Synthesis of powder containing a dual phase mixture of 27R-SiAlON and AlN has been successfully carried out through carbothermal reduction and nitridation route. The probable reaction sequences of formation have been identified through the analysis of transient appearances of intermediate phases associated with parameters like loss of carbon, oxygen and weight as well as nitrogen uptake. Formation of 27R-SiAlON takes place through further reaction of a primary polytype phase, Si₃Al₇O₃N₉. FTIR spectra provide supplementary evidence for supporting the revealed model of reaction sequences. Particles are agglomerative in nature consisting of fine grains, as low as below 50 nm in size. Spark plasma sintering was applied for an initial densification trial of this bi-phasic powder without externally added sintering aid. The densified samples exhibited elongated grain-reinforced composite microstructure with improved properties over monolithic AlN.

中文翻译：

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27R-SiAlON增强AlN复合材料：合成，烧结和表征

通过碳热还原和氮化途径已成功地合成了包含27R-SiAlON和AlN的双相混合物的粉末。通过分析与碳，氧和重量损失以及氮吸收等参数相关的中间相的瞬时出现，已经确定了可能的形成反应顺序。27R-SiAlON的形成是通过一级多晶型相Si ₃ Al ₇ O ₃ N _9的进一步反应而发生的。FTIR光谱为支持揭示的反应序列模型提供了补充证据。颗粒本质上是团聚的，由细小的颗粒组成，尺寸低至50 nm以下。在没有外部添加烧结助剂的情况下，将火花等离子体烧结用于该双相粉末的初始致密化试验。致密化的样品表现出细长的晶粒增强复合微结构，其性能优于整体AlN。