Lithafrax® powders are thermally stable and ROHS compliant crystalline compounds of the formula LiAlSixOy with near zero thermal expansion coefficients. They are designed to be added as a filler for lowering the coefficient of thermal expansion (CTE) of a matrix.
These fillers have been successfully employed in lowering thermal expansion of thermoset resins, including epoxy and urethanes, frits and glasses, and specialty adhesives used in bonding and encapsulation of microelectronics, and as potting compounds.
Features and Benefits
- Near zero thermal expansion
- Low density
- High loading potential
Typical Chemical Properties of Lithafrax®
|Chemical||Grade 2121||Grade 2122|
|Li2O||11 - 13||3 - 5|
|Al2O3||35 - 40||15 - 20|
|SiO2||45 - 50||75 - 80|
Typical Physical Properties of Lithafrax®
|Sieve||-140 mesh||-140 mesh|
|Particle Size||95% 325 mesh (-)||95% 325 mesh(-)|
|Horiba PSA D50 (light scattering)||2.8 +/- 1.0µm||2.8 +/- 1.0µm|
|Bulk Density (lbs./cu.ft.)|
|True Density (g/cc)||2.37 to 2.43||2.40 to 2.47|
|Thermal Stability||to 2,300°F||to 2,300°F|
|Coefficient of Thermal Expansion (ppm/°C)|
|50° - 200°C||-2.2 x 10-6||1.2 x 10-6|
|50° - 500°C||-3.6 x 10-6||N/A|
|pH||9.0 - 10.5||7.5 - 8.0|
Why are low thermal expansion fillers needed?
Low thermal expansion fillers serve a very useful purpose of modifying properties of resins, frits, glasses, and coatings. These engineered materials are oftne used as potting compounds or adhesives. As such, low thermal expansion is key to improve the physical stability of the bond when application temperature changes.
What makes Saint-Gobain Performance Ceramics & Refractories’ low thermal expansion fillers unique?
Saint-Gobain Performance Ceramics & Refractories’ low thermal expansion fillers offer some of the lowest thermal expansion available in the market. For example, Lithafrax® 2121 actually has a negative coefficient of thermal expansion up to 200°C.
What are the other advantages of Lithafrax®?
Compared to other commonly used fillers, Lithafrax® fillers are lower density, higher purity crystalline materials. They can be used for high loading without significantly altering the properties of a matrix.
Saint-Gobain Performance Ceramics & Refractories is a world-leader in the delivery of innovative, reliable and consistent ceramics for composite armor systems. The company specializes in high-performance, lightweight ceramic materials designed to protect against current and emerging ballistic threats.