Speaker
Description
The detection of hydrogen in atom probe tomography (APT) tips is challenging due to the residual hydrogen in the currently used stainless steel measurement chambers. While adjusting measurement parameters can reduce the presence of contaminant hydrogen, complete elimination is not feasible and interpretability is therefore limited. Consequently, Deuterium or Tritium is employed as an alternative for investigating hydrogen in APT-tips through identification by isotopic nature. Charging of D and T can occur through either electrochemical or gas-phase methods. Gas-phase charging setups have been in use for a while and have shown promising results as they do not introduce corrosion or contamination on the specimen. The use of a gas instead of an electrolyte also removes the temperature restrictions of an aqueous electrolyte, thus enabling bulk charging of fcc materials such as austenitic stainless steels or Ni bases superalloys. Gas charging setups have been built as standalone devices or integrated into existing atom probes. However, previously existing configurations have been relatively complex and thus expensive to acquire and limited in ultimate pressure. In this presentation, we aim to showcase two approaches for hydrogen gas charging of APT-tips. One with minimal material costs and straightforward manufacturing methods, making them accessible to a broader range of laboratories, and another one with 1000 bar / 300 °C capability, requiring a dedicated H enables laboratory. The former setup is user-friendly and, due to their size, maximum temperature, and pressure application, are not subject to safety regulations. The successful use of these setups will be demonstrated through charged palladium tips. The intended use of these setups is limited to lower charging pressures (up to 10 bar at 90 °C), still allowing for a wide range of experiments with H or potentially other gases. We also introduce a system for high-pressure charging of APT-tips. This setup can generate pressures up to 1000 bar at 300 °C, enabling the charging of various types of APT-tips to levels comparable to electrochemical charging, all while introducing no contamination or corrosion.
