Borosilicate Glass Material Properties

Borosilicate Glass (SiO2 and B2O3), has a very low coefficient of thermal expansion making it more resistant to thermal shock than any other common glass. It also has very high electrical resistivity and dielectric strength, high chemical stability, withstands high applied torque loads and is visible to near Infrared transmission.

Applications for precision balls include: valves, pumps, insulators, calibration, spacer

Borosilicate Glass

PHYSICAL PROPERTIES
composition	SiO2 65-85%
	B2O3 8-15%
	Na2O 3-9%
	Al2O3 1-5%
	K2O max 2%
density	2.23 g/cm3
max working temperature	300 – 400°C
THERMAL PROPERTIES
melting point	1252°C
softening temperature	821°C
thermal conductivity	1.15 W/(m·K)
shock resistance	300°C
MECHANICAL PROPERTIES
hardness	Mohs 6
	Knoop 420 – 520
Poisson’s ratio	0.20
Young’s modulus	64 GPa
compressive strength	9327 kg/cm2
tensile strength	832 kg/cm2
ELECTRICAL PROPERTIES
volume resistivity	>10^15 Ω·m
OPTICAL PROPERTIES
refractive index	1.471 nm
MAGNETIC PROPERTIES
relative magnetic permeability	diamagnetic <-1

*values are for guidance only