Study On Multi-Component (TiMe)N Hard Coatings Synthesized By Pulsed Bias Arc Ion Plating

A series of multi-component (TiMe)N coatings are investigated in this paper, which are synthesized by pulsed bias arc ion plating on the surface of high speed steal substrates. Transition metal elements: Nb, G, Zr are used because of their differences with Ti in the ability of combining with electrons. The phase compositions and properties of the coatings are tested. The effects of deposition particles' energy on the phase compositions, structures and properties of the coatings have been discussed.The phase compositions of (TiMe)N multi-component coatings are investigated. It is determined by the thermodynamics performances of solute element, and is correlated to the deposition particles' energy. The Gibbs free energy of different compounds in the deposition system has been calculated according to the thermodynamics theory, and the phase structure and properties of the coatings are discussed. For (TiNb)N and (TiCr)N coatings, because of the higher Gibbs free energy of NbN and CrN than TiN, the structures are all face-centered cubic which is similar to that of TiN coating at low pulsed bias, while the mixed phase of NbN and TiN phase co-existed in the (TiNb)N coatings at higher pulsed bias, and the mixed phase doesn't show in the (TiCr)N. For (TiZr)N coatings, the Gibbs free energy of ZrN and TiN are comparable, so the mixed phase of ZrN and TiN phase co-existed in the coatings at all pulsed bias which is applied in this paper.The micro-hardness and scratch test show that, compared with TiN coatings, the general properties of multi-component (TiMe)N coatings are enhanced. The maximum hardness of (TiNb)N and (TiCr)N coatings are obtained when it is match to the culmination of the residual stress of coatings, that means the residual stress is a leading factor to the hardness of the coatings. Furthermore, the TEM results of (TiNb)N coatings show that, the grains of coatings obtained at higher pulsed bias are fine and uniform. The Hall-Pech effect is another important factor to the enhanced hardness of coatings. It is argued that the bombardment of an ion with the surface of the film accelerated by the pulsed bias may result in a very short time process of high temperature and high pressure within a very small volume, which is useful to synthesis the fine grains. Multi-layer (TiNb)N coatings are synthesized and investigated in this paper, the machine properties tests show that, the general performance are enhanced, the micro-hardness and adhesion are all increased for two reasons: one is the refining effect of the fine grains, and the other is that, the dislocations are blocked when moving among the layers.