Si₃N₄@(TiN–Si₃N₄) composites with heteroshelled structure were designed for enhanced conductivity and successfully synthesized through the simultaneous reduction and in-situ cocoating process in liquid ammonia at around −40°C. The heteroshells were composed of nanosized TiN and Si₃N₄ particles, which were amorphous with the size ranging from 10 to 40 nm. Using spark plasma sintering, dense bulk composite with >98.1% relative density of theoretical value were obtained and their electrical conductivity were increased to an adequate value (6.62 × 10² S·cm⁻¹) for electrical discharge machining by compositing 15 vol% TiN to Si₃N₄, which is superior to the previous reports. The excellent electric performance could be attributed to the heteroshelled structure which guarantees the conductive network can be formed and kept with minimal TiN content. The nanosized Si₃N₄ powders in the shells reduce the content of conductive powders and limit the growth of TiN particles.

中文翻译：

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高导电性的Si3N4 @（TiN–Si3N4）的建筑设计和低温合成

设计具有杂壳结构的Si ₃ N ₄ @（TiN–Si ₃ N ₄）复合材料以提高电导率，并通过同时还原和原位共涂覆过程在-40°C左右的液氨中成功合成。杂壳由纳米尺寸的TiN和Si ₃ N ₄颗粒组成，它们是无定形的，尺寸范围为10至40 nm。通过火花等离子体烧结，获得了理论值相对密度> 98.1％的致密块状复合材料，并通过复合15％（体积）的TiN将其电导率提高至足够的值（6.62×10 ²  S·cm ^-1）用于放电加工。到硅₃ N ₄，它优于以前的报告。优异的电性能可归因于杂化结构，该结构可确保以最小的TiN含量形成并保持导电网络。壳中的纳米级Si ₃ N ₄粉末会降低导电粉末的含量并限制TiN颗粒的生长。