“…After heating the W surface to remove impurities and ensure that pure W remains, FCC metals, such as Pd, Pt, Au, Ir, and Rh, can be deposited on a clean W tip, after which a faceting process is utilized to form a nanopyramid. Nanopyramids can be made using a variety of FCC metals on the top of BCC-structured W. Among several FCC metals, due to corrosion resistance to reactive gases and strong bonding between Ir and W, Ir/W tips can have the highest brightness, stability, and durability levels when oxygen-gas-based charged particle beams are generated (Jeng et al, 2010; Oshima et al, 2018). The most common way to manufacture such FCC-on-BCC tips is the electroplating method, in which the target FCC metal element is coated onto the tip after the removal of the oxide film in an electrolyte (Kuo et al, 2004, 2009).…”