Structural member

Abstract

A structural member 10 includes a base material 100 formed of a polycrystalline material, and a protective film 200 covering a surface 110 of the base material 100. In a cross section obtained by cutting the base material 100 perpendicular to the surface 110, when an average value of cross-sectional areas of multiple crystal grains 150F exposed on the surface 110 among crystal grains 150 constituting the base material 100 is defined as a first cross-sectional area, and an average value of cross-sectional areas of multiple crystal grains 150B located deeper than the surface 110 among the crystal grains 150 constituting the base material 100 is defined as a second cross-sectional area, the first cross-sectional area is smaller than the second cross-sectional area in the structural member 10.

Dependencies are inferred from the claim text.