Compositional Exploration and Microstructural- Environmental Evaluation of Alloys for Glass Vitrification Applications
type: CreativeWork
description: This thesis investigates the multi-environment performance of alternative alloys for high-temperature glass vitrification, with the aim of improving the durability of Co-101 alloy spinners used in glass mineral wool production. These components operate under aggressive thermal and chemical conditions that accelerate oxidation and corrosion, limiting service life. To address this challenge, two alloying strategies were explored for Co-101: (i) variations in C (0.25 and 0.5 wt%) and Si (1 and 4 wt%) content, and (ii) the addition of Ta (up to 3.1 at.%). The microstructural evolution and oxidation behaviour of these modified alloys were assessed at 800°C, 1000°C, and 1200°C, followed by evaluation of their corrosion resistance under partial immersion in a glass melt at 1100°C. Among the C and Si variations tested, Si had the most pronounced influence on microstructure and performance. Increasing Si promoted the formation of M12C over M23C6 carbides and introduced the χ phase in the low-C, high-Si variant. These changes enhanced oxidation resistance at 800°C and 1200°C through oxidation-induced Laves phase formation and the development of continuous silica scales, albeit at the expense of room-temperature ductility. Ta additions promoted MC carbide formation and, at the highest concentration, replaced the Cr-rich M23C6 network with σ and Laves phases. Moderate Ta contents improved oxidation resistance at 800°C and 1000°C by disrupting continuity of the Cr-rich carbide network; however, at 1200°C, resistance declined due to CrTaO4 formation, which disrupted the silica subscale. In static partial-immersion in modified soda-lime glass at 1100°C, high-Si alloys exhibited the greatest corrosion resistance across air-exposed, transition, and melt-immersed regions. Two low-Si alloys suffered catastrophic oxidation in the air-exposed region, attributed to reduced Cr mobility, exacerbated by volatile-species interactions and galvanic effects. Ta improved corrosion resistance onl…
abstract: This thesis investigates the multi-environment performance of alternative alloys for high-temperature glass vitrification, with the aim of improving the durability of Co-101 alloy spinners used in glass mineral wool production. These components operate under aggressive thermal and chemical conditions that accelerate oxidation and corrosion, limiting service life. To address this challenge, two alloying strategies were explored for Co-101: (i) variations in C (0.25 and 0.5 wt%) and Si (1 and 4 wt%) content, and (ii) the addition of Ta (up to 3.1 at.%). The microstructural evolution and oxidation behaviour of these modified alloys were assessed at 800°C, 1000°C, and 1200°C, followed by evaluation of their corrosion resistance under partial immersion in a glass melt at 1100°C. Among the C and Si variations tested, Si had the most pronounced influence on microstructure and performance. Increasing Si promoted the formation of M12C over M23C6 carbides and introduced the χ phase in the low-C, high-Si variant. These changes enhanced oxidation resistance at 800°C and 1200°C through oxidation-induced Laves phase formation and the development of continuous silica scales, albeit at the expense of room-temperature ductility. Ta additions promoted MC carbide formation and, at the highest concentration, replaced the Cr-rich M23C6 network with σ and Laves phases. Moderate Ta contents improved oxidation resistance at 800°C and 1000°C by disrupting continuity of the Cr-rich carbide network; however, at 1200°C, resistance declined due to CrTaO4 formation, which disrupted the silica subscale. In static partial-immersion in modified soda-lime glass at 1100°C, high-Si alloys exhibited the greatest corrosion resistance across air-exposed, transition, and melt-immersed regions. Two low-Si alloys suffered catastrophic oxidation in the air-exposed region, attributed to reduced Cr mobility, exacerbated by volatile-species interactions and galvanic effects. Ta improved corrosion resistance onl…
author: Pek, Ming En
language: eng
keywords: Co-based Superalloy, Corrosion, Materials Science, Metallurgy, Oxidation
license: https://www.repository.cam.ac.uk/bitstreams/51cf4246-33f6-4354-8416-67c22af1aab8/download
license: https://creativecommons.org/licenses/by/4.0/
date published: 2025-08-10
date modified: 2026-07-22T22:24:04Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.126207