ORCID

https://orcid.org/0009-0005-9333-1494

Keywords

Powder Atomic Layer Deposition, Nanocrystalline Ceramics, Sintering

Abstract

Nanocrystalline ceramics promise superior mechanical, electrical and optical properties, yet their fabrication is impeded by a lack of scalable manufacturing methods. This thesis explores atomic layer deposition (ALD) as an enabler to manufacturing nanocrystalline ceramics. Chapter 1 frames the scientific and industrial motivation for combining traditional sintering methods with ALD, highlighting the challenges involved in nanocrystalline ceramics manufacturing, and the opportunities that lie in the combination of the two techniques. Chapter 2 surveys the state-of-the-art in nanocrystalline ceramics manufacturing, powder ALD chemistry and reactor design. Three challenges of powder ALD are highlighted and a critical comparison of fluidized-bed versus rotary-bed reactors sets the stage for new hardware solutions. To address these challenges, Chapter 3 details the design and construction of a hybrid fluidized/rotary ALD reactor equipped with in situ quadrupole mass spectrometry. The system accommodates both “A/B powders” and “C/D powders” (based on Geldart’s classification scheme), while maintaining uniform precursor exposure and minimal agglomeration. Chapter 4 demonstrates the impact of ultrathin ALD Al₂O₃ coating on 60 nm ZnO nanopowders hot-pressed at 850 °C under 150 MPa. Relative to the uncoated control ceramic with a grain size of 2.76 ± 0.50 μm, a 1 nm coating suppresses grain growth to 89 ± 23 nm in partially densified regions, while a 10 nm coating further limits grains to 55 ± 7 nm. Chapter 5 concludes that ALD enables sub-nanometer precision control of grain-boundary chemistry and opens a scalable path toward dense, nanocrystalline ceramics using conventional sintering techniques. This work lays the foundation for future work in the field of ceramics manufacturing, where full densification of nanocrystalline ceramics with additional functionalities can be made possible via ALD-enabled grain boundary engineering.

Completion Date

2025

Semester

Summer

Committee Chair

Parag Banerjee

Degree

Master of Science in Materials Science and Engineering (M.S.M.S.E.)

College

College of Engineering and Computer Science

Department

Materials Science and Engineering

Format

PDF

Identifier

DP0029521

Language

English

Document Type

Thesis

Campus Location

Orlando (Main) Campus

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