Synthesis of biomorphic ZrC/C ceramics from rattan through zirconium oxychloride infiltration and carbothermal reduction
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Synthesis of biomorphic ZrC/C ceramics from rattan through zirconium oxychloride infiltration and carbothermal reduction Carlos R. Rambo1,2 · Joseane C. Bernardes2 · Heino Sieber3 · Daliana Müller2 Accepted: 3 September 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract This work reports the synthesis of biomorphic ZrC/C ceramics derived from rattan through infiltration of a Zr-containing salt and further carbothermal reduction of Z rO2. Discs of dried in natura rattan were first pyrolyzed at 800 °C in nitrogen to form bio-carbon templates. The templates were infiltrated with an aqueous solution of Z rOCl2 that precipitated Z rO2 in situ on the bio-carbon cell walls. After five infiltration/drying cycles a weight gain of 112 wt% was achieved. The salt decomposed and the precipitated amorphous ZrO2 crystallized to tetragonal phase at temperatures between 400 and 600 °C as indicated by an exothermic broad peak centered at 530 °C in the differential thermal analysis (DTA) curve. The infiltrated samples were submitted to heat treatments at temperatures between 1200 and 1600 °C for 1–2 h in argon. Carbothermal reaction took place between 1400 and 1500 °C, where both tetragonal Z rO2 and cubic ZrC were identified by X-ray diffractometry (XRD). Above 1500 °C only ZrC was detected, resulting in porous biomorphic ZrC/C ceramics, where the original anatomic features of the rattan templates were maintained. Keywords Carbothermal reduction · ZrC · Biomorphic ceramics · Biotemplating
1 Introduction Although zirconium carbide is a promising candidate for a wide range of high temperature applications, it has not been investigated like other extensively studied carbides like SiC or TiC. ZrC exhibits very high melting point (> 3400 °C), high Young´s modulus (355 GPa), and good thermomechanical properties, which are suitable for applications as high-temperature thermionic cathode material, as nuclear material and in electronic devices [1–3]. Among few routes to produce ZrC, such as solid-state reactions [4], mechanosynthesis [5], microwave synthesis [6] or precursor infiltration and pyrolysis [7] the carbothermal reduction of ZrO2 is * Carlos R. Rambo [email protected] 1
Department of Electrical and Electronic Engineering, Federal University of Santa Catarina, Florianopolis 88040‑900, Brazil
2
Graduate Program on Materials Science and Engineering, Federal University of Santa Catarina, Florianopolis 88040‑900, Brazil
3
Werkstofftechnik Motoren, AUDI AG - I/GQ-L13, 85045 Ingolstadt, Germany
the most common. It can be accomplished through Z rO2/C powder mixtures or from carbonaceous/zirconia gels to produce ZrC powders [8–10]. Reports on porous ZrC, however, are scarce. Li et al. [11] produced ZrC foams with excellent thermal stability up to 2400 °C. Nam et al. [12] synthesized porous ZrC fibrous as thermal storage barrier membranes. Ning et al. [13] produced flexible ZrC-Carbon fibrous mats with three-dimensional macrostructures. Shen et al. [14] produced ZrC hollow na
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