Metallic Materials with Embedded Luminescent Particles

Abstract

Formation of an authentication element by deposition of a metal layer with embedded particles on a metal substrate, wherein the embedded particles are configured to convert energy from one wavelength to another. The embedded particles may be upconverters, downconverters, or phosphorescent phosphors, which can be detected and measured with analytical equipment when deposited in the metal layer. A metal substrate may include coinage.

What is claimed is: 
     
         1 . A method for depositing a metal layer having embedded luminescent particles onto a metal substrate, comprising:
 mixing the luminescent particles with a metallic material to produce a plating solution;   inserting the metal substrate into the plating solution; and   performing a plating process to coat the metal substrate with the metal layer, wherein the metal layer contains embedded luminescent particles, wherein the plating process is an electroless plating process.   
     
     
         2 . A method according to  claim 1 , wherein the embedded luminescent particles have a composition configured to emit energy comprising a second wavelength when excited by energy comprising a first wavelength. 
     
     
         3 . The method of  claim 2 , wherein the plated metal layer is selected from the group consisting of nickel, nickel-phosphorus, copper, brass, gold, silver, and platinum. 
     
     
         4 . The method of  claim 3 , wherein the metal substrate is selected from the group consisting of copper, brass, bronze, mild steel, stainless steel, and titanium. 
     
     
         5 . The method of  claim 1 , wherein the metal substrate is a negotiable coin. 
     
     
         6 . The method of  claim 1 , wherein the luminescent particles have a density of 5.0 g/cm3 or more. 
     
     
         7 . The method of  claim 1 , wherein the density of the luminescent particles is greater than 7.4 g/cm3 
     
     
         8 . The method of  claim 1 , wherein the luminescent particles comprise rare earth doped yttrium oxide-based phosphors. 
     
     
         9 . The method of  claim 1 , wherein the luminescent particles comprise rare earth doped gadolinium oxide-based phosphors. 
     
     
         10 . A metal substrate comprising an electroless plated metal layer on the metal substrate, the electroless plated metal layer containing embedded luminescent particles. 
     
     
         11 . The metal substrate of  claim 10 , wherein the embedded luminescent particles have a composition configured to emit energy comprising a second wavelength when excited by energy comprising a first wavelength. 
     
     
         12 . The metal substrate of  claim 11 , wherein the electroless plated metal layer is selected from the group consisting of nickel, nickel-phosphorus, copper, brass, gold, silver, and platinum. 
     
     
         13 . The metal substrate of  claim 11 , wherein the metal substrate is selected from the group consisting of copper, brass, bronze, mild steel, stainless steel, and titanium. 
     
     
         14 . The metal substrate of  claim 10 , wherein the metal substrate is a negotiable coin. 
     
     
         15 . The metal substrate of  claim 10 , wherein the luminescent particles have a density of 5.0 g/cm3 or more. 
     
     
         16 . The metal substrate of  claim 10 , wherein the density of the luminescent particles is greater than 7.4 g/cm3 
     
     
         17 . The metal substrate of  claim 10 , wherein the luminescent particles comprise rare earth doped yttrium oxide-based phosphors. 
     
     
         18 . The metal substrate of  claim 10 , wherein the luminescent particles comprise rare earth doped gadolinium oxide-based phosphors.