The Fabrication of ZrO₂–ZrC Microspheres by Internal Gelation and Carbothermal Reduction Process

Abstract

ZrO 2 -ZrC (ZrCO) ceramic microspheres were fabricated by combination of internal gelation and carbothermal reduction process. The internal gelation broth containing carbon powders was prepared and stored at room temperature of 25°C to form a precursor of microspheres. By dropping droplets of the broth into hot silicone, the gel microspheres would solidify within a few seconds by decomposition of hexamethylenetetramine (HMTA). The dispersability of the carbon powders in the broth is the key factor to producing ZrCO microspheres with uniform density distribution, as zirconium carbides are generated by the direct reduction of ZrO 2 with carbon. The ZrCO ceramic microspheres fabricated with various mass ratio of ZrO 2 and ZrC have good sphericity and no cracks through optimizing washing and heat treatment process.

Preparation of ZrO2 beads by an improved micro‐droplet spray forming process

“…However, the spheres made by rolling forming present relatively poor compactness and sphericity and large size distribution; as for spray granulation, it requires high‐cost equipment and the products usually contain some voids 19,20 . Regarding gel casting and sol–gel techniques, apart from needing a long production cycle and complicated fabrication procedures, complex chemical reactions will happen during both of these two processes 13,21,22 . In addition, it is difficult to control the size and microstructure of beads by using the emulsion method 15 .…”

“…19,20 Regarding gel casting and sol-gel techniques, apart from needing a long production cycle and complicated fabrication procedures, complex chemical reactions will happen during both of these two processes. 13,21,22 In addition, it is difficult to control…”

Microstructure and properties of C/C–ZrC composites prepared by hydrothermal deposition combined with carbothermal reduction

“…Hydrothermal technology is a common method for the preparation oxide nanoparticles [18,19]. The UHTCs can be prepared by the reaction of the oxide nanoparticles with carbon at high temperature [20,21]. In this study, we proposed a novel method to prepare C/C-ZrC composites containing sub-micron scale ZrC particles.…”

Carbon Nanofiber Arrays Grown on Three-Dimensional Carbon Fiber Architecture Substrate and Enhanced Interface Performance of Carbon Fiber and Zirconium Carbide Coating

“…The introduction of ultrahigh-temperature ceramics (UHTCs) coating onto the CNFs-CF hierarchical substrates to improve their thermal stability has been shown to be a good method for combining the excellent mechanical property of CF and good high-temperature performance of ceramics. , Zirconium carbide (ZrC) is considered as the promising ceramic material to prevent CF from oxidation and ablation in the application of ultrahigh temperature area due to the excellent performance such as high hardness, outstanding chemical stability, and superior melting point, etc. , In recent years, several methods have been used to coat ZrC or other ceramic layer onto the carbon fiber/fabrics, such as polymer infiltration and pyrolysis method, alloyed reactive melt infiltration, CVI combined with RMI, hot-press and sinter processing, and in situ reaction method. − Every processing route has its disadvantages, such as high cost, inconvenience in adjusting reactions, poor distribution of the ceramics phase, and bad performance of the composite. Although scientists have acquired some considerable achievements in this field, the preparation and performance of CNFs-CF coated with ZrC ceramic coating composite fabricated by the CVD combined PIP process have not been reported.…”

“…29,30 Zirconium carbide (ZrC) is considered as the promising ceramic material to prevent CF from oxidation and ablation in the application of ultrahigh temperature area due to the excellent performance such as high hardness, outstanding chemical stability, and superior melting point, etc. 31,32 In recent years, several methods have been used to coat ZrC or other ceramic layer onto the carbon fiber/fabrics, such as polymer infiltration and pyrolysis method, alloyed reactive melt infiltration, CVI combined with RMI, hot-press and sinter processing, and in situ reaction method. 33−36 Every processing route has its disadvantages, such as high cost, inconvenience in adjusting reactions, poor distribution of the ceramics phase, and bad performance of the composite.…”