sapphire glass window front view
angled view of sapphire window for viewports
sapphire window edge close-up showing thickness and bevel
backside view of sapphire glass window polished rear surface
sapphire glass window packaged with label and protective film

Sapphire Glass — High-Strength Sapphire Windows & Viewports

Sapphire glass windows and viewports for harsh environments. High hardness (Mohs 9), wide transmission, high temperature & abrasion resistance. Datasheets & custom sizes available.

Category:

Description

Sapphire glass windows deliver outstanding mechanical, thermal and optical performance in extreme environments. Use sapphire glass viewports for laser systems, high-pressure sight windows, vacuum viewports and abrasion-resistant observation ports.

Product at a glance

  • Material: single-crystal sapphire (Al₂O₃) — Mohs hardness 9.
  • Optical range: UV–visible–NIR (typical transmission 200–5000 nm depending on thickness & grade).
  • Key benefits: extreme scratch & abrasion resistance, high temperature stability, excellent chemical resistance.
  • Typical uses: sapphire glass windows, sapphire viewports, laser windows, aerospace & semiconductor viewports.
  • Manufacturing options: round/rectangular discs, custom cut, AR/AR-coatings, metal brazing / metal-to-sapphire seals.

Why choose sapphire glass?

Sapphire glass offers best-in-class hardness and thermal stability. Therefore, it resists scratching in abrasive processes. Moreover, it keeps optical clarity under high temperature and pressure. As a result, engineers choose sapphire when they need a durable, contamination-free optical window for demanding environments.

Key features

  • Mohs hardness ≈ 9 — only diamond is harder.
  • High thermal limit — continuous service in many designs up to +1000°C (grade & mounting dependent).
  • Wide optical transmission — good for UV, visible and NIR; low absorption for many laser wavelengths.
  • Exceptional chemical resistance — resists acids and solvents under service conditions.
  • Durable seals — supports metal brazing and high-vacuum metal-to-sapphire seals for UHV applications.
  • Optional coatings — AR, laser damage-resistant, IR-reflective coatings available.

Typical specifications

 

Material — Properties

General performance
Chemical Formula Al₂O₃
Crystal System Trigonal
Class Hexagonal-scalenohedral
Melting Temperature 2050 °C
Thermal performance
Thermal Expansion Parallel to C-axis: 6.7 × 10⁻⁶
Perpendicular to C-axis: 5.0 × 10⁻⁶
Specific Heat 0.18 Cal/g·°K (25 °C)
Mechanical properties
Density 3.99 – 4.10 g/cm³
Hardness 9 Moh’s Scale
(Hv) ≥ 1700 kg/mm²
Modulus of Elasticity 340 – 380 GPa
Compressive Strength 2.1 GPa
Tensile Strength 0.19 GPa
Optical performance
Index of Refraction Parallel to C-axis: 1.769
Perpendicular to C-axis: 1.760
Index of IR Transmission 3–5.5 μm ≥ 90% (coated with anti-reflective film)
Electrical performance
Electrical Resistance 10¹¹ /cm
10⁶ /cm
10³ /cm
Dielectric Constant 7.5 – 10
Chemical performance
Corrosion Resistance Cannot be corroded by acid or alkali at normal temperature; only attackable by HF at ~300 °C

Applications & industries

  • Laser windows and laser processing equipment.
  • High-pressure sight windows and viewports (oil & gas, pressure testing).
  • Semiconductor lithography and vacuum viewports (UHV-compatible metal-to-sapphire seals).
  • Aerospace instrumentation and high-temperature sensors.
  • Optical instruments, spectrometers, and harsh-environment sensors.

FAQ

Q1: What is sapphire glass used for?
A: Engineers use sapphire glass for windows and viewports in harsh environments where abrasion, high temperature or vacuum compatibility matter.

Q2: Can sapphire be vacuum sealed?
A: Yes. We offer metalized edges and metal-to-sapphire brazed windows for HV/UHV applications.

Q3: How does sapphire compare to fused silica?
A: Sapphire is much harder and more abrasion-resistant. Fused silica can have better UV transmission below ~200 nm and lower thermal expansion. Choose based on wavelength, abrasion and thermal needs.

Q4: Do you provide AR or laser-resistant coatings?
A: Yes — AR, LDT-optimized and IR coatings are available. Specify coating wavelength and laser parameters.

 

 

 

 

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