A method for making a diamond compact includes pre-heating a diamond body which includes a carbonate catalyst to convert at least a portion of the carbonate catalyst into an oxide, assembling the diamond body and a substrate, providing a braze material between the diamond body and the substrate to form a diamond compact, heating the braze material to melt the braze material and form a braze joint between the diamond body and the substrate, and cooling the braze material after increasing the pressure. A bit having a diamond compact including a carbonate catalyst and a metal oxide mounted thereon.