Glass-ceramics are high-performance materials synthesized through controlled crystallization, combining the formability of glass with the superior physical and chemical properties of ceramics.
Core Process: Controlled Crystallization
The key technology involves precise thermodynamic control of the nucleation-crystallization process. A base glass of specific composition is first melted, followed by a two-stage heat treatment—forming numerous uniform crystal nuclei at the nucleation temperature, then growing crystals at a higher temperature. This results in a dense composite material consisting of nano- to micron-sized crystals within a residual glass phase. By adjusting the formula (e.g., Li₂O-Al₂O₃-SiO₂ system) and process, the main crystal phase and final properties can be directionally controlled.
Key Performance Advantages
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Excellent Thermal Stability: Wide adjustable range of thermal expansion coefficient (can approach zero expansion), high resistance to thermal shock (>800°C temperature difference), and high long-term use temperature (up to ~1200°C).
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Outstanding Mechanical Properties: High mechanical strength (flexural strength of 200-400 MPa), high hardness, and good wear resistance. Its comprehensive mechanical performance far exceeds that of ordinary glass and rivals many engineering ceramics.
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Stable Chemical Performance: Possesses high chemical durability, resisting acid and alkali corrosion, with excellent airtightness.
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Good Functional Characteristics: Exhibits excellent electrical insulation, and some systems can achieve infrared transmission or visible light transparency.
Main Application Fields
Due to its designable excellent properties, glass-ceramics are key materials in several high-end fields:
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High-End Induction Cooktop Panels: Its heat resistance, thermal shock resistance, high strength, and infrared transmission make it the ideal choice.
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Astronomy & Precision Optics: Its near-zero expansion characteristics make it the perfect material for large telescope mirror blanks.
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Defense & Aerospace: Used for components in extreme environments like missile radomes and spacecraft windows.
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Biomedical: Used as bioactive materials for dental restorations and bone implants.
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Industrial Corrosion-Resistant Components: Manufacturing chemical pipelines, high-temperature observation windows, and precision instrument platforms.
Development Trends
The future development of glass-ceramics is oriented towards transparency and functional integration (e.g., for laser devices), improved machinability, development of low-carbon manufacturing processes, and promotion of cost reduction for wider adoption.
In summary, glass-ceramics exemplify the materials science paradigm of achieving exceptional macroscopic properties through microscopic structural design, playing an irreplaceable role in numerous cutting-edge technological fields with stringent performance requirements.
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