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High‐strength zirconia (ZrO2) continuous fibers, which are potential candidates as ultra‐high temperature thermal insulators and reinforced materials, are typically fabricated by dry spinning an organozirconium precursor. However, the uncontrolled decomposition of organozirconium precursor usually occurs upon heat treatment that breaks the continuous fibers into pieces, resulting in the loss of tensile strength. Herein, in this contribution, we aimed to maintain the integrity of ZrO2 precursor fibers during heat treatment. For this purpose, novel high‐pressure vapor (HPV) pretreatment of ZrO2 precursor fiber was introduced. The HPV pretreatment is considered to be efficient for the removal of the organics in precursor, promoting the formation of amorphous structures of Zr(OH)4 and Zr(OH)3HCO3. Combining the studies of microstructures and tensile strengths, it was found that the amorphous structures played roles of cross‐linking points, keeping the fibers integrity during the followed heat treatment. After HPV pretreatment, the high‐strength ZrO2 continuous fibers would be obtained by direct sintering in air without any atmosphere which substantially lowered the cost. The tensile strengths of sintered ZrO2 continuous fibers pretreated by an optimized HPV procedure could reach up to as high as 1.299 GPa. The HPV pretreatment method provides a high‐efficiency, low‐cost technique for preparing high‐quality ceramic fibers. [ABSTRACT FROM AUTHOR]

A chemical bath deposition method without using ZnO seed layers was developed to grow dense ZnO nanorods (NRs) on TiO2 fibers in saturated nutrition solution. The crystal phase, microstructure and photoluminescence of the as received heterostructure were examined by X-ray diffraction (XRD), scanning-electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX) and photoluminescence spectroscopy (PL). The structure consists of a TiO2 fiber core and a radial ZnO NR shell, with growth directions almost perpendicular to the central fibers. Luminescence quenching of TiO2 was observed in the PL spectra of the heterostructure due to the shielding effect of the covered ZnO NRs. According to the results of SEM, XRD, infrared spectroscopy (IR) and EDX, the seedless growth mechanism was discussed. It was found that at room temperature, Zn-based layered double hydroxides (Zn-LDHs) with positive charges, which are the building blocks for the nucleation and growth of ZnO NRs, were firstly formed in ZnO growth solution. The Zn-LDHs were deposited on the negatively charged TiO2 fibers through electrostatic attraction followed by being dehydrated into ZnO NRs at an elevated temperature. The cooperative interaction between the TiO2 fibers and ZnO NRs was investigated. The two components in the structure have a robust interaction that even violent ultrasonic power could not peel the ZnO NRs off from the TiO2 fibers. [ABSTRACT FROM AUTHOR]

For zirconia continuous fibers, tensile strength is a very important performance parameter, which is affected by the crystal phase, its stability, grain size, processing temperatures, and so on. In this paper, the crystalline phases were adjusted through the Y 2 O 3 contents and heat treatment temperatures in the range of 1000–1500°C. We found that interfacial segregation of Y3+ at high temperatures led to crystal phase instability, which was observed near the grain boundaries of the 13.8YSZ fibers. At high temperatures, the grain growth of different fibers occurred to different degrees. The regularities between the tensile strength, the strength retention and temperature, Y 2 O 3 contents were discussed in detail. According to the highest tensile strength of a single fiber and Weibull modulus m, we found that the 5.4YSZ fibers were the most stable with the highest tensile strength and slow grain growth rate. The average strength was 1.6 GPa after heat-treating at 1500°C and the strength retention rate was about 54% under 1500°C for 60 min. Finally, the twistable 5.4YSZ continuous fibers with high strength were obtained by dry spinning technology. These results can provide reliable theoretical support and data sources for its high-temperature applications. • The twistable 5.4YSZ continuous fibers had a tensile strength of 1.6 GPa after 1500 °C. • Strength retention rate of 5.4YSZ continuous fibers was up to 54 % after 1500 °C/60 min • Crystalline phase was stable and grain growth was controlled through Y 2 O 3 content. [ABSTRACT FROM AUTHOR]