The formation of a Sm/SiC alloy after deposition of 2-3 ML of Sm in UHV on clean reconstructed carbon(000-1)- and silicon(0001)-terminated SiC surfaces is studied by photoemission (XPS and UPS) and low energy electron diffraction (LEED). The valence of the Sm overlayer after deposition at RT is estimated to be approximately 2.75, while upon annealing the Sm/SiC surface alloys on the bulk crystal becomes predominately 3+ valent. After further oxidation of the 1-2 ML thick Sm/4H-SiC surface alloys, the initial growth appears to proceed in a nearly epitaxial manner, and a modified oxide-SiC interface is formed. Samarium does not appear to induce a catalytically enhanced oxidation growth rate. Growth proceeds on the Si-face by forming SiO 2 on top of a samarium silicide oxide, whereas at the interface primarily silicon oxide is found.