超重力冶金:科学原理、实验方法、技术基础、应用设计

Supergravity metallurgy: principles, experimental methods, techniques, and applications

  • 摘要: 超重力显著增大两相间的重力差,可用于加速固−液、液−液、液−气高温黏稠混和体的相分离速度;超重力具有定向性,避免搅拌等技术产生的熔体湍流返混,可用于深度脱除金属液中细小夹杂物;超重力条件下固−液界面张力微不足道,可容易实现微孔渗流;超重力条件下进行结晶凝固,按结晶顺序实现固−液分离,可用于制备梯度材料;超重力加速固−液分离,可细化凝固组织晶粒,但对非共晶熔体也易产生宏观偏析。将超重力技术应用于冶金及材料生产过程中,有望解决高温冶金和材料制备的一些难题,如复杂矿冶金渣有价组分的分离提取、冶炼渣中金属液的分离回收、多金属的熔析结晶分离、复杂矿直接还原铁的渣−金分离;在高端金属材料方面,应用超重力技术,有望解决近零夹物金属材料的精炼除杂难题,提高梯度功能材料、金属−陶瓷复合材料、多孔金属材料、器件材料表面电沉积修饰的制造水平。此外,在材料科学研究方面,超重力凝固可作为一种材料基因组高通量制备方法。

     

    Abstract: Supergravity significantly increases the gravity difference between two phases and thus can accelerate phase separation in solid–liquid mixtures, liquid–liquid mixtures, and liquid–bubble mixtures that have high temperatures and viscosities. Due to its directionality, supergravity avoids turbulent backmixing in melts, typically seen in agitation and other separation techniques, and is applicable toward the deep removal of fine inclusions in liquid metals. Under supergravity, solid–liquid interfacial tension is negligible and microporous seepage is straightforwardly achievable. Particle–liquid separation during crystallization can be performed under supergravity to prepare gradient materials. Supergravity accelerates particle–liquid separation, which refines solidified grains, but can also produce macroscopic segregation in noneutectic melts. Supergravity is widely applicable and beneficial to many fields. In metallurgy and materials production, supergravity can be used to improve the separation and extraction of valuable components from metallurgical slags of complex ores, separation and recovery of molten metal in smelting slags, melt crystallization separation of polymetals, and slag–metal separation of reduced iron from complex ores. In addition, supergravity can also be applied to high-end metal materials to improve the refinement and removal of impurities in metal materials toward near zero inclusion. Furthermore, supergravity can improve the manufacturing of functional gradient materials, metal–ceramic composites, porous metal materials, and device materials via electrodeposition modification. Finally, supergravity solidification can be used as a high-throughput method for the preparation of material genomes.

     

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