Chromizing over cathodic arc coating

An article comprising:

• a) a substrate;
• b) a MCrAlY cathodic arc coating on the substrate, wherein M is a metal alloy comprising nickel, cobalt, iron, or a combination thereof and the cathodic arc coating comprises Si and 25 to 50% chromium by weight based on the weight of the MCrAlY;
• and
• c) a diffused chromide coating atop the MCrAlY cathodic arc coating;
• wherein the diffused chromide coating atop the MCrAlY has a higher content of chromium than the MCrAlY cathodic arc coating, the combined thickness of the diffused chromide coating and the MCrAlY cathodic arc coating is 2.5 to 3 mil (0.0635 to 0.0762 mm), and the diffused chromide coating and the MCrAlY cathodic arc coating have a chromium rich phase with a depth of 0.1 to 2.5 mils (0.00254 to 0.0635).

A method of producing a chromium-rich cathodic arc coating comprising steps of:

• a) applying a MCrAlY cathodic arc coating on a substrate, wherein M is a metal alloy comprising nickel, cobalt, iron, or a combination thereof and the cathodic arc coating comprises Si and 25 to 50% chromium by weight based on the weight of the MCrAlY;
• and
• b) applying a diffused chromide coating atop the MCrAlY cathodic arc coating at a temperature of 1800 to 2200° F.;
• wherein the diffused chromide coating has higher content of chromium than the MCrAlY cathodic arc coating and the combined thickness of the diffused chromide coating, the MCrAlY cathodic arc coating is 2.5 to 3 mil (0.0635 to 0.0762 mm) and the chromium-rich cathodic arc coating has a chromium rich phase with a depth of 0.1 to 2.5 mils (0.00254 to 0.0635 mm).