Preparation of ZrC/Mo-Si metal silicides composite nano powder by direcrt electrochemical process in molten salt
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摘要: ZrC/Mo-Si系金属硅化物复合材料的制备主要以ZrC和Mo-Si系金属硅化物粉末为原料通过高温(1750~2100 ℃)或高压烧结方式进行,存在高成本、高能耗、高资源消耗等问题。本文以ZrSiO4、MoO3和C为原料,采用熔盐电化学法一步制备出了ZrC/Mo-Si系金属硅化物纳米复合粉体,致力于实现其短流程、低能耗、低成本制备。研究了固体阴极制备工艺、碳含量和碳源的类型对电化学合成ZrC/Mo-Si系金属硅化物纳米复合粉体的影响机制。结果表明:以CaCl2-NaCl共晶熔盐作为电解质,在800 ℃、3.1 V电化学还原15 h可制备出ZrC/Mo-Si系金属硅化物复合粉体材料,其由粒径小于50 nm的近球形颗粒组成。小尺寸、无定型结构的碳粉更适合作为电化学合成ZrC/Mo-Si系金属硅化物复合材料的碳源。原料中碳的含量会影响ZrC与金属硅化物相的比例,也会影响最终产物中金属硅化物的组成。
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关键词:
Abstract: ZrC/Mo-Si metal silicide composites are normally prepared by the sintering techniques at high temperature (1750~2100 ℃) or high pressure using ZrC and Mo-Si metal silicide powders as raw materials. However, these methods typically suffer from high cost, high energy consumption and high resource consumption. It is highly desired to develop a simple, low energy consuming and low-cost preparation method. In this work, ZrC/Mo-Si metal silicide composite nano-powder was prepared from a ZrSiO4/ MoO3/C mixture through a one-pot electrolytic process in molten salt. The effects of the preparation process of solid cathode, carbon content and type of carbon source on the electrochemical synthesis of ZrC/Mo-Si metal silicide composite nano-powder were investigated. The results show that ZrC/Mo-Si metal silicide composite nano-powder was prepared by electrochemical reduction at 800 ℃ under 3.1 V for 15 h in CaCl2-NaCl eutectic molten salt, and it was composed of nearly spherical particles with particle size less than 50 nm. It was found that the carbon powder with amorphous structure and relatively smaller particle size is more suitable as carbon source for electrochemical synthesis of ZrC/Mo-Si metal silicide composites. Moreover, the ratio of ZrC and metal silicide phases, as well as the composition of metal silicide in the final product can be controlled by adjusting the amount of carbon in the original material.-
Key words:
- Molten salt electrochemistry /
- ZrC /
- Metal silicides /
- Nano-powders /
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