Hardness 9.0 CF Flanged Sapphire Glass Viewports For Vacuum Equipment

Sapphire glass is an application of synthetic sapphire generally produced by subjecting aluminum oxide powder under extreme heat and pressure. Further heat treatment removes internal stresses before processing into thin sheets. The resulting output is a transparent material that is more durable than standard glass. Take note that a synthetic sapphire has the same physical properties as naturally-occurring sapphire.

ADVANTAGES OF SAPPHIRE GLASS

Although sapphires are blue in color, a sapphire glass is highly transparent to wavelengths of light between 150 nanometers and 5500 nanometers. This range gives the material a very wide optical transmission band from ultraviolet to near-infrared.

It is worth mentioning that the human eye can only discern wavelengths between 380 nanometers and 750 nanometers. In other words, a sapphire glass passes the most basic requirement of an ideal screen: light should pass through it, and an individual should clearly see through it.

But the real advantage of sapphire glass lies in its extraordinary hardness. The material is nearly twice as hard as standard glass, and it is almost as hard as a diamond. For a quick reference, the sapphire has a value of 9, while a diamond has a value of 10 under the Mohs scale of mineral hardness. This means that sapphire glass is almost resistant to scratch unless it will come in direct and hard abrasive contact with a diamond.

HOW DOES IT WORK?

 Glass sapphire windows allow the window to be mounted as close to the chamber as reasonably possible and allow the clearest access from the window surface on the air side. These windows are silver-brazed to Kovar® sleeves. They are mounted in stainless steel tube-weld adapters and CF type flanges for use below 1x10-11, or ISO type Kwik-Flange®. Optional flange weldments are available as special order.

Sapphire Window surfaces which are extremely hard and scratch resistant offer a minimum of distortion and provide maximum light transmission suitable for most applications. UV grade viewports have a 90° crystal orientation normal to the optical axis.

Features:

• Offers greater distortion-free view area
• ¾” and 1” are UV grade.
• Magnetic Kovar® content only 1% to 3%
• >80% Transmission from 250nm (UV Grade) to 4000nm
• CF and Weld mount bakeable to 450°C, 25°C/Min gradient
• Kwik-Flange® bakeable to 200°C

We can offer "Sapphire Viewports" available in series of standard sizes from 3/4 inch through 2 inch with a variety of flange options. Dimensions are in inches unless otherwise noted.

CAUTION: Although sapphire has a reasonable thermal conductivity, for safety, we strongly recommend that no viewport is exposed to a temperature ramp of greater than 2-3°C per minute, and that no viewport be exposed to direct thermal radiation. To limit thermal gradients when heating viewports, we recommend the viewing area and the flange be covered with many layers of aluminum foil to act as a reflective shield.