Low Temperature Fabrication fo High Quality Powders by Ultra - fine Grinding under Electrical Discharge

复合粒子正是创造各种新材料的关键材料。本研究旨在开发新型粉末加工技术，利用电火花辅助超细粉碎机制，在低温条件下快速制备出高质量的复合粒子。并对其形成机理进行了探讨。实验从颗粒处理装置的研制开始。然后，在没有任何热辅助的情况下直接合成了复合氧化物纳米颗粒，并在NH3/N2气体条件下进行了二氧化钛纳米颗粒的表面修饰。在前者实验中，选择了工业上使用的La和Mn粉末，并用高机械能设备对这两种粉末进行了加工。因此，在没有任何热辅助的情况下，只需机械能输入即可合成纳米LaMnO_3颗粒。在大气中水的辅助下，通过机械力化学反应讨论了反应路线。对于第二个实验，在机械加工条件下，在氨氮混合气体中进行了二氧化钛纳米颗粒表面的氮掺杂。结果，成功地实现了氮掺杂，没有纳米颗粒的生长。通过对其进行表面修饰，在可见光下也获得了光催化活性。通过等离子体气氛下氮气和二氧化钛的反应模型对掺杂机理进行了探讨。这些结果表明，本研究开发的加工技术在制备各种高功能粉末方面具有广阔的前景。

Composite particles are just key materials which create various kinds of new materials. This study aimed at developing novel powder processing technique to fabricate high quality composite particles rapidly under low temperature processing by making use of ultra-fine grinding mechanism assisted by electrical discharge. The formation mechanism of these powders was also discussed. The experiments started from the development of particle processing apparatus. Then, direct synthesis of composite oxide nanoparticles were conducted without any heat assistance, and the surface modifications of titanium dioxide nanoparticles were also conducted in NH3/N2 gas conditions with glow discharge. For the former experiment, La and Mn powders used in industries were selected, and both powders were processed by the apparatus with high mechanical energy. Consequently, nanosized particles of LaMnO_3 were synthesized only by mechanical energy input without any heat assistance. The reaction route was discussed by a mechanochemical reaction with the assistance of water in the atmosphere. For the latter experiment, nitrogen doping onto the surface of titanium oxide nanoparticles was conducted in the mixed gas of ammonium and nitrogen with glow discharge under mechanical processing. As a result, the nitrogen doping was successfully achieved without any grain growth of nanoparticles. The photocatalytic activity was also obtained by such surface modification under visible light. The doping mechanism was also discussed by a reaction model of nitrogen and titanium dioxides under plasma atmosphere. These results suggest that the processing technique developed by this study is promising for creating various kinds of high functional powders.