JP6170099B2 - White copper alloy with reduced nickel content - Google Patents

Description

  [0001] The present invention relates to US Provisional Patent Application No. 61/095719 “WHITE-COLORED COPPER ALLOY” filed September 10, 2008, and US Provisional Patent Application No. 61/09, filed September 10, 2008. No. 095733 "IMPROVED WHITE-COLORED COPPER ALLOY WITH REDUCED NICKEL CONTENT" is claimed.

  [0002] The present invention relates to white or silver copper-based alloys having a reduced nickel content compared to standard alloys of similar colors.

  [0003] Copper-based alloys are widely used because they have a combination of ease of processing, corrosion resistance, electrical and thermal conductivity, and availability in a wide range of attractive colors. They are the preferred materials around the world for circulating coinage, often as part of a multilayer composite system. In addition, recent studies have shown that copper and copper alloy surfaces can be made antibacterial to inactivate various microorganisms in less than 2 hours.

  [0004] Copper itself has a red color, but with the addition of most alloying elements, it becomes a somewhat red or yellowish color. These colors are typically well known and have descriptive names (brass, gold, bronze, etc.). Alloys with a whiter color (reflecting all light wavelengths more uniformly) are also available, but good without strong red or yellowish nuances, especially after the material is discolored or partially oxidized It is generally difficult to achieve a good white color. These whiter alloys are generally achieved using large amounts of nickel (white copper and silver). Unfortunately, nickel is more expensive than most other alloying elements, and when used in contact with human skin and other tissues, it has been implicated as a major cause of the increased case of allergic contact dermatitis. Yes. It is an object of the present invention to provide a copper alloy that has a good white color but uses a reduced nickel content.

  [0005] Alloys composed primarily of copper and nickel (with minor amounts of other elements added) are known as white copper or copper-nickel. As the nickel content increases, the color changes from copper red to light red / purple with 10% Ni (C706) to moderately pure white with 25% Ni (C713). This white copper-nickel is widely used in US circulating money as a material for 5 cent coins and as the outside of a three-layer composite for 10 cent, 25 cent and 50 cent coins. While the alloy is attractive and durable, it is expensive due to the high Ni content because the price of Ni is typically more than twice that of copper. Due to the high cost of C713, compound money is used in the United States; the desired appearance can be achieved at a lower cost by substituting a cheaper copper core surrounded by silver C713. Another alternative to the costly white copper-nickel is to replace a portion of the copper with zinc in the alloy to form an alloy known as “Western Silver” because the color is silver. Although not as effective as nickel as a copper alloy whitener, Zn reduces the need for Ni and is less dense and cheaper than either Cu or Ni. Copper alloys with high manganese content (20% or more) are certainly white, but they are difficult to hot work and have very low electrical and thermal conductivity, so they are compared to “Western silver”. Low melting point and increased fluidity have mainly been used as castings.

  [0006] By replacing most of the nickel in the white copper alloy with a combination of Zn and Mn, an alloy with a similar appearance and other novel properties and at a lower cost is possible. Other white copper-based alloys that appear to be similar to the proposed alloys have been disclosed so far, but none comparable to the composition range of the present invention as will become apparent below.

  [0007] A large number of copper-nickel and silver with a somewhat white color is provided by various copper alloy manufacturers. Of the 41 types of forged copper-nickel alloys listed in Non-Patent Document 1, there are only 2 types (C71640 and C72220) that have a Mn content of over 1%; Does not contain more Zn. Of the 25 types of forged silver silver (Cu—Zn—Ni alloys) listed, only 4 have the lowest Mn content; all of these have Pb added to improve machining properties. It has been added. A copper-aluminum alloy (aluminum bronze) contains Zn or Mn, but not both. The CDA database lists only two forged Cu-Zn-Mn alloys, but both -C66900 and C66950- do not contain nickel. The first contains up to 0.25% Fe (as impurities) and up to 0.20% other impurities, with no other additives. The second (Wieland Alloy FX9) contains 14-15% Zn, 14-15% Mn, 1.0-1.5% Al and the balance Cu.

  [0008] Cast 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. The only exception to this is the alloy known as “Bronwite” (C99750), which contains 17-23% Mn, 17-23% Zn and at least 0.5% Pb up to 5% Ni. Contains. Bronwite is very white, very fluid and has a relatively low melting temperature. Bronwite makes this suitable for small, thin, and elaborate castings, such as imitation jewelry, but causes problems related to the current Restrictions on Hazardous Substitutes (RoHS) and Consumer Product Safety regulations. Contains enough Pb.

  [0009] Many white alloys that do not have nickel have been disclosed. Wieland Alloy FX9 (C66950) has been described above. YKK Corporation in Tokyo, Japan holds many patents for alloys that do not have nickel. Patent Document 1 includes the following two ranges: 1) 70 to 85% Cu, 5 to 22% Zn, 7 to 15% Mn, and 0 to 4% Al or Sn or Al and Sn. A combination of both (having white); and 2) 70-85% Cu, 10-25% Zn, 0-7% Mn and 0-3% Al or Sn or a combination of both Al and Sn ( It has a clear yellow color). The second YKK patent (Patent Document 2) contains 0.5-5% Zn, 7-17% Mn, 0.5-4% Al and the remainder copper and has nickel. An alloy is disclosed that can contain up to 0.3% of one or more of Cr, Si and / or Ti. A third such patent (Patent Document 3) includes a white alloy with 0.5-30% Zn and 1-7% Ti and no Ni, Al, Sn, Mg and Alloys are taught that may contain up to 4% of one or more combinations of Mn.

  [0010] Other European patents (Patent Document 4) generally have less copper (50-70% Cu) and more Mn (8-25% Mn) than YKK, with the balance being zinc An alloy having no nickel is disclosed. Most of these nickel-free white alloys disclosed so far have become jewelry (due to allergies and sensitization problems) that are in “direct and long-term contact with human skin”, It is intended to meet the EU regulations that limit Ni in eyeglasses and similar items by completely eliminating Ni, and is generally intended for use as a cast article or wire product.

  [0011] The alloy disclosed in US Pat. No. 6,057,047 (Brauer, et.al) contains 5-10% Mn, 10-14% Zn, 3.5-4.5% Ni, and 0.07%. Less than Al is contained, and the balance is Cu. The content of the alloy of US Pat. No. 6,057,059 is an alternative to the standard alloy C713 (75Cu-25Ni) in both a monolithic and metallized form for use in US coins, with a “golden appearance” In particular, Susan B. It is specifically balanced to provide both conductivity suitable for use as a substitute for the yellow alloy of the Anthony (SBA) dollar coins, and is currently in the Sacajaya dollar and US presidential coin series. Used as the outer metallization layer for both circulating coins. Previously related patents mentioned in the application documents of US Pat. No. 5,099,056 (US Pat. No. 6,569,5 to Berwick, assigned to Olin Inc.) have a minimum of 5% Ni and other additives A quaternary (quaternary) alloy of the Cu-Zn-Ni-Mn type is taught which is substantially free.

  [0012] Other alloys that are substantially free of Ni are specifically described in US Pat. No. 6,057,059 (Shapiro, as a substrate for silver-plated articles such as flat tableware or deep containers for food service. et.al.). This alloy consists of 8-16% Mn, 20-31% Zn and the remainder Cu, and other elements (Al, Fe, Sn, Si, Co, Mg, Mo, Ni, P, As, Sb) Addition of small amounts of is acceptable but not essential. Nickel is allowed up to 0.3%, but it is preferred not to add Ni. Patent Document 8 (Goldman, et. Al.) Is a patent relating to an alloy containing 0.5-5% Ni, which is also limited as a substrate for silver-plated articles. Other Cu—Mn—Zn alloys that do not have Ni are disclosed in US Pat. Nos. 6,099,059 (Reichenecker, relating to cast electrical resistance alloys) and US Pat.

  [0013] Patent Literature 1, Patent Literature 2, Patent Literature 5, Patent Literature 6, Patent Literature 8, Patent Literature 7, Patent Literature 9, and Patent Literature 3 and Patent Literature 4 are incorporated herein by reference in their entirety. To do.

US Pat. No. 5,997,663 U.S. Pat. No. 6,340,446 European Patent EP 1306453 European Patent EP 0 658 564 U.S. Pat. No. 6,432,556 U.S. Pat. No. 2,445,868 U.S. Pat. No. 3,778,237 U.S. Pat. No. 3,778,236 U.S. Pat. No. 2,772,962 U.S. Pat. No. 2,479,596

Copper Development Association (CDA) database

  [0014] An object of at least one aspect of the present invention is to provide a copper-based alloy having a white or silver appearance and a reduced nickel content compared to conventional copper alloys having a similar appearance. Another object of at least one aspect of the present invention is that the alloys of the present invention exhibit at least the same colorfastness as other copper alloys of similar color. Yet another object of at least one aspect of the present invention is that the alloys of the present invention exhibit at least equivalent stain resistance (when repeatedly contacted to human skin) with other copper alloys of similar color. It is. Another object of at least one aspect of the present invention is that the alloys of the present invention exhibit substantially the same electrical conductivity as stainless steels or alloys currently used in circulating money. Yet another object of at least one aspect of the present invention is to provide published data on copper-based alloys in which these alloys have been exposed to similar colors by bacteria exposed on the uncoated surface of the alloys. The antibacterial property is equivalent to or higher and exhibits a deactivation rate far superior to that of stainless steel of the same color.

[0015] The above objects, features and advantages will become more apparent from the following specification and drawings.
(1) At least one aspect of the present invention is characterized in that the claimed copper-based alloy has a white or silver appearance, and various types of decorative articles, especially (but not limited to) It is suitable for manufacturing hardware for construction and construction shops. It can further create a new material system with features tailored to specific applications, either in a unitary form or due to the color, discoloration resistance and antibacterial and other properties of the alloys of the present invention. In some cases, it can be used as part of a composite system with other materials.
(2) Yet another feature of at least one embodiment of the present invention is that the alloy contains both zinc and manganese and reduced levels of nickel compared to conventional white copper-based alloys.
Another feature of at least one aspect of the present invention is to obtain improved (3) color and (4) discoloration resistance and (5) stain resistance compared to alloys having neither nickel nor iron. Iron can be used in place of or in addition to nickel.
(6) Another feature of at least one aspect of the present invention is that the alloy has a white appearance and electrical conductivity similar to CDA alloy C713 used in US circulating money.
(7) Yet another feature of at least one aspect of the present invention is that the alloy has the same appearance as stainless steel and also exhibits conductivity in the same range as stainless steel.

  [0016] Advantages of at least one aspect of the present invention include that the white copper-based alloy of the present invention has antimicrobial properties. The inactivation rate of the bacteria placed on the surface composed of the alloy of at least one embodiment of the present invention is superior to other copper-based alloys of similar color and has the components of the proposed alloy It is superior to the deactivation rate predicted from the deactivation rate found in commercial binary alloys of copper.

[0017] In accordance with the present invention, a white copper alloy is provided that includes up to 30% zinc, up to 20% manganese, and up to 5% nickel with the balance of copper by weight. More preferably, the alloy contains 6% to 25% zinc, 4% to 17% manganese, 0.1% to 3.5% nickel and the balance copper. The remaining copper in the alloy is further:
At least one of the group consisting of Sn, Si, Co, Ti, Cr, Fe, Mg, Zr and Ag up to 0.5%; and at least one of the group consisting of P, B, Ca, Ge, Se, Te Up to 0.1%,
At least one of the following. This alloy preferably contains 12% to 20% Zn, 10% to 17% Mn, and 0.5% to 3.5% Ni. More preferably, it contains 13% to 16% Zn, 14% to 17% Mn, and 1.5% to 2.5% Ni. It can also contain up to 0.3% by weight of Zr.

[0018] In accordance with the present invention, there is also provided a white copper alloy comprising up to 30% zinc, up to 20% manganese, and up to 4% iron with the balance of copper by weight. More preferably, the alloy contains 6% to 25% zinc, 4% to 17% manganese, 0.1% to 2.5% iron and the balance copper. The remaining copper in the alloy is further:
At least one of the group consisting of Sn, Si, Co, Ti, Cr, Ni, Mg, Zr and Ag up to 0.5%; and at least one of the group consisting of P, B, Ca, Ge, Se, Te Up to 0.1%,
At least one of the following. Preferably, the alloy contains Ni only as an impurity (ie, less than about 0.1%), 12% -20% Zn, 10% -17% Mn, and 0.5% -2.5% Fe. More preferably, it contains 15% to 18% Zn, 14% to 17% Mn, and 0.5% to 1.5% Fe.

[0019] Further in accordance with the present invention, there is provided a white copper alloy comprising up to 30% zinc, up to 20% manganese, up to 6% nickel, up to 4% iron with the remainder copper, based on weight. More preferably, the alloy comprises 6% to 25% zinc, 4% to 17% manganese, 0.1% to 5% nickel, 0.05% to 2.5% iron and the balance copper. Containing. The remaining copper in the alloy is further:
At least one of the group consisting of Sn, Si, Co, Ti, Cr, Mg, Zr and Ag up to 0.5%; and at least one of the group consisting of P, B, Ca, Ge, Se, Te 0.1%,
At least one of the following. This alloy preferably contains 12% to 20% Zn, 10% to 17% Mn, 0.5% to 3.5% Ni and 0.1% to 1% Fe. More preferably, it contains 13% to 16% Zn, 14% to 17% Mn, 1.5% to 2.5% Ni and 0.2% to 0.6% Fe. The alloy can further contain up to 1.0% Al.

[0020] Further, according to the present invention, having an electrical conductivity greater than 2.5% IACS at an eddy current gauge excitation frequency of 60 kHz to 480 kHz, up to 30% zinc, up to 20% manganese, up to 10% based on weight A white copper alloy is provided that contains up to 4% nickel, up to 1% Zr, and up to 1% Zr, with the remaining copper. More preferably, the alloy comprises 6% to 25% zinc, 4% to 17% manganese, 0.1% to 9% nickel, up to 2.5% iron, up to 0.5% Zr and Contains excess copper. The remaining copper in the alloy is further:
At least one of the group consisting of Sn, Si, Co, Ti, Cr, Mg and Ag up to 0.5%; and at least one of the group consisting of P, B, Ca, Ge, Se, Te up to 0. 1%
At least one of the following. This alloy preferably contains 10% to 18% Zn, 4% to 7% Mn, 4% to 9% Ni and 0.05% to 0.2% Zr. More preferably, it contains 12% to 16% Zn, 4% to 6% Mn, 5% to 9% Ni and 0.05% to 0.15% Zr; It has a conductivity of% IACS to 7% IACS.

That is, the gist of the present invention is as follows.
[1] An effectively antibacterial copper alloy having an appearance similar to that of one of stainless steel and “Western silver”, the copper alloy comprising:
a) 6-25% zinc (Zn)
b) 4-17% manganese (Mn),
c) 0.1-3.5% nickel (Ni),
d) a residue that is substantially Cu; and e) a combination of ad that exhibits a white appearance and is effectively antimicrobial,
Including the copper alloy,
[2] The remainder which is substantially Cu,
At least one of the group consisting of Sn, Si, Co, Ti, Cr, Fe, Mg, Zr, Ag up to 0.5%; and at least one of the group consisting of P, B, Ca, Ge, Se, Te Up to 0.1%,
The copper alloy according to [1], which also contains at least one of the above, wherein the alloy has a time to complete deactivation of less than 60 minutes,
[3] A copper alloy with a white appearance similar to one of stainless steel and one of “Western silver”, wherein the copper alloy is substantially a) 6-25% zinc (Zn),
b) 4-17% manganese (Mn),
c) 0.1-2.5% iron (Fe),
d) Residue substantially Cu e) where the combination of a to d exhibits a white appearance and is effectively antimicrobial,
The copper alloy comprising:
[4] The remainder, which is substantially copper,
At least one of the group consisting of Sn, Si, Co, Ti, Cr, Ni, Mg, Zr, Ag is at most 0.5%, and at least one of the group consisting of P, B, Ca, Ge, Se is at most 0.1%,
The copper alloy according to [3], which also contains at least one of
[5] A copper alloy having a white appearance similar to one of stainless steel and one of “Western silver”, the copper alloy being substantially a) 6-25% zinc (Zn),
b) 4-17% manganese (Mn),
c) 0.1-5% nickel (Ni),
d) 0.05-2.5% iron (Fe), and e) a residue that is substantially Cu;
f) where the combination of a to e is effectively antibacterial and has a white appearance.
The copper alloy comprising:
[6] At least one of the group consisting of Sn, Si, Co, Ti, Cr, Mg, Zr, and Ag is at most 0.5%, and at least one of the group consisting of P, B, Ca, Ge, Se, Te Up to 0.1%,
The copper alloy according to [5], which also contains at least one of
[7] The copper alloy according to [1], wherein the combination exhibits discoloration resistance at room temperature exposure in the air and has a time to complete deactivation of less than 60 minutes,
[8] The copper alloy according to [7], containing 12 to 20% Zn, 10 to 17% Mn, and 0.5 to 3.5% Ni,
[9] It contains 13 to 16% Zn, 14 to 17% Mn, and 1.5 to 2.5% Ni, and the time until the complete inactivation is less than 20 minutes, [8] The described copper alloys,
[10] The copper alloy according to [1], containing a maximum of 0.3% by weight of Zr,
[11] The copper alloy according to [3], which is effectively antibacterial and contains Ni only as an impurity,
[12] The copper alloy according to [11], containing 12 to 20% Zn, 10 to 17% Mn, and 0.5 to 2.5% Fe,
[13] The copper alloy according to [12], containing 15 to 18% Zn, 14 to 17% Mn, and 0.5 to 1.5% Fe,
[14] The copper alloy according to [5], which exhibits high-temperature discoloration resistance,
[15] The copper alloy according to [14], containing 12 to 20% Zn, 10 to 17% Mn, 0.5 to 3.5% Ni and 0.1 to 1.0% Fe. ,
[16] The copper alloy according to [15], containing 13 to 16% Zn, 14 to 17% Mn, 1.5 to 2.5% Ni and 0.2 to 0.6% Fe ,
[17] The copper alloy according to [14], containing at least one of the following:
Up to 1.0% Al; and at least one of the group consisting of Sn, Si, Co, Ti, Cr, Mg, Zr, Ag up to 0.5%, and;
At least one of the group consisting of P, B, Ca, Ge, Se, Te is up to 0.1%;
At least one of
[18] A copper alloy having a white appearance, showing resistance to discoloration due to contact, and used for money as a direct substitute for C713, the copper alloy comprising:
a) 6-25% zinc (Zn),
b) 4-17% manganese (Mn),
c) 0.1-9.0% nickel (Ni),
d) a residue that is substantially Cu; and e) has a white appearance, is effectively antibacterial, and has a conductivity greater than 2.5% IACS at an eddy current gauge excitation frequency of 60 kHz to 480 kHz, a combination of ad, the copper alloy comprising:
[19] The remainder which is substantially Cu,
At least one of the group consisting of Sn, Si, Co, Ti, Cr, Fe, Mg, Zr, Ag up to 0.5%; and at least one of the group consisting of P, B, Ca, Ge, Se, Te Up to 0.1%,
The copper alloy according to [18], which also contains at least one of
[20] The copper alloy according to [19],
The conductivity is between 4% IACS and 7% IACS;
And furthermore, has a time to complete inactivation of less than 60 minutes,
The copper alloy,
[21] The copper alloy according to [19],
Contains up to 0.3% by weight of Zr; and the time to complete inactivation is less than 30 minutes,
The copper alloy,
[22] The copper alloy according to [21],
10-18% Zn, 4-7% Mn, 4-9% Ni and 0.05-0.20% Zr; and the time to complete deactivation is less than 20 minutes,
The copper alloy,
[23] The copper alloy according to [22],
Contains 12-16% Zn, 4-6% Mn, 5-9% Ni and 0.05-0.15% Zr; and the time to complete deactivation is less than 15 minutes,
The copper alloy,
[24] The copper alloy according to [18], which is formed on a coin base plate.

  The present invention provides a copper-based alloy having a white or silver appearance and a reduced nickel content compared to conventional copper alloys having a similar appearance.

[0021] FIG. 1 illustrates CIELAB color chart attributes relating to lightness, hue, and saturation known from the prior art. [0022] FIG. 2 shows an alloy of the present invention and a comparative alloy plotted on a two-dimensional CIELAB color chart illustrating the desired color range. FIG. 3 shows the same data as FIG. 2, but focusing on the desired “white appearance” range. [0024] FIG. 4 shows the antibacterial efficacy of the alloy of the present invention.

[0025] For the purposes of the following claims, the following definitions shall apply:
[0026] All compositions are given in weight percentages. The composition listed as Cu-18Zn-17Ni refers to nominal 18 wt% Zn, 17 wt% Ni and residual copper and the necessary impurities. Other compositions listed in similar form can be understood by analogy with this example.

[0027] "Copper-based alloy" is hereinafter referred to as:
It shall be defined as an alloy having a minimum of 50 wt% Cu with one or more elemental components, or a multi-component alloy with a higher percentage of Cu than any other component.

[0028] The “white appearance” is hereinafter:
Color (measured with spectrophotometer of D / 8 illuminant and observation field 10 ° d / 8 sphere geometry (including specular reflection)) -2 ≦ a on CIE1976L ^* a ^* b ^* (CIELAB) scale ^* ≦ 3 and −2 ≦ b ^* ≦ 10 shall be defined.

[0029] “Effective antibacterial” refers to the following:
It shall be defined that 99.9% of the bacteria in the suspension placed on the uncoated surface are inactivated by exposure within 120 minutes.

[0030] "Time to complete inactivation" shall be defined thereafter as the time from when bacteria are placed on the surface until 99.9% of the bacteria are inactivated.
[0031] "Discoloration resistance" is hereinafter referred to as:
Color change between the initial and final colors after exposure for 30 days in air at 20-25 ° C. without contact with human skin or body fluids ΔE _CMC (ASTM D2244-07, pages 2-3) Is defined to be less than 1.

[0032] "High temperature discoloration resistance" is hereinafter:
After 24 hours exposure in air at 150 ° C., the color change ΔE _CMC (defined in ASTM D2244-07, page 2-3) between the first and final colors is less than 20 Shall be defined.

  [0033] The determination of color (alloy or other material color) can be by spectroscopic methods or other objective means. X-Rite, Inc (Grand Rapids, MI) or Hunter Associates Laboratory, Inc. In instruments such as those supplied by (Reston, Virginia), colors are quantified according to two color attributes, “hue” and “saturation”, and a brightness attribute known as “brightness”. The Hue is color vision, that is, recognizing an object as red, green, yellow, blue, or the like. Saturation is the shade of color (intensity or saturation) ranging from gray to pure hues. Lightness is a measure of the brightness of a tone ranging from pure white to pure black. The combination of these values gives a unique position in the color space in polar coordinates, where in FIG. 1 the hue indicates the hue (angular location), the saturation indicates the sharpness (radial position), Lightness indicates brightness (vertical position).

[0034] Another method of identifying colors is by the CIELAB scale. CIE is an abbreviation for Commission Internationale de l'Eclairage, and LAB is an abbreviation for L ^* , a ^* , b ^* coordinates on the scale; therefore, CIELAB is CIE1976L ^* a ^* b ^* color scale. Is an abbreviation. On this scale, the hue is expressed in terms of a pair of colors where + a ^* is red and -a ^* is green, + b ^* is yellow and -b ^* is blue. Saturation (sharpness or saturation) is expressed as a value from the center of the coordinate system (0 is gray) to the maximum sharpness of the color component that is ± 60. The larger the value of any component, the darker the color, and the smaller the value, the closer the measured material is to colorless. The degree of brightness L ^* ranges from 0 (pure black) to 100 (pure white). Again, the specific combination of L ^* , a ^* and b ^* values identifies the unique position in the color space and the specific color, saturation and brightness.

[0035] All alloy colors are X-Rite Inc. Analysis was performed using a SP-62 spectrophotometer manufactured by (Grand Rapids, Michigan). The analysis conditions were d / 8 spherical geometry (including specular reflection) with a D65 light source and an observation field of 10 °. All color measurements are reported on the CIE 1976 L ^* a ^* b ^* (CIELAB) scale. For the first color measurement, the sample is prepared with the same surface finish (6-18Ra; surface roughness scale) and cleaned to both the first color measurement and the subsequent analysis of resistance to discoloration in the atmosphere. Removed surface oxides that could affect. The chemistry and color of the alloys according to the present invention are shown in Table 1 along with the same data for the comparative copper alloys and selected stainless steels. Alloys according to the present invention are listed in the table as I1, I2, I3, etc. Comparative copper alloys are listed as C1, C2, C3, and the like. Comparative alloys that are not based on copper (carbon and stainless steel, zinc and aluminum alloys, pure metals other than copper, etc.) are listed as S1, S2, S3, and the like.

  [0036] Table 1. Chemical nature and original (true metal) color

[0037] One of the problems in creating a "white" copper base alloy is determining exactly what "white" means. Since many of the early uses of these alloys were as cheaper alloys for money, flat dishes and deep containers, the desired color was similar to legal sterling silver and money silver. It was. Recently, “white” copper alloys have come to be considered as substitutes for stainless steel or matte nickel finish materials in industrial hardware and construction applications, resulting in the antibacterial properties of copper alloys being stainless steel. It can be used in conjunction with a modern look and feel. Many conventional “white” copper alloys have been analyzed for color, along with other alloys that exhibit a slight but clearly red or yellowish nuance. In addition to pure nickel, zinc and tin as found on the surface of white plated products, stainless steel and carbon steel have also been analyzed. These materials were compared to determine the actual limit of CIELAB values for the white alloy. A material with both measured values of a ^* and b ^* near zero appears nearly colorless, and thus either a ^* or b ^* is greater at the same overall brightness (L ^* ) degree. Looks whiter than things. The degree of brightness (L ^* ) of the copper alloy is typically 75-86 for a surface with no oxide and a surface roughness of 6-18 Ra; this is a bright yellow cartridge brass ( This is true for all copper alloys measured, from alloy C2, Cu-30Zn) to red pure copper (alloy C1) to the strong white copper-nickel (alloy C5) used in US coins.

[0038] In order to determine the desired white color, the upper limit of a ^* is hereinafter defined at the point where the copper alloy appearance is no longer predominantly white, but becomes white with a distinct red hue for the first time. This transition from white to red is defined by the a ^* value of alloy C31 (Cu-15Ni). Alloy C31 has an a ^* value of 2.9. A comparable commercial copper alloy (alloy C4, Cu-10Ni-1Fe) is significantly reddish and has an a ^* value of 3.7. For purposes of the present invention, it is appropriate to consider alloys having an a ^* value less than 3 and a suitable b ^* value (on the CIELAB scale) as white.

[0039] For copper alloys having a white appearance, the upper limit of b ^* is defined in that the copper alloy is no longer predominantly white, but for the first time becomes a clear yellow (or white with a yellow hue). This transition from white to yellow is defined by the b ^* value of comparative alloy C3 (Cu-12Zn-7Mn-4Ni). This is a patented alloy (discussed in US Pat. No. 6,432,556 B1 to Brauer et al.) Having a “golden appearance”, which is 18K more than the white of alloy C5 used in US circulating coins. Specifically formulated to exhibit a color close to gold; the alloy has a measured b ^* value of 10.2. We set the upper limit of b ^* to 10 so that only alloys that are not as yellow as alloy C3 are acceptable.

[0040] The lower limits of a ^* and b ^* were set based on the color of pure zinc (alloy C35, a ^* -1.7, b ^* -1.9). Pure zinc looks essentially white, but there is a faint blue and greenish nuance on the freshly prepared and prepared surface. Therefore, the lower limits of both a ^* and b ^* were set to −2 so that zinc was included in the white alloy zone. All copper alloys measured in our study had CIELAB values of a ^* > − 1.5 and b ^* > 1.5.
In order to be considered white, the copper alloy must meet the constraints listed above for both a ^* and b ^* ; that is, a ^* is preferably from about −2 to about +3, and b ^* is preferably Is about -2 to about +10. More preferably, a ^* is about −2 to about +2 and b ^* is about −2 to about +8. Most preferably, a ^* is from about −2 to about +1 while b ^* is from about −2 to about +7. An alloy that satisfies one or the other but not both is not considered white. For example, the alloy C2 (Cu-30Zn) has a CIELABa ^* , b ^* value of (−1.5, 21.5); this is within the range of a ^* for white (less redness), but white The maximum permissible b ^* to be considered, so alloy C2 is a yellow copper alloy. Another example is CIELABa ^* , an alloy C4 (Cu-10Ni-1Fe) with a b ^* value of (3.7, 8.2); the b ^* value is in the white range (yellowish Less), the tolerance a ^* is exceeded, and it is visually reddish. Further, ranges having endpoints within the above ranges are contemplated even if the endpoints or ranges are not specifically listed. For example, the range of values for a ^* can have -1.9, -1.8, -1.7, etc. to +2.7, +2.8 and +2.9 lower endpoints, while the upper endpoint is From +2.9, +2.8, +2.7, etc. to -1.7, -1.8 and -1.9. Similar endpoints for the value b ^* are also conceivable. It is also conceivable to combine any of the a ^* ranges with any of the b ^* ranges. For example, the range of values for a ^* can be -2 to +2, and the range of values for b ^* can be -2 to about +10.

[0041] The present invention includes alloys based on weight, up to 30% zinc, up to 20% manganese, up to 5% nickel and the balance copper. More preferably, these alloys contain 6% to 25% zinc, 4% to 17% manganese, 0.1% to 3.5% nickel and the balance copper. The remaining copper in the alloy is further:
At least one of the group consisting of Sn, Si, Co, Ti, Cr, Fe, Mg, Zr and Ag up to 0.5%; and at least one of the group consisting of P, B, Ca, Ge, Se, Te Up to 0.1%,
At least one of the following. These alloys preferably contain 12% to 20% Zn, 10% to 17% Mn, and 0.5% to 3.5% Ni. More preferably, it contains 13% to 16% Zn, 14% to 17% Mn, and 1.5% to 2.5% Ni. These alloys can also contain up to 0.3% by weight of Zr. In the most preferred embodiment, the alloy of the composition is also a white copper-based alloy; that is, they are preferably a ^* of about −2 to about +3, while b ^* is preferably about −2 to about It has a CIELAB value of +10. More preferably, a ^* is about −2 to about +2 and b ^* is about −2 to about +8. Most preferably, a ^* is from about −2 to about +1 while b ^* is from about −2 to about +7. It is believed that the composition can be combined with each range of the CIELAB values.

[0042] The present invention includes alloys based on weight up to 30% zinc, up to 20% manganese, up to 4% iron and the balance copper. More preferably, these alloys contain 6% to 25% zinc, 4% to 17% manganese, 0.1% to 2.5% iron and the balance copper. The remaining copper in the alloy is further:
At least one of the group consisting of Sn, Si, Co, Ti, Cr, Ni, Mg, Zr and Ag up to 0.5%; and at least one of the group consisting of P, B, Ca, Ge, Se, Te Up to 0.1%,
At least one of the following. Preferably, these alloys contain Ni only as an impurity (ie, less than about 0.1%), 12% -20% Zn, 10% -17% Mn, and 0.5% -2.5. % Fe. More preferably, these alloys contain 15% to 18% Zn, 14% to 17% Mn, and 0.5% to 1.5% Fe. In the most preferred embodiment, the alloy of the composition is also a white copper-based alloy; that is, they are preferably a ^* of about −2 to about +3, while b ^* is preferably about −2 to about It has a CIELAB value of +10. More preferably, a ^* is about −2 to about +2 and b ^* is about −2 to about +8. Most preferably, a ^* is from about −2 to about +1 while b ^* is from about −2 to about +7. It is believed that the composition can be combined with each range of the CIELAB values.

[0043] The present invention includes alloys based on weight up to 30% zinc, up to 20% manganese, up to 6% nickel, up to 4% iron and the balance copper. More preferably, these alloys contain 6% to 25% zinc, 4% to 17% manganese, 0.1% to 5% nickel, 0.05% to 2.5% iron and the balance. Contains copper. The remaining copper in the alloy is further:
At least one of the group consisting of Sn, Si, Co, Ti, Cr, Mg, Zr and Ag up to 0.5%; and at least one of the group consisting of P, B, Ca, Ge, Se, Te 0.1%,
At least one of the following. These alloys preferably contain 12% to 20% Zn, 10% to 17% Mn, 0.5% to 3.5% Ni and 0.1% to 1% Fe. More preferably, these alloys contain 13% to 16% Zn, 14% to 17% Mn, 1.5% to 2.5% Ni and 0.2% to 0.6% Fe. To do. These alloys can further contain up to 1.0% Al. In the most preferred embodiment, the alloy of the composition is also a white copper-based alloy; that is, they are preferably a ^* of about −2 to about +3, while b ^* is preferably about −2 to about It has a CIELAB value of +10. More preferably, a ^* is about −2 to about +2 and b ^* is about −2 to about +8. Most preferably, a ^* is from about −2 to about +1 while b ^* is from about −2 to about +7. It is believed that the composition can be combined with each range of the CIELAB values.

[0044] In another aspect of the invention, the alloy has a conductivity greater than 2.5% IACS at an eddy current gauge excitation frequency of 60 kHz to 480 kHz, up to 30% zinc, up to 20% based on weight Is manganese, up to 10% nickel, up to 4% iron, up to 1% Zr and the balance copper. More preferably, these alloys contain 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 copper in the alloy is further:
At least one of the group consisting of Sn, Si, Co, Ti, Cr, Mg and Ag up to 0.5%; and at least one of the group consisting of P, B, Ca, Ge, Se, Te up to 0. 1%
At least one of the following. These alloys preferably contain 10% to 18% Zn, 4% to 7% Mn, 4% to 9% Ni and 0.05% to 0.2% Zr. More preferably, the alloy 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 above compositions also has a conductivity of 4% IACS to 7% IACS. In the most preferred embodiment, the alloy of the composition is also a white copper-based alloy; that is, they are preferably a ^* of about −2 to about +3, while b ^* is preferably about −2 to about It has a CIELAB value of +10. More preferably, a ^* is about −2 to about +2 and b ^* is about −2 to about +8. Most preferably, a ^* is from about −2 to about +1 while b ^* is from about −2 to about +7. It is believed that the composition can be combined with each of the above CIELAB values and with each of the above conductivity characteristics.

[0045] Some specific examples of possible compositions are:
1) 6-25% zinc, 4-17% manganese, 0.1-3.5% nickel and residual Cu; and
2) As in 1), at least one of Sn, Si, Co, Ti, Cr, Fe, Mg, Zr or Ag is 0.5% and P, B, Ca, Ge, Se or Te is at most 0. Have 1%.

3) Same as 1) or 2), with 0.1 to 2.5% iron.
4) Same as 1) or 2), with 0.1-5% nickel and 0.05% -2.5% iron.

5) 12-20% Zn, 10-17% Mn, and 0.5-3.5% Ni and residual Cu.
6) 13-16% Zn, 14-17% Mn, and 1.5-2.5% Ni and residual Cu.

7) Same as 1) with a maximum of 0.3% Zr.
8) 12-20% Zn, 10-17% Mn, and 0.5-2.5% Fe and residual Cu.

9) 15-18% Zn, 14-17% Mn, and 0.5-1.5% Fe and residual 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 balance Cu.
12) Same as 11) with a maximum of 0.3% Zr.

13) 10-18% Zn, 4-7% Mn, 4-9% Ni, 0.05-0.20% Zr and residual Cu.
14) 12-16% Zn, 4-6% Mn, 5-9% Ni, 0.05-0.15% Zr and residual Cu.
Is included.

All of these examples can be combined with any combination of a ^* and b ^* values and any range of conductivity.
[0046] With respect to all components in the composition, ranges having endpoints within the above ranges are also contemplated even if the endpoints or ranges are not specifically listed. For example, the range of values for Zn can have lower endpoints of 6.1%, 6.2%, 6.3%, etc. to 24.7%, 24.8% and 24.9%, while Upper endpoints can be 24.9%, 24.8%, 24.7%, etc. to 6.3%, 6.2%, and 6.1%. Similar endpoints are conceivable for the range of other components. A combination of any of the ranges specifically mentioned for Zn and any of the ranges specifically mentioned for other components is also conceivable. For example, a range of 6% to 25% zinc can be combined with a range of 10% to 17% Mn and 0.5% to 3.5% Ni.

  [0047] A feature of the present invention is that the alloy contains both Zn and Mn and lower levels of Ni than conventional "white" copper-based alloys. This is due to the synergistic effect of the alloying elements and results in a combination of multiple components that cannot be obtained with a simple binary alloy.

  [0048] Nickel is a strong whitening in copper alloys. Adding 10% Ni to Cu (alloy C4) gives an alloy that is whitish but still has a reddish purple hue. Addition of 15% Ni (alloy C31) or more clearly results in a white color, and when the Ni content increases to 30% (alloy C6) the alloy becomes more colorless. The increased Ni contributes to the resistance to discoloration in the atmosphere and suppresses the formation of dark copper oxide. Unfortunately, Ni is also significantly more expensive than Cu (generally costs 2 to 3 times), thus there is a strong economic advantage of producing an alloy that is similar in appearance but less Ni. Also, the Ni addition should be kept to a minimum consistent with the desired color and discoloration resistance, as the added amount of Ni decreases the antimicrobial effectiveness of the alloy. Nickel is considered as a major cause of metal-contact dermatitis, which led to the European Union, European Patent Publication No. EP 0 635 564 B1 (Ammannati); “Copper-zinc-manganese alloy for the products of the chemicals commoditization. and prolonged contact with the human skin "; December 1, 2000; title, page 1-2, as seen in jewelry, glasses, and the like that will be in" direct and long-term contact with human skin " For these items, the legislation of alloys that do not have Ni is being implemented.

[0049] Manganese is also an effective whitening in copper alloys, but binary alloys are weak in strength, difficult to ingot and hot-roll, and have low ductility and inconsistency with regard to short-range order. Was not very important. When 12% or more of Mn is added to Cu, a relatively white alloy (alloy C30, [a ^* , b ^* ] = [5.05, 8.27]) is obtained, which is a short distance in the binary alloy. It is the range where the order becomes remarkable. Manganese is generally used at low levels for reinforcement in more complex copper alloys containing Al, Zn, Si, Ni or combinations thereof. These low levels of Mn addition can also improve the casting and hot rolling properties of these alloys.

  [0050] When Zn is added to a copper alloy, the color changes strongly, but the alloy does not become "white" or colorless; instead, a Cu-Zn alloy ("brass") contains about 30% Zn As it rises, it turns from golden to yellow. If it exceeds 33% Zn, a new crystal structure is formed and the alloy becomes reddish again. High Zn-brass also exhibits short-range order under certain conditions, which limits ductility and can change properties during use. Zinc can reduce the need for Ni in the whitening of copper-based alloys (the basic raw material for “Western silver” Cu—Ni—Zn alloys). The appearance is close to a white Cu—Ni alloy, and slightly yellow is mixed due to the Zn content.

[0051] Addition of iron to the copper alloy is limited due to its low solubility. If it exceeds 3.5% Fe, a difference in miscibility is observed, and casting of an alloy with higher Fe is prevented. From 0.5% to 2.5%, Fe can be retained in the solid solution by a suitable heat treatment, and Fe is a whitening that is as effective as Ni at the same level. Fe can be a strong reinforcing agent and can form precipitates directly in the alloy and by reaction with P (phosphorus).

  [0052] Zinc and aluminum are similar in copper alloys as far as color is concerned, but Al is significantly more effective in achieving a bright yellow color. When 6% Al is added (alloy C32), a color similar to Cu-15Zn (alloy C29) is obtained. Over time, Cu-Al alloys (including those with other elements such as Zn, Mn and Fe) form dense immobile oxide thin films that are beneficial to discoloration and corrosion resistance. This same action reduces the antibacterial effectiveness of Cu alloys with Al, so Al should be kept to a minimum for antibacterial applications. Hot and cold rolling and heat treatment of Al-containing alloys are more complicated than alloys without Al due to interactions with many other alloying elements.

  [0053] One of the main objectives of the present invention is to provide a copper alloy that is white in appearance but has a reduced Ni content. The above description of the effect of alloying additives on the color of copper-based alloys presents a method for achieving this goal. By replacing part of Ni with Zn, an alloy with a reduced Ni content can be created, but the color tends to be yellower than a Cu-Ni alloy with the same total Cu content. By further replacing part of the remaining Ni with Mn, an alloy with a much lower Ni content and a substantially white (colorless) appearance is possible. We know that retention of low levels of Ni (at a particular total alloy content) helps maintain the desired white color, as well as resistance to atmospheric discoloration and contact with fluids from human skin It has been found to have a benefit in terms of reducing pollution caused by. Thus, white appearance copper alloys are found by replacing the Ni in conventional alloys with a combination of Zn and Mn and maintaining a low level of Ni for improved color and discoloration resistance.

[0054] Another feature of the present invention is that Fe can be used in place of or in addition to Ni to improve the whiteness of Cu-Zn-Mn alloys. When measuring the color of commercial Cu-Ni alloys, we found that the whiteness of some of these alloys was better than expected from the Ni content only. The alloys were found to contain large amounts of Fe added to improve the casting and hot and cold work characteristics of these alloys. Further investigation of Cu-Fe alloys shows that they are still clearly red due to the low overall alloy content, but whiter than expected for Cu-Zn or Cu-Mn with the same alloy content. It was shown to be close (with a CIELAB scale and a smaller a ^* value). Based on this, we have added up to 2.5% iron to the alloys of the present invention and found that improved whiteness persists even when the total alloy content exceeds 30%. Furthermore, we have found that either or both can be used to improve the whiteness of Cu-Zn-Mn alloys since the presence of Ni does not interfere with the action of Fe. We also note that the presence of Fe in the solid solution in the alloy (at a certain total alloy content) helps maintain the desired white color, as well as resistance to discoloration in the atmosphere and from human skin. It has been found to have a benefit in terms of reducing contamination caused by contact with fluids. This is similar to the effect of low levels of Ni on these properties. These effects were also found when Fe or a combination of Fe and Ni was used instead of Ni alone. Thus, a copper alloy with a white appearance replaces Ni in conventional alloys with a combination of Zn and Mn, and a low level of Ni or Fe or a combination of both Ni and Fe for improved color and resistance to discoloration Is found by maintaining

  [0055] An important factor in the selection of copper-based alloys for appearance (eg, architectural and construction hardware) is appearance stability over time. Stainless steel does not change significantly in appearance when exposed to the atmosphere; this is because the formation of a passive oxide layer prevents visible discoloration and corrosion, and stainless steel is considered “rustless” That is why. Unfortunately, stainless steel is not available in a wide range of colors and tones that can be achieved with copper-based alloys, and stainless steel does not possess the antibacterial properties of properly prepared copper alloys. Traditionally, Ni has been added to copper alloys to obtain improved atmospheric discoloration resistance because Ni forms a passive oxide layer on the surface that is similar in function to the passive surface of stainless steel. Yes. We have tailored the chemical composition of white copper alloys with reduced Ni content to achieve a desirable white appearance and discoloration resistance in air that is substantially similar to conventional white copper-based alloys with higher Ni. It has been found that it is possible to obtain an alloy having

  [0056] The discoloration of the copper alloy is due to the formation of an oxide thin film over a long period of time by reaction with oxygen from the atmosphere. Although it generally appears as a darkening of the surface, the various colors of the oxide formed from the substrate (and the action of the interference layer) can cause differences in hue and saturation compared to the original appearance of the material. There is also sex. By comparing the colors before and after exposure, the magnitude of the color change can be quantified and an objective comparison of various alloys can be made.

[0057] Color differences between samples for which CIELAB values are measured are easily calculated; various color difference and color tolerance equations can be found in ASTM Standard D2244-07 ^ε1 “Standard Practices for Calculation of Color Tolerances and Color Differences. from Instrumentally Measured Color Coordinates "; ASTM International; May 1, 2007; The total color difference ΔE ^* _ab of the two colors given for L ^* , a ^* , b ^* respectively is:
ΔE ^* _ab = [(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² ] ^1/2
It can be calculated as follows.

[0058] ΔE ^* _ab provides the magnitude of the color difference, but does not indicate the relative amount and direction of the difference in hue, saturation and lightness, and therefore does not give an indication of the difference feature. (ASTM standard D2244-07 ^ε1 , section 6.2.2.). It is most useful when the color change is governed by one of three factors and the nature of the color change is easily understood, but two or three components are evident in the measured color change It is not very useful if it contributes to L ^* , a ^* , b ^* Cartesian coordinates can be converted to L ^* , C ^* , H ^* cylindrical coordinates to better understand the relative differences of lightness L ^* , saturation C ^* and hue H ^* It is. In that case, the equivalent total color difference equation is:
ΔE ^* _ab = [(ΔL ^* ) ² + (ΔC ^* ) ² + (ΔH ^* ) ² ] ^1/2
[0059] The other calculated color difference ΔE _CMC (as defined by the Color Measurement Committee (CMC) of the Society of Dyers and Colleges in the UK) is a single-number equation that determines the success or failure of a tone. number shade-passing equation) (also defined in ASTM D2244-07 ^ε1 ). It has been developed as a tolerance system based on CIECH cylindrical coordinates and defines an ellipse around a standard color (a specific point in color space) within which the difference from the standard is acceptable for the intended application . The color difference ΔE _CMC is:
ΔE ^* _CMC = cf [(ΔL ^* / (l · S _L )) ² + (ΔC ^* / (c · S _C )) ² + (ΔH ^* / (S _H ))) ² ] ^1/2
Given by.

[0060] The parameters in the equation explain the difference in spectral sensitivity and the relative importance of lightness with respect to saturation and hue, and thus on the number of colors visually acceptable to human perception. The acceptable range and the actual range are better matched. Among other things, the commercial factor cf can be varied to fit the desired range for a given application. To represent just the perceivable color difference, assume that ΔE _cmc = 1.

[0061] In order to compare resistance to color changes due to exposure to the atmosphere, ΔE _CMC was calculated based on the actual color difference of the sample before exposure (time = 0) and after exposure at a given time and temperature. . A smaller value of ΔE _CMC (less color change upon exposure) is considered a better measure of resistance to discoloration in air.

  [0062] Table 2: Discoloration table in air-room temperature

[0063] Table 2 shows the color change due to the color change in the atmosphere. After 30 days at room temperature, many of the comparative alloys without alloys (alloys C11 to C24) show ΔE _CMC > 1. The nickel-containing comparative alloys C3 to C8 (with Ni content> 4%) are all ΔE _CMC <1, indicating less color change. The alloys of the present invention (Alloys I1-I9) also show ΔE _CMC <1 even when Ni <3.5%. When alloy C16 is compared with alloy I8, the addition of 1% Fe (to the color-balanced Cu-Zn-Mn alloy) cannot reduce discoloration resistance and makes the appearance more colorless. It is expected that it can be seen that Similarly, it is expected that when alloy I7 is compared to alloy C16, the addition of 3% Ni can also result in a whiter alloy and significantly improve discoloration resistance. The addition of both Ni and Fe (Alloy I9) is expected to show that the benefits of both elements in color and discoloration are independent and cannot interfere with each other.

[0064] High temperatures are often used to simulate long-term exposure for oxidation or corrosion studies. It is important to select a temperature-time regime in which the nature of the oxide or corrosion product is the same as the simulated conditions. For example, at moderately high temperatures in air (above 200 ° C.), the direct formation of black CuO is preferred over red Cu ₂ O, which later converts to CuO; this has three elements: hue, saturation and Affects the nature of the color change during atmospheric discoloration for all (lightness). These exposures also indicate the reaction of the material when used at moderately high temperatures (such as panels on kitchenware) or when subjected to an automatic dishwasher or autoclave sterilization cycle.

[0065] Table 3 shows the color change due to atmospheric exposure at high temperatures. Alloy samples (also called coupons) were cleaned and prepared by the same procedure as the other color samples and CIELAB color was measured before exposure. The color was re-evaluated after exposure and ΔE _CMC was calculated. After treatment in an oven at 150 ° C. for 7 or 24 hours, the alloys of the present invention (alloys I2 to I9) exhibited a color change equivalent to or less than any of the comparative copper alloys listed in Table 3 (alloys C3 to C26). . Preferred embodiments of the invention (alloys I7-I9) showed the least color change of any of the copper alloys listed. Of particular interest is a comparison of Alloy C16 with these preferred embodiments. Alloy C16 is substantially the same as these embodiments, but has no Ni or Fe; after 24 hours at 150 ° C., the color change ΔE _CMC = 15.6. For the same alloy with 1% Fe (Alloy I8), ΔE _CMC = 11.9, indicating that the addition of Fe not only improved the whiteness of the alloy, but also increased the resistance to discoloration. The same applies to alloys I7 and I9 (ΔE _CMC = 9.1 to 9.9) (more true); the addition of Ni (or Ni plus Fe) to the base Cu-Zn-Mn alloy is Dramatically improved discoloration resistance and whiteness.

  [0066] Contact surfaces (such as handrails, door accessories, countertops, appliance panels, hospital equipment, etc.) repeatedly contact thin films of water, sweat, sebum and other bodily fluids as part of their function. Is in a state. These body fluids contain complex mixtures of materials, many of which are highly corrosive to copper and copper alloys. Assessing the change in appearance of these alloys after repeated contact with human skin is not only important in the selection of these alloys for contact surface applications, but is necessary to maintain their appearance. It is also useful for determining the frequency of cleaning. From a functional point of view, once a week to multiple daily cleaning and sterilization cycles are recommended for stainless steel and similar hospital surfaces to minimize cross-contamination in health care settings.

[0067] Coupons of the alloy were cleaned and prepared with the desired surface finish (6-18Ra). The initial color was determined before any contact with human skin and / or fluid. Coupons were contacted daily and color changes were determined and calculated for comparison. The results are listed in Table 4. After 3 days of repeated skin contact, all white alloys showed little difference in anti-fouling properties; ΔE _CMC was 1.2-2.8. There appeared to be no strong correlation with the content of any particular alloying element or combination of elements. After 7 days of repeated exposure, the difference between the alloys was even smaller, but the overall color change was greater; the ΔE _CMC was 2.9-4.4. The alloys of the present invention are resistant to changes in color due to contact with human skin and / or body fluids, even though the Ni and / or Fe content is significantly lower than the Ni content of conventional white copper-based alloys. Not as bad as conventional alloys in terms.

  [0068] Many applications of copper-based alloys involve electrical conduction or resistance to such conduction. For example, controlled conductivity or resistivity is used as a security feature to discriminate between legitimate circulating or substitute coins and legally invalid “counterfeit coins”, in this regard color and A specific combination of electrical properties is desirable. It is also used to control the operation of electrical equipment such as fuses and breakers. Conductivity is primarily controlled by alloy content; adding various alloying elements to pure copper (having 100% IACS conductivity) reduces the conductivity to some extent. The conductivity of the comparative alloy and the alloy according to the invention are listed in Table 1.

  [0069] When comparing comparative alloy C29 (Cu-15Zn, 37% IACS), alloy C31 (Cu-15Ni, 9.15% IACS) and alloy C30 (Cu-12Mn, 4.15% IACS), we found that It can be seen that various alloying elements have different effects on conductivity. Taking advantage of this, it is possible to design an alloy to obtain a specific conductivity while maintaining a specific appearance. Alloy I1 has the same white appearance and conductivity (5.1% IACS) as Alloy C5, but contains only 6% Ni compared to 24.5% Ni in C5 and is a US circulating currency. Can lead to significant cost savings.

  [0070] Advantages of the present invention include the white copper-based alloy of the present invention having antibacterial properties. Copper and many copper-based alloys, when properly prepared, reduce the viability of bacteria and other microorganisms exposed on the surface of these alloys. The effectiveness of the alloy surface in inactivating bacteria is related to the chemical nature of the alloy and other factors, such as surface roughness as demonstrated in PCT application_PCT / US2007 / 069413. The exposure time required to inactivate 99.9% of the bacteria on the surface is a useful measure of the antibacterial properties of the alloys under consideration and is supported by Copper Development Association (Wilks, et.al), 2003 11 Test procedures based on tests in the monthly study were used to compare with their published values.

[0071] Coupons of the alloy (squares about 22 mm on each side) were prepared and sterilized before exposure. The prepared coupon was placed on a sterile filter paper in a petri dish. A 5-20 μL aliquot of a suspension of active bacterial culture (E. Coli, American Type Culture Collection [ATCC] strain 11229, Gram negative) in nutrient broth was applied on the surface of the coupon; It contained a minimum of 10 ⁶ to 10 ⁸ colony forming units (CFU / mL) per milliliter. After the desired exposure time, the coupon is placed in a tube containing 20 mL of sterile Butterfield buffer (3.1 × 10 ⁻⁴ M K ₂ HPO _{4 in} filtered laboratory grade deionized water / reverse osmosis water). All viable bacterial colonies were suspended from the surface of the coupon by sonicating for minutes. The suspension of viable bacterial colonies was serially diluted 4 times (1/10, 1/100, 1/1000 and 1/10000). This initial suspension and 20 μL aliquots of each dilution were placed on nutrient agar and incubated at 35-37 ° C. for 48 hours to count viable colonies. To confirm the baseline (number of colonies in the first inoculum exposed on the coupon), a 20 μL aliquot of the initial inoculum is placed in a tube containing 20 mL of sterile buffer without exposure on the metal coupon. After placing directly, it was treated in the same way as the suspension of survivors from the coupon (sonication, dilution, placing on an agar plate, culturing and counting). Duplicate coupons were exposed and dilutions were placed in duplicate to average out statistical fluctuations common in biological experiments. Count the number of colonies present on each agar plate, calculate the number of colony forming units (CFU) per mL in suspension from the initial baseline and exposed coupons and reveal for all dilutions did. In order to minimize statistical variability, only plates showing 5-400 colonies were used in the final calculation. The exposure time and time to complete inactivation required to achieve a 99.9% reduction in the total number of bacteria (3 Log ₁₀ reduction in CFU) are major measures of antibacterial efficacy.

[0072]
[0073] E.E. Table 5 and FIG. 4 show the results of the antibacterial test of the alloy of the present invention tried at Coli. For comparison, E.I. Published information (from Wilks and Keevil) regarding commercial alloys being attempted at Coli is included below.

  [0074] Comparative alloy C32 (Cu-10Zn) showed a 99.9% reduction in total bacterial count after 90-105 minutes of exposure, indicating complete inactivation after 105 minutes. Alloy C4 (Cu-10Ni-1Fe) has substantially the same effectiveness as alloy C32. Similar alloys with higher alloy content (C2 [Cu-30Zn] and C5 [Cu-25Ni-0.5Fe]) show slightly lower effectiveness, with a 99.9% decrease in 90-105 minutes, Complete inactivation is finally after 120 minutes. Alloy C8 (Cu-17Zn-18Ni) is intermediate in chemical nature among these alloys and exhibits an intermediate antimicrobial efficacy only slightly lower than C22000 alloy C32 and alloy C4. Commercial money alloys (Y90 from Olin Brass, comparative alloy C3, Cu-12Zn-4Ni-7Mn) also contain Mn like the alloys of the present invention, but this is not the substantially white color of the present invention. Balanced to have a “golden appearance”. The antibacterial efficacy of C3 is slightly better than the alloy without Mn, with a 99.9% reduction after approximately 90 minutes exposure and complete inactivation after 120 minutes. Alloy C1 (commercially pure copper) shows a 99.9% reduction in total bacterial count after 75-90 minutes of exposure, with complete inactivation after 90 minutes.

  [0075] Based on these published results, we expected that the antimicrobial efficacy of the alloy of the present invention would be similar to alloy C3 (Y90). There is somewhat more zinc (resulting in longer times compared to Alloy C32 and Alloy C2) and slightly less nickel (shorter times compared to Alloys C4 and C5). Comparing alloys C8 and C3, Mn did not appear to have a strong effect on antibacterial efficacy, but the gradual and earlier decline in bacterial counts, rather than the sharp decline seen with most alloys Existed. Surprisingly, in the first test, the 99.9% reduction in the total number of CFUs is 45-60 minutes (40% faster than the other alloys) and the complete deactivation is after 60 minutes (40-50% faster). It was shown that. Subsequent tests showed a 99.9% reduction in as little as 10 minutes and complete inactivation in 15-30 minutes, using the same sample preparation and procedure, with the same alloy and Gram-positive bacteria Staph. Similar results were shown when attempted with Aureus [ATCC 6538]. The mechanism responsible for the increased mortality in our modified Mn-rich alloys is unclear, but seems to be related to the suppression of the passive oxide layer present on Cu alloys with Zn and Ni .

  [0076] Clearly, in accordance with the present invention, copper alloys have been provided that fully meet the objects, features and advantages of the present invention as set forth herein. While the invention has been described in conjunction with specific embodiments thereof, it is evident that there are many alternatives, modifications and variations based on these descriptions, which will be apparent to those skilled in the art. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variations that fall within the broad spirit and scope of the appended claims and is not limited to the specific examples shown herein. Absent.

  [0077] Further, the functions or structures of multiple components or stages can be combined into a single component or stage, or the functions or structures of one stage or component can be divided into multiple stages or structures. Will be understood. The present invention contemplates all these combinations. Unless otherwise noted, the dimensions and shapes of the various structures depicted herein are not intended to be limited to those of the present invention, and other dimensions or shapes are possible. Multiple structural components or stages can be provided by a single integrated structure or stage. Alternatively, a single integrated structure or stage may be divided into separate components or stages. In addition, while features of the invention may have been described in the context of only one of the illustrated embodiments, such features may be used in any given application for one or more other embodiments. You may combine with the feature of. It will also be appreciated from the above that the processing and operation of the unique structures herein is also a component of the method according to the present invention. The present invention also covers intermediate products and final products resulting from the performance of the methods herein. The use of “including” or “including” also contemplates aspects “consisting essentially of” or “consisting of” the listed feature.

  [0078] The descriptions and illustrations presented herein are intended to convey the invention, its principles, and its practical application to others skilled in the art. One skilled in the art can adapt and adapt the present invention in many ways so that it can be optimized for the requirements of a particular application. Accordingly, the specific embodiments of the present invention as set forth are not intended as being exhaustive or limiting of the invention. The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with the full scope of equivalents to which such claims are entitled. It is. The disclosures of all articles and references, including patent application documents and patent publications, are incorporated by reference for all purposes.

Claims (30)

(A) 6-25 wt% zinc,
(B) 7 to 17% by weight of manganese,
(C) 0.1-3.5 wt% nickel, and (d) the remaining copper
A product containing copper alloy consisting of, copper alloy, having a CIELAB b ^* value of the CIELAB a ^* values and -2～10 of -2～3 product. (A) 6-25 wt% zinc,
(B) 7 to 17% by weight of manganese,
(C) 0.1-3.5 wt% nickel,
(D) up to 0.5 wt % of one or more of Sn, Si, Co, Ti, Cr, Fe, Mg, Zr or Ag, or 0 of one or more of P, B, Ca, Ge, Se or Te. Up to 1% by weight or up to 0.5% by weight of one or more of Sn, Si, Co, Ti, Cr, Fe, Mg, Zr or Ag and 1 of P, B, Ca, Ge, Se or Te Both up to 0.1% by weight , and
(E) Remaining copper
A product comprising a copper alloy comprising: a product having a CIELAB a ^* value of -2 to 3 and a CIELAB b ^* value of -2 to 10 . The product of claim 1 wherein the copper alloy has a CIELAB a ^* value of -2 to 2 and a CIELAB b ^* value of -2 to 8. (A) 6-25 wt% zinc,
(B) 7 to 17% by weight of manganese,
(C) 0.1-3.5 wt% nickel,
(D) Zr up to 0.3% by weight , and
(E) Remaining copper
A product comprising a copper alloy comprising: a product having a CIELAB a ^* value of -2 to 3 and a CIELAB b ^* value of -2 to 10 .   The product of claim 1, wherein the copper alloy has a conductivity greater than 2.5% IACS at an eddy current gauge excitation frequency of 60 kHz to 480 kHz. (A) 6-25 wt% zinc,
(B) 7 to 17% by weight of manganese,
(C) 0.1-3.5 wt% nickel, and (d) the remaining copper
A copper alloy having a CIELAB a ^* value of −2 to 3 and a CIELAB b ^* value of −2 to 10 and a 22 mm × 22 mm square copper alloy comprising : inactivated within 120 min 99.9% from exposure bacteria in suspension 5~20μl present on the surface of the copper alloy that is not co computing, the suspension is 10 per milliliter ⁶ A product comprising- 10 ⁸ colony forming units of the bacterium, wherein the bacterium is Escherichia coli or Staphylococcus aureus .   The product of claim 6, wherein the copper alloy inactivates 99.9% of bacteria within 60 minutes of exposure.   8. The product of claim 7, wherein the copper alloy inactivates 99.9% of bacteria within 45 minutes of exposure.   9. The product of claim 8, wherein the copper alloy inactivates 99.9% of bacteria within 10 minutes of exposure.   The product of claim 6 comprising a contact surface.   11. A product according to claim 10, wherein the bacterium is E. coli.   11. A product according to claim 10, wherein the bacterium is Staphylococcus aureus.   11. The product of claim 10, wherein the product is a hospital instrument part or door hardware.   13. A product according to claim 11 or 12, wherein the product is a part of a hospital instrument. (A) 6-25 wt% zinc,
(B) 7 to 17% by weight of manganese,
(C) 0.1-3.5 wt% nickel, and (d) the remaining copper
A copper alloy having a CIELAB a ^* value of -2 to 3 and a CIELAB b ^* value of -2 to 10, the copper alloy comprising human skin or body fluid A product having a ΔE _CMC of less than 1 after 30 days exposure in air at 20-25 ° C. without contact. The product of claim 15, wherein ΔE _CMC is 0.73 or less. The product according to claim 16, wherein ΔE _CMC is 0.52 or less. (A) 6-25 wt% zinc,
(B) 7 to 17% by weight of manganese,
(C) 0.1-3.5 wt% nickel, and (d) the remaining copper
A copper alloy having a CIELAB a ^* value of −2 to 3 and a CIELAB b ^* value of −2 to 10; wherein the copper alloy is in air at 150 ° C. A product having a ΔE _CMC of less than 20 after 24 hours exposure. The product of claim 18, wherein ΔE _CMC is 15.1 or less. 20. A product according to claim 19, wherein the [Delta] E _CMC is 9.9 or less. (A) 6-25 wt% zinc,
(B) 7 to 17% by weight of manganese,
(C) 0.1-3.5 wt% nickel,
(D) 0.05 wt% to 2.5 wt% iron , and
(E) Remaining copper
A product comprising a copper alloy comprising: a product having a CIELAB a ^* value of -2 to 3 and a CIELAB b ^* value of -2 to 10 . The 22 mm × 22 mm square copper alloy inactivates 99.9% of the bacteria in 5-20 μl suspension on the surface of the uncoated copper alloy within 120 minutes of exposure, and the suspension 10 suspensions per milliliter ⁶ -10 ⁸ 22. A product according to claim 21 comprising the bacteria of a colony forming unit, wherein the bacteria are Escherichia coli or Staphylococcus aureus. Less than 1 ΔE after the copper alloy has been exposed in air at 20-25 ° C. for 30 days without contact with human skin or body fluids _CMC The product of claim 21, comprising: After the copper alloy was exposed in air at 150 ° C. for 24 hours, a ΔE of less than 20 _CMC The product of claim 21, comprising: The product of claim 1, 15 or 18 comprising a contact surface.   26. The product of claim 25, wherein the product is a hospital instrument part or door hardware. The product is a coin base plate, product of claim 1,6,15 or 1 8. The copper alloy comprises 9 wt% to 15 wt% zinc, 12 wt% to 16 wt% manganese, 2.5 wt% to 3 wt% nickel and 66 wt% to 76.5 wt% Cu; The product according to claim 1, 6, 15 or 18 . The copper alloy comprises 11.5 to 17 wt% manganese and the copper alloy has a CIELAB a ^* value of 0.09 to 2.01 and a CIELAB b ^* value of 5.32 to 8.43. The product according to any one of 1, 2, and 4-27. The copper alloy comprises 12-16 wt% manganese and the copper alloy has a CIELAB a ^* value of 0.64 to 2.01 and a CIELAB b ^* value of 6.23 to 8.43. The product according to any one of 2, and 4-29.

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