Getter Sorption Testing

Getter Sorption Testing (also known as Delta-P Testing) is a getter qualification and lot conformance test used on getter materials to provide safer operational environments for the cryogenic, nuclear, aerospace and defense industries. Getter Sorption Testing measures the sorption speed, capacity and lifetime of hydrogen (H2), oxygen (O2), carbon dioxide (CO2), nitrogen (N2), carbon monoxide (CO) and organic getters in a sealed chamber. Our accurate and precise test results provide our clients with the necessary data to qualify and verify the performance of batches of getters at a wide range of operating conditions.

Hydrogen getters are critical in eliminating failures in microelectronics, cryogenics and energy storage systems. A getter is typically a reactive material that is placed inside a closed system to maintain a vacuum or other desired gas composition. When molecules strike the getter, they combine with it by both adsorption and absorption. This process of removing residual gas in this way is known as gettering.

Hydrogen sorption rates can be determined by the change in pressure or Delta-P in a test chamber of constant volume and temperature over time. Delta-P Sorption Testing is applicable for three primary types of hydrogen sorption:

  1. Hydride Sorption – When hydrogen is absorbed into a metal through gettering
  2. Sorption by Reduction – When a metal oxide reacts with hydrogen to create a pure metal and water vapor
  3. Hydrogenation Sorption – When hydrogen is absorbed into a getter to counteract the creation of water vapor

ORS Delta-P Test System

ORS’s Delta-P Model 410 test system consists of a test chamber, a data acquisition system, various sensors, and the associated plumbing to introduce, vent and sample the test gas. See the diagram below for how this all fits together.

In testing, the first step is to seal the getter in a test chamber that is set at a designated temperature and evacuated to < 1 torr or purged.  In the case of a hydrogen getter, a 3% or lower certified hydrogen test gas mix is introduced into the vessel at a specified pressure. A hydrogen concentration of 3% or lower is required to ensure that the hydrogen concentration in the test system is below the lower flammability limit for hydrogen of 4%. Pressure and temperature data are then collected for the specified duration to obtain a proper sorption curve.

Delta-P Test Conditions

Temperature: -40C to 400C

Fill Pressure: 0 torr to 1520 torr

Chamber Volume: < 1 Liter

Delta-P Test Results

  • Initial, transitional and long-term sorption rates
  • Getter sorption capacity
  • Quantity of hydrogen sorbed
  • Pre- and post-test gas analysis results utilizing Internal Vapor Analysis

Typical Delta-P Sorption Curve