Cerámicas de alúmina: Propiedades para aplicaciones de ingeniería

Introducción

Alumina ceramics (Al₂O₃), or aluminum oxide, are advanced non-metallic materials known for their mechanical strength, thermal stability, and electrical insulation. Available in purities of 95%, 97.5%, 99%, and 99.5% Al₂O₃, these ceramics are ideal for engineering applications in electronics, mechanical systems, and thermal management. This article details the key properties of alumina ceramics, supported by a comparative table, to highlight their suitability for engineering solutions.

Properties of Alumina Ceramics

Alumina ceramics offer a range of mechanical, thermal, electrical, and chemical properties, making them suitable for demanding engineering applications. Below are their primary characteristics:

• Alta dureza: Vickers hardness ranges from 13.7 GPa (95% Al₂O₃) to 17.5 GPa (99.5% Al₂O₃), ideal for wear-resistant components.
• Resistencia mecánica: Flexural strength from 310 MPa (97.5% Al₂O₃) to 400 MPa (99.5% Al₂O₃), suitable for load-bearing applications.
• Conductividad térmica: Ranges from 24 W/(m·K) (95% Al₂O₃) to 34 W/(m·K) (99.5% Al₂O₃), supporting heat dissipation.
• Aislamiento eléctrico: Volume resistivity >10¹⁴ ohm-cm across all grades, ensuring reliability in electronic systems.
• Resistencia a la corrosión: Minimal weight loss in acids (e.g., 0.03 mg/cm²/day in HNO₃ for 99.5% Al₂O₃), perfect for harsh environments.

Tabla detallada de propiedades

The table below compares the properties of alumina ceramics across 95%, 97.5%, 99%, and 99.5% Al₂O₃ grades.

Propiedad	95% Al₂O₃	97.5% Al₂O₃	99% Al₂O₃	99.5% Al₂O₃
Main Characteristics
Color	Blanco	Blanco	Blanco	Blanco
Main Applications	Metallization, wear resistance	High wear resistance	High temperature, wear resistance	High temperature, wear resistance
Characteristics	High strength, wear resistance, corrosion resistance, insulation	High strength, corrosion resistance	High strength, corrosion resistance	High strength, corrosion resistance
Propiedades mecánicas
Bulk Density (g/cm³)	3.7	3.8	3.9	3.9
Water Absorption (%)	0	0	0	0
Vickers Hardness (GPa)	13.7	15.2	17.2	17.5
Resistencia a la flexión (MPa)	350	310	380	400
Compressive Strength (MPa)	—	—	—	3800
Young’s Modulus (GPa)	320	360	380	380
Relación de Poisson	0.23	0.23	0.23	0.23
Fracture Toughness (MPa m¹/²)	3–4	5–6	—	—
Propiedades térmicas
Specific Heat Capacity (J/(kg·K) × 10⁻³, 400°C)	7.2	7.2	7.2	7.2
Thermal Conductivity (W/(m·K))	24	25	32	34
Thermal Shock Resistance (ΔT°C)	200	200	200	200
Propiedades eléctricas
Resistividad volumétrica (ohm-cm)	>10¹⁴	>10¹⁴	>10¹⁴	>10¹⁴
Dielectric Strength (kV/mm)	15	15	15	15
Dielectric Constant (1 MHz)	9.4	9.9	9.9	9.9
Dielectric Loss (×10⁻⁴)	38	20	10	10
Chemical Properties
Nitric Acid (60%) Weight Loss (mg/cm²/day)	0.10	0.05	0.03	0.03
Sulfuric Acid (95%) Weight Loss (mg/cm²/day)	0.33	0.22	0.19	0.19
Caustic Soda (30%) Weight Loss (mg/cm²/day)	0.06	0.04	0.03	0.03

Notas de la tabla:

• Propiedades mecánicas: Higher-purity grades (99% and 99.5% Al₂O₃) offer increased hardness (17.2–17.5 GPa) and flexural strength (380–400 MPa).
• Propiedades térmicas: Thermal conductivity improves with purity, from 24 W/(m·K) to 34 W/(m·K).
• Resistencia química: Higher purity reduces weight loss in acids, enhancing corrosion resistance.

Conclusión

Alumina ceramics offer exceptional mechanical strength, thermal stability, and electrical insulation, making them ideal for engineering applications in electronics, mechanical systems, and thermal management. The range of purities allows for tailored solutions in demanding environments.

Centro de cerámica avanzada is a leading manufacturer and supplier of high-quality alumina ceramic products in forms of plates, sheets, rods, tubes, crucibles, substrates, and customized parts, offering customized solutions for various industrial and research applications.