HEM Sapphire for Mechanical Applications


GT’s HEM sapphire is used in many mechanical applications because of its large size, strength, abrasion resistance and chemical stability.  HEM sapphire has undergone extensive compressive and tensile strength testing at many different temperatures in order to understand its intrinsic failure modes and suitability for different applications.  HEM sapphire has thus been optimized for various mechanical applications by leveraging its intrinsic strength and the company’s application specific sapphire performance knowledge.  Sapphire’s anisotropic nature requires that crystallographic orientations be optimized for the direction of forces and temperatures to which the component will be subjected. Leverage GT’s 40 years of sapphire growth, testing and fabrication knowledge to help you understand the benefits of HEM Sapphire for your mechanical applications. 


Coefficient of Thermal Expansions Curves

Coefficient of Thermal Expansions Curves


  • Melting point of 2040 C
  • Hardness of 9 on the mohs scale 
  • High conductivity at cryogenic temperatures
  • Inert to chemicals at high temperatures
  • Low coefficient of thermal expansion
  • High compressive strength
  • High flexural strength at elevated temperatures



Mechanical Application Sapphire Fracture Toughness

Sapphire Fracture Toughness


  • >10” diameter C-plane components available
  • >15” diameter A-plane components available
  • No thickness restrictions
  • >99.996% purity



There are an increasing number of mechanical sapphire applications including semiconductor wafer carriers, wear parts, nozzles, bearings, blades, tubes and jewel bearings.  HEM sapphire possesses excellent hardness, strength, thermal shock resistance with operating temperatures over 1400 degrees Celsius.  These attributes allow HEM sapphire to safely operate where other structural materials will fail.  The current and emerging engineering applications for mechanical sapphire rely on consistent mechanical strength, purity and orientation homogeneity.  GT Crystal Systems’ unique crystal growth processes and large fabrication capabilities are fueling the replacement of less performance optimized materials with that of HEM Sapphire. 


Please contact sapphiresales@gtat.com or call +1.978.745.0088 with any questions.