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Updated: May 31, 2026
Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Enhancing crystallization and structural modification in SiO2-CaO-Al2O3 glass-ceramics using mineral-based Mn source
Majid Bagheri1, Mostafa Karamouz2, Mohsen Hajizamani3
1Department of Metals, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, PO Box 117-76315, Kerman, Iran. m.bagheri@kgut.ac.ir.
This study explores how adding natural manganese ore affects the crystallization and properties of SiO₂-CaO-Al₂O₃ glass-ceramics. Researchers prepared samples with varying Mn content and analyzed their structure and performance. They found that Mn improves the formation of key crystalline phases like anorthite, rhodonite, and bustamite. At 1000°C, Mn-rich samples showed larger, sharper grains and better long-range order. Physicochemical tests revealed improved hardness, lower water absorption, and higher corrosion resistance. However, adding more than 10 wt% Mn led to structural flaws. The study suggests Mn enhances crystallization through network depolymerization but requires careful control to avoid defects.
Area of Science:
- Glass and ceramic materials science
- Mineralogy in materials engineering
- Structural characterization of inorganic composites
Background:
Prior research has shown that incorporating mineral additives can influence crystallization in glass-ceramics. Established knowledge includes the role of network modifiers in altering glass structure. However, the specific impact of natural manganese ore on SCA systems remains unclear. This gap motivated the investigation into how Mn sources affect crystallization and microstructure. No prior work had resolved the optimal Mn content for structural enhancement. Existing studies focus on synthetic nucleating agents, not natural minerals. The need to explore Mn’s role in phase formation is evident. This study aims to clarify these effects in SCA glass-ceramics.
Purpose Of The Study:
The study aimed to assess how natural manganese ore affects crystallization and microstructure in SCA glass-ceramics. Researchers sought to determine the optimal Mn content for structural improvement. The motivation stems from the need to enhance material properties through mineral-based additives. They focused on Mn’s role in phase formation and network depolymerization. The problem lies in balancing Mn content to avoid excessive grain growth. Understanding Mn’s influence on physicochemical properties is key. This approach could lead to better-performing glass-ceramics. The study addresses a specific gap in Mn-rich composite research.
Main Methods:
The researchers prepared SCA glass-ceramics by melting and quenching base materials like feldspar and calcium carbonate. They added 0–15 wt% natural manganese ore to the mixtures. The samples were synthesized at varying temperatures to observe crystallization effects. Characterization techniques included X-ray diffraction and scanning electron microscopy. Physicochemical tests measured hardness, water absorption, and corrosion resistance. The NBO/T ratio was calculated to assess network depolymerization. Comparative analysis tracked changes in grain morphology and phase formation. The study used controlled conditions to isolate Mn’s effects on microstructure.
Main Results:
The addition of manganese ore increased the formation of anorthite, rhodonite, and bustamite phases. At 1000°C, Mn-rich samples showed larger and sharper rhodonite and bustamite grains. The NBO/T ratio rose with higher Mn content, indicating greater network depolymerization. X-ray analysis confirmed the presence of new Mn-containing phases. Scanning electron microscopy revealed improved long-range order in Mn-rich samples. Physicochemical tests showed higher hardness and lower water absorption in these samples. Corrosion resistance improved with Mn addition up to 10 wt%. Exceeding 10 wt% Mn caused excessive grain growth and internal flaws.
Conclusions:
The authors propose that natural manganese ore enhances crystallization in SCA glass-ceramics. They suggest Mn improves phase formation and microstructure up to 10 wt%. The study indicates that Mn increases network depolymerization, aiding crystallization. The findings suggest Mn-rich samples have better mechanical and corrosion properties. The authors propose that Mn addition beyond 10 wt% leads to structural flaws. They suggest Mn can act as a nucleating agent in SCA systems. The results suggest Mn improves the NBO/T ratio and glass structure. The authors propose that Mn’s role in phase formation is significant but dose-dependent.
Frequently Asked Questions
The authors suggest that manganese increases the NBO/T ratio, leading to network depolymerization and enhanced crystallization.
X-ray diffraction and scanning electron microscopy were used to identify new Mn-containing phases and grain morphology.
At 1000°C, Mn-rich samples showed larger and sharper rhodonite and bustamite grains, indicating optimal crystallization.
A higher NBO/T ratio suggests greater network depolymerization, which the authors propose enhances crystallization and phase formation.
Mn-rich samples showed higher hardness, lower water absorption, and improved corrosion resistance up to 10 wt% Mn.
Exceeding 10 wt% Mn caused excessive grain growth and internal flaws, underscoring the need for compositional balance.
