Nickel-free platinum alloy composition

Abstract

A platinum alloy composition is composed of, in weight percent, 0.0 to 5.0 gold, 0.0 to 2.5 cobalt, 0.0 to 3.0 copper, 0.0 to 5.0 iron, 0.0 to 2.75 gallium, 0.0 to 3.0 indium, 0.0 to 5.0 iridium, 0.0 to 5.0 manganese, 0.0 to 5.0 palladium, 0.0 to 5.0 rhenium, 0.0 to 5.5 rhodium, 0.0 to 5.0 ruthenium, 0.0 to 3.0 tin, 0.0 to 5.0 silver, and incidental impurities, where the sum of platinum and iridium is 95.0 or more, and wherein the following formula is satisfied, in which the sum of platinum and iridium is 95.0 or more. WCo, WCu, WFe, WGa, WIn, WNi, WPd, WSn, WRh, WIr, WAu, WRu, WRe, WAg and WMn are respectively weight percentages of cobalt, copper, iron, gallium, indium, nickel, palladium, tin, rhodium, iridium, gold, ruthenium, rhenium, silver and manganese in the alloy, 60 + WPd * 2.5 + WRh * 3.4 + WIr * 6.455 + WIr * 16.6 + WNi * 16.9 + WMn * 18.48 + WCo * 18.69 + WFe * 21.879 + WIn * 29 + WSn * 28.207 + WGa * 42.379 + WAg * 9.0 > = 130, and wherein the following conditions are satisfied, in which the weight percentages of cobalt, copper, iron -0.10406 * WAg-0. 1028 * WCo-0. 1201 * WCu-0. 2113 * WFe-0. 3368 * WGa-0. 1125 * WIn-0. 1639 * WNi-0. 0959 * WSn + 17.276261-0.20 * WMn + 0.0678 * WRu + 0.035 * WIr + 0.045 * WRh-0. 059 * WAu + 0.066 * WRe < = 17.1, and wherein the following formula is satisfied in which WCo, WCu, WFe, WGa, WIn, WNi, WPd, WSn, WMn, WRu, WIr, WRh, WAu, WAg and WRe are respectively aluminum, cobalt, copper, iron, gallium, indium, nickel, palladium

Description

Technical Field

[0001] This invention relates to a platinum alloy composition, particularly a platinum alloy composition for jewelry, and an alloy composition for jewelry with improved castability and suitable for jewelry. Background Technology

[0002] For jewelry applications, pure platinum is not hard enough. This results in poor abrasion resistance, but also other problems, such as easy deformation of the jewelry and inability to securely hold gemstones. To improve the hardness of platinum jewelry, pure platinum is alloyed with other (alloying) elements. However, alloying elements can adversely affect the castability of platinum alloys.

[0003] WO2022074363A1 describes alloys that serve similar purposes. Summary of the Invention

[0004] The object of this invention is to provide a platinum alloy with suitable hardness for ornaments, which has an improved balance of castability and weldability.

[0005] This invention provides a platinum alloy composition comprising, by weight percentage: 0.0 to 5.0 gold, 0.0 to 2.5 cobalt, 0.0 to 3.0 copper, 0.0 to 5.0 iron, 0.0 to 2.75 gallium, 0.0 to 3.0 indium, 0.0 to 5.0 iridium, 0.0 to 5.0 manganese, 0.0 to 5.0 palladium, 0.0 to 5.0 rhenium, 0.0 to 5.0 rhodium, 0.0 to 5.0 ruthenium, 0.0 to 3.0 tin, 0.0 to 5.0 silver, and incidental impurities, wherein the sum of platinum and iridium is 95.0 or more, wherein the following formula is satisfied, wherein W Co W Cu W Fe W Ga W In W Ni W Pd W Sn W Rh W Ir W Au W Ru W Re W Ag and W Mn These are the weight percentages of cobalt, copper, iron, gallium, indium, nickel, palladium, tin, rhodium, iridium, gold, ruthenium, rhenium, silver, and manganese in the alloy.

[0006] 60+W Pd *2.5+W Rh *3.4+W Ir *6.455+W Au *11.93+W Ru*13.241+

[0007] W Cu *14.328+W Re *16.6+W Ni *16.9+W Mn *18.48+W Co *18.69+W Fe *21.879+

[0008] W In *29+W Sn *28.207+W Ga *42.379+W Ag *9.0≥130

[0009] and the platinum alloy composition satisfies the following equations, where W Co , W Cu , W Fe , W Ga , W In , W Ni , W Pd , W Sn , W Mn , W Ru , W Ir , W Rh , W Au , W Pt , W Ag and W Re are the weight percent of cobalt, copper, iron, gallium, indium, nickel, palladium, tin, manganese, ruthenium, iridium, rhodium, gold, platinum, silver and rhenium in the alloy, respectively,

[0010] 16.6<-0.10406*W Ag -0.1028*W Co -0.1201*W Cu -0.2113*W Fe -0.3368*W Ga -0.1125*W In -0.1639*W Ni -0.015*W Pd -0.1959*W Sn +17.276261-0.20*W Mn +0.0678*W Ru +0.035*W Ir +0.045*W Rh -0.059*W Au +0.066*W Re ≤17.1,

[0011] and wherein the following is satisfied, W Co , W Cu , W Fe , W Ga , W In , W Ni , W Pd , W Sn , W Mn , W Ru , W Ir , W Rh , W Au , W Ag and W Re are the weight percent of aluminum, cobalt, copper, iron, gallium, indium, nickel, palladium, tin, titanium, manganese, ruthenium, iridium, rhodium, gold, silver, and rhenium, respectively, in the alloy,

[0012] 4.22W Ag 2 +0.041W Au W Co +0.122W Au W In +1.96W Au W Ni +1.87W Au W Sn +0.903W Au 2 +1.74W Co W Ga +13.4W Co W In +1.24W Co W Mn +5.04W Co W Sn +1.02W Co 2 +8.97W Cu W Fe +1.74W Cu W Ga +4.38W Cu W In +1.16W Cu W Mn +0.491W Cu W Ni +3.69W Cu W Sn +0.22W Cu 2 +1.68W Fe W Ga +3.31W Fe W In -1.26W Fe W Mn+5.07W Fe W Sn +0.199W Fe 2 +5.35W Ga W In +0.086W Ga W Mn +3.27W Ga W Re +33.3W Ga W Rh +4.56W Ga W Ru +2.21W Ga W Sn +29.0W Ga +8.49W Ga 2 +9.09W In W Mn -0.28W In W Ni +15.4W In W Rh +0.992W In W Ru +11.7W In +6.68W In 2 +0.863W Ir 2 +5.73W Mn W Ni -0.02W Mn W Ru +5.68W Mn W Sn +18.4W Mn -0.89W Mn 2 +0.49W Ni W Ru +0.186W Ni 2 +4.48W Re W Sn +1.15W Re 2 -5.11W Rh W Sn +2.04W Rh 2 +0.885W Ru W Sn +1.28W Ru 2 +1.58W Sn +9.49W Sn 2+11.6 < 100.

[0013] Such alloys have a good balance between hardness, castability, and weldability.

[0014] In embodiments, the platinum alloy composition consists of 95.0 or more platinum by weight percent. Such alloys are accepted worldwide as the hallmark standard for jewelry applications.

[0015] In embodiments, the platinum alloy composition satisfies the following formula, where W Co , W Cu , W Fe , W Ga , W In , W Ni , W Pd , W Sn , W Rh , W Ir , W Au , W Ru , W Re , W Ag , and W Mn are the weight percent of cobalt, copper, iron, gallium, indium, nickel, palladium, tin, rhodium, iridium, gold, ruthenium, rhenium, silver, and manganese in the alloy, respectively,

[0016] 60 + W Pd * 2.5 + W Rh * 3.4 + W Ir * 6.455 + W Au * 11.93 + W Ru * 13.241 +

[0017] W Cu * 14.328 + W Re * 16.6 + W Ni * 16.9 + W Mn * 18.48 + W Co * 18.69 + W Fe * 21.879 +

[0018] W In * 29 + W Sn * 28.207 + W Ga * 42.379 + W Ag * 9.0 < 140,

[0019] Preferably, where

[0020] 60 + W Pd * 2.5 + W Rh * 3.4 + W Ir * 6.455 + W Au * 11.93 + WRu *13.241+

[0021] W Cu *14.328+W Re *16.6+W Ni *16.9+W Mn *18.48+W Co *18.69+W Fe *21.879+

[0022] W In *29+W Sn *28.207+W Ga *42.379+W Ag *9.0≥150,

[0023] More preferably, wherein

[0024] 60+W Pd *2.5+W Rh *3.4+W Ir *6.455+W Au *11.93+W Ru *13.241+W Cu *14.328+W Re *16.6+W Ni *16.9+W Mn *18.48+W Co *18.69+W Fe *21.879+W In *29+W Sn *28.207+W Ga *42.379+W Ag *9.0≥160,

[0025] Still more preferably, wherein

[0026] 60+W Pd *2.5+W Rh *3.4+W Ir *6.455+W Au *11.93+W Ru *13.241+

[0027] W Cu *14.328+W Re *16.6+W Ni *16.9+W Mn *18.48+W Co *18.69+W Fe *21.879+

[0028] WIn *29 + W Sn *28.207 + W Ga *42.379 + W Ag *9.0 ≥ 170.

[0029] Such alloys have increased hardness and are useful for certain jewelry applications.

[0030] In embodiments, the platinum alloy composition satisfies the following formula, where W Ga , W In , and W Sn are the weight percentages of gallium, indium, and tin in the alloy,

[0031] W Sn + W In + W Ga ≥ 0.25, preferably W Sn + W In + W Ga ≥ 0.40, more preferably W Sn + W In + W Ga ≥ 0.50, and most preferably W Sn + W In + W Ga ≥ 0.75. Such alloys have increased hardness.

[0032] In embodiments, the platinum alloy composition consists of 2.0 or less iridium by weight percentage. Such alloys have lower cost.

[0033] In embodiments, the platinum alloy composition consists of 2.0 or less rhodium by weight percentage. Such alloys have lower cost.

[0034] In embodiments, the platinum alloy composition consists of 3.0 or less ruthenium, preferably 2.5 or less ruthenium, preferably 2.0 or less ruthenium by weight percentage. Such alloys have lower cost and reduced melting point.

[0035] In embodiments, the platinum alloy composition consists of 2.0 or less rhenium by weight percentage. Such alloys have reduced cost.

[0036] In embodiments, the platinum alloy composition consists of 2.0 or less indium, preferably 1.7 or less indium by weight percentage. Such alloys have improved castability and weldability.

[0037] In embodiments, the platinum alloy composition consists of 2.0 or less tin, preferably 1.5 or less tin, more preferably 1.0 or less tin by weight percentage. Such alloys have improved castability and weldability.

[0038] In embodiments, the platinum alloy composition satisfies the following equation, where W Ga , W Sn , W Ag , and W Au are the weight percentages of gallium, tin, silver, and gold in the alloy, respectively,

[0039] 0.45W Ag + 0.35W Au + 0.6W Sn + 0.6W In + W Ga ≤ 4.0,

[0040] Preferably

[0041] 0.45W Ag + 0.35W Au + 0.6W Sn + 0.6W In + W Ga ≤ 3.0.

[0042] Such an alloy has a low solidification range.

[0043] In embodiments, the platinum alloy composition consists of 3.0 or less gold by weight percentage, preferably 2.0 or less gold by weight percentage, more preferably 0.5 wt% or less gold by weight percentage, and most preferably gold is substantially absent. Such an alloy has improved castability and weldability.

[0044] In embodiments, the platinum alloy composition consists of 2.0 or less copper by weight percentage, preferably 1.0 or less copper by weight percentage. Such an alloy has a reduced solidification range.

[0045] In embodiments, the platinum alloy composition consists of 2.0 or less gallium by weight percentage, preferably 1.5 or less gallium by weight percentage. Such an alloy has a reduced solidification range.

[0046] In embodiments, the platinum alloy composition consists of 0.25 wt% or more total weight percentage of iridium, rhenium, rhodium, and ruthenium by weight percentage, preferably 0.5 wt% or more total weight percentage of iridium, rhenium, rhodium, and ruthenium by weight percentage, more preferably 0.75 wt% or more total weight percentage of iridium, rhenium, rhodium, and ruthenium by weight percentage, more preferably 1.0 wt% or more total weight percentage of iridium, rhenium, rhodium, and ruthenium by weight percentage, more preferably 1.2 wt% or more total weight percentage of iridium, rhenium, rhodium, and ruthenium by weight percentage, more preferably 1.4 wt% total weight percentage of iridium, rhenium, rhodium, and ruthenium by weight percentage, or most preferably 1.5 wt% or more total weight percentage of iridium, rhenium, rhodium, and ruthenium by weight percentage. Such an alloy has an increased melting point without a significant increase in solidification range.

[0047] In embodiments, the platinum alloy composition satisfies the following formula, where W Co , W Cu , W Fe , W Ga , W In , W Ni , W Pd , W Sn , W Mn , W Ru , W Ir , W Rh , W Au , W Ag , and W Re are the weight percent of aluminum, cobalt, copper, iron, gallium, indium, nickel, palladium, tin, titanium, manganese, ruthenium, iridium, rhodium, gold, silver, and rhenium in the alloy, respectively,

[0048] 4.22W Ag 2 +0.041W Au W Co +0.122W Au W In +1.96W Au W Ni +1.87W Au W Sn +0.903W Au 2 +1.74W Co W Ga +13.4W Co W In +1.24W Co W Mn +5.04W Co W Sn +1.02W Co 2 +8.97W Cu W Fe +1.74W Cu W Ga +4.38W Cu W In +1.16W Cu W Mn +0.491W Cu W Ni +3.69W Cu W Sn +0.22W Cu 2 +1.68W Fe W Ga +3.31W Fe W In -1.26W Fe WMn +5.07W Fe W Sn +0.199W Fe 2 +5.35W Ga W In +0.086W Ga W Mn +3.27W Ga W Re +33.3W Ga W Rh +4.56W Ga W Ru +2.21W Ga W Sn +29.0W Ga +8.49W Ga 2 +9.09W In W Mn -0.28W In W Ni +15.4W In W Rh +0.992W In W Ru +11.7W In +6.68W In 2 +0.863W Ir 2 +5.73W Mn W Ni -0.02W Mn W Ru +5.68W Mn W Sn +18.4W Mn -0.89W Mn 2 +0.49W Ni W Ru +0.186W Ni 2 +4.48W Re W Sn +1.15W Re 2 -5.11W Rh W Sn +2.04W Rh 2 +0.885W Ru W Sn +1.28W Ru 2 +1.58W Sn +9.49W Sn2 + 11.6 < 90,

[0049] Preferably

[0050] 4.22 W Ag 2 + 0.041 W Au W Co + 0.122 W Au W In + 1.96 W Au W Ni + 1.87 W Au W Sn + 0.903 W Au 2 + 1.74 W Co W Ga + 13.4 W Co W In + 1.24 W Co W Mn + 5.04 W Co W Sn + 1.02 W Co 2 + 8.97 W Cu W Fe + 1.74 W Cu W Ga + 4.38 W Cu W In + 1.16 W Cu W Mn + 0.491 W Cu W Ni + 3.69 W Cu W Sn + 0.22 W Cu 2 + 1.68 W Fe W Ga + 3.31 W Fe W In - 1.26 W Fe W Mn + 5.07 W Fe W Sn + 0.199 W Fe 2 + 5.35 W Ga W In + 0.086 W Ga W Mn + 3.27 W Ga W Re + 33.3 W Ga W Rh + 4.56 W Ga W Ru+2.21 W Ga W Sn +29.0 W Ga +8.49 W Ga 2 +9.09 W In W Mn -0.28 W In W Ni +15.4 W In W Rh +0.992 W In W Ru +11.7 W In +6.68 W In 2 +0.863 W Ir 2 +5.73 W Mn W Ni -0.02 W Mn W Ru +5.68 W Mn W Sn +18.4 W Mn -0.89 W Mn 2 +0.49 W Ni W Ru +0.186 W Ni 2 +4.48 W Re W Sn +1.15 W Re 2 -5.11 W Rh W Sn +2.04 W Rh 2 +0.885 W Ru W Sn +1.28 W Ru 2 +1.58 W Sn +9.49 W Sn 2 +11.6 ≤ 85,

[0051] more preferably

[0052] 4.22 W Ag 2 +0.041 W Au W Co +0.122 W Au W In +1.96 W Au W Ni +1.87 W Au W Sn +0.903 WAu 2 +1.74W Co W Ga +13.4W Co W In +1.24W Co W Mn +5.04W Co W Sn +1.02W Co 2 +8.97W Cu W Fe +1.74W Cu W Ga +4.38W Cu W In +1.16W Cu W Mn +0.491W Cu W Ni +3.69W Cu W Sn +0.22W Cu 2 +1.68W Fe W Ga +3.31W Fe W In -1.26W Fe W Mn +5.07W Fe W Sn +0.199W Fe 2 +5.35W Ga W In +0.086W Ga W Mn +3.27W Ga W Re +33.3W Ga W Rh +4.56W Ga W Ru +2.21W Ga W Sn +29.0W Ga +8.49W Ga 2 +9.09W In W Mn -0.28W In W Ni +15.4W In W Rh +0.992W In W Ru +11.7W In +6.68WIn 2 +0.863W Ir 2 +5.73W Mn W Ni -0.02W Mn W Ru +5.68W Mn W Sn +18.4W Mn -0.89W Mn 2 +0.49W Ni W Ru +0.186W Ni 2 +4.48W Re W Sn +1.15W Re 2 -5.11W Rh W Sn +2.04W Rh 2 +0.885W Ru W Sn +1.28W Ru 2 +1.58W Sn +9.49W Sn 2 +11.6≤80,

[0053] even more preferably

[0054] 4.22W Ag 2 +0.041W Au W Co +0.122W Au W In +1.96W Au W Ni +1.87W Au W Sn +0.903W Au 2 +1.74W Co W Ga +13.4W Co W In +1.24W Co W Mn +5.04W Co W Sn +1.02W Co 2 +8.97W Cu W Fe +1.74W CuW Ga +4.38W Cu W In +1.16W Cu W Mn +0.491W Cu W Ni +3.69W Cu W Sn +0.22W Cu 2 +1.68W Fe W Ga +3.31W Fe W In -1.26W Fe W Mn +5.07W Fe W Sn +0.199W Fe 2 +5.35W Ga W In +0.086W Ga W Mn +3.27W Ga W Re +33.3W Ga W Rh +4.56W Ga W Ru +2.21W Ga W Sn +29.0W Ga +8.49W Ga 2 +9.09W In W Mn -0.28W In W Ni +15.4W In W Rh +0.992W In W Ru +11.7W In +6.68W In 2 +0.863W Ir 2 +5.73W Mn W Ni -0.02W Mn W Ru +5.68W Mn W Sn +18.4W Mn -0.89W Mn 2 +0.49W Ni W Ru +0.186WNi 2 +4.48W Re W Sn +1.15W Re 2 -5.11W Rh W Sn +2.04W Rh 2 +0.885W Ru W Sn +1.28W Ru 2 +1.58W Sn +9.49W Sn 2 +11.6≤75,

[0055] Most preferably

[0056] 4.22W Ag 2 +0.041W Au W Co +0.122W Au W In +1.96W Au W Ni +1.87W Au W Sn +0.903W Au 2 +1.74W Co W Ga +13.4W Co W In +1.24W Co W Mn +5.04W Co W Sn +1.02W Co 2 +8.97W Cu W Fe +1.74W Cu W Ga +4.38W Cu W In +1.16W Cu W Mn +0.491W Cu W Ni +3.69W Cu W Sn +0.22W Cu 2 +1.68W Fe W Ga +3.31W Fe W In -1.26WFe W Mn +5.07W Fe W Sn +0.199W Fe 2 +5.35W Ga W In +0.086W Ga W Mn +3.27W Ga W Re +33.3W Ga W Rh +4.56W Ga W Ru +2.21W Ga W Sn +29.0W Ga +8.49W Ga 2 +9.09W In W Mn -0.28W In W Ni +15.4W In W Rh +0.992W In W Ru +11.7W In +6.68W In 2 +0.863W Ir 2 +5.73W Mn W Ni -0.02W Mn W Ru +5.68W Mn W Sn +18.4W Mn -0.89W Mn 2 +0.49W Ni W Ru +0.186W Ni 2 +4.48W Re W Sn +1.15W Re 2 -5.11W Rh W Sn +2.04W Rh 2 +0.885W Ru W Sn +1.28W Ru 2 +1.58W Sn +9.49WSn 2 +11.6 < 70.

[0057] Such alloys have a reduced solidification range and thus improved castability and weldability.

[0058] In embodiments, the platinum alloy composition satisfies the following formula, where W Co , W Cu , W Fe , W Ni , and W Pd are the weight percentages of cobalt, copper, iron, nickel, and palladium in the alloy,

[0059] W Co + W Pd + W Fe + W Ni + W Cu ≥ 1.0

[0060] Preferably

[0061] W Co + W Pd + W Fe + W Ni + W Cu ≥ 2.0.

[0062] Such alloys have a lower melting point without a significant increase in solidification range.

[0063] In embodiments, the platinum alloy comprises at least one element from the list of cobalt, palladium, iron, and copper, preferably where the sum of cobalt, palladium, iron, and copper is 1.0 wt% or more, more preferably 1.1 wt% or more. Such alloys achieve an excellent balance of castability, weldability, and hardness.

[0064] In embodiments, the platinum alloy composition comprises at least one element from the list of ruthenium, rhenium, iridium, and rhodium, preferably where the sum of ruthenium, rhenium, iridium, and rhodium is 0.25 wt% or more, preferably 0.5 wt% or more, more preferably 0.75 wt% or more, more preferably 1.0 wt% or more, more preferably 1.2 wt% or more, and most preferably 1.4 wt% or more. Such alloys achieve an excellent balance of castability, weldability, and hardness.

[0065] In embodiments, the platinum alloy composition comprises at least one element from the list of tin, indium, and gallium, preferably where the sum of tin, indium, and gallium is 1.2 wt% or more, more preferably 1.6 wt% or more. Such alloys achieve an excellent balance of castability, weldability, and hardness.

[0066] In embodiments, the platinum alloy composition satisfies the following formula, where W Co , WCu , W Fe , W Ga , W In , W Ni , W Pd , W Sn , W Mn , W Ru , W Ir , W Rh , W Au , W Pt , W Ag and W Re are the weight percentages of cobalt, copper, iron, gallium, indium, nickel, palladium, tin, manganese, ruthenium, iridium, rhodium, gold, platinum, silver and rhenium, respectively, in the alloy,

[0067] 16.65 < -0.10406*W Ag -0.1028*W Co -0.1201*W Cu -0.2113*W Fe -0.3368*W Ga -0.1125*W In -0.1639*W Ni -0.015*W Pd -0.1959*W Sn +17.276261 -0.20*W Mn +0.0678*W Ru +0.035*W Ir +0.045*W Rh -0.059*W Au +0.066*W Re ,

[0068] Preferably

[0069] 16.70 < -0.10406*W Ag -0.1028*W Co -0.1201*W Cu -0.2113*W Fe -0.3368*W Ga -0.1125*W In -0.1639*W Ni -0.015*W Pd -0.1959*W Sn +17.276261 -0.20*W Mn +0.0678*W Ru +0.035*W Ir +0.045*W Rh -0.059*WAu +0.066*W Re .

[0070] Such alloys have further improved weldability while maintaining castability.

[0071] In embodiments, the platinum alloy composition satisfies the following formula, where W Co , W Cu , W Fe , W Ga , W In , W Ni , W Pd , W Sn , W Mn , W Ru , W Ir , W Rh , W Au , W Pt , W Ag and W Re are the weight percentages of cobalt, copper, iron, gallium, indium, nickel, palladium, tin, manganese, ruthenium, iridium, rhodium, gold, platinum, silver, and rhenium in the alloy, respectively,

[0072] -0.10406*W Ag -0.1028*W Co -0.1201*W Cu -0.2113*W Fe -0.3368*W Ga -0.1125*W In -0.1639*W Ni -0.015*W Pd -0.1959*W Sn +17.276261-0.20*W Mn +0.0678*W Ru +0.035*W Ir +0.045*W Rh -0.059*W Au +0.066*W Re ≤ 17.00.

[0073] Such alloys have improved castability.

[0074] In embodiments, the platinum alloy composition consists of platinum, indium, ruthenium, tin, and iron. Such alloys achieve an excellent balance of castability, weldability, and hardness.

[0075] In embodiments, the platinum alloy composition consists of platinum, ruthenium, iron, and gallium. Such alloys achieve an excellent balance of castability, weldability, and hardness.

[0076] In embodiments, the platinum alloy composition comprises 0.5 to 2.0 indium by weight percent. Such an alloy has a lower melting point and increased hardness without substantially increasing the solidification range.

[0077] In embodiments, the platinum alloy composition comprises 1.0 to 2.5 ruthenium by weight percent. Such an alloy has increased hardness without substantially increasing the cost.

[0078] In embodiments, the platinum alloy composition comprises 0.2 to 1.0 tin by weight percent. Such an alloy has a lower melting point and increased hardness without substantially increasing the solidification range.

[0079] In embodiments, the platinum alloy composition comprises 0.5 to 1.75 iron by weight percent. Such an alloy has a lower melting point and increased hardness at a low cost with a low risk of ferromagnetism.

[0080] In embodiments, the platinum alloy composition comprises 0.5 to 1.75 gallium by weight percent. Such an alloy has a lower melting point and increased hardness without substantially increasing the solidification range.

[0081] In embodiments, the platinum alloy composition comprises 4.0 wt% or less iron, preferably 2.5 wt% or less iron, more preferably 2.25 wt% or less iron, more preferably 2.0 wt% or less iron, more preferably 1.75 wt% or less iron, more preferably 1.75 wt% or less iron by weight percent. Such an alloy has a lower risk of ferromagnetism.

[0082] In embodiments, the platinum alloy composition comprises 2.0 or less cobalt, preferably 1.0 or less cobalt, more preferably substantially no cobalt by weight percent. Such an alloy has a lower risk of ferromagnetism and a lower allergy problem.

[0083] In embodiments, the platinum alloy composition comprises 3.0 or less palladium, preferably 2.5 or less palladium, more preferably 2.0 or less palladium, more preferably 1.5 or less palladium, more preferably 0.1 or less palladium, most preferably substantially no palladium by weight percent. Such an alloy has a lower cost.

[0084] In embodiments, the platinum alloy composition comprises 3.0 or less manganese, preferably 2.5 or less manganese, more preferably 0.1 or less manganese, most preferably substantially no manganese by weight percent. Such an alloy has a lower risk of volatilization.

[0085] In embodiments, the platinum alloy composition comprises 0.5 or more indium by weight percent, preferably 0.75 or more indium, more preferably 1.0 or more indium. Such an alloy has improved hardness.

[0086] In embodiments, the platinum alloy composition comprises 0.5 or more ruthenium by weight percent, preferably 0.8 or more ruthenium, more preferably 1.0 or more ruthenium, more preferably 1.2 or more ruthenium. Such an alloy has higher hardness at lower cost.

[0087] In embodiments, the platinum alloy composition comprises 0.2 or more tin by weight percent. Such an alloy has improved hardness.

[0088] In embodiments, the platinum alloy composition comprises 0.25 or more iron by weight percent, preferably 0.5 or more iron, more preferably 0.75 or more iron, more preferably 1.0 or more iron. Such an alloy has improved hardness without a significant increase in solidification range.

[0089] In embodiments, the platinum alloy composition comprises 0.5 or more gallium by weight percent, preferably 0.75 or more gallium, more preferably 1.0 or more gallium. Such an alloy has a reduced melting point and increased hardness.

[0090] In embodiments, the platinum alloy composition has a total of 1.5 wt% or less cobalt, palladium, iron, and copper. Such an alloy has increased hardness.

[0091] In embodiments, the platinum alloy composition has a total of 2.7 wt% or less, more preferably 2.6 wt% or less, ruthenium, rhenium, iridium, and rhodium. Such an alloy has a reduced solidification range.

[0092] In embodiments, the platinum alloy composition has a total of 2.7 wt% or less, more preferably 2.5 wt% or less, tin, indium, and gallium. Such an alloy has improved castability and weldability.

[0093] In embodiments, the platinum alloy composition consists of 1.2 ± 0.2 iron, 1.5 ± 0.2 indium, 1.5 ± 0.2% ruthenium, 0.6 tin, the balance (optionally at least 95%) platinum and incidental impurities by weight percent. Such an alloy has been shown to exhibit good castability, weldability, and hardness.

[0094] In embodiments, the platinum alloy composition consists of 1.2 ± 0.2 iron, 1.2 ± 0.2 gallium, 2.4 ± 0.2 ruthenium, the balance (optionally at least 95%) platinum and incidental impurities by weight percent. Such an alloy has been shown to exhibit good castability, weldability, and hardness.

[0095] In embodiments, the platinum alloy composition consists of, in weight percent: 1.2 ± 0.2 iron, 1.5 ± 0.2 indium, 1.5 ± 0.2% ruthenium, 0.6 tin, the balance (optionally at least 95%) being platinum and incidental impurities. This alloy has been shown to exhibit good castability, weldability, and hardness.

[0096] The term "consisting of is used herein to indicate a 100% reference to a composition, and excludes the presence of additional components, such that the percent adds up to 100%. BRIEF DESCRIPTION OF DRAWINGS

[0097] The application is more fully described by reference to the following examples, with reference to the attached drawings, wherein:

[0098] Figure 1 Porosity measured on cast samples of some embodiments of the invention and comparative examples is shown.

[0099] Figure 2 Cast defects of comparative examples are shown, in contrast to no defects in embodiments of the invention.

[0100] Figure 3 Weldability of comparative examples and embodiments of the invention is shown.

[0101] Figure 4 Silicon dioxide inclusions present on the fracture surface of comparative example 14 are shown. The presence of silicon dioxide indicates poor castability of the alloy.

[0102] Figure 5 A tree part of an embodiment of the invention is compared to a comparative example of the same geometry cast under the same conditions. Unlike the comparative example, the embodiment of the invention shows excellent form filling ability.

[0103] Figure 6 An SEM EDS line scan of a cast part made from a comparative example is shown, perpendicular to several secondary dendrite arms in the as-cast condition. It shows severe segregation of Sn and In in the interdendritic space, which is typically associated with significant shrinkage porosity. DETAILED DESCRIPTION

[0104] Hardness of the platinum alloy results from two chemical determination mechanisms:

[0105] I. Solid solution hardening - achieved by the distortion of the platinum metal lattice by solute elements due to differences in atomic radii.

[0106] II. Precipitation hardening - for added elements, if beyond the solubility limit of platinum, secondary phases can occur. These phases increase the resistance of the alloy to deformation.

[0107] While it is desirable to add elements to platinum to increase hardness, the addition of alloying elements can adversely affect the castability of the material in the following ways:

[0108] i. Increased melting temperature - the addition of certain elements to pure Pt will increase the overall melting temperature of the alloy. Higher melting temperatures will increase the risk of the molten metal eroding and reacting with the crucible and mould materials during casting. This increases the risk of casting defects and reduces the surface quality of the cast piece. Since the crucible is typically made of silica which has a melting point close to that of pure platinum, the molten platinum alloy cannot be heated much above ~1850°C before casting, otherwise the molten silica will contaminate the melt. For platinum alloys with high melting points, this restriction results in reduced alloy flowability during casting as the metal will solidify before fully filling the mould.

[0109] ii. Casting micro-porosity - during the later stages of solidification during casting, liquid metal becomes trapped between dendritic arms. The contraction of this trapped liquid results in the formation of porosity. The porosity formed is typically visible and will render the cast jewellery article unacceptable in terms of visual appearance. The degree of contraction and the resulting porosity increases with the solidification range of the alloy, as the alloy will undergo more thermal contraction before it can fully solidify. Alloying additions are known to cause significant changes in the volume of the liquid alloy metal, increasing the tendency for micro-porosity.

[0110] iii. Hot tearing - alloys with a very wide solidification temperature range are subject to a combination of increased thermal stresses caused by temperature reduction and limited mechanical strength due to liquid films between growing grains. The combination of increased stresses and poor mechanical strength causes the metal to tear at high temperatures, resulting in scrap parts.

[0111] It was found that the alloys described in WO2022074363A1 have high hardness and good castability due to their low melting temperature. However, weldability is only a secondary consideration and for many alloys their performance is largely dependent on the addition of nickel, which is a known allergenic element and therefore less and less popular in the jewellery industry.

[0112] In the present invention, acceptable castability is achieved by optimising several material properties which are reflected in the merit indices. These indices include a mid-melting point index to reduce the risk of silica inclusions and improve castability and a low solidification range index to reduce porosity during casting and improve weldability. That is, the values of the melting point index and the solidification range index are related to the risk of typical casting defects: shrinkage porosity, formation of inclusions, poor surface finish and poor form fill.

[0113] The wear resistance and gemstone setting ability are improved by increasing the hardness to a hardness index of at least 130, resulting in excellent mechanical properties. The alloys in the present invention have tunable hardness and can achieve a hardness of 150 HV or more, thus offering the possibility to trade off between ease of formability and improved wear resistance depending on the application.

[0114] Excellent weldability is achieved by avoiding the formation of low melting point regions in the as-cast state. By increasing the melting point of the alloy to a level greater than suggested in WO2022074363A1 and additionally keeping the solidification range narrow (both predicted using the figure of merit), these regions can be avoided. This requirement is traded off against one of the requirements for good castability (lower melting point of the alloy). Therefore, an intermediate melting point is required to balance the castability requirement (reduction of silicon dioxide inclusions) and the weldability (avoidance of low melting point regions). To improve both castability and weldability, the solidification range can be minimized, which can be used to compensate for the fact that the melting point cannot be as low as suggested in WO2022074363A1 to meet the weldability requirement.

[0115] A modelling-based method for isolating new platinum alloys is described herein, which addresses at least some of the above-mentioned problems. The method utilizes a computational materials modelling framework combined with machine learning to estimate design-relevant properties within a broad composition space. In principle, such an alloy design tool can solve the so-called inverse problem; determining the best alloy composition that best satisfies a set of specified design constraints.

[0116] The first step in the design process is to define a list of elements and associated upper and lower composition limits. Table 1 lists the composition limits for each element addition considered in the present invention, referred to as the “alloy design space”. These limits were chosen by the inventors based on the explanations given below. Some insights come from metallurgical experience, while other insights, such as the effect on platinum alloy melting point, castability and inclusion presence, were established by the inventors based on thermodynamic calculations over a wider composition range than listed in Table 1.

[0117] Table 1: Composition limits used The method searches and identifies compositions within the composition range claimed in the present invention.

[0118]

[0119] It is relatively easy to increase the hardness of pure platinum by adding alloying elements. However, it is not easy to do so while maintaining good castability and weldability. In addition to this, it is necessary to limit any rise in the alloy solidification range caused by the alloying elements, avoid excessive precipitation of intermetallic phases in the last stages of solidification, and avoid the formation of reactive element induced slags. All of these mechanisms can lead to casting defects. For other reasons, it is necessary to limit some elements that would otherwise be suitable to meet at least some of these conflicting requirements.

[0120] With this in mind, the reasons for the selection of the elements in Table 1 and their ranges are as follows:

[0121] The minimum amount of platinum in the alloy is set at 95.0 in weight percent because this is the typical hallmark standard for platinum alloys for jewelry applications. In some cultures, any iridium content in a platinum alloy is considered equivalent to platinum, which means that the platinum content in the alloy is considered equal to the sum of platinum and iridium.

[0122] Cobalt, copper, iron, manganese, and palladium: All lower the melting point of pure platinum and increase the hardness by a combination of solid solution strengthening and precipitation strengthening. In addition, they are relatively unreactive, which means that alloys with Pt can be repeatedly remelted without significantly changing the composition of the alloy due to reactions with the atmosphere, the crucible walls, or the mold walls. The amounts of cobalt, manganese, and iron are limited in Table 1 because additions beyond the ranges specified in Table 1 are unlikely to bring additional benefits. This is because such additions can not further significantly lower the melting point, can result in too high a proportion of intermetallic phases upon cooling of the cast piece, or can increase the solidification range. In addition, high amounts of cobalt can make the alloy ferromagnetic, which can cause manufacturing problems. Likewise, iron can cause unwanted ferromagnetism and also form intermetallic phases at high temperatures, which are believed to impair ductility, and manganese is prone to evaporate from the melt, which can cause processing problems. Each of these elements can be limited to 5.0 wt% or less independently of the others. Copper is limited to 3.0 wt% or less because it has been found to have a relatively high impact on increasing the solidification range while providing relatively little hardness compared to the other elements in this group. These effects are undesirable. Therefore, copper is preferably limited to 2.5 wt% or less, more desirably 2.0 wt% or less, even more desirably 1.5 wt% or less, most desirably 1.0 wt% or less, or even 0.5 wt% or less. Of these elements, iron is particularly useful because it increases the solidification range less than copper and does not have the drawbacks of the other elements (palladium is expensive, manganese is prone to evaporate during processing, and cobalt causes allergy problems and imparts ferromagnetism in very small amounts). Therefore, iron is preferably present in an amount of 0.25 wt% or more, preferably 0.5 wt% or more, even more preferably 0.75 wt% or more. The best performing alloys can even have 1.0 wt% or more of iron. However, iron is preferably limited to 4.0 wt% or less, even 3.0 wt% or less, even 2.5 wt% or less, even 2.25 wt% or less, even 2.0 wt% or less, even 1.75 wt% or less, so that the alloy can contain more of the other elements, which can have a stronger beneficial effect than iron or can have a different beneficial effect. Cobalt is limited to 2.5 wt% or less because cobalt makes the alloy ferromagnetic, which can cause manufacturing problems and also causes allergy problems. For this reason, it is desirably limited to 2.0 wt% or less, or 1.5 wt% or less, or even 1.0 wt% or less. In embodiments, cobalt is limited to 0.5 wt% or less, even 0.1 wt% or less, or can be substantially absent. Due to the high cost, palladium is limited to 5.0 wt% or less. Preferably, palladium is limited to 4.0 wt% or less, or preferably 3.0 wt% or less, or 1.5 wt% or less, or 1.0 wt% or less, even 0.1 wt% or less, to keep the alloy cost low.In embodiments, palladium is present in an amount of 2.5 wt% or less (or 2.0 wt% or less) to take advantage of its effects in lowering melting point and increasing hardness, without adding too much to the cost of the alloy. In embodiments, palladium is not present to reduce cost. Manganese is limited to 5.0 wt% or less because it is prone to volatilize during processing. Preferably, manganese is limited to 4.0 wt% or less, more preferably 3.0 wt% or less, or 2.5 wt% or less, or 2.0 wt% or less, or even 1.5 wt% or less, or even 0.1 wt% or less to avoid volatilization. In embodiments, palladium is not present. In embodiments, at least one element of the group of cobalt, palladium, iron, and copper is present. This helps to achieve a balance of hardness, solidification range, and melting temperature. In all of the following examples, the sum of cobalt, palladium, iron, and copper is at least 1.0 wt%, and this is desirable. In embodiments, the sum of cobalt, palladium, iron, and copper is at least 1.5 wt%.

[0123] Gold and silver: Both of these elements are non-reactive, meaning that alloys with platinum can be repeatedly remelted without significantly changing the composition of the alloy due to reactions with the atmosphere, crucible walls, or mold walls. Both of these elements also slightly lower the melting temperature of platinum alloys at low concentrations, and increase hardness. However, both of these elements increase the solidification range of Pt alloys at higher concentrations, which has a detrimental effect on weldability and castability. Therefore, gold and silver are limited to 5.0 wt% or less, more preferably 4.5 wt% or less or 4.0 wt% or less. In embodiments, gold and silver are limited to 3.0 wt% and 1.5 wt%, respectively, more preferably 2.5 wt% and 1.5 wt%, respectively, even more preferably 2.0 wt% and 1.0 wt%, respectively. Gold and / or silver can each be limited to 0.5 wt% or less to avoid increasing the solidification range. Most preferably, gold and silver are not present in the alloy because their presence would hinder recyclability due to the difficulty of separating them from platinum.

[0124] Rhodium, iridium, ruthenium and rhenium: These elements are non-reactive, meaning that alloys with platinum can be repeatedly remelted without significantly changing the composition of the alloy due to reactions with the atmosphere, crucible walls or mold walls. In addition, these elements slightly increase the hardness through solid solution strengthening. However, excessive additions of iridium and / or rhodium and / or rhenium can significantly increase the cost of the alloy and increase the melting point of the alloy, thereby adversely affecting the castability of the alloy. Therefore, the amount of rhodium, iridium and rhenium is each limited to 5.0 wt% or less, preferably each is 4.0 wt% or less, more preferably each is 3.5 wt% or less, more preferably each is 3.0 wt% or less, and most preferably each is 2.5 wt% or less or 2.0 wt% or less. In embodiments, one or more of rhodium, iridium, rhenium and ruthenium are not present in the alloy because their presence would hinder recyclability due to difficulty in separating them from platinum. Of these elements, Ru is particularly useful because it is the least expensive while not significantly increasing the melting point and solidification range. Therefore, in embodiments, Ru is present in an amount of 0.5 wt% or more, more preferably 0.8 wt%, most preferably 1.0 wt% or more, or even 1.2 wt% or more.

[0125] Tin, indium, gallium: Each significantly lowers the melting point of pure Pt and strongly increases the hardness through solid solution and / or precipitate strengthening. However, excessive additions can result in too high a proportion of intermetallic phases upon cooling of the cast piece, or can excessively increase the solidification range, thereby adversely affecting weldability and castability. Therefore, the amount of indium is limited to 3.0 wt% or less (preferably 2.5 wt% or less, or 2.0 wt% or less, and most preferably 1.7 wt% or less), and the amount of tin is limited to 3.0 wt% or less (preferably 2.5 wt% or less, or 2.0 wt% or less, more preferably 1.5 wt% or less, and most preferably 1.0 wt% or less). The amount of gallium is limited to 2.75 wt% or less (preferably 2.25 wt% or less, or 2.0 wt% or 1.75 wt% or less, or 1.5 wt% or less). Without these elements, it is difficult to achieve high hardness in an alloy containing 95 wt% platinum, which means that, preferably, the alloy contains 0.4 wt% or more, or even 0.4 wt% or more, or even 0.6 wt% or more of tin, indium and gallium in total. For the same reason, it is preferable that the alloy contains 0.2 wt% or more of tin, and / or 0.5 wt% or more of gallium, as in Examples 1 and 2. Examples 1 and 2 show the benefit of at least 0.5 wt% indium, and this is preferred. 0.75 wt% or more of indium and / or gallium is even more preferred, and 1.0 wt% or more of indium and / or gallium is still more preferred.

[0126] In addition to the ranges in Table 1, the alloys in the present application can also contain small amounts of other elements as incidental impurities. These include titanium, aluminum, chromium, zinc, yttrium, hafnium, zirconium, vanadium, niobium, tantalum, molybdenum, tungsten, nickel, scandium, any lanthanide, germanium. The total incidental impurities are 1.0 wt% or less of the alloy, preferably 0.5 wt% or less of the alloy. Any single impurity element is present at a level of 0.5 wt% or less, preferably 0.25 wt% or less, or even 0.1 wt% or less. Many of these elements are highly reactive and can reduce castability and / or cause the formation of intermetallic precipitates, which in large amounts can cause embrittlement and cracking at the grain boundaries, thereby reducing ductility. In embodiments, aluminum and / or chromium and / or titanium can effectively be absent.

[0127] The second step relies on thermodynamic calculations to calculate the phase diagram and thermodynamic properties of a particular alloy composition. This is commonly referred to as the CALPHAD (CALculation of PHAse Diagrams) approach.

[0128] The third stage involves the development of an alloy composition with the desired properties calculated in the second step. Candidate alloys in the composition space under investigation are selected for good castability, good weldability, and good mechanical properties. These properties are reflected in various merit indices described below.

[0129] The performance index for castability is:

[0130] Melting point index: This reflects the melting point of the alloy. The melting point can be directly obtained from the thermodynamic calculations. Lower values are generally better, as a low melting point implies that metal-mold reactions can be suppressed, thereby reducing gas porosity and improving surface finish. A lower melting point also enables a higher superheat relative to a higher melting point. Higher superheat increases flowability and improves the shape filling characteristics of the alloy. However, to ensure good weldability, the melting point of the alloy should be significantly higher than that of the welding material, thereby setting a lower limit on the melting point for the use of ordinary welding materials. These often contain about 90 wt% Pt, with the balance usually consisting of elements such as Ga, In, and Ag that help to lower the melting point of the alloy to below 1500°C, and sometimes as low as 950°C. Since the thermodynamic calculations for the melting point are too complex to use here, we derive a simpler merit index that reflects the variation of the melting point with alloy composition:

[0131] Melting point index = -0.10406 * W Ag -0.1028 * W Co -0.1201 * W Cu -0.2113 * W Fe -0.3368 * W Ga-0.1125*W In -0.1639*W Ni -0.015*W Pd -0.1959*W Sn +17.276261-0.20*W Mn +0.0678*W Ru +0.035*W Ir +0.045*W Rh -0.059*W Au +0.066*W Re .

[0132] A melting point index greater than 16.6 in combination with the lower end of the solidification range index contributes to good castability and ensures good weldability. Preferably, the melting point index is 16.65 or greater, more preferably 16.70 or greater. A melting point index of 17.1 or lower is obtained with sufficient castability. Preferably, the melting point index is 17.00 or lower.

[0133] Solidification range index: The temperature range over which an alloy will solidify, assuming perfect thermodynamic equilibrium is maintained throughout the solidification process. That is, assuming thermodynamic equilibrium, the solidification range is the temperature range between the temperature at which the liquid first appears upon heating and the temperature at which the last solid melts upon heating. This range can be directly derived from thermodynamic calculations. A larger range is typically associated with excessive elemental segregation in the as-cast microstructure, which leads to poor mechanical properties of the cast part, increased risk of hot cracking, higher porosity, and poor weldability. Since the thermodynamic calculations to derive the solidification range are too complex to be used here, we instead derive a merit index that more simply reflects changes in the solidification range:

[0134] Solidification range index = 4.22W Ag 2 +0.041W Au W Co +0.122W Au W In +1.96W Au W Ni +1.87W Au W Sn +0.903W Au 2 +1.74W Co W Ga +13.4W Co W In +1.24W Co W Mn +5.04W Co W Sn +1.02W Co2 +8.97W Cu W Fe +1.74W Cu W Ga +4.38W Cu W In +1.16W Cu W Mn +0.491W Cu W Ni +3.69W Cu W Sn +0.22W Cu 2 +1.68W Fe W Ga +3.31W Fe W In -1.26W Fe W Mn +5.07W Fe W Sn +0.199W Fe 2 +5.35W Ga W In +0.086W Ga W Mn +3.27W Ga W Re +33.3W Ga W Rh +4.56W Ga W Ru +2.21W Ga W Sn +29.0W Ga +8.49W Ga 2 +9.09W In W Mn -0.28W In W Ni +15.4W In W Rh +0.992W In W Ru +11.7W In +6.68W In 2 +0.863W Ir 2 +5.73W Mn W Ni -0.02W Mn W Ru +5.68W Mn W Sn +18.4W Mn -0.89WMn 2 +0.49W Ni W Ru +0.186W Ni 2 +4.48W Re W Sn +1.15W Re 2 -5.11W Rh W Sn +2.04W Rh 2 +0.885W Ru W Sn +1.28W Ru 2 +1.58W Sn +9.49W Sn 2 +11.6.

[0135] It was found that good casting properties are obtained with a solidification range index of 100 or less, as described below with reference to Figure 1 Lower solidification range indices of less than 90 are preferred because this leads to even lower porosity. Solidification indices of 85.0 or less are preferred, and Examples 1 to 4, 6, 8, 9, 12, 13, 15 and 17 to 31 all achieve this, so these are the most preferred examples for this property. Solidification ranges of 80.0 or less are even more preferred. The best alloys for low porosity and weldability have solidification range indices of 75 or less, or even 70 or lower, which is preferred.

[0136] The inventors also found that ensuring that the following is satisfied: 0.45W Ag +0.35W Au +0.6W Sn +0.6W In +W Ga ≤4.0 helps to produce alloys with a small solidification range. Preferably, 0.45W Ag +0.35W Au +0.6W Sn +0.6W In +W Ga ≤3.0.

[0137] Hardness Index: gives the hardness of the as-cast alloy in terms of elemental composition. This index is based on a statistical analysis of experimental hardness data available in the literature for a wide range of platinum alloys. Higher values are generally better, although hardness values in excess of about 220 HV can have an adverse effect on gemstone setting and so can not be desirable for some applications.

[0138] Hardness Index = 60 + WPd *2.5 + W Rh *3.4 + W Ir *6.455 + W Au *11.93 + W Ru *13.241 + W Cu *14.328 + W Re *16.6 + W Ni *16.9 + W Mn *18.48 + W Co *18.69 + W Fe *21.879 + W In *29 + W Sn *28.207 + W Ga *42.379 + W Ag *9.0.

[0139] The alloys of the present invention have a hardness index of 130 or greater. The lower limit on hardness ensures adequate wear resistance. Even higher hardness is preferred, and the hardness index of the alloy is preferably 140 or greater, and even more preferably 150 or greater. The hardness index of Examples 1-4, 6, 10, 12, 14, 15, and 17-31 are all 150 or greater, so these are the most preferred embodiments for this property. The hardest possible alloys have a hardness index of 160 or greater, or even 170 or greater, while still meeting the other criteria.

[0140] Thus, Examples 1-4, 6, 12, 15, and 17-31 achieve a good balance between hardness (hardness index of 150 or greater) and solidification range (solidification range of 85.0 or less), while still keeping the melting point index in the desired range (16.6-17.1), with a chemical composition falling within the following ranges: 0.0-5.0 gold, 0.0-2.5 cobalt, 0.0-3.0 copper, 0.0-5.0 iron, 0.0-2.75 gallium, 0.0-3.0 m indium, 0.0-5.0 iridium, 0.0-5.0 manganese, 0.0-5.0 palladium, 0.0-5.0 rhenium, 0.0-5.0 rhodium, 0.0-5.0 ruthenium, 0.0-3.0 tin, 0.0-5.0 silver, and incidental impurities, with the sum of platinum and iridium being 95.0 or more.

[0141] Thus, the alloys in the present invention are characterized by a combination of a narrow solidification range and an intermediate melting point, which combination results in good castability, weldability and sufficient hardness. Three groups of different alloying elements can be identified: those alloying elements that improve castability by lowering the melting point without excessively increasing the solidification range (Co, Fe, Pd and Cu), those alloying elements that improve weldability by increasing the melting point without excessively increasing the solidification range (Ru, Re, Ir, Rh), and those alloying elements that increase hardness by increasing the solidification range without decreasing castability and weldability (Sn, In, Ga).

[0142] Ideally, the alloys in the present invention require at least one element from each of the above groups. In particular, when reaching W Co +W Pd +W Fe +W Cu ≥ 1.0, preferably W Co +W Pd +W Fe +W Cu ≥ 1.1, the melting point can be sufficiently lowered without excessively increasing the solidification range. In embodiments, 1.5 ≥ W Co +W Pd +W Fe +W Cu to avoid too high a solidification range. When W Ru +W Re +W Ir +W Rh ≥ 0.25, the melting point is increased without making a large sacrifice in increasing the solidification range. Optionally, W Ru +W Re +W Ir +W Rh even more, for example ≥ 0.5 or ≥ 0.75 or ≥ 1.0, or even ≥ 1.2, preferably ≥ 1.4 and most preferably ≥ 1.5, in order to increase the melting point without too much increasing the solidification range. In embodiments, 2.7 ≥ W Ru +W Re +W Ir +W Rh , preferably 2.6 ≥ W Ru +W Re +W Ir +W Rhto avoid a too high solidification range. In order to achieve the intermediate melting point index required by the present application, it is preferred that there is at least one element from each of these two groups, i.e. at least one element from the group of Co, Fe, Pd and Cu and at least one element from the group of Ru, Re, Ir, Rh. The most preferred elements from these two groups are Fe and Ru, as these two elements both expand the solidification range the least among the elements from their respective group. In addition, Ru does not increase the melting point too much relative to the other elements from its group. Preferably, the alloy has W Sn +W In +W Ga ≥ 0.25, so as to achieve the required hardness, but at the expense of castability and weldability. Preferably, the alloy has W Sn +W In +W Ga ≥ 0.5, or even W Sn +W In +W Ga ≥ 0.75, so as to achieve the required level of hardness. Preferably, the alloy has W Sn +W In +W Ga ≥ 1.2, or even W Sn +W In +W Ga ≥ 1.6. In embodiments, 2.7 ≥ W Sn +W In +W Ga , preferably 2.5 ≥ W Sn +W In +W Ga , so as to avoid a decrease in castability and / or weldability. Preferably, the alloy has at least one element present from each of the three groups.

[0143] Examples and Comparative Examples

[0144] Table 2: List of comparative and inventive examples. Comparative examples 1-5 are custom alloys from internal trials, while the rest are commonly used alloys in jewelry.

[0145]

[0146]

[0147]

[0148]

[0149]

[0150] Figure 1Porosity measured on cast samples of some embodiments and comparative examples is shown. Due to their limited solidification ranges, the embodiment alloys show significantly lower porosity. All alloys were cast into identical tree parts under identical conditions (superheat, pouring time and atmosphere, and flask geometry, material and temperature). Porosity was measured using optical metallography and image processing at multiple fixed locations on the cast tree parts. Since porosity analysis was performed on multiple samples, some embodiments have multiple bars.

[0151] Figure 2 It is shown that unlike the alloys of the present invention, some comparative examples have silicon dioxide inclusions, which are primarily caused by the high melting point of the alloys. When the temperature of the metal exceeds the melting point of the silicon dioxide in the crucible / mold, the silicon dioxide is eroded from the walls and entrained into the cast part. The resulting inclusions accumulate at the grain boundaries, weakening the grain boundaries and causing extreme brittleness. This results in cast part defects and cast part rejection. In comparative examples 4 and 14, the brittleness is immediately apparent from the large intergranular cracks. In contrast, embodiment 3 shows no cracks.

[0152] Figure 3 It is shown that the joint quality of several platinum alloy rings produced using a solder with a high melting point (about 1700°C) (Stuller soldering solder). This solder is commonly referred to as a "hard" solder in the jewelry industry because it is difficult to melt, unlike "easy" solder with a low melting point. Hard solders are preferred in manufacturing because they can be later repaired with soldering, which usually uses easy solder. If a workpiece is manufactured using easy solder, then in later repair attempts, the solder can melt and the workpiece can split. Embodiments 1 and 3 of the present invention have a relatively high melting point index and a narrow solidification range index, which show clean joints with only some solder penetration into the nearby ring surface. This joint is easy to machine to conform to the original shape of the workpiece. On the other hand, comparative examples 13, 15 and 17, which have a significantly lower melting point index, show deformation of the ring, which is more difficult to repair.

[0153] Figure 4 It is shown that silicon dioxide inclusions are present on the fracture surface of comparative example 14. For further explanation, see the description of Figure 2 .

[0154] Figure 5A cast piece made from Comparative Example 14 is shown, having the same geometry as Example 1. Both molds were prepared in the same manner, and in both cases the melt was preheated to the same temperature. The mold had three mesh-like cavities in it, which allowed the forming fill capability of the alloy to be evaluated. Due to its low melting point, Example 1 showed greater filling of the mesh-like structure. The low melting point helped the alloy to remain flowable for a longer time, thus better filling the complex shape. In contrast, Comparative Example 14 showed poor forming fill capability.

[0155] Figure 6 An SEM EDX line scan of a cast piece made from Comparative Example 16 is shown, perpendicular to several secondary dendrite arms in the as-cast condition. It shows severe segregation of Sn and In in the interdendritic space, which is typically associated with significant shrinkage porosity. Note that the Sn and In signals were combined into one signal, as the EDX spectra of the two elements overlap and it is difficult to accurately deconvolute.

[0156] Thus, it has been demonstrated that Examples 1, 2, and 3 have the desired superior combination of properties. From these examples, it can be seen that alloys containing 0.5 wt% to 2.0 wt% indium (Examples 1 and 2) are preferred. Alternatively (Example 3) or additionally (Examples 1 and 2), alloys containing 1.0 wt% to 2.5 wt% ruthenium are preferred. Examples 1 and 2 show that it is also beneficial to additionally have 0.2 to 1.0 wt% tin. Each of Examples 1, 2, and 3 has iron in an amount of 0.5 wt% to 1.75 wt%, so this is additionally beneficial. Example 3 shows that gallium in an amount of 0.5 wt% to 1.75 wt% is beneficial, e.g., as a replacement for or in addition to indium and / or tin.

[0157] In an embodiment, the alloy consists of, in weight percent: 1.2 ± 0.2 iron, 1.5 ± 0.2 indium, 1.5 ± 0.2 ruthenium, 0.6 tin, the balance (optionally at least 95) being platinum and incidental impurities.

[0158] In an embodiment, the alloy consists of, in weight percent: 1.2 ± 0.2 iron, 1.2 ± 0.2 gallium, 2.4 ± 0.2 ruthenium, the balance (optionally at least 95) being platinum and incidental impurities.

[0159] In an embodiment, the alloy consists of, in weight percent: 1.2 ± 0.2 iron, 1.5 ± 0.2 indium, 1.5 ± 0.2 ruthenium, 0.6 tin, the balance (optionally at least 95) being platinum and incidental impurities.

[0160] The preferred ranges for the alloys are shown in Table 3 below, with the preferred embodiments encompassing all of Examples 1 to 4, 6, 12, 15, and 17 to 31, with the more preferred ranges encompassing all of Examples 1 to 3.

[0161] Table 3

[0162]

[0163]

Claims

1. A platinum alloy composition consisting of, in weight percent: 0.0 to 5.0 gold, 0.0 to 2.5 cobalt, 0.0 to 3.0 copper, 0.0 to 5.0 iron, 0.0 to 2.75 gallium, 0.0 to 3.0 indium, 0.0 to 5.0 iridium, 0.0 to 5.0 manganese, 0.0 to 5.0 palladium, 0.0 to 5.0 rhenium, 0.0 to 5.0 rhodium, 0.0 to 5.0 ruthenium, 0.0 to 3.0 tin, 0.0 to 5.0 silver, and incidental impurities, wherein the sum of platinum and iridium is 95.0 or more, wherein the following is satisfied, wherein W Co , W Cu , W Fe , W Ga , W In , W Ni , W Pd , W Sn , W Rh , W Ir , W Au , W Ru , W Re , W Ag and W Mn are the weight percent of cobalt, copper, iron, gallium, indium, nickel, palladium, tin, rhodium, iridium, gold, ruthenium, rhenium, silver, and manganese, respectively, in the alloy, 60 + W Pd * 2.5 + W Rh * 3.4 + W Ir * 6.455 + W Au * 11.93 + W Ru * 13.241 + W Cu * 14.328 + W Re * 16.6 + W Ni * 16.9 + W Mn * 18.48 + W Co * 18.69 + W Fe * 21.879 + W In *29 + W Sn *28.207 + W Ga *42.379 + W Ag *9.0 ≥ 130, and wherein the following conditions are met, where W Co , W Cu , W Fe , W Ga , W In , W Ni , W Pd , W Sn , W Mn , W Ru , W Ir , W Rh , W Au , W Pt , W Ag and W Re are the weight percent of cobalt, copper, iron, gallium, indium, nickel, palladium, tin, manganese, ruthenium, iridium, rhodium, gold, platinum, silver and rhenium in the alloy, respectively, 16.6 <-0.10406*W Ag -0.1028*W Co -0.1201*W Cu -0.2113*W Fe -0.3368*W Ga -0.1125*W In -0.1639*W Ni -0.015*W Pd -0.1959*W Sn +17.276261-0.20*W Mn +0.0678*W Ru +0.035*W Ir +0.045*W Rh -0.059*W Au +0.066*W Re ≤17.1, and wherein the following formula is satisfied, wherein W Co , W Cu , W Fe , W Ga , W In , W Ni , W Pd , W Sn , W Mn , W Ru , W Ir , W Rh , W Au , W Ag and W Re are the weight percent of aluminum, cobalt, copper, iron, gallium, indium, nickel, palladium, tin, titanium, manganese, ruthenium, iridium, rhodium, gold, silver, and rhenium, respectively, in the alloy, 4.22W Ag 2 +0.041W Au W Co +0.122W Au W In +1.96W Au W Ni +1.87W Au W Sn +0.903W Au 2 +1.74W Co W Ga +13.4W Co W In +1.24W Co W Mn +5.04W Co W Sn +1.02W Co 2 +8.97W Cu W Fe +1.74W Cu W Ga +4.38W Cu W In +1.16W Cu W Mn +0.491W Cu W Ni +3.69W Cu W Sn +0.22W Cu 2 +1.68W Fe W Ga +3.31W Fe W In -1.26W Fe W Mn +5.07W Fe W Sn +0.199W Fe 2 +5.35W Ga W In +0.086W Ga W Mn +3.27W Ga W Re +33.3W Ga W Rh +4.56W Ga W Ru +2.21W Ga W Sn +29.0W Ga +8.49W Ga 2 +9.09W In W Mn -0.28W In W Ni +15.4W In W Rh +0.992W In W Ru +11.7W In +6.68W In 2 +0.863W Ir 2 +5.73W Mn W Ni -0.02W Mn W Ru +5.68W Mn W Sn +18.4W Mn -0.89W Mn 2 +0.49W Ni W Ru +0.186W Ni 2 +4.48W Re W Sn +1.15W Re 2 -5.11W Rh W Sn +2.04W Rh 2 +0.885W Ru W Sn +1.28W Ru 2 +1.58W Sn +9.49W Sn 2 +11.6≤100.

2. The platinum alloy composition of claim 1 consisting of 95.0 or more platinum in weight percent.

3. The platinum alloy composition of claim 1 or 2, wherein the following is satisfied, wherein W Co Cu Fe Ga In Ni Pd Sn Rh Ir Au Ru Re Ag and W Mn are the weight percentages of cobalt, copper, iron, gallium, indium, nickel, palladium, tin, rhodium, iridium, gold, ruthenium, rhenium, silver, and manganese in the alloy, respectively,​​​​​​​​​​​​​​​ 60 + W Pd * 2.5 + W Rh * 3.4 + W Ir * 6.455 + W Au * 11.93 + W Ru * 13.241 + W Cu * 14.328 + W Re * 16.6 + W Ni * 16.9 + W Mn * 18.48 + W Co * 18.69 + W Fe * 21.879 + W In * 29 + W Sn * 28.207 + W Ga * 42.379 + W Ag * 9.0 ≥ 140 Preferably, wherein 60 + W Pd * 2.5 + W Rh * 3.4 + W Ir * 6.455 + W Au * 11.93 + W Ru * 13.241 + W Cu * 14.328 + W Re * 16.6 + W Ni * 16.9 + W Mn * 18.48 + W Co * 18.69 + W Fe * 21.879 + W In * 29 + W Sn * 28.207 + W Ga * 42.379 + W Ag * 9.0 ≥ 150 More preferably, wherein 60 + W Pd * 2.5 + W Rh * 3.4 + W Ir * 6.455 + W Au * 11.93 + W Ru * 13.241 + W Cu * 14.328 + W Re * 16.6 + W Ni * 16.9 + W Mn * 18.48 + W Co * 18.69 + W Fe * 21.879 + W In * 29 + W Sn * 28.207 + W Ga * 42.379 + W Ag * 9.0 ≥ 160, Still more preferably, wherein 60 + W Pd * 2.5 + W Rh * 3.4 + W Ir * 6.455 + W Au * 11.93 + W Ru * 13.241 + W Cu * 14.328 + W Re * 16.6 + W Ni * 16.9 + W Mn * 18.48 + W Co * 18.69 + W Fe * 21.879 + W In * 29 + W Sn * 28.207 + W Ga * 42.379 + W Ag * 9.0 ≥ 170.

4. The platinum alloy composition of claim 1, 2, or 3, wherein the following is satisfied, wherein W Ga , W In , and W Sn are the weight percentages of gallium, indium, and tin in the alloy, respectively. W Sn +W In +W Ga ≥ 0.25, preferably W Sn +W In +W Ga ≥ 0.40, more preferably W Sn +W In +W Ga ≥ 0.50, and most preferably W Sn +W In +W Ga ≥ 0.

75.

5. The platinum alloy composition of any one of the preceding claims consisting of 2.0 or less iridium in weight percent.

6. The platinum alloy composition of any one of the preceding claims consisting of 2.0 or less rhodium in weight percent.

7. The platinum alloy composition of any one of the preceding claims consisting of 3.0 or less ruthenium, preferably 2.5 or less ruthenium, preferably 2.0 or less ruthenium in weight percent.

8. The platinum alloy composition of any one of the preceding claims consisting of 2.0 or less rhenium in weight percent.

9. The platinum alloy composition of any one of the preceding claims consisting of 2.0 or less indium, preferably 1.7 or less indium in weight percent.

10. The platinum alloy composition of any one of the preceding claims consisting of 2.0 or less tin, preferably 1.5 or less tin, more preferably 1.0 or less tin in weight percent.

11. The platinum alloy composition of any of the preceding claims, wherein the following is satisfied, wherein W Ga , W Sn , W Ag , and W Au are the weight percentages of gallium, tin, silver, and gold in the alloy, respectively. 0.45W Ag +0.35W Au +0.6W Sn +0.6W In +W Ga ≤4.0, Preferably 0.45W Ag +0.35W Au +0.6W Sn +0.6W In +W Ga ≤3.

0.

12. The platinum alloy composition of any one of the preceding claims consisting of 3.0 or less gold, preferably 2.0 or less gold, more preferably 0.5 wt% or less gold in weight percent, most preferably wherein gold is substantially absent.

13. The platinum alloy composition of any one of the preceding claims consisting of 2.0 or less copper, preferably 1.0 or less copper in weight percent.

14. The platinum alloy composition of any one of the preceding claims consisting of 2.0 or less gallium, preferably 1.5 or less gallium in weight percent.

15. The platinum alloy composition of any one of the preceding claims consisting of 0.25 wt% or more collectively of iridium, rhenium, rhodium and ruthenium, preferably 0.5 wt% or more collectively of iridium, rhenium, rhodium and ruthenium, more preferably 0.75 wt% or more collectively of iridium, rhenium, rhodium and ruthenium, more preferably 1.0 wt% or more collectively of iridium, rhenium, rhodium and ruthenium, more preferably 1.2 wt% or more collectively of iridium, rhenium, rhodium and ruthenium, more preferably 1.4 wt% collectively of iridium, rhenium, rhodium and ruthenium, and most preferably 1.5 wt% or more collectively of iridium, rhenium, rhodium and ruthenium in weight percent.

16. The platinum alloy composition of any one of the preceding claims, wherein, satisfies the following formula, where W Co , W Cu , W Fe , W Ga , W In , W Ni , W Pd , W Sn , W Mn , W Ru , W Ir , W Rh , W Au , W Ag , and W Re are the weight percentages of aluminum, cobalt, copper, iron, gallium, indium, nickel, palladium, tin, titanium, manganese, ruthenium, iridium, rhodium, gold, silver, and rhenium, respectively, in the alloy, 4.22W Ag 2 +0.041W Au W Co +0.122W Au W In +1.96W Au W Ni +1.87W Au W Sn +0.903W Au 2 +1.74W Co W Ga +13.4W Co W In +1.24W Co W Mn +5.04W Co W Sn +1.02W Co 2 +8.97W Cu W Fe +1.74W Cu W Ga +4.38W Cu W In +1.16W Cu W Mn +0.491W Cu W Ni +3.69W Cu W Sn +0.22W Cu 2 +1.68W Fe W Ga +3.31W Fe W In -1.26W Fe W Mn +5.07W Fe W Sn +0.199W Fe 2 +5.35W Ga W In +0.086W Ga W Mn +3.27W Ga W Re +33.3W Ga W Rh +4.56W Ga W Ru +2.21W Ga W Sn +29.0W Ga +8.49W Ga 2 +9.09W In W Mn -0.28W In W Ni +15.4W In W Rh +0.992W In W Ru +11.7W In +6.68W In 2 +0.863W Ir 2 +5.73W Mn W Ni -0.02W Mn W Ru +5.68W Mn W Sn +18.4W Mn -0.89W Mn 2 +0.49W Ni W Ru +0.186W Ni 2 +4.48W Re W Sn +1.15W Re 2 -5.11W Rh W Sn +2.04W Rh 2 +0.885W Ru W Sn +1.28W Ru 2 +1.58W Sn +9.49W Sn 2 +11.6≤90, Preferably 4.22W Ag 2 +0.041W Au W Co +0.122W Au W In +1.96W Au W Ni +1.87W Au W Sn +0.903W Au 2 +1.74W Co W Ga +13.4W Co W In +1.24W Co W Mn +5.04W Co W Sn +1.02W Co 2 +8.97W Cu W Fe +1.74W Cu W Ga +4.38W Cu W In +1.16W Cu W Mn +0.491W Cu W Ni +3.69W Cu W Sn +0.22W Cu 2 +1.68W Fe W Ga +3.31W Fe W In -1.26W Fe W Mn +5.07W Fe W Sn +0.199W Fe 2 +5.35W Ga W In +0.086W Ga W Mn +3.27W Ga W Re +33.3W Ga W Rh +4.56W Ga W Ru +2.21W Ga W Sn +29.0W Ga +8.49W Ga 2 +9.09W In W Mn -0.28W In W Ni +15.4W In W Rh +0.992W In W Ru +11.7W In +6.68W In 2 +0.863W Ir 2 +5.73W Mn W Ni -0.02W Mn W Ru +5.68W Mn W Sn +18.4W Mn -0.89W Mn 2 +0.49W Ni W Ru +0.186W Ni 2 +4.48W Re W Sn +1.15W Re 2 -5.11W Rh W Sn +2.04W Rh 2 +0.885W Ru W Sn +1.28W Ru 2 +1.58W Sn +9.49W Sn 2 +11.6≤85, More preferably 4.22W Ag 2 +0.041W Au W Co +0.122W Au W In +1.96W Au W Ni +1.87W Au W Sn +0.903W Au 2 +1.74W Co W Ga +13.4W Co W In +1.24W Co W Mn +5.04W Co W Sn +1.02W Co 2 +8.97W Cu W Fe +1.74W Cu W Ga +4.38W Cu W In +1.16W Cu W Mn +0.491W Cu W Ni +3.69W Cu W Sn +0.22W Cu 2 +1.68W Fe W Ga +3.31W Fe W In -1.26W Fe W Mn +5.07W Fe W Sn +0.199W Fe 2 +5.35W Ga W In +0.086W Ga W Mn +3.27W Ga W Re +33.3W Ga W Rh +4.56W Ga W Ru +2.21W Ga W Sn +29.0W Ga +8.49W Ga 2 +9.09W In W Mn -0.28W In W Ni +15.4W In W Rh +0.992W In W Ru +11.7W In +6.68W In 2 +0.863W Ir 2 +5.73W Mn W Ni -0.02W Mn W Ru +5.68W Mn W Sn +18.4W Mn -0.89W Mn 2 +0.49W Ni W Ru +0.186W Ni 2 +4.48W Re W Sn +1.15W Re 2 -5.11W Rh W Sn +2.04W Rh 2 +0.885W Ru W Sn +1.28W Ru 2 +1.58W Sn +9.49W Sn 2 +11.6≤80, Even more preferably 4.22W Ag 2 +0.041W Au W Co +0.122W Au W In +1.96W Au W Ni +1.87W Au W Sn +0.903W Au 2 +1.74W Co W Ga +13.4W Co W In +1.24W Co W Mn +5.04W Co W Sn +1.02W Co 2 +8.97W Cu W Fe +1.74W Cu W Ga +4.38W Cu W In +1.16W Cu W Mn +0.491W Cu W Ni +3.69W Cu W Sn +0.22W Cu 2 +1.68W Fe W Ga +3.31W Fe W In -1.26W Fe W Mn +5.07W Fe W Sn +0.199W Fe 2 +5.35W Ga W In +0.086W Ga W Mn +3.27W Ga W Re +33.3W Ga W Rh +4.56W Ga W Ru +2.21W Ga W Sn +29.0W Ga +8.49W Ga 2 +9.09W In W Mn -0.28W In W Ni +15.4W In W Rh +0.992W In W Ru +11.7W In +6.68W In 2 +0.863W Ir 2 +5.73W Mn W Ni -0.02W Mn W Ru +5.68W Mn W Sn +18.4W Mn -0.89W Mn 2 +0.49W Ni W Ru +0.186W Ni 2 +4.48W Re W Sn +1.15W Re 2 -5.11W Rh W Sn +2.04W Rh 2 +0.885W Ru W Sn +1.28W Ru 2 +1.58W Sn +9.49W Sn 2 +11.6≤75, Most preferably 4.22W Ag 2 +0.041W Au W Co +0.122W Au W In +1.96W Au W Ni +1.87W Au W Sn +0.903W Au 2 +1.74W Co W Ga +13.4W Co W In +1.24W Co W Mn +5.04W Co W Sn +1.02W Co 2 +8.97W Cu W Fe +1.74W Cu W Ga +4.38W Cu W In +1.16W Cu W Mn +0.491W Cu W Ni +3.69W Cu W Sn +0.22W Cu 2 +1.68W Fe W Ga +3.31W Fe W In -1.26W Fe W Mn +5.07W Fe W Sn +0.199W Fe 2 +5.35W Ga W In +0.086W Ga W Mn +3.27W Ga W Re +33.3W Ga W Rh +4.56W Ga W Ru +2.21W Ga W Sn +29.0W Ga +8.49W Ga 2 +9.09W In W Mn -0.28W In W Ni +15.4W In W Rh +0.992W In W Ru +11.7W In +6.68W In 2 +0.863W Ir 2 +5.73W Mn W Ni -0.02W Mn W Ru +5.68W Mn W Sn +18.4W Mn -0.89W Mn 2 +0.49W Ni W Ru +0.186W Ni 2 +4.48W Re W Sn +1.15W Re 2 -5.11W Rh W Sn +2.04W Rh 2 +0.885W Ru W Sn +1.28W Ru 2 +1.58W Sn +9.49W Sn 2 +11.6≤70。 17. The platinum alloy composition of any one of the preceding claims, wherein, satisfies the following equation, where W Co , W Cu , W Fe , W Ni , and W Pd are the weight percentages of cobalt, copper, iron, nickel, and palladium in the alloy, respectively. W Co +W Pd +W Fe +W Ni +W Cu ≥1.0 Preferably W Co +W Pd +W Fe +W Ni +W Cu ≥2.

0.

18. The platinum alloy composition of any one of the preceding claims, wherein, The alloy comprises at least one element from the list of cobalt, palladium, iron and copper, preferably wherein the sum of cobalt, palladium, iron and copper is 1.0 wt% or more, more preferably 1.1 wt% or more.

19. The platinum alloy composition of any of the preceding claims, wherein, The alloy comprises at least one element from the list of ruthenium, rhenium, iridium and rhodium, preferably wherein the sum of ruthenium, rhenium, iridium and rhodium is 0.25 wt% or more, preferably 0.5 wt% or more, more preferably 0.75 wt% or more, more preferably 1.0 wt% or more, more preferably 1.2 wt% or more, most preferably 1.4 wt% or more.

20. The platinum alloy composition of any of the preceding claims, wherein, The alloy comprises at least one element from the list of tin, indium and gallium, preferably wherein the sum of tin, indium and gallium is 1.2 wt% or more, more preferably 1.6 wt% or more.

21. The platinum alloy composition of any of the preceding claims, wherein, The alloy consists of platinum, indium, ruthenium, tin and iron.

22. The platinum alloy composition of any one of the preceding claims, wherein, The alloy consists of platinum, ruthenium, iron and gallium.

23. The platinum alloy composition of any one of the preceding claims, wherein, The alloy comprises 0.5 to 2.0 indium in weight percent.

24. The platinum alloy composition of any one of the preceding claims, wherein, The alloy comprises 1.0 to 2.5 ruthenium in weight percent.

25. The platinum alloy composition of any one of the preceding claims, wherein, The alloy comprises 0.2 to 1.0 tin in weight percent.

26. The platinum alloy composition of any one of the preceding claims, wherein, The alloy comprises 0.5 to 1.75 iron in weight percent.

27. The platinum alloy composition of any one of the preceding claims, wherein, The alloy comprises 0.5 to 1.75 gallium in weight percent.

28. The platinum alloy composition of any of the preceding claims, wherein, The alloy comprises 4.0 wt% or less iron in weight percent, preferably 2.5 wt% or less iron in weight percent, more preferably 2.25 wt% or less iron in weight percent, more preferably 2.0 wt% or less iron in weight percent, more preferably 1.75 wt% or less iron in weight percent, more preferably 1.75 wt% or less iron in weight percent.

29. The platinum alloy composition of any of the preceding claims, wherein, The alloy comprises 2.0 or less cobalt in weight percent, preferably 1.0 or less cobalt in weight percent, more preferably substantially no cobalt.

30. The platinum alloy composition of any of the preceding claims, wherein, The alloy comprises 3.0 or less palladium in weight percent, preferably 2.5 or less palladium in weight percent, more preferably 2.0 or less palladium in weight percent, more preferably 1.5 or less palladium in weight percent, more preferably 0.1 or less palladium in weight percent, most preferably substantially no palladium.

31. The platinum alloy composition of any of the preceding claims, wherein, The alloy comprises 3.0 or less manganese in weight percent, preferably 2.5 or less manganese in weight percent, more preferably 0.1 or less manganese in weight percent, most preferably substantially no manganese.

32. The platinum alloy composition of any of the preceding claims, wherein, satisfies the following formula, where W Co , W Cu , W Fe , W Ga , W In , W Ni , W Pd , W Sn , W Mn , W Ru , W Ir , W Rh , W Au , W Pt , W Ag , and W Re are the weight percentages of cobalt, copper, iron, gallium, indium, nickel, palladium, tin, manganese, ruthenium, iridium, rhodium, gold, platinum, silver, and rhenium, respectively, in the alloy, 16.65 ≤ -0.10406*W Ag -0.1028*W Co -0.1201*W Cu -0.2113*W Fe -0.3368*W Ga -0.1125*W In -0.1639*W Ni -0.015*W Pd -0.1959*W Sn +17.276261 -0.20*W Mn +0.0678*W Ru +0.035*W Ir +0.045*W Rh -0.059*W Au +0.066*W Re , Preferably 16.70 ≤ -0.10406*W Ag -0.1028*W Co -0.1201*W Cu -0.2113*W Fe -0.3368*W Ga -0.1125*W In -0.1639*W Ni -0.015*W Pd -0.1959*W Sn +17.276261 -0.20*W Mn +0.0678*W Ru +0.035*W Ir +0.045*W Rh -0.059*W Au +0.066*W Re .

33. The platinum alloy composition of any of the preceding claims, wherein, satisfies the following formula, where W Co , W Cu , W Fe , W Ga , W In , W Ni , W Pd , W Sn , W Mn , W Ru , W Ir , W Rh , W Au , W Pt , W Ag , and W Re are the weight percentages of cobalt, copper, iron, gallium, indium, nickel, palladium, tin, manganese, ruthenium, iridium, rhodium, gold, platinum, silver, and rhenium, respectively, in the alloy, -0.10406*W Ag -0.1028*W Co -0.1201*W Cu -0.2113*W Fe -0.3368*W Ga -0.1125*W In -0.1639*W Ni -0.015*W Pd -0.1959*W Sn +17.276261-0.20*W Mn +0.0678*W Ru +0.035*W Ir +0.045*W Rh -0.059*W Au +0.066*W Re ≤ 17.

00.

34. The platinum alloy composition of any one of the preceding claims, wherein, The alloy comprises 0.5 or more indium in weight percent, preferably 0.75 or more indium in weight percent, more preferably 1.0 or more indium in weight percent.

35. The platinum alloy composition of any of the preceding claims, wherein, The alloy comprises 0.5 or more ruthenium in weight percent, preferably 0.8 or more ruthenium in weight percent, more preferably 1.0 or more ruthenium in weight percent, most preferably 1.2 or more ruthenium in weight percent.

36. The platinum alloy composition of any one of the preceding claims, wherein, The alloy comprises 0.2 or more tin in weight percent.

37. The platinum alloy composition of any of the preceding claims, wherein, The alloy comprises 0.25 or more iron in weight percent, preferably 0.5 or more iron in weight percent, more preferably 0.75 or more iron in weight percent, more preferably 1.0 or more iron in weight percent.

38. The platinum alloy composition of any one of the preceding claims, wherein, The alloy comprises 0.5 or more gallium in weight percent, preferably 0.75 or more gallium in weight percent, more preferably 1.0 or more gallium in weight percent.

39. The platinum alloy composition of any of the preceding claims, wherein, The sum of cobalt, palladium, iron and copper is 1.5 wt% or less.

40. The platinum alloy composition of any of the preceding claims, wherein, The sum of ruthenium, rhenium, iridium and rhodium is 2.7 wt% or less, more preferably 2.6 wt% or less.

41. The platinum alloy composition of any of the preceding claims, wherein, The sum of tin, indium and gallium is 2.7 wt% or less, more preferably 2.5 wt% or less.

42. A platinum alloy composition consisting of, in weight percent: 1.2 ± 0.2 iron, 1.5 ± 0.2 indium, 1.5 ± 0.2% ruthenium, 0.6 tin, the remainder (optionally at least 95%) being platinum and incidental impurities.

43. A platinum alloy consisting of, in weight percent: 1.2 ± 0.2 iron, 1.2 ± 0.2 gallium, 2.4 ± 0.2 ruthenium, the remainder (optionally at least 95%) platinum and incidental impurities.

44. A platinum alloy consisting of, in weight percent: 1.2 ± 0.2 iron, 1.5 ± 0.2 indium, 1.5 ± 0.2% ruthenium, 0.6 tin, the remainder (optionally at least 95%) platinum and incidental impurities.

45. A cast piece comprising the platinum alloy composition of any of the preceding claims.

46. A jewelry item comprising the platinum alloy composition of any of claims 1 to 44.

47. The jewelry item of claim 47, further comprising a gemstone embedded in the platinum alloy composition.

Images