High purity alumina (usually α-Al₂O₃ with a purity of ≥99.9%) plays a vital role in the electronics industry due to its excellent physical, chemical, and electrical properties.

LED Substrates: While sapphire is the mainstream material, transparent alumina ceramics (such as single-crystal sapphire, which is itself α-Al₂O₃) are important LED substrate materials, especially in early-stage LEDs and for certain specialized applications. High-purity alumina ceramic substrates are also used in high-power LED packaging, providing excellent insulation, thermal conductivity, and mechanical support.

Phosphor Carrier: In LEDs and certain display devices, high-purity alumina powder is often used as an inert carrier or dispersion medium for phosphors. Its excellent chemical stability, excellent light transmittance, and high thermal conductivity contribute to improved light efficiency and heat dissipation.

Display Panels: In LCD/OLED manufacturing, high-purity alumina powder is also used in polishing slurries for glass substrates.

HTCC (High-Temperature Co-fired Ceramics): High-purity alumina is the primary material for HTCC substrates. Alumina powder is mixed with a binder and plasticizer and cast into a green tape. Holes are then punched, filled, and printed with conductors (usually tungsten or molybdenum-manganese). The tape is then co-fired at high temperatures (1500-1600°C) in a hydrogen atmosphere. This material is used for high-power, high-reliability modules (such as IGBTs, automotive electronics, and aerospace).

Thick-Film Circuit Substrates: Using a pre-sintered high-purity alumina ceramic substrate, thick-film resistors, conductors (such as silver or gold pastes), and dielectrics are printed onto it, and then sintered to form circuits. These substrates are widely used in hybrid integrated circuits, sensors, power modules, and more.

Heat sink substrate: Highly thermally conductive alumina ceramic sheets are mounted directly beneath power semiconductor devices (such as transistors and diodes) to conduct heat to the heat sink.

Lithium Battery Separator Coating: Coating a polyolefin separator with a layer of nano-alumina particles significantly improves the separator's high-temperature resistance, electrolyte wettability, thermal dimensional stability, and safety (preventing thermal runaway), thereby extending battery life.

Sensors: Used as an insulating substrate or protective layer in certain gas and pressure sensors.