Spark plug

A spark plug comprising:

• a center electrode extending in an axial direction;
• and
• a ground electrode forming a gap between the ground electrode and the center electrode,
• wherein at least one of the center electrode and the ground electrode includes:
• an electrode base material;
• a discharge member having a discharge surface that forms the gap;
• an intermediate member disposed between the discharge member and the electrode base material;
• and
• a diffusion layer formed between the discharge member and the intermediate member,
• the electrode base material contains not less than 50 wt. % of nickel (Ni),
• the discharge member contains not less than 45 wt. % of platinum (Pt), and at least one of nickel and rhodium (Rh),
• the intermediate member contains platinum and nickel,
• in the discharge member, a content of platinum is highest, and a total content of platinum, rhodium, and nickel is not less than 92 wt. %,
• in the intermediate member, a content of one of platinum and nickel is not less than 50 wt. %, a content of nickel is higher than a content of nickel in the discharge member, and a total content of platinum, rhodium, and nickel is not less than 85 wt. %, and
• a thickness of the diffusion layer is not less than 0.002 mm and not more than 0.065 mm.