Dy α-βSialon 陶瓷的制备与相变研究

Fabrication and Study on Phase Transformation of Dy_2O_3-Densified α-βSialon Ceramics

在Dy-Si-Al－O－N系统相关系的研究基础上，设计了以DyAG和M’相作为晶界相的单相α-Sialon和β-Sialon以及复相α－β-Sialon材料．研究了它们的致密化行为，热处理过程中的α’→β’相变机制以及力学性能．结果表明：可以制备出以DyAG和M’相作为晶界相的单相α-Sialon和β-Sialon以及复相α－β-Sialon材料．作为烧结助剂，DyAG比M’更能有效地促进致密化．Dy-α’较之其他的含Dy的物相更易于形成，因此烧结样品的α’相含量比设计值高．通过热处理，使α'→β'转变发生，可以达到设计的α’/α’+β’值．

Based on the phase relationships in the Dy-Si-Al-O-N system, α-Sialon ceramics and α-βSialon composite ceramics with garnet and/or melilite as grain boundary phases were designed.The densification behavior, α'-β' phase transformation in heat-treatment, mechanical properties and microstructure characteristic were studied. The results show that Dy-α' and Dy-α'-β' ceramics with garnet and/or M' as grain boundary phases call be fabricated by HP. DyAG as an additive is more effective than M' in promoting densification. Dy-α' is kinetically more favourable to be formed over the other Dy-containing phases ulnhke the other Ln-α-Sialons, thereby the fractions of the α' phase in the as sintered specimens is higher than the designed ones. By post sintering heat-treatment, the α'→β' phase transformation occurs and the designed α'/α'+β' ratios can then be achieved.