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Sapphire optics & Windows

28 April 2011 No Comment

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Sapphires full of promise

Public anticipation of Friday’s Royal festivities in the UK began with the announcement of Prince William’s engagement to Kate Middleton. The Prince demonstrated his intentions by presenting his future bride with a highly recognisable family heirloom; an 18-carat blue sapphire rimmed with diamonds, the same ring the Prince of Wales had presented to Lady Diana Spencer 30 years before.

Here at Malvern, we also woo with sapphires, promising them to every purchaser of an Insitec L or Parsum real-time particle size analyzer. With self-cleaning sapphire windows at the heart of both systems, what’s not to love?

Sapphire optics

Sapphire is a gemstone variety of the mineral corundum, a pure form of aluminium oxide (α-Al2O3) with no porosity or grain boundaries. It has favourable chemical, electrical, mechanical, optical, surface and thermal properties, and is highly durable. This makes it a preferred material for high performance systems and components in areas such as aerospace and semiconductor technology, as well as for analytical optics

Optical quality sapphire is used for short and long wavelength applications (UV and IR) beyond the acceptable performance ranges of conventional materials. Lenses, prisms, and other laser and infrared optics made from sapphire can withstand both elevated temperatures and hostile environments, yet deliver the broadest spectral transmission.

Sapphire windows in action

Both Insitec L and Parsum are process analytical instruments that measure particle size continuously – in wet systems, in real time. The Insitec L is a laser diffraction system while the Parsum probe uses advanced spatial filter velocimetry to access a larger, but overlapping, size range. The sapphire windows for both are superbly resistant to abrasion delivering the high reliability and low maintenance demanded in a process environment, even when working with highly abrasive slurries.

Q: When is a sapphire not a sapphire? A: When it’s a ruby!

For those of us not used to dealing with precious gems, it may be a surprise that sapphires and rubies are both corundum! It is simply trace amounts of other elements such as iron, titanium, or chromium that give the blue, yellow, pink, purple, orange, or greenish colour that distinguishes one from another.

Corundum containing traces of pure chromium is red – rubies. Our sapphires are (rather unromantically, but of necessity) colourless, unlike the combination of titanium and iron impurities that gives the classic deep-blue, as in the royal engagement ring.

If you have any gems to impart on aspects of particle size analysis, please do leave a comment.