Flash cold sintering of Nb2O5: polarity and electrolyte effects

We report on a novel consolidation technique based on the combination of a liquid (cold sintering) and electricity (flash sintering). The evolution of hydrogen from electrolysis of the solvent triggered the Flash Cold Sintering (FCS) event without need for external heating. Electrochemical effects became pronounced in the presence of acetic acid solution as the electrolyte had an increased conductivity compared to pure water. By adjusting the acetic acid molar concentration to 0.5 M and by inverting the polarity during FCS a 5 mm diameter 0.8 mm thick Nb2O5 sample was evenly sintered up to 99% in 100 s at a temperature as low as 350°C. Conventional sintered counterparts achieved a 95% relative density when dwelled for 240 min at 1400°C. The inherent complexity of the proposed FCS approach resulted in enhanced densification and weakly translucent samples.本研究报道了一种结合液相（冷烧结（cold sintering））与电能（闪烧（flash sintering））的新型固结技术。溶剂电解过程中析出的氢气可触发闪冷烧结（Flash Cold Sintering，FCS）过程，无需外部加热。相较于纯水，乙酸溶液作为电解质时电导率更高，因此电化学效应更为显著。通过将乙酸摩尔浓度调整至0.5 M，并在FCS过程中反转电极极性，可在低至350°C的温度下，于100秒内将直径5 mm、厚度0.8 mm的五氧化二铌（Nb₂O₅）样品均匀烧结至99%致密度。传统烧结的对照样品则需在1400°C下保温240分钟，才能达到95%的相对致密度。所提出的FCS方法凭借其固有复杂性，实现了更优异的致密化效果，并可制备出具有微透光性的样品。