hue and chromaticity compared to the original appearance of the material. By comparing the colors before and after exposure, the size of the discoloration can be quantified and an objective comparison can be made between different alloys.

The color difference between samples with measured CIELAB values is easily calculated, and the relationship between the various color differences and color-tolerance can be calculated from the color coordinates measured with the ASTM standard D2244-07 ^ε1 ["machine. And standard practice for calculating color differences "; ASTM International; May 1, 2007]. The total color change ΔE ^* _ab between the two colors represented by L ^* , a ^* , b ^* , respectively, can be calculated by the following equation.

ΔE ^* _ab provides the magnitude of the color difference, but not the nature of the difference, since the value does not indicate the relative magnitude and direction of the hue, chromaticity and lightness difference ( ASTM standard D2244-07 ^ε1 , see Section 6.2.2). This is usually useful when the color change prevails in one of the three factors and the nature of this color change is easily understood, but less useful when two or three factors contribute significantly to the measured color change. It is also possible to convert L ^* , a ^* , b ^* Cartesian coordinates into L ^* , C ^* , H ^* cylindrical coordinate systems to better understand the relative differences between brightness L ^* , chromaticity C ^*, and hue H ^* . . Therefore, the corresponding total color difference equation is as follows.

An alternative, calculated color difference ΔE _CMC (as defined by the Color Measurement Committee (CMC) of the British Dyeing and Colorist Association) is a single-number shade-passing It is intended to be used as a shade-passing equation (also defined in ASTM standard D2244-07 ^ε1 ). It was developed as a tolerancing system based on the CIELCH cylindrical coordinate system and defines an ellipsoid around a standard color (specific point in color space) where the difference from the standard value falls within the limits suitable for the intended use. The color difference ΔE _CMC is given by the following formula.

The variables in the above equations account for the differences in spectral sensitivity and the relative importance of lightness versus chromaticity and hue, and thus better agreement between the actual range and numerical tolerance of visually acceptable colors for human detection. This exists. In particular, the commercial factor cf may vary to suit the desired range for a given use. ΔE _CMC = 1 is believed to represent only a detectable color difference.

To compare resistance to color change due to atmospheric exposure, ΔE _CMC was calculated based on the actual color change between samples before and after exposure (time = 0) at a given time and temperature. Smaller E _CMC The value (smaller color change due to exposure) is considered a measure of good atmospheric discoloration resistance.

TABLE 2

The color change due to discoloration in the atmosphere is shown in Table 2 above. After 30 days at room temperature, a number of nickel-free comparative alloys (alloys C11 to C24) showed ΔE _CMC > 1. Nickel-containing comparative alloys C3 to C8 (with more than 4% Ni content) all showed less color change, ΔE _CMC <1. The alloys of the invention (alloys I1 to I9) also exhibited ΔE _CMC <1, even with Ni less than 3.5%. Comparing alloys C16 and I8, the addition of 1% Fe (to the balanced color Cu-Zn-Mn alloy) is expected to reduce discoloration resistance, but the visual appearance is expected to move closer to colorless. . Similarly, comparing alloys I7 and C16, as can be appreciated, it is expected that addition of 3% Ni will also provide a whiter alloy and significantly improve discoloration resistance. If both Ni and Fe are added (alloy I9), the color and discoloration benefits of these two elements are expected to appear independently and not interfere with each other.

[Table 3]

In order to simulate longer periods of exposure for the purpose of oxidation or corrosion studies, elevated temperatures are often used. It is important to select temperature-time conditions with the same properties of oxides or corrosion products under the conditions to be simulated. For example, at moderately elevated temperatures in the air (above 200 ° C.), it is desirable to form black CuO directly on red Cu ₂ O (hereafter converted to CuO), which is a component of all three elements (hue, color and brightness). In terms of color, it affects the nature of color change during atmospheric discoloration. This exposure also shows how the material will react when used at moderately elevated temperatures (eg, panels on kitchen appliances) or when subjected to an automatic dishwashing or autoclave sterilization cycle.

The color change due to elevated ambient exposure is presented in Table 3 above. Alloy samples (also called coupons) were washed and prepared in the same procedure as other color samples, and CIELAB color was measured prior to exposure. After exposure the color was reevaluated and ΔE _CMC was calculated. After furnace treatment at 150 ° C. for 7 or 24 hours, the alloys of the present invention (alloys I2 to I9) are less than or equal to any of the comparative copper alloys (alloys C3 to C26) listed in Table 3. Color change was shown. Preferred embodiments of the invention (alloys I7 to I9) exhibited the smallest color change among any of the copper alloys listed. Of particular interest is a comparison between alloy C16 and the above preferred embodiments. Alloy C16 is essentially the same as the above embodiment, but without Ni or Fe, after 24 hours at 150 ° C., the color change ΔE _CMC is 15.6. For the same alloy with 1% Fe (alloy I8), ΔE _CMC is 11.9, which illustrates that addition of Fe not only improves whitening of the alloy but also increases discoloration resistance. This is true (or even more so) for alloys I7 and I9 (ΔE _CMC is 9.1 to 9.9) and when Ni (or Ni and Fe) is added to the basic Cu-Zn-Mn alloy, Whitening also improves sharply.

Contact surfaces (handrails, door hardware, countertops, appliance panels, hospital equipment, etc.) are part of their function and repeatedly contact with films of water, sweat, sebum, and other body fluids. Such body fluids contain a complex mixture of components, many of which are significantly corrosive to copper and copper alloys. Evaluating how the appearance of these alloys changes after repeated contact with human skin is important not only in selecting these alloys for contact surface use, but also in determining the frequency of cleaning needed to maintain their appearance. Do. From a functional point of view, for stainless steel and similar hospital surfaces, cleaning and sterilization cycles ranging from once a week to several times daily are recommended to minimize cross-infection in healthcare situations.

[Table 4]

Coupons of the alloy of interest were washed and made to the desired surface finish (6-18 Ra). Initial color was determined prior to any contact with human skin and / or body fluids. The coupons were contacted daily, color changes were determined and calculated for comparison. The results are shown in Table 4 above. After 3 days of repeated skin contact, all white alloys showed a slight difference in fouling resistance and ΔE _CMC ranged from 1.2 to 2.8. No strong association with the content of any particular alloying element or combination of elements was seen. After 7 days of repeated exposure, the differences between the alloys were even smaller, but the total color change was greater and the ΔE _CMC was 2.9 to 4.4. The alloys of the present invention, although the content of Ni and / or Fe were significantly lower than the Ni content of conventional white copper-based alloys, the alloys of the present invention are conventional in terms of resistance to color changes due to contact with human skin and / or body fluids. Not bad compared to

Many uses of copper-based alloys include electrical conductivity or resistance to such conductivity. For example, controlled electrical conductivity or resistance is used as a preferred security feature in certain combinations of color and electrical properties in the distinction between legal circulation coins or tokens and illegal "slug". It is also used to control the activity of electrical equipment (eg fuses and circuit breakers). Conductivity is mainly controlled by alloy content, and adding other alloying elements to pure copper (with 100% IACS conductivity) will reduce the conductivity to some extent. The conductivity of the comparative alloys and the alloys according to the invention is listed in Table 1.

Comparing Alloy C29 (Cu-15Zn, 37% IACS), Alloy C31 (Cu-15Ni, 9.15% IACS) and Alloy C30 (Cu-12Mn, 4.15% IACS), various alloying elements have different effects on electrical conductivity. It can be seen that. With this advantage, it is possible to design alloys with specific conductivity while maintaining a certain visual appearance. Alloy I1 has a white visual appearance and has a similar electrical conductivity (5.1% IACS) to alloy C5, but contains only 6% Ni compared to 24.5% Ni in C5, thereby saving significant costs when replacing US distribution coins. Can be provided.

An advantage of the present invention is that the white copper-based alloy of the present invention has antibacterial properties. Copper and many copper-based alloys, when properly prepared, reduce the viability of bacteria and other microorganisms exposed on the surface of the alloy. The effect of the alloy surface on inactivating bacteria is related to the chemical composition of the alloy as well as other factors such as surface roughness as set forth in International Patent Application No. PCT / US2007 / 069413. The exposure time required to inactivate 99.9% of bacteria on the surface is a useful measure of the antimicrobial properties of the alloy under consideration, and a November 2003 study sponsored by the Copper Development Association (Wilks) to compare with published values. Test trains based on

Coupons of the alloy of interest (about 22 mm square) were prepared and sterilized prior to exposure. The prepared coupons were placed on sterile filter paper in Petri dishes. Aliquots of 5-20 μL of active bacterial cultures (E. coli, American Type Culture Collection (ATCC) strain 11229, Gram-negative) in the nutrient solution were applied to the surface of the coupon, the inoculum being at least 10 Contain ⁶ to 10 ⁸ colony-forming units / milliliter (CFU / mL). After the desired exposure time, the coupon was a tube containing 20 mL of sterile Butterfield buffer (3.1 × 10 ^-4 MK ₂ HP0 _{4 in} filtered and deionized / reverse osmosis laboratory-grade water). Into, and sonicated for 5 minutes, suspending any viable bacterial colonies from the surface of the coupon. Suspensions of viable bacterial colonies were diluted serially four times (1/10, 1/100, 1/1000, and 1/10000). 20 μL aliquots of the original suspension and each dilution were plated on nutrient agar and incubated at 35-37 ° C. for 48 hours to count viable colonies. To check the baseline (number of colonies in the original inoculum exposed on the coupon), 20 μL aliquots of the original inoculum were placed directly into a tube containing 20 mL of sterile buffer without exposing it on a metal coupon. And then treated in the same manner as in the suspension of survivors from the coupon (sonically agitated, diluted, placed on agar plates and counted after incubation). Replicated coupons were exposed and the dilutions were plated twice to average normal statistical deviations in biological experiments. All dilutions were identified by counting the number of colonies present on each agar plate and counting [number of colony-forming units (CFU)] / mL and CFU number / mL from the exposed coupon in the original baseline. It was. To minimize statistical variability, only plates representing 5 to 400 colonies were used for the final calculation. The exposure time required to achieve a 99.9% reduction in bacterial counts (a decrease of 3 log ₁₀ in CFU) and the time for complete inactivation are the main measures of antimicrobial effect.

The antimicrobial test results of the alloys of the present invention tested using E. Coli are shown in Table 5 and FIG. 4. For comparison, published information (Wilks and Keevil) for commercial alloys tested using E. Coli is included in Table 5 below.

TABLE 5

Comparative alloy C32 (Cu-10Zn) showed a 99.9% decrease in bacterial counts after 90-105 minutes of exposure and showed full inactivation after 105 minutes. Alloy C4 (Cu-10Ni-1Fe) had essentially the same effect as alloy C32. Similar alloys with higher alloy content (C2 [Cu-30Zn] and C5 [Cu-25Ni-0.5Fe]) were found to be slightly less effective, showing a 99.9% reduction in 90-105 minutes and only after 120 minutes Inactivation was indicated. Alloy C8 (Cu-17Zn-18Ni) is a chemical intermediate between these alloys and exhibited slightly less intermediate antibacterial effects than C22000 alloy C32 and alloy C4. Commercial coin alloys (Y90 from Olin Brass, Comparative Alloys C3, Cu-12Zn-4Ni-7Mn) also contain Mn similarly to the alloy of the invention, but are not substantially white in the present invention. Balanced to have a "gold visual appearance". The antimicrobial effect of C3 was slightly better than the alloy without Mn, showing a 99.9% reduction at nearly 90 minutes of exposure and a full inactivation after 120 minutes. Alloy C1 (commercially pure copper) showed a 99.9% reduction in bacterial counts after 75 to 90 minutes of exposure and showed full inactivation after 90 minutes.

Based on the published results, it was expected that the antibacterial effect of the alloy of the present invention would be similar to that of Alloy C3 (Y90). Zinc was somewhat higher (helping for longer time, from comparison of Alloy C32 and Alloy C2) and nickel was slightly lower (shorter time, comparing Alloys C4 and C5). Comparing alloys C8 and C3, Mn does not appear to have a significant effect on the antimicrobial effect, but there was a more gradual and earlier decrease than the sharp decrease in bacterial counts seen in most alloys. Unexpectedly, the initial test showed a 99.9% reduction in CFU counts (40% faster than other alloys) between 45 and 60 minutes, and full inactivation after 60 minutes (40-50% faster). Subsequent tests showed a 99.9% reduction in a short time of 10 minutes or less, complete inactivity between 15 and 30 minutes, using the same preparation methods and procedures, and using the Gram-positive bacteria Staph Aureus (Staph. Similar results were obtained for the same alloys tested using Aureus (ATCC 6538). The mechanism responsible for the increased kill rate in the modified high-Mn alloy of the present application is not clear, but it appears to be related to the inhibition of the oxide passivation layer present on the alloys of Cu, Zn and Ni. .

It is clear that a copper alloy is provided in accordance with the present invention that fully satisfies the objects, features and advantages of the present invention as disclosed herein. While the present invention has been described in conjunction with specific embodiments, it will be apparent to those skilled in the art that many alternatives, modifications, and variations are apparently based on this description. Accordingly, it is intended that the present invention include many such alternatives, modifications and variations that fall within the broader spirit and scope of the appended claims, and are not limited to the specific embodiments disclosed herein.

In addition, it will be understood that the functions or structures of multiple elements or steps may be combined into one element or step, or that the functions or structures of one step or element may be separated into multiple steps or elements. The present invention contemplates all these combinations. Unless stated otherwise, the dimensions and shapes of the various structures depicted herein are not intended to limit the invention, and other dimensions or shapes are possible. Multiple structural elements or steps may be provided in a single integrated structure or step. Alternatively, a single integrated structure or step may be separated into individual elements or steps. In addition, while features of the present invention have been described in the context of only one of the illustrated embodiments, such features may be combined with one or more other features of other embodiments for any given use. It will also be understood from the above that the manufacture of the unique structures herein and the manipulation thereof also constitute the method according to the invention. The invention also encompasses intermediates and end products derived from the practice of the methods herein. In addition, the use of the term "comprising" also contemplates embodiments that are "consisting essentially of" or "consisting of" the features mentioned.

The description and examples presented herein are intended to enable those skilled in the art to become familiar with the invention, its principles, and their practical application. Those skilled in the art can modify and apply the present invention in various forms and may best suit the requirements of a particular application. Accordingly, certain embodiments of the invention as disclosed are not intended to be exhaustive or to limit the invention. Accordingly, the scope of the invention should not be determined with reference to the above-mentioned description, but rather with reference to the appended claims and the full scope of equivalents to which such claims are entitled. The disclosures of all references (including patent applications and documents) are incorporated herein by reference for all purposes.

Claims (24)

A copper alloy with a visual appearance similar to one of stainless steel and "nickel silver" and having an antibacterial effect,
(a) 6 to 25% zinc (Zn)
(b) 4 to 17% manganese (Mn),
(c) 0.1 to 3.5% nickel (Ni), and
(d) residual amount of substantial Cu
Including,
(e) A copper alloy in which the combination of (a) to (d) exhibits a white visual appearance and has an antibacterial effect. The method of claim 1,
The remaining amount of substantial Cu is further
(1) at least 0.5% of at least one of the group consisting of Sn, Si, Co, Ti, Cr, Fe, Mg, Zr and Ag; And
(2) at least 0.1% of at least one of the group consisting of P, B, Ca, Ge, Se, and Te;
Contains at least one of
And the alloy has a complete inactivation time of less than 60 minutes. A copper alloy with a visual appearance similar to one of stainless steel and "sheep silver",
(a) 6 to 25% zinc (Zn)
(b) 4 to 17% manganese (Mn),
(c) 0.1 to 2.5% iron (Fe), and
(d) residual amount of substantial Cu
Essentially consists of
(e) A copper alloy wherein the combination of (a) to (d) exhibits a white visual appearance and is effective antimicrobial. The method of claim 3, wherein
The remaining amount of substantial copper is further
(1) at least 0.5% of at least one of the group consisting of Sn, Si, Co, Ti, Cr, Ni, Mg, Zr and Ag, and
(2) at least 0.1% of at least one of the group consisting of P, B, Ca, Ge, and Se;
Copper alloy containing at least one of. A copper alloy with a white visual appearance similar to one of stainless steel and "sheep silver",
(a) 6 to 25% zinc (Zn)
(b) 4 to 17% manganese (Mn),
(c) 0.1 to 5% nickel (Ni),
(d) 0.05 to 2.5% iron (Fe), and
(e) the residual amount of substantial Cu
Essentially consists of
(f) A copper alloy in which the combination of (a) to (e) exhibits a white visual appearance and has an antibacterial effect. The method of claim 5, wherein
The copper alloy further,
(1) at least 0.5% of at least one of the group consisting of Sn, Si, Co, Ti, Cr, Mg, Zr and Ag, and
(2) at least 0.1% of at least one of the group consisting of P, B, Ca, Ge, Se, and Te;
Copper alloy containing at least one of. The method of claim 1,
Wherein the combination is discolored upon exposure to room temperature in air and has a complete inactivation time of less than 60 minutes. The method of claim 7, wherein
The copper alloy, wherein the copper alloy contains 12 to 20% Zn, 10 to 17% Mn, and 0.5 to 3.5% Ni. The method of claim 8,
And the copper alloy contains 13 to 16% Zn, 14 to 17% Mn, and 1.5 to 2.5% Ni, and the complete inactivation time is less than 20 minutes. The method of claim 1,
A copper alloy, wherein said copper alloy contains 0.3 wt% or less of Zr. The method of claim 3, wherein
A copper alloy, wherein said copper alloy is effectively antimicrobial and contains only Ni as an impurity. The method of claim 11,
Wherein said copper alloy contains 12-20% Zn, 10-17% Mn, and 0.5-2.5% Fe. The method of claim 12,
Wherein said copper alloy contains 15-18% Zn, 14-17% Mn, and 0.5-1.5% Fe. The method of claim 5, wherein
Copper alloy, wherein the copper alloy is temperature-resistant discoloration resistance. The method of claim 14,
Wherein said copper alloy contains 12-20% Zn, 10-17% Mn, 0.5-3.5% Ni and 0.1-1.0% Fe. The method of claim 15,
Wherein the copper alloy contains 13-16% Zn, 14-17% Mn, 1.5-2.5% Ni and 0.2-0.6% Fe. The method of claim 14,
The copper alloy,
(1) Al 1.0% or less; And
(2) at least one of 0.5% or less of the group consisting of (a) Sn, Si, Co, Ti, Cr, Mg, Zr, and Ag; and (b) of the group consisting of P, B, Ca, Ge, Se, and Te. At least one of one or more and 0.1% or less
Copper alloy containing at least one of. A copper alloy with a white visual appearance and contact discoloration resistance for use in coinage applications as a direct replacement for C713,
(a) 6 to 25% zinc (Zn),
(b) 4 to 17% manganese (Mn),
(c) 0.1 to 9.0% nickel (Ni), and
(d) residual amount of substantially Cu
Including,
The combination of (a) to (d) has a white visual appearance, is effectively antimicrobial, and 2.5% International Annealed Copper Standard in an eddy current gauge that excites frequencies in the range of 60 kHz to 480 kHz. Copper alloy, having an electrical conductivity greater than). The method of claim 18,
Substantially the remaining amount of Cu is further
(1) at least 0.5% of at least one of the group consisting of Sn, Si, Co, Ti, Cr, Fe, Mg, Zr and Ag, and
(2) at least 0.1% of at least one of the group consisting of P, B, Ca, Ge, Se, and Te;
Copper alloy containing at least one of. The method of claim 19,
Wherein the electrical conductivity is between 4% IACS and 7% IACS and further wherein the alloy has a full inactivation time of less than 60 minutes. The method of claim 19,
And the copper alloy contains 0.3 wt% or less of Zr and the total inactivation time is less than 30 minutes. The method of claim 21,
And the copper alloy contains 10 to 18% Zn, 4 to 7% Mn, 4 to 9% Ni, and 0.05 to 0.20% Zr, and the complete inactivation time is less than 20 minutes. The method of claim 22,
And the copper alloy contains 12 to 16% Zn, 4 to 6% Mn, 5 to 9% Ni and 0.05 to 0.15% Zr, and the complete inactivation time is less than 15 minutes. The method of claim 18,
A copper alloy, wherein the copper alloy is molded into a planchet.

Images