Versatility of the Ultra-high-temperature Sintering (UHS) Method: Densification, Microcrack Healing, Surface Modification

The ultra-high-temperature sintering (UHS) method, developed by Wang et al. in 2020, utilizes carbon felt as a resistive heating element to achieve temperatures up to 3000°C within seconds. Since its introduction, UHS has been widely adopted as a superior sintering technique capable of achieving rapid densification. However, new applications leveraging its unique utility as a general heat treatment method are increasingly being reported. This paper reviews three topics conducted by our research group. WC-Co cemented carbides were fully densified in just 65 seconds at 1400°C. This rapid process successfully suppressed cobalt volatilization via insulation between carbon felts and green compacts. Microcracks on yttria-stabilized zirconia were completely healed within 20 seconds, facilitated by accelerated neck formation driven by rapid heating. A conductive TiO layer was formed on (001) surface of SrTiO3 single crystals via UHS. The strong reducing atmosphere generated by the carbon felt induced selective strontium volatilization, creating a metallic TiO surface phase. These findings demonstrate that the UHS method is a powerful tool not only for rapid densification but also for advanced materials processing.