Suprax

SUPRAX (8488) is a brand name for a borosilicate glass from Schott AG , which is used exclusively under license by Auer Lighting GmbH. Due to its increased resistance to alkali, it is used as a (safety) sight glass and due to its low thermal expansion coefficient and favorable optical properties it is used to manufacture reflectors, lenses and collimators .

In 1911 the SUPRAX brand was registered with the Reich Patent Office and registered in 1912. In 1916 the MAXOS brand for laboratory glassware was registered.

SUPRAX was first produced in 1971 in the composition "8488". The composition "8486" shows a good fusion adaptation for tungsten (use as a lamp bulb).

composition

SUPRAX consists of

• 76% silicon dioxide (SiO ₂ )
• 12% boron trioxide (B ₂ O ₃ ).
• 6% sodium oxide (Na ₂ O)
• 4% aluminum oxide (Al ₂ O ₃ )
• 1% barium oxide (BaO)
• 1% zirconium oxide (ZrO ₂ )

properties

The mechanical, optical and chemical properties are given here.

property	value
Refractive index	${\displaystyle n_{\text{d}}=1{,}4812}$
Abbe number	${\displaystyle \nu _{\text{d}}=65}$
Thermo-optical coefficient	${\displaystyle dn/dT\approx 0}$
density	${\displaystyle \rho =2{,}31~\mathrm {g\;cm^{-3}} }$
Modulus of elasticity	${\displaystyle E=67\cdot 10^{3}~{\rm {N~mm^{-2}}}}$
Relative dielectric constant	${\displaystyle \varepsilon _{\text{r}}=5{,}4}$
Coefficient of thermal expansion	${\displaystyle \alpha =4{,}1\cdot 10^{-6}~\mathrm {K^{-1}} }$
Thermal conductivity	${\displaystyle k=1{,}2~{\rm {W~K^{-1}~m^{-1}}}}$
Specific heat capacity	${\displaystyle C=800~{\rm {J~kg^{-1}~K^{-1}}}}$
Maximum working temperature	${\displaystyle T_{\rm {max}}=450~{\rm {^{\circ }C}}}$
Thermal shock resistance	${\displaystyle \Delta T=130~{\rm {K}}}$
Glass transition temperature	${\displaystyle T_{\rm {g}}=545~{\rm {^{\circ }C}}}$

As a borosilicate glass, SUPRAX is almost inert to most chemicals :

	Hydrolytic resistance	Acid resistance	Alkali resistance
Test according to	ISO 720 Class 1 (HGA1)	ISO 1776	ISO 695 Class A2
Max. Removal	0.1	<100 µg Na 2 O / dm²	> 75 - 175 mg / dm²
Max. Ablation MAXOS	0.05	<60 µg Na 2 O / dm²	> 100 mg / dm²

Web links

• SUPRAX properties on the manufacturer's website

Individual evidence

1. ↑ Information on the “Suprax” brand  in the register of the German Patent and Trademark Office (DPMA)
2. ↑ Information on the "Maxos" trademark  in the register of the German Patent and Trademark Office (DPMA)
3. ↑ from Schott technical glasses, physical and chemical properties from 1999
4. ↑ data sheet
5. ↑ Information on the "MAXOS" trademark  in the register of the German Patent and Trademark Office (DPMA)