| 摘要 |
A mixture suitable for firing to an oxide of the formula (II), Ba0.m(A12xCr2y03), where 4.6 ≤ m ≤ 6.6; (x + y) = 1; and 0 ≤ y ≤ 0.5, said mixture comprising at least one of: (a) barium oxide; (b) a clean thermal precursor (as hereinbefore defined) of barium oxide, such as barium carbonate or barium hydroxide; and (c) barium mono-aluminate, Ba0.A1203; with at least one of: (A) alumina, A1203; (B) hydrated forms of alumina, such as boehmite, A1203.H20; and (C) a clean thermal precursor (as hereinbefore defined) of aluminium oxide; and, where y is not zero, with at least one of (D) chromium (III) oxide, Cr203; (E) hydrous chromium (III) oxide; and (F) a clean thermal precursor (as hereinbefore defined) of chromium (III) oxide, the relative amounts of the components of the mixture being adjusted to give the desired values of m and y when the mixture is heated. Also disclosed is a grain mix suitable for forming refractory and/or ceramic articles prepared by comminuting either or both of: (a) The above mixture and (b) an oxide of the formula (II), Ba0.m(A12xCr2y03), where 4.6 ≤ m ≤ 6.6; (x + y) = 1; and 0 ≤ y ≤ 0.5. |
