Process for recycling vapor phase aluminiding donor alloy

A process comprising the steps of:

• vapor phase depositing a diffusion aluminide on an article by heating the article, an activator and a particulate aluminum alloy donor material within an enclosure while the article is out of contact with the donor material, particles of the donor material being depleted of aluminum at surfaces thereof during deposition such that each particle subsequently comprises an aluminum alloy core encased in an aluminum-depleted shell;
• tumbling the donor material to remove the aluminum-depleted shell, the tumbling step comprising tumbling an abrasive media with the donor material, the abrasive media comprising particulate material of two different size distributions, a first size distribution having a size range that is larger than a second size distribution of the two different size distributions, the abrasive media having the second size distribution being introduced about one to about ten hours after commencing the tumbling step with the first size distribution;
• sieving the donor material to remove shell fragments from the donor material;
• and then
• reusing the donor material to deposit a diffusion aluminide on a second article by heating the second article, an activator and the donor material within an enclosure while the article is out of contact with the donor material.

A process comprising the steps of:

• vapor phase depositing a diffusion aluminide on an article by heating the article, an activator and a particulate CrAl donor material within an enclosure while the article is out of contact with the donor material, particles of the donor material being depleted of aluminum at surfaces thereof during deposition such that each particle subsequently comprises a CrAl core encased in an aluminum-depleted shell consisting essentially of chromium and up to 15 weight percent aluminum;
• tumbling the donor material for a duration of about two to about twelve hours to remove the aluminum-depleted shell, the tumbling step comprising tumbling a first abrasive media having a particle size distribution of about 0.25 to about 3 mm with the donor material for a duration of about two to about twelve hours, adding a second abrasive media having a particle size distribution of about 25 to about 65 μm to the donor material about one to about ten hours after commencing the tumbling step with the first abrasive material, and thereafter tumbling the first and second abrasive media with the donor material for the duration of the tumbling step;
• sieving the donor material to remove shell fragments and particles smaller than 4 mm from the donor material;
• and then
• reusing the donor material to deposit a diffusion aluminide on a second article by heating the second article, an activator and the donor material within an enclosure while the article is out of contact with the donor material.