Borosilicate
H-PZ33 Low Expansion Glass
H-PZ33 is a low expansion borosilicate glass characterized by high light transmittance, excellent thermal stability, excellent mechanical hardness, and excellent chemical durability. H-PZ33 has become the glass of choice for MR11 reflectors, MR16 reflectors, UHP lamps, parabolic aluminized reflectors, telescope mirrors, and any application where a low coefficient of thermal expansion is called for.
| H-PZ33 Physiochemical Properties | |
| Refractive index (nd) | 1.47200 |
| Dispersion (nF - nC) | 0.00719 |
| Coefficient of Linear thermal expansion (x10-6/°C) | 3.25 |
| Thermal conductivity (W/(m * °C)) | 1.14 |
| Average thermal capacity (KJ/ (kg * °C)) | 0.83 |
| Maximal operation temperature (°C) Short Term Long Term Thermal stability | 500 450 375 |
| Density (g/cm3) | 2.23 |
| Elastic modulus E (kN/mm3) | 64 |
| Hardness (HK) | 480 |
| Poission's Ratio | 0.2 |
| Climatic resistance (ISO - 719 - HGB) | Grade 1 |
| Acid resistance | Grade 1 |
| Alkali resistance | Grade 1 |
| Melting temperature (°C) | 1680 |
| Working Point (°C) | 1252 |
| Softening Point (°C) | 820 ± 10 |
| Annealing Point (°C) | 560 ± 10 |
| Stress Point (°C) | 510 ± 10 |
| Surface Tension (dyn/cm) | 340-350 (1252 °C) |
| Dielectric constant (1MHz, 20°C) | 4.6 |
| Dielectric loss (1MHz, 20°C) | 37 x 10-4 |
| Dielectric strength (50MHz, 25°C) Kv/mm | 16 |
| Color Code (λ5/λ80) | 297.6/337.2 |
| Volume Sensitivity (log ρ) 250°C 350°C | 8.0 6.5 |
| Environmental Protection | Pb < 50 ppm As < 5 ppm Cd < 5 ppm |