19 Mar 2025 Borosilicate 3.3 (PZ33) is the alternative for borofloat 33(BF33).The content of borosilicate : boron: 12.5 ～ 13.5%, silicon: 78 ～ 80%. Therefore, this kind of glass is called high borosilicate glass.
Product Performance:
1. mechanical properties
Density ρ: 2.23 ± 0.02g / cm3
Mohs hardness: greater than 7
2. Thermodynamic Properties
Thermal expansion coefficient: (0-300 ° C) (3.3 ± 0.1) × 10-6K -1
Softening point: 820 ± 10 ℃
Strain point: 516 ± 10 ℃
Specific heat capacity: (20-100 ℃) 0.82KJ × (kg × K) -1
Thermal conductivity: 1.2W × (m × K) -1
Thermal shock resistance: 180 K
The same temperature difference performance: 100 K
Maximum operating temperature: short (<10h) 500 ℃, long (> 10h) 450 ℃
3. Chemical Properties
Acid resistance ISO1776 / DIN12116 1
Alkali resistance ISO 695 / DIN52322 A2
4. Optical Performance
Refractive index: Nd: 1.47384
Transmittance:> 91%
5. Electrical Performance
Resistivity lgρ 250 ℃ 8.0Ω × cm
Dielectric loss tanσ (1 MHz 20 ° C) 38 × 10-4 | 
