The material. Borosilicate glass is soda lime glass with most of the lime replaced by borax, B203. It has a higher melting point than soda-lime glass and is harder to work, but it has a lower expansion coefficient and a high resistance to thermal shock, so it is used for glassware and laboratory equipment.
Composition
74% SiO2/1% Al2O3/15% B2O3/4% Na2O/6% PbO General properties
|
Density |
2200 |
– 2300 |
kg/m3 |
|
Price |
*4.15 |
– 6.22 |
USD/kg |
|
Mechanical properties |
|||
|
Young’s modulus |
61 |
– 64 |
GPa |
|
Yield strength (elastic limit) |
*22 |
– 32 |
MPa |
|
Tensile strength |
22 |
– 32 |
MPa |
|
Compressive strength |
*264 |
– 384 |
MPa |
|
Elongation |
0 |
% |
|
|
Hardness—Vickers |
*83.7 |
– 92.5 |
HV |
|
Fatigue strength at 107 cycles |
*26.5 |
– 29.3 |
MPa |
|
Fracture toughness |
*0.5 |
– 0.7 |
MPa. m12 |
Thermal properties
|
Glass temperature |
450 |
– 602 |
°C |
|
Maximum service temperature Thermal conductor or insulator? |
230 – 460 Poor insulator |
°C |
|
|
Thermal conductivity |
*1 |
– 1.3 |
W/m. K |
|
Specific heat capacity |
*760 |
– 800 |
J/kg. K |
|
Thermal expansion coefficient |
3.2 |
– 4 |
p, strain/°C |
Electrical properties
|
Electrical conductor or insulator? |
Good insulator |
||
|
Electrical resistivity |
3.16 X 1021 – |
3.16 X 1022 |
pohm. cm |
|
Dielectric constant |
4.65 – |
6 |
|
|
Dissipation factor |
0.01 – |
0.017 |
|
|
Dielectric strength |
*12 – |
14 106 |
V/m |
