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Single-crystal sapphire is a transparent ceramic material with high hardness, strength, rigidity, wear resistance, heat resistance, and plasma resistance, in addition to outstanding optical transparency. Processing single-crystal sapphire is extremely difficult and requires a high level of processing technology.
Over 50-plus years in of processing expertise, Kyocera has accumulated expertise in optical-level lapping and polishing for sapphire wafer shapes, complex shapes (such as rings), grooves, uneven surfaces, spheres, and curved surfaces.


  • Capable of Lapping and Polishing Complex Shaped Sapphire Products
    Lapping and polishing possible for various shapes, such as rings, grooves, uneven surfaces, spheres, and curved surfaces.
  • Lapped and Polished Surfaces are Smooth
    Outstanding optical transmittance is possible by surface roughness of Ra ≤ 0.05 μm
  • Low Particulates
    High-precision surface finishing reduces particle generation (dust generation).

Application Examples

Due to their superior material properties, single-crystal sapphire parts are being used more frequently in applications with harsh environments, such as semiconductor manufacturing equipment, automobile/mobility, industrial machinery, and aerospace/astronomy.
Kyocera can manufacture from large diameter and long sapphire materials and single-crystal sapphire that does not fluoresce under lasers.
We also have extensive experience mirror polishing complex shaped products, including large single-crystal sapphire rings.

  • Plasma Tube

    Plasma Tube

    Φ30 × φ25 × 250L (mm)

  • Sensor Window

    Sensor Window

    Φ5 × φ3 × 70L (mm)

  • Cylinder


    Φ100 × φ80 × 150L (mm)

  • Sensor Lens

    Sensor Lens

    Φ50 × 30H (mm) hollow

  • Guide Rail

    Guide Rail

    Groove: 5 (width) x 3 (depth) x 10L (mm)

  • Gas and Fluid Nozzles

    Gas and Fluid Nozzles

    Flow channel diameter: φ4 × 50L (mm)

*Above numbers are processing examples

Design Guide

Standard Specifications
Material Single-Crystal Sapphire
Material Code SA100
Full Length (L) - 500 [mm]
Outer Diameter (ΦD) 5.0 - 100.0 [mm]
Inner Diameter (Φd) 2.0 - 80.0 [mm]

*Refer to the following figures for dimensions in parentheses.

Design Guide

Lapping and Polishing Evaluation

We develop single-crystal sapphire with outstanding optical transmittance by improving the level of lapping and polishing of the finished surface.

Surface Roughness

Observation image of finished surface by a laser microscope


Observation Image (x1,200)

*Characteristics vary depending on orientation and thickness


Visible light transmittance of lapped and polished complex surface and optical polished surface measured by a spectrophotometer


*Without AR coating
*Characteristics vary depending on orientation and thickness

Property Data Comparison

Comparison of main properties of single-crystal sapphire and transparent materials

Material Code
Quartz Glass Glass
Melting Point 2053 1600 720
Vickers Hardness HV9.807N GPa 22.5 8.8 5.4
Flexural Strength (3-Point Bending) MPa 690 68.6 49.0
Young's Modules GPa 470 73 72
Thermal Conductivity 20℃ W/(m・K) 42 1.2 0.8
C.T.E. 40-400℃ × 10-6/K Parallel to the C-axis 7.7 0.51
(RT -100℃)
Perpendicular to C-axis 7.0

Plasma Resistance

Single-crystal sapphire has outstanding plasma resistance.
It suppresses particle generation (dust generation) and is effective in reducing contamination by impurities.
For these reasons, single-crystal sapphire is used for windows and parts of sputtering equipment, CVD equipment, and etching equipment.


Corrosion resistance test of single-crystal sapphire and quartz glass

Etching Rate
Etching Rate
Measurement Condition
Size : φ150mm
Reactant Gas : Chlorine Trifluoride (CIF3)
Time : 270 hours
Corrosion resistance test results

*State after one month of use under reactant gas

Corrosion resistance test results
Measurement Condition
Reactant gas : Mixed gas of tetrafluoromethane (CF4) +
Time : 1 month

Are you looking for materials with high hardness or high wear resistance to replace quartz glass? Kyocera develops single-crystal sapphire for harsh environments, such as astronomy, aerospace, and chemical handling. We also help decrease maintenance costs and increase the lifespan for replacement parts.
Contact us for a free consultation with one of our product solution experts.

Values are based on typical material properties and
may vary according to product configuration and manufacturing process.