Glass Materials

Glass relatively inexpensive and readily available, with a wide range of applications. Due to the high thermal expansion coefficient has a low resistance to sudden changes in temperature.

ROBAX® glass ceramic panels consist of a transparent glass ceramic material. Because of its material characteristics the product is designed for the use as thermal window in fireplaces.

This technical delivery specification applies to ROBAX® glass ceramic panels (delivery form: flat stock-size sheets, cut-to-size-panels and bent panels with or without decoration) for applications which require a low thermal expansion and transparency:

• electric, oil or gas stoves
• conventionally heated fireplaces and room heaters (wood, coal, pellets …)

• Transparent, slightly coloured due to the material composition and production process
• Surface appearance: plane, slightly textured due to the production process

Impact Resistance: The impact resistance of ROBAX® depends on the kind of installation, the size and thickness of the panel, the kind of impact, the geometry of the panel and especially here on the drilled holes and their position on the ROBAX® panel. Therefore information regarding the impact resistance can only be given with knowledge of the respective application (especially in combination with the technical standards regarding impact resistance that have to be met for single applications). Corresponding guideline values on request.

Resistance to Temperature Differences (RTD): Resistance of the panel to temperature differences between heated zone and cold panel edge (room temperature). No cracking due to thermal stress at T_es, _max¹⁾ ≤ 700°C.

Thermal Shock Resistance: Resistance of the panel to thermal shock when the hot panel is quenched with cold water (room temperature). No cracking due to thermal stress at T_es, _max¹⁾ ≤ 700°C.

Temperature / Time Load Capacity: The temperature / time load capacity specifies the maximum permissible temperature for given load times for the fireplace panels, below which no cracking due to thermal stress occurs. The value pairs specified in the following table 2.1 are relevant to the practical use of the glass ceramic material as fireplace panel. The temperature values refer to the hottest point on the exterior side of the panel (Tes, max) because this temperature can be measured more easily and more reliably.

Note: for ROBAX® fireplace panels the temperature / time load capacity specified in table 2.1 must be maintained. It must be ensured that this temperature / time load capacity is not exceeded during use, to prevent cracking due to thermal stress.

The temperature / time load data for even temperature distributions within an entire glass ceramic panel (e.g. homogeneous heating conditions in a testing furnace) are given in table 2.2. This data is to be seen purely as characteristic data for the glass ceramic material itself. It is not typical for use of the ROBAX® glass ceramic material as fireplace panels, which have a temperature distribution totally different from evenness. The temperatures refer to the homogeneous heating of the ROBAX® panel (T_hom).

Change of Surface due to Use: ROBAX® has a good resistance against chemical surface attack. In isolated cases and under special critical conditions, e.g. aggressive exhaust gases (acidification at high temperatures) changes of the surface may occur. For such applications practice tests have to be carried out before being used.

Material Characteristics: Visual inspection in the normal installation position without visual aids and illumination of approx. 800 Lux when viewed from a minimum distance of 1 m. The inspection shall be executed with a background in the colour of fireclay bricks: Light ivory RAL-1015.

Bubbles: Bubbles are gaseous inclusions within the glass ceramic material. Closed bubbles can appear as low-spots on the surface depending on their size and position within the glass. Open bubbles are open towards the panel surface and are not permissible if bigger than 1 mm. The production of material totally free of bubbles is not possible due to the production process. Table 3.2 contains the permissible number of closed bubbles in dependence of their length and the panel size.

Clear fused quartz glass is a unique material with an unrivalled combination of purity, high temperature resistance, thermal shock resistance, high electrical insulation, optical transparency and chemical inertness.

SiO2 Content – 99.995%

Total Metallic Impurities – 10ppm (Typical)

Chemical Inertness: fused quartz does not react with acids with the exception of hydrofluoric and at high temperatures phosphoric. There is a slow reaction with caustic alkalies at normal temperatures. There is no reaction with water and steam at moderate temperatures and pressures.

Alumina ceramic substrate has lots of advantages, it has good thermal conductivity, stable insulation, thermal shock resistance, wear resistance, Anti-acid and Anti-alkali etc. Can be used in thick film hybrid integrated circuits HTC, LED ceramic heat sink, power modules, semiconductor devices and other fields. Commonly used ceramic substrates are Al2O3, AlN, SiC, BeO, BN, ZrO2 and glass ceramics. Although the thermal conductivity of Al2O3 ceramic substrate is not high (20W/m.K), it is the most widely used ceramic substrate because of its relatively simple production process, low cost and low price.

D 263® T eco thin glass is a clear borosilicate glass that has a high chemical resistance and is produced by a SCHOTT specific down-draw method. It is available in a variety of thicknesses ranging from 0.03 mm to 1.1 mm. D 263® T eco borosilicate glass is available in standard stock size sheets or can be custom cut into round or square shapes. D 263® T eco thin glass is used as substrate glass for coatings or as replacement for plastic for applications in the automotive and electronics industries. D 263® T eco is manufactured with eco-friendly refining agents.