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EB-348

What is NASA outgassing?

Description

product image EB-348 epoxy by EpoxySet

Many aerospace and spacecraft applications use a standard known as NASA outgassingo screen materials for use. Outgassingis the release of a gas that was dissolved, trapped, frozen or absorbed in some material. Outgassing products can condense onto optical elements, thermal radiators, or solar cells and obscure them. Many polymer materials go through rigorous testing to see it passes NASA Outgassing Standards. This test method covers a screening technique todetermine volatile content of materials when exposed to avacuum environment. Two parameters are measured: totalmass loss (TML) and collected volatile condensable materials(CVCM). An additional parameter, the amount of watervapor regained (WVR), can also be obtained after completion of exposures and measurements required for TML andCVCM. To meet NASA outgassing standards the TML cannot excel 1.0% and the CVCM cannot exceed 0.10%. Materials can have very different results depending on mix, cure, or changes in formulation over the years

EB-348 is a thixotropic, low expansion, high temperature adhesive. When cured properly (2hr/100°C + 2hr/190°C) EB-348 meets NASA Outgassing standards. It also has extremely low CTE of 23 in/in/°C. Its paste like rheology allows for application by syringe dispensing, screen printing, pin transfer, or manual application. EB-348 is used as a die attach adhesive to be used at temperatures exceeding 250°C.

Specifications

No.of Components 2
Mix Ratio by Weight 100/5
Mixed Viscosity @RT(cps) 300,000
Pot Life @25°C(100 gram) 2 hrs
Recommended Cure 2 hrs @ 100°C + 2hrs @ 175°C
Alternate Cure 1 hr @ 165°C
Color Black
Specific Gravity 1.76
Hardness(Shore) D-93
Refractive Index NA
Lap Shear Strength @25°C(psi) 2000
Tg(°C) 194
CTE(Below Tg)10-6/°C 23
Service Temp.Range -55°C to 230°C
Thermal Conductivity(W/m°K) 0.5
Volume Resistivity(500 V) 2 x 10^15