High adhesion diamond films deposited on stainless steel by using nanocomposite films with mosaic interface as an interlayer

Abstract It suffers from poor adhesion to deposit diamond films on steel by using normal metal compound films as an interlayer. Here, high adhesion diamond films were successfully prepared on stainless steel by using Cr/CrSiN nanocomposite film as interlayer. The results show that with Si contents increasing to 10.6 at.%, spikes appear at the interface between diamond films and interlayer, exhibiting high adhesion with hardness increasing to 80 GPa. With Si contents further increasing to 15.5 at.%, the spikes disappear and diamond film peels off even though its hardness still keeps 62 GPa. This indicates that spikes, composed of Cr-C compounds, supply mosaic structure and mechanical lock effects to improve the adhesion. The spikes’ composition means that carbon atoms react with Cr/CrNx crystals in interlayer during HFCVD. Under lower Si contents, amorphous SiNx/Si phases are few, Cr/CrNx crystals can easily react with carbon atoms via different velocities, causing the co-existence of longer and shorter Cr-C phase to form the spikes. As Si content increases, more amorphous phases envelop the crystals, limiting the reaction of carbon atoms with Cr/CrNx crystals, so the spikes disappear. This supplies a way to control the adhesion of diamond films by adjusting Si contents to produce different interface structures.