Method for reducing surface roughness

A method comprising

• (a) coating an initial surface using a first slurry to form a coated surface;
• (b) heat-treating the coated surface at a first temperature to form a first aluminized layer and a sublayer;
• (c) removing at least a portion of the first aluminized layer by acid etching to expose the sublayer;
• (d) coating the sublayer using a second slurry to form a coated sublayer;
• (e) heat-treating the coated sublayer at a second temperature to form a second aluminized layer, wherein the second temperature is less than the first temperature;
• and
• (f) removing at least a portion of the second aluminized layer by acid etching to form a processed surface, wherein a roughness of the processed surface is less than the roughness of the initial surface.

A method comprising

• (a) aluminizing an initial cobalt-rich surface at a temperature greater than 1000 degrees Celsius to form a first aluminized layer and a sublayer;
• (b) removing at least a portion of the first aluminized layer to expose the sublayer;
• (c) aluminizing the sublayer at a temperature less than 800 degrees Celsius to form a second aluminized layer;
• and
• (d) removing at least a portion of the second aluminized layer to form a processed cobalt-rich surface, wherein a roughness of the processed cobalt-rich surface is less than the roughness of the initial cobalt-rich surface.