Silver alloy excellent in reflectance maintenance property

Abstract

The present invention is a silver alloy including silver as the main component and at least one precious metal element as a first dopant element, and excellent in reflectance maintenance property. In the present invention, the first dopant element is preferably platinum, gold, palladium, rhodium, ruthenium and iridium. Also, in the present invention, the silver alloy preferably includes, as a second dopant element, at least one element selected from copper, manganese, silicon, chromium, nickel, cobalt, iron, scandium, zirconium, niobium, molybdenum, tantalum, tungsten, indium, tin, lead, aluminum, calcium, germanium, gallium, bismuth, antimony, strontium, hafnium, gadolinium, samarium, neodymium, lanthanum, cerium, ytterbium and europium.

1 . A silver alloy for use in a reflective film, comprising silver as a main element and at least one precious metal element as a first dopant element.  
   
   
       2 . The silver alloy for use in a reflective film according to  claim 1 , wherein the first dopant element is at least any one of platinum, palladium, gold, rhodium, ruthenium and iridium.  
   
   
       3 . The silver alloy for use in a reflective film according to  claim 1 , comprising as a second dopant element at least one element selected from gallium, dysprosium and thulium.  
   
   
       4 . The silver alloy for use in a reflective film according to  claim 1 , comprising as a second dopant element at least one element selected from magnesium, zinc, nickel, molybdenum, terbium, gadolinium and erbium.  
   
   
       5 . The silver alloy for use in a reflective film according to  claim 1 , comprising as a second dopant element at least one element selected from aluminum, neodymium and holmium.  
   
   
       6 . The silver alloy for use in a reflective film according to  claim 1 , comprising as a second dopant element at least one element selected from copper, cobalt, tin, titanium, bismuth, scandium, yttrium, praseodymium and manganese.  
   
   
       7 . The silver alloy for use in a reflective film according to  claim 1 , comprising as a second dopant element at least one element selected from germanium, indium, samarium, ytterbium, strontium, boron, silicon, chromium, iron, zirconium, niobium, tantalum, tungsten, rhodium, lead, calcium, antimony, hafnium, lanthanum and cerium.  
   
   
       8 . The silver alloy for use in a reflective film according to  claim 1 , wherein a total of the concentration of the first dopant element and the concentration of the second dopant element are 0.01 to 5.0 atomic %.  
   
   
       9 . The silver alloy for use in a reflective film according to  claim 8 , wherein the total of the concentration of the first dopant element and the concentration of the second dopant element are 0.01 to 2.0 atomic %.  
   
   
       10 . A sputtering target, comprising the silver alloy as defined in  claim 1 .  
   
   
       11 . The silver alloy for use in a reflective film according to  claim 2 , comprising as a second dopant element at least one element selected from gallium, dysprosium and thulium.  
   
   
       12 . The silver alloy for use in a reflective film according to  claim 2 , comprising as a second dopant element at least one element selected from magnesium, zinc, nickel, molybdenum, terbium, gadolinium and erbium.  
   
   
       13 . The silver alloy for use in a reflective film according to  claim 2 , comprising as a second dopant element at least one element selected from aluminum, neodymium and holmium.  
   
   
       14 . The silver alloy for use in a reflective film according to  claim 2 , comprising as a second dopant element at least one element selected from copper, cobalt, tin, titanium, bismuth, scandium, yttrium, praseodymium and manganese.  
   
   
       15 . The silver alloy for use in a reflective film according to  claim 2 , comprising as a second dopant element at least one element selected from germanium, indium, samarium, ytterbium, strontium, boron, silicon, chromium, iron, zirconium, niobium, tantalum, tungsten, rhodium, lead, calcium, antimony, hafnium, lanthanum and cerium.  
   
   
       16 . The silver alloy for use in a reflective film according to  claim 2 , wherein a total of the concentration of the first dopant element and the concentration of the second dopant element are 0.01 to 5.0 atomic %.  
   
   
       17 . The silver alloy for use in a reflective film according to  claim 3 , wherein a total of the concentration of the first dopant element and the concentration of the second dopant element are 0.01 to 5.0 atomic %.  
   
   
       18 . The silver alloy for use in a reflective film according to  claim 4 , wherein a total of the concentration of the first dopant element and the concentration of the second dopant element are 0.01 to 5.0 atomic %.  
   
   
       19 . An optical recording medium comprising a substrate and a silver alloy on the substrate which silver alloy comprises silver and at least one of platinum, palladium, gold, rhodium, ruthenium and iridium as a first dopant element, and as a optional second dopant element at least of gallium, dysprosium, thulium, magnesium, zinc, nickel, molybdenum, terbium, gadolinium, erbium, aluminum, neodymium, holmium, copper, cobalt, tin, titanium, bismuth, scandium, yttrium, praseodymium, manganese, germanium, indium, samarium, ytterbium, strontium, boron, silicon, chromium, iron, zirconium, niobium, tantalum, tungsten, rhodium, lead, calcium, antimony, hafnium, lanthanum and cerium.  
   
   
       20 . A method for producing an optical recording medium which comprises forming a film of a silver alloy on a substrate, which silver alloy comprises a first dopant element selected from at least one of platinum, palladium, gold, rhodium, ruthenium and iridium; and which silver alloy optionally further comprises a second dopant element selected from at least one of gallium, dysprosium, thulium, magnesium, zinc, nickel, molybdenum, terbium, gadolinium, erbium, aluminum, neodymium, holmium, copper, cobalt, tin, titanium, bismuth, scandium, yttrium, praseodymium, manganese, germanium, indium, samarium, ytterbium, strontium, boron, silicon, chromium, iron, zirconium, niobium, tantalum, tungsten, rhodium, lead, calcium, antimony, hafnium, lanthanum and cerium.