We powder coat alloy mtb frames but the only way we can get powder to stick well is to chemical etch first. this process actually eats metal away and we've got to allow for this in the cnc machine parts that hold headset and pivot bearings. The powder will get heated to about 180 degrees in the oven. Check how powder coater will prepare, some use a bead blast which can work ok and doesn't eat metal but it doesn't key as well. Make sure your powder coater knows what they are doing !!