Patent ID: 8592504

Claim:
An amorphous siliceous powder blend comprising a first powder component and a second powder component such that an average particle size of the first powder component is from 15 μm to 70 μm, and an average content (A) of Al is 100 to 30000 ppm in terms of its oxide; and an average particle size of the second powder component is from 3 μm to 15 μm, and an average content (B) of Al is 100 to 7000 ppm in terms of its oxide; a ratio (A)/(B) of the average contents of Al of each powder component is 1.2 to 20; and in the amorphous siliceous powder blend as a whole a combined content of SiO 2 and Al 2 O 3 is 99.5% by mass or more in terms of oxides, and an average content of Al is 100 to 25000 ppm in terms of its oxide.