Sealing composition for sealing aluminum nitride and aluminum oxynitride ceramics
View Patent ↗There is described a sealing composition for sealing aluminum nitride and aluminum oxynitride ceramics comprising: a mixture of SiO 2 , at least one other metal oxide, and a silicon additive comprising at least one of silicon metal or a silicide. The silicon additive acts to suppress the formation of nitrogen bubbles during the sealing of articles comprised of aluminum nitride or aluminum oxynitride ceramics, e.g., as in the case of a ceramic discharge vessel for a high intensity discharge lamp.
1. A sealing composition consisting essentially of a mixture of silicon metal powder and an oxide mixture consisting essentially of 20 wt. % Al 2 O 3 , 15 wt. % SiO 2 and 65 wt. % Dy 2 O 3 .
2. The sealing composition of claim 1 wherein the amount of silicon metal powder is 5 percent of the weight of the oxide mixture.
3. A sealing composition for sealing aluminum nitride and aluminum oxynitride ceramics comprising: a mixture of SiO 2 , Al 2 O 3 , Dy 2 O 3 , and a silicon additive comprising at least one of silicon metal or a silicide.
4. The sealing composition of claim 3 wherein the silicide is a silicide of W, Mo, Ta, Nb, Pd, Re, Pt, or Rh.
5. The sealing composition of claim 3 wherein the mixture contains at least 1 percent SiO 2 by weight.
6. The sealing composition of claim 3 wherein the silicide is tungsten silicide or molybdenum silicide.
7. The sealing composition of claim 3 wherein the silicon additive comprises 0.1 to 5 weight percent of the mixture.
8. The sealing composition of claim 3 wherein the silicon additive comprises 0.5 to 2.5 weight percent of the mixture.