ALUMINUM OXIDE 3N

Chemical formula: Al₂O₃

Chemical purity: 3N

Mechanical Properties:

Density g/cc (#/in³): 3.96 (0.14)

Surface Finish - CLA:                                                Micrometers       Microinches

              As-Fired:                                                       0.5                       20

              Ground:                                                         0.9                       35

              Polished:                                                        <0.03                   <1

Crystal Size:

              Range:                                                            1-6                       39-236

              Average:                                                        3                          118

Water Absorption Percent: 0

Gas Permeability: 0

Color: Ivory

                                                                                      MPa                    psi × 10³

Flexural Strength (Mor) at 20 ^oC:                             552                      80

                                                                                      GPa                     psi × 10⁶

Elastic Modules at 20 ^oC:                                           386                      56

Shear Modules at 20 ^oC:                                             158                      23

Bulk Modules at 20 ^oC:                                              228                      33

                                                                                      m/sec.                  ft/sec.

Trans. Sonic Vel. at 20 ^oC:                                         9.9 × 10³              32 × 10³

Poisson's Ratio at 20 ^oC: 0.22

Stiffness/Weight at 20 ^oC (GPa/g/cc): 97

Fracture Toughness at K_IC (MPA ⋅ m 1/2): 4-5

                                                                                      MPa                    kpsi

Compressive Strength at 20 ^oC:                                 3792                    550

Tensile Strength: at 25 ^oC:                                       310                      45

                            at 1000 ^oC:                                      221                      32

                                                                                      GPa                     kg/mm²

Hardness:           Knoop 1000 g:                                 15.2                     1551

                            Rockwell 45N:                                90

Thermal Properties:

                                                                                      W/m ^oK              Btu⋅in/ft²⋅h⋅ ^oF

Thermal Conductivity at 20 ^oC:                                38.9                     270

                                                                                      10^-6/ ^oC               10^-6/ ^oF

Coefficient of Thermal Expansion at 25-1000 ^oC:   8.4                       4.7

                                                                                      J/kg⋅ ^oK              cal/g⋅ ^oC

Specific Heat at 100 ^oC:                                              880                      0.21

                                                                                      ^oC                        ^oF

Thermal Shock Resistance, ΔTc:                                200                      392

Maximum use temperature:                                       1900                    3452

Electrical Properties:

Dielectric Strength:                                                     ac-kv/mm           ac-volts/mil

              at 6.35 mm:                                                    9.4                       240

              at 3.18 mm:                                                    12.8                     325

              at 1.27 mm SPEC:                                        18.1                     460

              at 0.64 mm Thick:                                         23.2                     590

              at 0.25 mm:                                                    31.5                     800

                                                                                      1 kHz                  1 MHz                 1 GHz

Dielectric Constant at 25 ^oC:                                     9.9                       9.8                       

Dissipation Factor at 25 ^oC:                                       0.0020                 0.0002                 

Loss Index at 25 ^oC:                                                    0.020                   0.002                   

Volume Resistivity:                                                     ohm-cm²/cm

              at 25 ^oC:                                                         >10¹⁴

              at 300 ^oC:                                                       >10¹⁴

              at 500 ^oC:                                                       3.3 × 10¹²

              at 700 ^oC:                                                       9.0 × 10⁹

              at 1000 ^oC:                                                     1.1 × 10⁷

                                                                                      ^oC                        ^oF

Te Value:                                                                     1170                    2138

Wear Chemical Properties:

Corrosion Resistance - Weight Loss:                        mg/cm²/day

              95% H₂SO₄ at 20 ^oC:                                   0.01

              95% H₂SO₄ at 100 ^oC:                                 0.1

Impingement: 0.14

Rubbing: 0.55