Stainless steel landing gear viewed through XPS, SEM, TEM and APT

A materials challenge remains to eliminate hazardous coatings that protect aerospace landing gear components. Here we describe a stainless steel landing gear cylinder with 1.6 wt% titanium as a replacement for carbon steel and any protective coating. Goals are to characterize the passivated surface with X-ray photoelectron spectroscopy (XPS), microscale inclusions with scanning electron microcopy (SEM), and nanoscale precipitates with transmission electron microscopy (TEM) and atom probe tomography (APT). A comparison is made between passivated and stained stainless steel cylinders. Microscale inclusions are noted to be quite different on the surface compared to the cross section. Precipitation hardening is made possible by producing ~10 nm diameter Ni3Ti, which is described in terms of particle size distribution and precise composition. This deep dive may offer new metallurgical insights for process engineers in the plant.