Capabilities

Tests can be executed with concurrent gaseous hydrogen exposure at pressure up to 140 MPa and at controlled temperature in the range of 220K to 450K.

– Subcritical cracking thresholds can be measured in constant displacement fracture tests.

– Instrumented test specimens enable the measurement of crack initiation, crack velocities, and crack arrest.

Exposure of polymers to gases such as nitrogen, argon, helium, and hydrogen is one of the primary challenges associated with large-pressure gradients during fuel consumption and refueling operations. Therefore, investigating the performance of polymers under the influence of a dynamic environment, such as high-pressure cycling of different gases with and without temperature cycling, is considered high value.

Measurement of frictional force and vertical wear depth profiles of polymers in 34 MPa hydrogen.

The developed in-situ Dynamic Mechanical Analysis system measures mechanical properties of targeted materials in situ at extreme conditions, such as high pressure. This system provides an understanding of the effects of extreme conditions on materials performance as well as the relationships among microstructure and materials performance in these conditions. The knowledge generated is of particular importance for developing new materials with improved performance.

Test specimens are exposed to high-pressure gaseous hydrogen or deuterium (up to 140 MPa) at elevated temperatures (up to 300ºC) for weeks to months to produce controlled hydrogen content within specimens prior to evaluation.

Environmental electron microscopy, high-resolution scanning transmission electron microscopy, scanning nanobeam diffraction, and crystallographic orientation mapping are just a few of the techniques available throughout the national labs to indirectly observe hydrogen interactions with surfaces, defect sites, and other microstructural features.

Thermal analysis of materials involves several different methods, including but not limited to differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis.

The gas permeation system consists of a hydrogen-compatible vacuum pump, a PNNL-certified environmental chamber, a stainless-steel permeation cell in which the sample is mounted, and hydrogen and nitrogen supply lines in accordance with PNNL flammable, compressed gas regulations. The system is primarily used for measuring the hydrogen permeability coefficient of polymer materials.

Thermal desorption provides an understanding of the compatibility of rubber composites under the high pressure of hydrogen. The rubber composites that are exposed to high-pressure hydrogen are tested to investigate maximum hydrogen capacity and their diffusion coefficients in a gas chromatography-mass spectroscopy environment.