| 摘要 |
<p>A substituted silicon nitride product whose main structural material comprises at least 50 % by weight of α-sialon having the formula: MxSi¿12-(m n)?Alm nOnN16-n wherein x is ≤ 2 and M is at least one cation selected from Y, Nd, Sm, Gd, Tb, Dy and Ho; and up to 20 % by weight of a substituted melilite phase M' of the formula: M2Si3-xAlxO3 xN4-x wherein 0 ∫ x ≤ 1 and M is as defined above. Such product is produced by sintering a mixture comprising silicon, aluminium, nitrogen, oxygen and M to temperatures at which a liquid phase is formed from which said α-sialon is precipitated; and then heat treating the sintered material at temperatures of at least 1400 °C so as to recrystallise brain boundary phase material and produce said substituted melilite phase M'.</p> |
