ORCID
0009-0003-9745-3929
Keywords
Optical Ceramics, MS-ZnS, Solute strengthening, Ga-RSF, SIMS, Hardness
Abstract
Multispectral zinc sulfide (MS-ZnS) is an important optical ceramic widely used in broadband imaging systems due to its wide transmission range and relatively low cost. However, its modest mechanical properties limit its durability in harsh environments. This dissertation investigates two solute strengthening methods, vapor transport deposition (VTD) and diffusion coupling (DC), to enhance the hardness of MS-ZnS windows through Ga2S3 incorporation while maintaining optical transparency. The VTD process successfully incorporated gallium in the subsurface, resulting in up to 120 % increase in microhardness compared to untreated samples, but with slight discrepancies in lateral gallium distribution. The DC technique demonstrated superior control and uniformity of gallium incorporation, achieving a 100% increase in average microhardness while preserving optical transmission. However, both methods initially resulted in subsurface cracking due to high gallium concentrations. To address this issue, modifications were implanted into both strategies to mitigate cracking: sulfurization during VTD and gradual diffusion for the DC technique. These modifications enabled crack-free gallium incorporation while maintaining hardness improvements. To better understand the effect of Ga on MS-ZnS, a series of characterization techniques were employed to provide insights into the gallium incorporation mechanisms and resulting material properties. This research demonstrates for the first time the feasibility of enhancing MS-ZnS hardness through controlled gallium doping, while maintaining good transparency. VTD and DC strategies could be combined with other established hardening techniques such as advanced coating technologies to create highly resilient MS-ZnS windows suitable for extreme environments or high-stress applications.
Completion Date
2025
Semester
Spring
Committee Chair
Gaumé, Romain
Degree
Doctor of Philosophy (Ph.D.)
College
College of Engineering and Computer Science
Department
Materials Science and Engineering
Identifier
DP0029398
Document Type
Dissertation/Thesis
Campus Location
Orlando (Main) Campus
STARS Citation
Soufiani, Hayat, "Enhancing the Hardness of the Multispectral ZnS Transparent Ceramics Through Ga2S3 Incorporation: A Comparative Study of Vapor Transport Deposition and Solid-Solid Reaction Methods" (2025). Graduate Thesis and Dissertation post-2024. 229.
https://stars.library.ucf.edu/etd2024/229