Method of making a silica-titania glass having a ternary doped critical zone

摘要

In one aspect the disclosure is directed to the preparaton of a binary silica-titania glass blank having a CTE of 0 ± 30 ppb/°C or less over a temperature range of 5°C to 35°C, and a doped silica-titania glass critical zone, wherein the dopant(s) are selected from the group consisting of aluminum oxide, and transition metal oxides, and amount of the dopant(s) is in the range of 0.05 wt.% to 8 wt.%. In various embodiments the dopants are selected from the group consisting of 0.25 wt.% to 8 wt.% Al 2 O 3 , 0.05 wt.% to 3 wt.% Nb 2 O 5 , and 0.25 wt.% to 6 wt.% Ta 2 O 5 , and mixtures thereof. A method of making such a doped slica-titania glass comprises preparing a slurry from silica-titania powder and dopandt powders, spray drying the slurry to obtain free-flowing fine particles, shaping and pressing / heating.