Coloured coatings containing mixed transition metal oxides

Glass coloured coatings of M_nO_m---N_pO_q---SiO₂ (M, N = Fe, Co, Ni, Mn, Cr) prepared on soda-lime-silica flat glasses by the sol-gel route using the dip-coating technique.

The optical properties of these films were investigated by spectrophotometry and the optical parameters obtained allowed the colouration mechanism acting in each case to be determined as well as a comparison to be made with the parameters on the single TMO coloured films. Colour coordinates were calculated in every case.

On the other hand coatings have been prepared consisting of two different single TMO films. The corresponding mixed coatings were compared with these double films, showing different behaviours and widening the colour spectrum of glass TMO coatings.     

Microscopic Theory of Tensosensibility of Multi‐Layer Polycrystalline Films

The microscopic theory for the coefficient of longitudinal tensosensibility of multi‐layer polycrystalline metal films has been developed. The theory takes into consideration as the scattering of conductivity electrons on external and internal surfaces of separate layers and crystalline boundaries, so as the dependence of specular reflection coefficient and coefficient of transmission of crystalline boundaries and boundaries between separate layers on deformation. The experimental verification of the theory done on three‐layer film systems Cr/Co/Cr, Cr/Cu/Cr and Ni/Co/Cr given as the quality correspondence.     

Modifications test of vacuum deposition Ni/Cr films with Mn and Si for thin film resistors

For producing Ni/Cr thin film resistors an Si addition would be especially suitable to reduce the TCR, as Si forms several phases with Ni and Cr. By evaporating powder mixtures deposition thin films were produced with constant Cr portions of 20 at.%, 30 at.% and 40 at.% and from 5 to 50 at.% Si or Mn, rest Ni. Whereas the layers containing Mn have an exclusively positive TCR, there is a shift to negative TCR in the layers containing much Si.     

O− centre formation in YAG crystals doped with iron group ions

The colour changes of YAG crystals doped with Ti, V, Cr, Mn, Fe, Co and Ni as well as those doped with Mg or Be are described. The comparison of samples annealed in hydrogen oxygen and argon and exposed to an UV irradiation is given. Yellow or brown colour of YAG crystals is attributed to the O⁻ centre formation which causes an increase of absorption, particularly near 400 nm. Most intensive coloration showed the crystals containing iron group ions in a higher valency state after UV irradiation and some crystals (e. g. YAG:Cr) annealed in argon.     

Electrophysical properties of double‐layer nickel‐base and vanadium‐base films within the intermediate temperature range

Phase composition of the double‐layer Ni‐base and V‐base films obtained and annealed in vacuum of 10^‐4–10^‐5 Pa within the temperature range of 700–900 K is studied by technique of electronography and transmission electron microscopy. Temperature dependence of resistance and temperature coefficient of resistance (TCR) was investigated. Comparison of TCR experimental data with the calculated data was made at T = 300 K on basis of semiclassical and macroscopic models and formula for TCR of alloys. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Metastable states in high carbon C–(Fe,Ni, Co) films obtained by three-electrode ion-plasma sputtering

Abstract

The effect of ion-plasma deposition on the structure of high-carbon films (at. %) Fe–(20–84) % С, Co–(5–52) % С, Ni–(7–61) % С was investigated. The lattice periods and crystallite sizes of nonequilibrium phases in the as-deposited state and after heating are determined. The temperatures of the beginning and end of the decay of metastable phases during heating at a constant speed are established. The transition from an amorphous to an equilibrium crystalline state in Fe–C films passes through the stage of formation and subsequent decomposition of an intermediate, metastable hcp phase of variable composition. The electrical and hysteretic magnetic properties of the films were measured in the as-deposited state and after heat treatment. The compositions and conditions for producing films with low values of the temperature coefficient of electrical resistance and high coercive force are established. Thus, high-carbon films of Ni–61% C in the as-depoteted state and Fe–69% C films after heating to 900?K are characterized by small TCR values (± 10^?6 К^?1) over a wide temperature range.     

Strukturuntersuchung Al-dotierter Ni/Cr-Schichten und Untersuchungen zur Legierungsbildung des Al-Zusatzes zur Dotierung mit der Legierung 80Ni-20Cr

The temperature coefficient of the electric resistance by sublimation deposition thin Ni/Cr-layers (>100 Ω/□ to nearly 2 k Ω/□) is reduced almost to zero by endow the layer with aluminium. The electron diffraction investigation of this layer shows three phases: the γ–γ′-phase [Ni₃(Cr, Al)], the α-phase (Cr) and NiCr₂O₄.— The Al-addition for endow the Ni/Cr layer give a different formation of alloy with the wire (2 mm ∅︁) of 80Ni/20Cr. Couse for the bad alloy formation is the existence of a continuous barrier layer of chromium. This barrier layer are exist in case that aluminium has a strong reaction to formation an intermetallic Ni/Al-phase.     

Synthesis and properties of Fe/Ni nanotubes

Fe/Ni nanotubes were formed in pores of polyethylenterephtalate-based template matrices by electrochemical deposition. The inner diameter, wall height, and thickness of the nanostructures, as well as the elemental and phase compositions, can be controlled by varying the deposition conditions. The volume deposition rate constants have been determined for each potential difference, due to which the nanostructure growth could be controlled. An X-ray diffraction analysis of the samples obtained at a potential difference of 1-1.6 V has revealed their composition to correspond to the substitutional solid solution, with an iron atom replaced by a nickel atom and dominance of the bcc a-Fe phase. The samples obtained at a potential difference of 1.8–2 V contain the bcc a-Fe phase and fcc Ni phase; the fcc phase dominates in the sample obtained at a potential difference of 2 V, which can be related to the high Ni content in nanotubes.     

Size Effect and Processes of Interdiffusion in Multilayer Films

The electrophysical properties of multilayer structures consisting of the alternate Co and Ni layers or Co and Cr layers obtained in high vacuum (˜ 10⁻³ Pa) were investigated. The size dependences of the temperature coefficient of the resistance (TCR) of the films were obtained experimentally and then compared with the R. Dimmich theoretical model. The analysis shows that the main reason of the difference between theoretical and experimental data of TCR is the interdiffusion of atoms from one layer to another.     

Nb redeposition on Si during plasma etching of Nb/SiO2/Si layers investigated by RBS

The redeposition of electrode material (Ni, Cr, Al) and material of a Nb layer on silicon surface during plasma etching of Nb, SiO₂ and Si by a CF₄ plasma has been investigated by Rutherford Back Scattering spectrometry. It is shown that a steady state exists, what causes a Nb contamination of etched Si surfaces. Obviously this steady state concentration (Nb)_ads is influenced by additional redeposition of non-etchable electrode material as Ni, Cr and Al.     

Superlattices and composition of phases of CVD layers based on TiCx,VCx, (Ti,V)Cx,and (Cr,Fe)7C3

Protective layers of TiC_x, VC_x, (Ti, V)C_x, and (Cr, Fe)₇C₃ on C100W1 tool steel have been investigated by X-Ray and electron diffraction. Superlattices have been observed in the VC_x− and (Cr, Fe)₇C₃−layers. As manufacturing of (Ti, V)C_x−layers the growth of carbides with low content of V and Ti respectively has been prefered.     

Strukturuntersuchung an aufgedampften mit Aluminium modifizierten Nickel/Chrom-schichten

The temperature coefficient of the electric resistance of evaporated low-resistive Ni/Cr layers is reduced almost to zero by modifying the layer by means of aluminium. According to the results of roentgenographic and electron diffraction, there are four phases in the ternary alloy layer: the α-phase (Cr), the β-phase (NiAl), the γ-phase (Ni) and the γ′-phase (Ni₃Al). They show a very imperfect status of arrangement and development. The lowest temperature coefficient values are to be found in those layers the composition of which renders development of the β-phase possible.     

On normal kinetics in the case of some refractory and transition metals' crystallization

In given work the crystal growth kinetics connected with some refractory and transition metals is considered. For melts of Fe, Co, Ni, Cr, Zr, Ti, Ag, Cu, and Pb in the vicinity of melting temperatures the solid phase growth is described by means of a fluctuation theory applied for the macro-systems. By virtue of the “unlimited” and limited spectrum solid state particle concentration fluctuations' theory some effective kinetic coefficients have been estimated in the work. The effective kinetic coefficients are specific in the case of normal crystal growth kinetics. In the case of the crystallization of Fe, Co, Ni, Cr, Zr, Ti, Ag, Cu, and Pb-melts a comparison between two effective kinetic coefficients (based on the fluctuation theory and so-called equilibrium growth points density) has been realized. In most cases a satisfactory agreement between the effective kinetic coefficients has been observed.     

On modifications of the well-known Hume-Rothery rules: Amorphous alloys as model systems

Structure formation in condensed matter physics is still far from being understood. One important approach, for a limited class of systems selected by some exclusion rules, goes back to Hume-Rothery. Here we review on measurements of the static structure, electronic properties, and the thermal stability of amorphous TM-Al (TM: Ti, V, Cr, Mn, Fe, Co, Ni) and Na–Sn alloys. Concluding from the results, we postulate that the Hume-Rothery rules can be lifted in some cases, extending the Hume-Rothery scheme, i.e., the opening of band gaps at the Fermi energy, to a much wider class of materials, making it more general.     

Orientation control of LaNiO3 thin films by RF magnetron sputtering with different oxygen partial pressure

Highly (1 1 0)- and (1 0 0)-oriented LaNiO₃ (LNO) thin films were successfully grown on Si (1 0 0) substrate using radio frequency (RF) magnetron sputtering at room temperature (RT). Effects of oxygen partial pressures on the orientation, film composition, surface morphology, and electrical properties of the films were investigated. The nearly complete (1 0 0) orientation was first achieved with oxygen partial pressure beyond 15% in the sputtering gas. The preferred (1 0 0) orientation of growing films is determined by uniform distribution of Ni³⁺ and La/Ni ratio in the films caused by oxygen during sputtering, as well as the lowest surface energy of the films in the crystalline process. LNO films with controlled orientation have low resistivity of 7.0×10⁻⁶ Ω m which is a good basis for integrating ferroelectric capacitors.     

The effect of transition M metals on the two-stage enthalpy relaxation behavior of (FeM)83P17 amorphous alloys

The anneal-induced relaxation behavior for (FeM)₈₃P₁₇ (M  Cr, Mo, Mn, Co or Ni) amorphous alloys was examined calorimetrically with the aim to clarify the effect of M substitution on the two-stage relaxation previously found by the present authors. Upon heating the sample annealed at temperatures below T_g, a reversible endothermic reaction (enthalpy relaxation) occurs above T_a. The changes in ΔC_p,endo and with T_a show two distinguishable stages only for The FeMoP alloy which exhibits glass transition; a low-temperature peak at a temperature that is lower by about 180 K than T_g and a high-temperature one just below T_g. However, any indication of the high-temperature peak is not detected for the other alloys which crystallize before T_g. From the data of ΔC_p,endo, ΔH_σ,endo and activation energy for the low-temperature peak which has been thought to generate by relaxation of metal atoms, the first-stage relaxation was concluded to become difficult in the order of Ni < Co < Mn < Cr < V < Mo, i.e., with the decrease in the group number of the periodic table. The change in the first-stage enthalpy relaxation behavior with the substitution of Fe by M is interpreted to originate from the change in the mobility (i.e., relaxation time) of metal atoms through the change in the bonding force among the constituent elements.     

Short-range order in ultrafine powder of an amorphous (Fe7Ni3)69B31 alloy

The short-range order structure of ultrafine powder of an amorphous (Fe₇Ni₃)₆₉B₃₁ alloy has been studied by ZAFS. The particles with diameters 1.7–15.3 nm are prepared by chemical reduction. The fact that the local environments around Fe or Ni are not the same suggests that there is chemical short-range order in this material. The mean distances of near neighbors surrounding an Fe and a Ni atom are shorter than those in amorphous Fe₈₀B₂₀ ribbon. The XANES spectra also show some differences between these two amorphous alloys. These indicate that the interaction between near neighbors is stronger in this amorphous ultrafine powder than in bulk amorphous material.     

微米及纳米WC-Co基BDD污水处理电极的制备研究

硼掺杂金刚石(BDD)是高级氧化法污水处理领域的一种电极材料，其衬底材料的选择是电极涂层制备的核心问题之一，良好的衬底材料可提高膜基结合力，从而延长电极的使用寿命。本文提出以热膨胀系数较小的WC-Co为衬底，采用热丝化学气相沉积(HFCVD)法制备微米、纳米两种表面形貌的BDD电极，并利用场发射扫描电子显微镜(FE-SEM)、拉曼光谱、X射线光电子能谱(XPS)、循环伏安法对两种电极的物理性能、表面状态及电化学性能进行表征，研究结果表明：在沉积速率方面，微米薄膜是纳米薄膜的1.5倍，但纳米薄膜具有更小的残余应力，仅为-0.6 GPa;两种电极在0.5 mol/L的H₂SO₄溶液中均展现较宽的电化学窗口(约为3.7～3.9 V)和极小的背景电流，在K₃[Fe(CN)₆]氧化还原系统中表现出良好的准可逆特性，这些特性均与常规Si、Nb、Ti基BDD电极相似。在此基础上，本文对两种电极开展了苯酚模拟废水处理和加速寿命试验(ALT),结果显示：相同参数下，纳米电极在ALT中使用寿命约为423 h,明显优于微...     

Epitaxial variations of Ni films grown on MgO(0 0 1)

Epitaxial Ni films were deposited on (0 0 1)MgO by DC magnetron sputtering under ultra-high vacuum conditions for studies involving magnetic-multilayer applications. The deposition temperatures of the Ni films studied in this work were 100 and 400°C. Examination by transmission electron microscopy (TEM) and electron diffraction revealed that the film deposited at the lower temperature was predominately Ni[0 0 1]MgO[0 0 1] and Ni(0 1 0)MgO(0 1 0) oriented and smooth, as expected. However, the higher temperature films were predominately of the Ni MgO[0 0 1] and Ni MgO(1 0 0) orientation and facetted. The orientation has been confirmed by X-ray diffraction, where this orientation was observed to be four-fold degenerate. For each of these four orientations there also existed a twin orientation, reflected about the MgO(1 0 0) planes, giving eight possible orientations for the Ni crystallites on MgO. This epitaxial relationship was studied by dark-field TEM and electron diffraction. Because these films were polycrystalline and hence produced many diffraction spots from both the Ni and MgO with similar lattice spacings, electron diffraction patterns of the films were indexed using an electron diffraction image processing (EDIP) technique. In this technique, the polycrystalline electron diffraction pattern was converted into a graph, with the x-axis displaying lattice spacings and the y-axis, integrated intensity.     

Stability and formation of pyrochlore phase in doped Sr0.8Bi2.3Ta2O9 thin films

Ferroelectric thin films of bismuth-containing layered perovskite Sr_0.8Bi_2.3Ta_2−xM_xO₉ (SBTM), where M is V, Ti, W, and Zr, have been prepared on Pt/Ti/SiO₂/Si substrates using the metal-organic decomposition method. The effect of the incorporated B-site cations on pyrochlore phase formation and microstructure evolution of SBTM films was investigated. The pyrochlore phase formation has been identified due to out-diffusion of titanium from underneath platinum layer to participate in the reaction with the films. Furthermore, the formation of pyrochlore phase in the SBTM films has been observed strongly dependent on the characteristics of incorporated M cation. The substitution of both W and V for Ta leads to the formation of pyrochlore phase at lower annealing temperature (750–800 °C). On the other hand, the addition of Zr can retard the formation of pyrochlore phase from 850 to 900 °C. A model based on the binding energy of octahedral structure is used to elucidate the formation and stability of the pyrochlore phase present in the SBT film.