Blue Sapphire Crystal Growth: The Critical Role of Graphite Molds and Specialized CNC Machining
The global market for synthetic sapphire crystals—used in LED substrates, optical windows, and semiconductor wafers—requires molds that withstand extreme thermal stress (1800–2200°C) while maintaining dimensional accuracy within ±0.01mm. Graphite’s high thermal conductivity (100–195 W/m·K), low coefficient of thermal expansion (CTE, 2.2–4.4×10⁻⁶/°C), and chemical inertness make it the only viable material for these molds. However, sapphire […]