Method for eliminating carbon contamination of platinum-containing components for a glass making apparatus
In the formation of sheet material from molten glass, molten glass is formed in a melting furnace and transported through a precious metal delivery system to the forming apparatus. Disclosed herein is a method to mitigate carbon contamination of individual components of the precious metal delivery system prior to and/or during their use. The method involves coating portions of the precious metal with an oxygen generating material prior to assembly of the component, and may comprise one or more heat treating steps of the component in an oxygen-containing atmosphere.
1. A method of making a platinum-containing component used in a glass making system comprising:
providing a first platinum-containing metallic member and a second platinum-containing metallic member;
coating at least a portion of either one or both of the first platinum-containing metallic member and the second platinum-containing metallic member with an oxygen generating material;
joining the first platinum-containing metallic member and the second platinum-containing metallic member to form an assembly, wherein at least a portion of the oxygen generating material is disposed in an interstitial volume between the first platinum-containing metallic member and the second platinum-containing metallic member; and
heating the assembly in a heat treating step to a temperature of at least 1450° C. for a period of time ≧12 hours in an atmosphere comprising oxygen in an amount of at least 20% by volume.
2. The method according to claim 1 , wherein joining the first platinum-containing metallic member and the second platinum-containing metallic member comprises welding the first platinum-containing metallic member to the second platinum-containing metallic member.
3. The method according to claim 1 , further comprising forming a venting passage between the interstitial volume and an atmosphere external to the interstitial volume.
4. The method according to claim 3 , further comprising heating the assembly and sealing the venting passage after the heating.
5. The method according to claim 1 , wherein the oxygen generating material comprises an oxide of tin.
6. A method of removing carbon contamination from a platinum-containing article comprising:
providing a first platinum-containing metallic member and a second platinum-containing metallic member;
coating at least a portion of either one or both of the first platinum-containing metallic member and the second platinum-containing metallic member with an oxygen generating material;
joining the first platinum-containing metallic member and the second platinum-containing metallic member to form an assembly, wherein at least a portion of the oxygen generating material is disposed in an interstitial volume between the first platinum-containing metallic member and the second platinum-containing metallic member;
forming a vent passage between the interstitial volume and an external atmosphere;
heating the assembly in a heat treating step to a temperature of at least 1450° C. for a period of time ≧12 hours in an atmosphere comprising oxygen in an amount of at least 20% by volume; and
sealing the vent passage after the heating step.
7. The method according to claim 6 , wherein the coating step comprises depositing the oxygen generating material as a powder.
8. The method according to claim 6 , further comprising stirring a molten glass material with a stirring apparatus comprising the assembly.
9. A method of removing carbon contamination from a platinum-containing article comprising:
providing a first platinum-containing metallic member and a second platinum-containing metallic member;
coating at least a portion of either one or both of the first platinum-containing metallic member and the second platinum-containing metallic member with tin oxide;
joining the first platinum-containing metallic member and the second platinum-containing metallic member to form an assembly, wherein at least a portion of the tin oxide is disposed in an interstitial volume between the first platinum-containing metallic member and the second platinum-containing metallic member; and
forming a vent passage in the assembly that connects the interstitial volume with an external atmosphere.
10. The method according to claim 9 , further comprising heating the assembly in a heat treating step to a temperature of at least 1450° C. for a period of time ≧12 hours in an atmosphere comprising at least 20% by volume oxygen.
11. The method according to claim 10 , further comprising sealing the vent passage after the heating step.
12. The method according to claim 9 , wherein the coating step comprises depositing the tin oxide as a powder.
13. The method according to claim 9 , further comprising processing a molten glass material using the assembly.
14. The method according to claim 13 , wherein processing the molten glass material comprises stirring the molten glass.
15. The method according to claim 13 , wherein processing the molten glass material comprises fining the molten glass.