Surface Composites Synthesized through the Incorporation of Atomic Layer Deposited AlO into Nanoporous Fuzzy Tungsten

The incorporation of energetic helium gaseous species into materials such as tungsten (W) imparts intrinsic surface fragility, yielding fuzzy tungsten. To enhance the robustness of the surface layers, aluminum oxide (AlO) was deposited by atomic layer deposition into the fuzzy W. The conformally deposited ceramic yields a new class of surface composites. Structural characterization of the fuzzy W-AlO composites through nanoindentation testing indicated enhanced indentation modulus (E_ind) and hardness (H_ind) and was modeled through various rules of mixtures approaches. The distribution of AlO in fuzzy W was explored and a systematic study of the extent of incorporation of the AlO into the fuzzy W was carried out. The synthesized composites may be utilized for improved structural characteristics, e.g., in reducing crack initiation and fracture.