Of Nbn Thin Films And Plasma Diagnostics

In this paper the purpose is to solve the problem of nuclear material U' erosion and wear and tear. At first the microwave ECR (MW-ECR) plasma in the cusp field is diagnosed with the Langmuir probe. Secondly according to the diagnostic results, taking the 45# steel as the substitute and NbN thin film was deposited on steel and Si (100) substrates by MW-ECR plasma assisted DC reactive unbalance magnetron sputtering. At the same time the plasma spacial composition is diagnosed with optical emission spectroscopy (OES). At last, XRD, TEM, SEM, AFM, EPMA, micro-hardness, wear and tear test and anode polarization were employed to characterize and analyse the phases, microstructure, surface morphology, hardness as well as wear and erosion characteristic.The conclusions in paper are as follows:1 The diagnostic results of the Langmuir probe: 1) In the reactive chamber electron temperature changes from 4. 5 to 8. 5eV and plasma density maintains on the magnitude of 10¹⁰ cm^-3. 2) Plasma density and electron temperature reduce with the gas pressure increasing. 3) Plasma density and electron temperature increase with the microwave power increasing and the changing trends are different in the different stage. 4) Along the reactive chamber' s axial direction there are two districts about ten cm in which plasma density is high and uniform. 5) In the center of the cusp field plasma density is lower.2 The diagnostic results of OES: there are Nb+, Ar+, Ar+ and N2+ in plasma and target poisoning appears with N2 flow increasing.3 Adjusting N2 flow and substrate bias and a series of NbN thin films were deposited. Through characterizing and analyzing it is found that:1) The film' s changing trend with N2 flow increasing:(1) The crystal structure converts from coexistence of hcp B-Nb2N and fcc -NbN to single phase hcp NbN0.95 and preferred orientation is evident.(2) The deposition rate reduces, the composition ratio (N/Nb) increases and the un-smooth surface topography appears.(3) The growth mode on steel substrate is island growth mode and the growth mode on Si (100) changes from no trend to island growth mode. The dimension of surface island reduces and Rms roughness increases and then reduces.(4) Hardness and wear capability of NbN films are better than steel substrate' s, but with N2 flow increasing hardness and wear capability are worse and friction coefficient increases.(5) Erosion potential increases and then reduces and it achieves the top at 2sccm. At this time the sample' s corrosion resistance is best.2) The film' s changing trend with substrate bias increasing:(1) The crystal structure converts from coexistence of bct Nb4N3 and hcp NbNo.95 to single phase hcp NbNo.95.(2) The deposition rate increases and then reduces, the composition ratio (N/Nb) changes in different stage and more flaws appear with the sputtering effect enhancing.(3) The growth mode is island growth mode, the dimension of surface island reduces, Rms roughness reduces and then increases a little.(4) Hardness reduces and friction coefficient increases. At the - 40V the wear capability is best.(5) Erosion potential reduces and the sample' s corrosion resistance is worse.