A Practical Application of X-Ray Spectroscopy in Ti-Al-N and Cr-Al-N Thin Films (original) (raw)
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2 A Practical Application of X-Ray Spectroscopy in Ti-AlN and Cr-AlN Thin Films
2017
Binary and ternary transition metal nitrides coatings have been used in numerous applications to increase the hardness and improve the wear and corrosion resistance of structural materials, as well as in various high-tech areas, where their functional rather than tribological and mechanical properties are of prime importance (Münz, 1986; Chen & Duh, 1991; PalDey & Deevi, 2003; Ipaz et al., 2010). Up to now, Ti-Al-N and Cr-Al-N films have been synthesized by a variety of deposition techniques including cathodic arc evaporation (Cheng et al., 2001), ion plating (Setsuhara et al., 1997), chemical vapor deposition (CVD) or plasma-enhanced CVD (Shieh & Hon, 2001) and d.c. / r.f. reactive magnetron sputtering (Musil & Hruby, 2000; Sanchéz et al., 2010). Performance of these coatings is equally dependent on their chemical composition and long-range crystalline structure, as well as on the nature and amount of impurities and intergranular interactions. Significant improvement in the mechani...
Characterization of nitride coatings by XPS
Surface and Coatings Technology, 2002
Nitride coatings have been used in numerous applications to increase the hardness and improve the wear and corrosion resistance of structural materials, as well as in various high-tech areas, where their functional rather than mechanical properties are of prime importance. Performance of these coatings is equally dependent on their chemical composition and long-range crystalline structure, as well as on the nature and amount of impurities and intergranular interactions. Significant improvement in the mechanical properties has recently been achieved with multi-component superlattice and nanocomposite nitride coatings. In the case of such multi-component systems, not only is close control of the elemental composition (stoichiometry) necessary to optimize the properties of the coatings, but the influence of chemical bond formation between the components is also of prime importance. Special care needs to be taken when non-equilibrium preparation conditions, activation of CVD and PVD by plasmas or energetic particle beams are applied, occasionally leading to unpredicted deviations, both in composition and structure. As is highlighted in this paper, nitride coatings or nitrided surfaces can be analyzed in detail by X-ray photoelectron spectroscopy (XPS) due to its excellent element selectivity, quantitative character and high surface sensitivity. More importantly, XPS reflects the atomic scale chemical interactions, i.e. the bonds between neighboring atoms, and thus it also provides reliable structural characteristics for amorphous or nano-crystalline coatings of complex composition, for which application of diffraction techniques is not straightforward. A number of examples of the application of XPS are given for various types of nitride coatings, including interstitial compounds, such as TiN, CrN , etc., as well as compounds with predominantly covalent bonding, such as AlN, GaN, x Si N and CN . Special emphasis is placed on ion beam-induced compositional and structural changes and to the formation of 3 4 x 'superstoichiometric' TiN , ZrN compounds. ᮊ
Applied Surface Science, 2001
Substrates of aluminium alloy 2011 have been plasma nitrided using an inductively coupled plasma source and then characterised by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The XRD analysis con®rmed the presence of a crystalline aluminium nitride (AlN) layer on the substrates surfaces. Both AlN and Al 2 O 3 were observed by XPS on the surface of the nitrided Al substrates. The binding energy (BE) of the C 1s photoelectron of adventitious hydrocarbon was found to be dependent on the thickness of the insulating AlN/Al 2 O 3 surface layer. None of the Al 2p, N 1s or O 1s BEs showed any shifts due to surface charge build up. The BE values of the Al 2p photoelectron for AlN, Al 2 O 3 and metallic Al were determined to be 74.5, 75.5 and 72.7 eV, respectively. The charge shifting of the BEs of all the photoelectrons occurs simultaneously only for oxidised Al substrates (not nitrided) with a suf®ciently thick oxidised surface layer. For a thinner oxidised surface layer the adventitious hydrocarbon C 1s photoelectron BE still shows charge shifting but this is not re¯ected in the BE of the Al 2p and O 1s XPS components.
Coatings and Thin-Film Technologies, 2019
For several decades, the increasing productivity in many industrial domains has led to a significant and ever-increased interest to protective and hard coatings. In this context, titanium-aluminum nitrides were developed and are now widely used in a large range of applications, due to their high hardness, good thermal stability, and oxidation resistance. This chapter reviews the thermodynamical characteristics of the Ti-Al-N system by reporting the progress made in the description of the Ti-Al-N phase diagram and the main mechanical and chemical properties of Ti 1Àx Al x N-based coatings. As a metastable phase, the existence of the fcc-Ti 1Àx Al x N depends on particular process parameters, allowing stabilizing this desirable solid solution. The influence of process parameters, with a particular interest for chemical vapor deposition (CVD) methods, on morphology and crystallographic structure is then described. The structure of Ti 1Àx Al x N thin films depends also on the aluminum content as well as on the annealing temperature, due to the spinodal nature of the Ti-Al-N system. These changes of crystallographic structure can induce an improvement of the hardness, oxidation resistance, and wear behavior of these coatings. The main mechanical and chemical properties of physical vapor deposition (PVD) and CVD Ti 1Àx Al x N-based coatings are also described.
Nanostructured Arc-PVD Coatings Based on Titanium and Chromium Nitrides
Russian Metallurgy (Metally), 2012
Multicomponent nanostructured coatings based on Ti–Cr–Al–N nitrides with a crystallite size of 10–100 nm are formed by arc physical vacuum deposition. The dependences of the structure and phase composition of the coatings on the deposition parameters, namely, the bias potential applied to a substrate and the arc current at a chromium cathode, are found. The appearance of chromium nitride phases in the coatings is accompanied by a decrease in the crystallite size. The hardness (up to 32 GPa) and the elastic mod ulus (up to 700 GPa) of the coatings are determined by both the crystallite size and the microstrains (up to 0.74%) induced by chemical heterogeneity in the coatings. The adhesion strength of the coatings is estimated at 90 N. Cutting hardalloy tools with the grown coatings are characterized by a high resistance coefficient during continuous (up to 5.1) and discontinuous (up to 5.7) cutting of 38KhNMA steel.
SIMS investigation of nitride coatings
Vacuum, 2005
The Ti-Cr-N coatings were formed by condensation from a plasma phase in a vacuum with ion bombardment of sample surfaces while combining Ti and Cr plasma flows of variable density in a residual nitrogen atmosphere. The elemental and phase composition and also microstructure were studied by secondary-ion mass spectroscopy (SIMS), Auger electron spectroscopy (AES), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SIMS and AES investigations show that the system of gradient by composition was formed. It is found that the gradient coating consists of basic layer of variable composition, in which concentration of Ti and Cr elements increase or decrease with the coating thickness and Cr-rich interlayer. XRD and TEM measurements show that a continuous series of solid solution Ti x Cr 1Àx N (0.60oxo0.84 and 0.25oxo0.67) of variable composition with preferred orientation (2 0 0) was formed. Cross-section SEM shows that the dense finegrained structures with the average grain size of 10-50 nm were formed.
Protection of Metals and Physical Chemistry of Surfaces, 2012
Multicomponent Ti–Cr–Al–N coatings with crystallites from 10 to 100 nm in size are obtained by vacuumarc ionplasma deposition. The dependence of the changes in the structure and phase composi tion of coatings on the parameters of deposition is established. An increase in the electric displacement potential (Ub) applied to the substrate leads to an occurrence of CrN in the coating in addition to complex nitride (Ti, Cr, Al)N and the TiCr2N phase. When the arc current at the chromium cathode (ICr = 130 A) and Ub are maximal, the second nitride Cr2N is produced. The emergence of chromium nitride phases is accom panied by a decrease in the size of crystallites in the coating structure. The values of both the strength of coat ings (up to 32 GPa) and the elastic modulus (up to 700 MPa) are determined by the crystallite size and microstrains; the latter occur owing to chemical inhomogeneity and may reach up to 0.74%. The adhesion strength of the coatings is characterized by values on the order of 90 N. Cutting hardalloy tools with these coatings exhibit high coefficients of resistance during uninterrupted and interrupted cutting of steel 38XHMA, which reach 5.1 and 5.7, respectively.
Ti-Al-N-Based Hard Coatings: Thermodynamical Background, CVD Deposition, and Properties. A Review
IntechOpen eBooks, 2019
For several decades, the increasing productivity in many industrial domains has led to a significant and ever-increased interest to protective and hard coatings. In this context, titanium-aluminum nitrides were developed and are now widely used in a large range of applications, due to their high hardness, good thermal stability, and oxidation resistance. This chapter reviews the thermodynamical characteristics of the Ti-Al-N system by reporting the progress made in the description of the Ti-Al-N phase diagram and the main mechanical and chemical properties of Ti 1Àx Al x N-based coatings. As a metastable phase, the existence of the fcc-Ti 1Àx Al x N depends on particular process parameters, allowing stabilizing this desirable solid solution. The influence of process parameters, with a particular interest for chemical vapor deposition (CVD) methods, on morphology and crystallographic structure is then described. The structure of Ti 1Àx Al x N thin films depends also on the aluminum content as well as on the annealing temperature, due to the spinodal nature of the Ti-Al-N system. These changes of crystallographic structure can induce an improvement of the hardness, oxidation resistance, and wear behavior of these coatings. The main mechanical and chemical properties of physical vapor deposition (PVD) and CVD Ti 1Àx Al x N-based coatings are also described.
Influence of the energy parameter on the microstructure of chromium nitride coatings
Surface and Coatings Technology, 2006
Increasingly, chromium nitride (CrN x) coatings are used as a replacement for titanium nitride coatings and electroplated hard chromium in various applications. This work reports an investigation of chromium nitride coatings deposited using unbalanced magnetron sputtering. The plasma characteristics as a function of the target-substrate distance were evaluated by means of Langmuir probes. Samples of CrN x were deposited at different ion energies and ion-current densities. Other deposition conditions, such as substrate temperature, pressure and target power, were kept constant. The microstructure and composition were analyzed by means of X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and Rutherford back-scattering spectrometry, respectively. The results are analyzed in terms of the energy parameter (E p), which combines both the ion energy and ion flux. The nitrogen to chromium ratio (N/Cr ≈ 1) and the microhardness (∼ 20 GPa) were nearly constant for all samples, although the energy parameter varied from 10 to 320 eV/atom. On the other hand, the microstructure varied from columns separated to a dense fibrous microstructure with almost equiaxed grains. Films deposited at low E p values presented about 80% of (200) orientation and 20% (111) and (220), whereas at higher E p values the orientation was completely (200).