Effect of ZrC Formation on Graphitization of Carbon Phase in Polymer Derived ZrC–C Ceramics

Abstract

Graphitization degree of carbon matrix in ZrC-modified carbon composites is crucial to mechanical and ablation properties of the materials. In order to investigate the effect of ZrC formation on graphitization of the carbon matrix, microstructure of the carbon phase was investigated by X-ray (XRD), Raman, and X-ray photoelectron spectroscopy (XPS) analysis of the ceramic products obtained from zirconium containing polymer precursors at different pyrolysis temperatures. Compared with pure carbon phase, significant increase of average crystal thickness and microcrystalline planar size was observed in the carbon phase of the ZrC-C ceramics, together with the decrease of interlayer spacing and integrated intensity ratio of D peak to the G peak, indicating a significantly increased graphitization degree during the formation of ZrC. With the increasing ZrC content, amorphous (A) carbon was reduced remarkably, while turbostratic (T) component and graphitic (G) carbon components were increased, showing a slight higher graphitization degree. Moreover, the formation of ZrC was the key "ice breaking" step to decrease the defects and improve structure order of the carbon matrix. And the graphitization was dramatically enhanced during carbothermal reduction to create ZrC by breaking the carbon structure. Furthermore, coarsening and aggregation of ZrC particles as a result of high-temperature heat-treatment at 2500 • C and a high content of ZrC exhibit some negative influences on the structure of the carbon phase in ZrC-C ceramics.

Ultrahigh Content Boron and Nitrogen Codoped Hierarchically Porous Carbon Obtained from Biomass Byproduct Okara for Capacitive Deionization

“…These diffraction peaks are very broad, indicating both samples consisted of a mixture of amorphous, turbostratic, and graphitic carbon phases. 46,47 The Raman spectra further reveals the difference in defect degree between NC and BNC. Figure 1f shows two characteristic peaks at ∼1336 cm −1 (D band) and 1578 cm −1 (G band), which correspond to the structural defects and the crystalline graphite, respectively.…”

Graphite phases in chemical vapour deposited grown ZrC/graphite layers

“…This coincides with the observation made by Liu et al . [19]Assumed disorder, attributed to the broader diffraction peak at 26° 2 Θ [19], has now been resolved and confirmed to be the contribution from a number of independent graphite phases. Electronic supplementary material, table S5 lists the detailed diffraction peaks for the graphitic phases and their corresponding indexes under Cu-radiationA number of ZrC phases exist, including a comparable number of ZrO 2 crystal phases which have been considered in this study.…”

“…Assumed disorder, attributed to the broader diffraction peak at 26° 2 Θ [19], has now been resolved and confirmed to be the contribution from a number of independent graphite phases. Electronic supplementary material, table S5 lists the detailed diffraction peaks for the graphitic phases and their corresponding indexes under Cu-radiation…”

“…As was explained in §1, this predominance of graphite in the layers was due to the decomposition of the methane precursor into carbon and hydrogen, but can also be attributed to the impact of graphitization at elevated CVD temperatures, above 1350°C, Liu et al . [19] and may relate to the non-stoichiometric presence of carbon-bearing species in the CVD reaction scheme. The carbon was deposited as mainly graphitic phases in the layers.…”

Aramid-Zirconia Nanocomposite Coating With Excellent Corrosion Protection of Stainless Steel in Saline Media

“…The peak at 291.1 eV is characteristic of the COO carboxyl groups. Also, the peaks positioned at around 283 eV are attributed to Zr-C bond (Liu et al, 2019).…”