The adhesion between 30 nm Ni films and quartz substrates was examined as a function of the interfacial chemistry and mixing induced by low temperature (<100 °C)40Ar+and28Si+ion mixing. The Ni/quartz specimens were implanted with either 65 keV40Ar+or 55 keV28Si+to doses between 1 and 10×1016atom/cm2. Both types of implants were observed to induce extensive interfacial grading. X‐ray photoelectron spectroscopy analyses indicated that Ni–O–Si types of interfacial complexes were present in the as‐deposited specimens, but that these complexes were eliminated by the40Ar+ion mixing. In contrast, high dose28Si+ion mixing was shown to induce the formation of new interfacial complexes (Ni–Si–O and new Ni–O–Si complexes). Adhesion measurements, performed using a scratch tester, indicated that the adhesion of the as‐deposited specimens was good (20 N), but that this adhesion got progressively worse (to less than 1 N) with40Ar+implantation. In the case of28Si+ion mixing, adhesion was reduced (to 5 N) in the low dose specimens, but was substantially increased (to 45 N) in the high dose specimens. Overall, Ni/quartz adhesion was shown to correlate with the concentration of interfacial complexes that could chemically attach the Ni films and quartz substrates.