Gradient ZrO2 nanocrystals strengthening electrospun SiC fibers

Ceramic ultrafine fibers (UFs) with flexibility and high strength have attracted considerable interest for use in extreme conditions. Herein, silicon carbide (SiC) UFs strengthening by gradient ZrO2 nanocrystals (NCs) were prepared by electrospinning, vacuum-maturating, and pyrolysis. Gradient NCs structure formed during vacuum-maturation can be classified as surface dense ZrO2 NCs, linear ZrO2 nanoclusters, and core homogeneous ZrO2 NCs. Notably, the obtained gradient ZrO2 NCs/SiC (g-ZS) UF exhibits 2.6 times higher strength and 1.8 times higher strain than SiC UF, which results in a high toughness (41.32 MJ m−3). The design strategy and fabrication method of such high strength with functional gradient NCs structure holds great promise for highly reliable micro/nanodevices and other ceramic ultrafine fibers.