L’Sintered alumina is a form of technical ceramic composed mainly of aluminum oxide (Al2O3). It is characterized by a very high density and a fine-grained microstructure, obtained by a thermal consolidation process without passing through the total liquid phase.
In-depth definition : Visit Sintering is a’Industrialisation where a compacted powder (alumina powder) is heated to a high temperature, but below its melting point (generally between 1400∘C and 1700∘C). Under the effect of heat, powder particles bind together by atomic diffusion, pores reduce and the material consolidates into a solid, dense and cohesive mass. Additives (called sintering aids) are often used to control grain size and facilitate densification.
Key Properties and Applications for Industrial Performance
Sintered alumina is appreciated in the Industrial Engineering for its unique combination of properties:
- Excellent wear and abrasion resistance: It is harder than most metals and is used for parts subject to intense friction.
- High mechanical strength (hardness and rigidity) : It maintains its strength even at high temperatures, superior to that of steel in these conditions.
- Chemical inertia : It resists corrosion by many acids and alkalis.
- Superior dielectric properties : It is an excellent electrical and thermal insulator.
- Microstructure Fine : Provides an excellent surface finish, essential for precision parts.
| Field of application | Example | Key role |
|---|---|---|
| Precision Mechanics | Seals, nozzles, wire guides | Wear resistance, dimensional accuracy. |
| Electronics | Integrated circuit substrates, high-voltage insulators | Electrical insulation, heat dissipation. |
| Medical | Hip prostheses (femoral heads), surgical instruments | Biocompatibility, hardness, chemical inertness. |
Sintered alumina is the preferred choice when the application calls for technical ceramics from high performance, dense and tightly toleranced, often in the glass and/or steel industry.