Electrospining: Grooved TiO2/ZrO2 ceramic fibers with thermal insulation and mechanical properties were prepared by coaxial electrospinning

Background

Against the backdrop of the growing global climate challenge, there is a growing need to improve energy efficiency and reduce emissions. In industry and construction, the use of thermal insulation reduces energy losses and improves energy efficiency, intensifying the focus on high-performance thermal insulation materials. At the forefront of aerospace technology, the stringent requirements for insulation materials are particularly prominent due to the extreme temperature challenges faced by aircraft during service. Aerogels have low density and porosity, and their excellent thermal resistance and very low thermal conductivity have been widely studied, with thermal conductivity as low as 0.025 W/m·K. However, the porous structure of aerogels is prone to shrinkage and cracking at high temperatures, and strong thermal shock or prolonged exposure to high temperatures can lead to brittleness and structural degradation. In addition, aerogels are generally rigid materials with limited flexibility, which hinders their ability to adapt to the dimensional changes required to encapsulate complex structures and makes them vulnerable to damage in vibration environments. Researchers have tried to enhance the mechanical properties of aerogels by incorporating materials such as fibers and whiskers, but the improvement in flexibility is not significant. These limitations have greatly restricted the application of aerogels.

The main point of this paper

Advantages of ceramic fibers:

Ceramic fibers are recognized as a class of advanced lightweight refractory materials due to their low thermal conductivity, low density, chemical inertness, excellent flexibility and thermal stability.

Development of electrospinning technology:

The development of electrospinning technology has significantly reduced the fiber diameter, improved the mechanical properties of the fiber, reduced thermal conductivity, and enhanced thermal insulation performance.

Characteristics of zirconia ceramic fibers:

Zirconium oxide ceramic fibers are known for their high temperature resistance, excellent oxidation resistance and excellent mechanical properties, and can meet the requirements of mechanical flexibility and thermal stability under extreme conditions.

Preparation of TiO2/ZrO2 ceramic fibers:

In this study, TiO2/ZrO2 ceramic fibers with groove structures were prepared using coaxial electrospinning technology, in which the TiO2 shell layer enhances infrared reflectivity and the ZrO2 core layer maintains mechanical integrity.

Composite fibers with core/shell structure:

The core/shell structure formed by coaxial electrospinning gives the fiber excellent high-temperature insulation and mechanical properties, and the seamless interface and diffused Zr atoms effectively inhibit the growth of TiO2 grains.

Characterization of material properties:

The phase composition and morphology of TiO2/ZrO2 ceramic fibers prepared at different core-shell solution injection rates were studied, and their mechanical and thermal insulation properties were characterized.

Grooved TiO2/ZrO2 ceramic fibers prepared by coaxial electrospinning: enhanced thermal insulation and mechanical properties

Preparation method:

This study successfully prepared TiO2/ZrO2 ceramic fibers with grooved structures using coaxial electrospinning technology.

Core-shell structure design:

The fiber has a unique core-shell structure, with the TiO2 shell acting as an effective radiation shield and the ZrO2 core maintaining the mechanical robustness of the fiber.

Interface properties:

The mutual diffusion of Zr and Ti atoms at the interface promotes a seamless transition between TiO2 and ZrO2, effectively inhibiting the coarsening of TiO2 grains.

Mechanical properties:

The tensile strength of the fiber is significantly improved, with the tensile strength of the TZ-5 sample reaching 1.47±0.08 MPa.

Fiber morphology optimization:

By controlling the injection speed during electrospinning, the fiber morphology is optimized, achieving a synergistic balance of strength, flexibility, and thermal insulation.

Thermal insulation performance:

The fibers exhibited excellent thermal insulation performance, with thermal conductivity ranging from 0.0294 to 0.0278 W m−1 K−1 and an average infrared reflectivity of more than 87%.

Thermal insulation experiment:

The experiment confirmed that the TiO2/ZrO2 fiber membrane has excellent thermal insulation performance and has practical application potential

Summary

Grooved TiO2/ZrO2 ceramic fibers prepared by coaxial electrospinning exhibit excellent thermal insulation and mechanical properties. The unique coaxial structure, with a TiO2 shell and a ZrO2 core, provides a synergistic combination of mechanical and thermal insulation properties. The mechanical properties are significantly improved, with the tensile strength of the TZ-5 specimen reaching 1.47±0.08 MPa. This enhancement is due to the diffusion of Zr atoms into the TiO2 lattice, resulting in an increase in the square ZrO2 content and a refinement of the grain size. The thermal conductivity is as low as 0.0278 W m−1 K−1 and the infrared reflectivity exceeds 87%, further improving the thermal insulation properties of the fiber membranes. Actual thermal insulation tests show that despite the higher temperature on the hot side, the temperature on the cold side increases only slightly, confirming the superior thermal insulation properties of the TiO2/ZrO2 fiber membranes. These results affirm their potential as advanced thermal insulation materials for high-temperature applications, especially in the aerospace and industrial fields where both mechanical strength and thermal insulation properties are unquestionable.