Technical Details of NEXTREMA®

SCHOTT NEXTREMA® mechanical properties

NEXTREMA® boasts a very high degree of mechanical strength for a ceramic material and doesn’t require any additional toughening processes. The glass-ceramic also exhibits extraordinary mechanical stability, even at high temperatures. All NEXTREMA® types offer bending stength according to DIN EN 1288 part 5R45 of 80 megapascals.

• Density: ρ approx. 2.5 – 2.6 g/cm³
• Modulus of elasticity (ASTM C-1259): E approx. 84 – 95 x 10³ MPa
• Poisson‘s ratio (ASTM C-1259): μ approx. 0.25 – 0.26
• Knoop hardness (ISO 9385): HK_{0.1 / 20}approx. 570 – 600
• Bending strength (DIN EN 1288, Part 5, R45): σ_bBapprox. ≥ 80 MPa

Impact resistance

The impact resistance of NEXTREMA® depends on the size, thickness and geometry of the panel, kind of installation and type of impact, especially on drilled holes and their position in the material. Therefore, information regarding impact resistance can only be given with knowledge of the respective and defined application, especially in combination with the technical standards regarding impact resistance that have to be met for some applications. The quality of the grinding profile also has an important influence on impact resistance.

SCHOTT NEXTREMA® thermal properties 

NEXTREMA® exceeds all expectations when it comes to temperature resistance. The material can withstand both extremely high and low temperatures, offering outstanding resistance up to 950 °C¹ (depending on the material type). From white hot to ice cold and back again, quick changes in temperature will have little impact on this heat resistant glass-ceramic, minimizing thermal stress fractures. Thanks to its near-zero thermal expansion, NEXTREMA® can also cope with temperature shocks of up to 820 °C² (depending on the material type), making it ideal for high-temperature applications.

¹ Applies to NEXTREMA® opaque white for 1 hour at 950°C homogenous heating. For inhomogeneous heating and other NEXTREMA® variants, the operating temperature may vary.
² Applies to NEXTREMA® transparent. Tested by quenching a homogeneously heated NEXTREMA® transparent panel (820°C) with room temperature water (20°C). Values may differ for other NEXTREMA® variants.

¹ T_{upper max} : Maximum temperature on the upper side at the hottest point
² T_{es, max} : Maximum temperature on the exterior side of the panel, that means the reverse side of the heat source, at the hottest point

Thermal expansion depending on the temperature

Resistance to Temperature Differences (RTD) 

• Resistance of the NEXTREMA® material to temperature differences which are measured at a distance of 25 mm between hot and cold zone (room temperature).

• Translucent white: No cracking due to thermal stress at Tupper max1 ≤ 560°C

• Opaque white: No cracking due to thermal stress at T_{upper max}¹ ≤ 580°C

• Tinted & Transparent: No cracking due to thermal stress at T_{upper max}¹ ≤ 700°C

• Translucent bluegrey & Opaque grey: on demand

¹ T_{upper max} : Maximum temperature on the upper side at the hottest point

Thermal schock resistance (TSR) up to 820°C (1,508°F)

Resistance of the material to thermal shock when the hot material is splashed with cold water at room temperature, without cracking due to thermal stress. NEXTREMA® transparent is the glass-ceramic with the highest resistance to temperature shocks out of all six NEXTREMA® variants. NEXTREMA® transparent panels resist to thermal shock when homogeneously heated up to 820°C and quenched with 20°C room temperature water.
That means no cracking due to thermal stress. Values differ for other NEXTREMA® variants.

Temperature/time load capacity (TTLC)

The TTLC specifies the maximum permissible temperatures for load times of the material, below which no cracking should occur due to thermal stress. The Temperature/Time Load data for uneven and even temperature distributions (e.g. homogeneous heating conditions) within the material are different. 

Temperature/time load capacity for nonuniformly heated glass-ceramic panel. Temperature/time load capacity is higher for homogenous heating. Operating temperature for NEXTREMA® opaque white for 1 hour homogenous heating is up to 950°C. For other NEXTREMA® variants, the operating temperature may vary.

SCHOTT NEXTREMA® chemical properties

NEXTREMA® is chemically resistant and remains stable in aggressive environments. It meets all subsequent ISO and DIN standards in its chemical resistance to acids, bases and hydrolytic influences. With the elimination of degradation enabling reliable material behavior, as well as stable process environments under typical corrosive conditions. This chemical- and base-resistant glass-ceramic is used in all fields of industrial and product design.

Principal constituents (DIN EN 1748-2-1)

The materials do not contain any harmful substances according to the European directive 2011/65/EU “Hazardous Substances in electrical and electronically Equipment” and fulfil the terms of RoHS(II) without any concerns. NEXTREMA® glass-ceramics consist of 100% UVCB substance glass. According to REACH, this kind of glass is not classified as a hazardous substance. When used within the limitation of the according material specification, NEXTREMA® glass-ceramics do not release any hazardous substances throughout the entire life cycle (including the disposal), that would violate existing legal limits. 

Chemical resistance

The chemical resistance of NEXTREMA® is more extensive than that of most other comparable materials.

1 = high resistance / low solubility
2 = medium resistance / medium solubility
3 = low resistance / high solubility