Sapphire tube use

1. semiconductor processing

Sapphire in the semiconductor processing industry than quartz, ceramic, and silicon carbide properties superior to Sapphire tube applications include:
Plasma tube
Gas ejector
Thermocouple components
2. measurement and analysis
Sapphire tubes can be used in a variety of analytical instruments, including:

NMR spectra
Fiber-optic temperature measurement
Online oil analysis
Mass spectrometry
Biological and chemical analysis of samples
Optical communications testing and analysis
3. lighting
Sapphire tube, can be transparent to visible light, infrared, or ultraviolet light, often used in ultra high temperature under high pressure, including:
Infrared countermeasures
UV sterilizers
Flash
High brightness lamp
Sapphire characteristics
Chemical composition: Al2O3 ceramics: a-Al2O3
Melting point: 2050 ° c boiling point: 3,500 ° c maximum operating temperature for a long time: 2000 c
Hardness: Mohs 9 wear coefficient-1.5 (comparison of steel)
Refractive index (sodium d line) birefringence No=1.768 Ne=1.760
Infrared transmittance: infrared transmittance 3~5 μ m band >85%

Source: http://www.ch-microtek.com/