Ar+ ions with 1 keV energy were irradiated on aluminum nitride in an O2 environment and on aluminum oxide in a N2 environment. AlON on AlN and AlN on Al2O3 are formed by the Ar1 irradiation in O2 gas and N2 gas environments, respectively, and the formation of new surface layers is confirmed on the basis of Al2p near core levels and O1s, N1s core levels XPS depth profile analysis. Cu(1000 Å) films were deposited by ion-beam sputtering on Ar+ irradiated/unirradiated AlN surfaces, and the change of the adhesion strength was investigated by a scratch test. Cu films deposited on the irradiated AlN under an O2 environment showed higher bond strength than that on the unirradiated AlN. The improvement of bond strength of Cu films on the AlN surface resulted from the interface bonds between Cu and the surface layers. The bending strength of polycrystalline Al2O3 irradiated by Ar+ ions in N2 environment was also increased and the formation of nitride layer on the alumina was confirmed. A possible new surface layer formation mechanism on ceramics by the ion assisted reaction has been discussed in terms of surface analysis, chemical bond, and mechanical strength.