Adhesion of nickel films on graphite.

Nickel dots from 0.8 to 1.6 mm in diameter and up to 500 nm thick were evaporated onto the stepped (0001) basal surface of stress‐annealed pyrolytic graphite. Leads were soldered or glued to the as‐deposited dots and increasing stress normal to the graphite basal planes was applied to the leads until rupture occurred, usually ≳1 MPa. The distribution of stress‐at‐failure data followed Weibull failure statistics. Auger electron spectroscopy (AES) of the fracture surface of dots ?200 nm thick showed only graphite. In‐depth AES revealed that nickel carbide was present at the nickel–graphite interface. Samples annealed at 400°C for 2 h had a lower characteristic tensile strength than unannealed samples and separated at the interface where AES detected no nickel carbide.