Multi-scale growth mechanism of pyrolytic carbon from acetylene by chemical vapor deposition in spouted bed environment--颗粒学报PARTICUOLOGY

Mollick, P. K., Sen, D., Roy, M., Venugopalan, R., Bathula, V., Ravikanth, K. V., . . . Tewari, R. (2025). Multi-scale growth mechanism of pyrolytic carbon from acetylene by chemical vapor deposition in spouted bed environment. Particuology, 104, 207-216. https://doi.org/10.1016/j.partic.2025.07.002

Multi-scale growth mechanism of pyrolytic carbon from acetylene by chemical vapor deposition in spouted bed environment

Palash Kumar Mollick^a *, Debasis Sen^b, Mainak Roy^c, Ramani Venugopalan ^a, Vishwanadh Bathula^d, K.V. Ravikanth^e, Kinshuk Dasgupta^a, Abhijit Ghosh^a, Joti Nath Sharma^a, Raghvendra Tewari^a

a Glass & Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
b Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
c Chemistry Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
d Materials Science Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
e Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Mumbai, 400085, India

10.1016/j.partic.2025.07.002

Volume 104, September 2025, Pages 207-216

Received 19 March 2025, Revised 4 July 2025, Accepted 8 July 2025, Available online 16 July 2025, Version of Record 24 July 2025.

E-mail: pmollick@barc.gov.in; pkmollick@gmail.com

Highlights

• Functionally active pyrolytic carbon coating was developed over zirconia microsphere using acetylene as a precursor.

• Development of pyrolytic coating was carried out in a spouted bed by chemical vapor deposition process.

• Atomic to micron scale structure of pyrolytic carbon was revealed with different advanced characterization techniques.

• A deposition mechanism of pyrolytic carbon nanocrystal was proposed aligning with the characterization results.

Abstract

The growth process of pyrolytic carbon (PyC) over zirconia microspheres was investigated at length scales starting from 10⁻¹⁰ m to 10⁻⁶ m using Transmission and Scanning Electron Microscopy, Raman spectroscopy, Small Angle X-ray and Neutron Scattering. The extent of multiphase reactions which evolved through the formation of nano-crystalline carbon have been studied here right from the formation of the disc shaped crystallites of about 3–4 nm in diameter to fused lumps comprising of spherical stacks ca. of 100 nm diameter. The observations have been correlated with the deposition conditions, which affect reaction mechanisms. Based on these observations, a plausible mechanism for the deposition of PyC coatings at different length scales has been proposed with a novel concept of role of thermal boundary layer adjacent to the deposition surface. Pore volume measurement further validated our proposed growth mechanism at a length scale of 10⁻⁶ m. Analysis of residence time of the acetylene precursor within the solid bed of zirconia microspheres has shown to have great potential in exploring growth mechanism of multiphase reactions.

Graphical abstract

Keywords

Pyrolytic carbon; Chemical vapor deposition; Deposition mechanism; Functional materials; Nano material

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