Use Of Intermediate Layer Research Articles

Влияние промежуточного слоя на адгезию и трение азотированных покрытий на основе титана на медной подложке

The structure, phase composition, adhesive and tribological properties of TiN coatings deposited on copper by cathode-arc deposition have been studied. The effect of intermediate layers of CuTi and NiCr on the phase composition and adhesive properties of coatings has been studied. During scratch testing of coatings, it was found that an increase in the load on the indenter leads to deformation of the copper base. In this case, the TiN coating on the CuTi sublayer does not collapse until the end of the tests, only transverse cracks appear on the coating at a load of ~ 35 N. The TiN coating on the NiCr sublayer begins to crack at an indenter load of ~ 23 N, and at a load of ~ 26 N, the coating peels off. These results indicate that the CuTi intermediate layer provides a higher adhesive strength of the coating to the substrate than the NiCr sublayer. X-ray phase analysis showed that the use of intermediate layers of CuTi and NiCr leads to different types of X-ray patterns of the Ti-N coating, which may be due to the type of texture formed in the coating on different intermediate layers. During tribological testing of coatings on a copper substrate with intermediate layers of CuTi and NiCr, friction coefficients were determined that behave stably over time.

ВЛИЯНИЕ ДВУХСЛОЙНОГО ПОКРЫТИЯ «АЛМАЗОПОДОБНЫЙ УГЛЕРОД + TIN/ ALTIN» НА ТРИБОЛОГИЧЕСКИЕ ХАРАКТЕРИСТИКИ МАСЕЛ ПРИ ГРАНИЧНОЙ СМАЗКЕ

The application of monocrystalline carbon to steel surfaces of rubbing bodies significantly increases the anti-friction and anti-wear properties of lubricants. (Research purpose) The research purpose is in choosing the optimal intermediate layer material based on the evaluation and comparison of the physical, mechanical and tribological characteristics of two-layer coatings obtained using titanium nitride and titanium aluminitride, respectively, as a solid intermediate layer, and compare them with each other. (Materials and methods) The cylindrical surfaces of 100Cr6 steel rollers with a diameter of 8 mm were coated with titanium nitride and titanium alumonitride, using the latest technologies, and on top of these coatings by pulsed condensation of carbon plasma with additional bombardment with argon ions - monocrystalline carbon. The micromechanical and microgeometric characteristics of the studied surfaces were evaluated using NanoScan-4D and SNeox devices. Pure base oil PAO-4, oil with the addition of oleic acid as a surface-active additive, and zinc dialkyldithiophosphate as a chemically active additive were used as a lubricant. (Results and discussion) The use of intermediate layers of titanium nitride and titanium aluminitride improves the adhesion of the carbon coating, which has a positive effect on its wear resistance. The main role in the antifriction effect of two-layer coatings is performed by a thin-layer carbon coating. (Conclusions) The article shows that the use of composite coatings from monocrystalline carbon + heat-resistant coating in friction units operating in the boundary lubrication mode serves as a reserve for improving the lubricating properties of oils, without requiring chemically active additives containing elements that negatively affect the environment. As an intermediate coating, the best result was shown by titanium aluminitride, it is more resistant to wear, and also provides lower friction.

AlMg6 to Titanium and AlMg6 to Stainless Steel Weld Interface Properties after Explosive Welding

This paper studies the weld interface microstructure and mechanical properties of AlMg6-stainless steel and AlMg6-titanium bimetals produced using explosive welding. The microhardness (HV), tear strength, and microstructure of the weld seams were evaluated. The interface of the weld zones had a flat profile. No structural disturbances or heterogeneity in the AlMg6-titanium weld interface were observed. On the other hand, the bimetal AlMg6-stainless steel had extensive zones of cast inclusions in the 10–30 µm range. SEM/energy-dispersive X-ray spectroscopy (EDS) analysis showed the presence of a hard and brittle intermetallic compound of Al and FeAl3 (with 770–800 HV). The microhardness of the AlMg6-titanium bimetal grew higher closer to the weld interface and reached 207 HV (for AlMg6) and 340 HV (for titanium). Both bimetals had average tear strength below 100 MPa. However, the tear strength of some specimens reached 186 and 154 MPa for AlMg6-titanium and AlMg6-stainless steel, respectively. It is also worth mentioning that heat treatment at 200 °C for one hour led to a uniform distribution of tear strength along the entire length of the bimetals. The study shows that one of the possible solutions to the problem of the formation of the brittle intermetallic compounds would be the use of intermediate layers of refractory metals.

Effect of Ge & ZnO inter-layer on the properties of CZTSSe absorber layer

The use of intermediate layer between Mo and CZTSSe highly affects the properties of Cu 2 ZnSn(S x Se 1-x ) 4 (CZTSSe) absorber layer. The goal of the present work is to get a deeper insight into the beneficial effects of incorporation of an inter-layer between Mo and CZTSSe on absorber layer properties. In this work Ge and ZnO thin layer deposited on the different Mo coated Soda lime glass (SLG) substrates, then a thin layer of CZTS were printed by Doctor blade method, followed by Selenium deposition by thermal evaporation. Films were annealed at 450 °C for 20 min and its structural, optical and electrical properties were studied. The main purpose of this work is to study the variation in the properties of the absorber layer with and without an inter-layer. The crystallinity, conductivity, grain size and mobility of the film improves with Ge as an intermediate layer as compared to Mo or Mo/ZnO. The band gap decreases for Ge intermediate layer and slightly increases with ZnO as an intermediate layer. The Germanium layered film enhances the grain growth and crystallinity of the film as compared to Mo and Zinc Oxide layered. The changes observed in the film properties with the incorporation of Ge and ZnO inter-layer is discussed in the present paper.

Gas Jet Deposition of Diamond onto a Steel Surface Covered by a Tungsten Carbide or Molybdenum Layer

Results of studying the growth of diamond structures on steel specimens with the use of intermediate layers of molybdenum or tungsten carbide cemented by cobalt are reported. The interlayers are deposited by means of detonation spraying. Subsequent deposition of diamond films onto the clad steel specimens is formed by the gas jet method and a special thermocatalytic reactor with extended activating surfaces. The nucleation process on the interlayer surfaces is intensified by preliminary seeding of the specimens in a colloid solution containing nanodiamonds. Information about the phase and structural composition of the resultant specimens and about the film surface morphology is obtained by scanning electron microscopy, Raman spectroscopy, and X-ray diffraction analysis. The tribology of the specimens is studied with the use of hardness nansensors and by the Rockwell hardness indentation method.

Prospects of Production and Application of Hybrid Structures and Composites Made of Titanium Alloys and Nitinol: Overview

Titanium-based alloys are widely used in various industries due to their combination of high mechanical properties and low density. These properties are most effectively used when fabricating aircraft components and medical implants. Shape-memory alloys based on titanium nickelide (nitinol) are promising materials for the fabrication of superelastic medical implants and tools, as well as thermomechanical elements in aerospace technology. The joint application of these materials as elements of hybrid structures or composites is promising for the development of products with a unique set of properties such as high mechanical properties, superelasticity, and damping capacity; increased wear resistance; and thermal shape memory. The basic properties of alloys based on titanium nickelide and the most widely used VT6 titanium alloy (Ti–6Al–4V) are analyzed. It is shown that the combination of functional properties of nitinol and structural properties of titanium alloys in an integrated structure makes it possible to fabricate various products, especially for aerospace and medical industries. To fabricate such structures, various welding (mainly laser and diffusion welding) and soldering methods are currently investigated, and the best prospects are associated with the use of intermediate layers that eliminate the formation of brittle intermetallic phases in permanent joints.

PROSPECTS OF PRODUCTION AND APPLICATION OF TITANIUM ALLOY AND NITINOL HYBRID STRUCTURES AND COMPOSITES.OVERVIEW

Titanium-based alloys are widely used in various industries thanks to a combination of high mechanical properties and low density. The most effective use of these properties is making aircraft components and medical implants. Shape memory alloys based on titanium nickelide (nitinol) are promising materials for production of superelastic medical implants and tools as well as thermomechanical elements in aerospace technology. The combination of these materials used as the elements of hybrid structures or composites can allow the creation of products with a unique set of properties such as high mechanical properties, superelasticity and damping capacity, increased wear resistance, and thermal shape memory. The basic properties of alloys based on titanium nickelide and the most widely used titanium alloy VT6 (Ti–6Al–4V) are analyzed. It is found that the functional properties of nitinol combined with structural properties of titanium alloys in an integrated structure make it possible to make a variety of products, especially for aerospace and medical industries. The possibilities to make high-strength permanent joints of titanium alloys with nitinol are analyzed. Various methods of welding (generally laser and diffusion welding) and soldering are currently investigated in order to produce such structures, and best prospects are associated with the use of intermediate layers that eliminate brittle intermetallic phase formation in the permanent joints.

(Invited) Ionic Conduction in Metal Borohydrides and Their Application to All-Sold-State Batteries

Metal borohydrides such as LiBH4 are widely used as a reducing agent in the synthesis of organic chemistry and a hydrogen storage medium. Meanwhile, ionic conduction as a new function of the metal borohydrides has been the focus of much attention since a high lithium ion conductivity of approximately 10-3 S/cm for LiBH4 was reported in 2007 [1]. To date, a number of metal borohydride-based ionic conductors such as Li3K3La2(BH4)12 and Na2B12H12 have been reported [2, 3]. In this study, the recent progress of metal borohydrides as an ionic conductor will be briefly overviewed. The advantages of the metal borohydrides as a solid electrolyte for secondary batteries follow: 1) good chemical compatibility with metallic anode such as Li, 2) good formability, 3) negligible grain boundary resistance, and 4) light weight. Meanwhile, because of its nature as a strong reducing agent, it comes with the risk of decomposing by reacting with oxidative cathode materials such as LiCoO2. The solution would be to use an intermediate layer in between the solid electrolyte and the cathode. In this study, all-solid-state batteries with the LiBH4 solid electrolyte were constructed and their cell performance was determined, especially focusing on the effect of the intermediate layer [4, 5]. In order to investigate the effects of an intermediate layer on electrochemical performance in all-solid-state cells, various materials such as TiO2 and Li3PO4 were deposited on LiCoO2 thin films. The thin films were grown by pulsed laser deposition (PLD) and atomic layer deposition (ALD). AC impedance analysis and galvanostatic charge-discharge measurements were carried out at 120°C, at which LiBH4 shows a high ionic conductivity of ≈10-3 S/cm. A cell using a bare LiCoO2 without an intermediate layer gave a large interfacial impedance more than 104 Ω. For the LiCoO2 cell with a 25 nm-thick Li3PO4 coating, the impedance reduced to around 20 Ω, and almost no change in resistance was observed even after 30 cycles of charge-discharge. The use of the intermediate layer resulted in significant improvements in both the capacity and cycle performance. The initial discharge capacity of the cell was estimated at 89 mAh/g. It also showed high capacity retention upon cycling: the discharge capacity after 30 cycles was more than 97% of the initial discharge capacity. Furthermore, a high-capacity composite anode comprising of the LiBH4 solid electrolyte and carbon materials was developed. In the composite anode, a massive aggregated graphite (MAG) and acetylene black (AB) were used as the carbon material. A ball-milled composite anode of AB and LiBH4 showed the first charge capacity of 883 mAh/g; however, the capacity fade was significant. 7Li-MAS NMR analysis revealed that the state of Li in the composite was not Li metal nor LiC6 but ionic Li on the surface and defects of AB. In addition, the peak of irreversible component suggests that Li inserted in the early stage is difficult to remove. This indicates that the irreversibility for the composite anode is caused by the poor contact between AB and LiBH4 at the discharge process. To overcome the problem, the use of intermediate layers was effective. The optimized composite anode showed the reversible capacity of higher than 500 mAh/g. The tasks and prospects for metal borohydride-based ionic conductor will be also mentioned. [1] M. Matsuo et al., Appl. Phys. Lett., 91 (2007) 224103. [2] M. Brighi et al., J. Alloys Comp., 662 (2016) 388. [3] T. J. Udovic et al., Chem. Comm., 50 (2014) 3750. [4] K. Takahashi et al., J. Power Sources, 226 (2013) 61. [5] K. Takahashi et al., Solid State Ionics, 262 (2014) 179.

The control and characterization of the crystallographic texture of longitudinal thin film recording media

In this overview we summarize our methods of changing important microstructural features such as grain size and crystallographic texture, in magnetic thin films for longitudinal recording. The methods we have used to better control the grain size and texture of the magnetic films include the use of different underlayers (NiAl and FeAl), the use of seed layers underneath the underlayers and the use of intermediate layers between the underlayer and the magnetic thin film. Examples of the structure and magnetic properties of such films will be presented and discussed. We also present our newly developed method of quantitatively characterizing the crystallographic textures of the thin films used in the multilayered structures. Our method relies on the examination of the intensity weighted reciprocal lattice by means of tilted electron beam diffraction patterns. These patterns contain arcs, the number and location of which can be correlated with specific thin film textures. We will present an overview of the technique from the point of view of the reciprocal lattice and include an example which shows how the crystallographic texture of thin films can be examined and characterized.

Improved Performance of MESFET Devices with L.T.GaAs Buffer Layers

AbstractWe have investigated the electrical properties of n-GaAs epilayers grown by MBE on the top of L.T.GaAs .The Hall mobility and the channel depth of the epilayer decreases as the growth temperature of the buffer decreases. The degradation of the electrical properties is attributed to the outdiffusion of precipitates and point defects from the L.T. buffer layer. The use of intermediate layers (GaAs grown at 400°C-600°C and GaAs/AlxGa1-xAs (x=0.5, 1) superlattices ) between L.T. buffer and n-GaAs active layers in MESFET devices improves the Hall mobility of the channel, the gm and fT performance of the devices.This improvement has been attributed to the AlGaAs layer which hinders the defects outdiffusion.

Novel Technique to Produce Strongly Adherent Diamond Films on Fe- and Ni-Base Alloys

ABSTRACTAn evaluation of the use of intermediate layers for promoting adhesion between diamond and Fe and Ni base alloys is presented. The lack of adhesion between diamond and such alloys has prevented its use as a protective coating in applications at intermediate temperatures. In this study we use a combination of plasma assisted deposition techniques together with controlled bias of the substrate in order to deposit intermediate layers, and simultaneously achieve a thorough intermixing of the elements at the interface, in order to increase the adhesion between the layers. We have compared the performance of different carbide forming metals, as well as other materials. Properties considered in the selection of the appropriate intermediate layers are: chemical affinity with carbon, thermal expansion coefficient, mechanical properties, and adhesion to diamond and to the base metal as well. In the case of multiple layers, adhesion strength was measured after every new layer was deposited, in order to identify any weak links of the composite structure. Transmission electron microscopy was used to determine the microstructure and phases. An analysis is provided of the resulting performance on the basis of the microstructure.

Summary Abstract: The use of intermediate layers to improve the adherence of diamondlike carbon films on ZnS and ZnSe

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Fabrication of large bubble circuits

Large magnetic bubble circuits, having a capacity of 2 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> bits and a storage density of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> /in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , have been fabricated on-the-chip by conductor-first processing using non-planar and planar processing approaches. Aluminum-copper and Ti/Au conductors have been examined with Al-Cu being preferable since it overcomes two major problems encountered when Ti/Au is used-resistance changes due to subsequent high temperature processing and adhesion of a P-glass dielectric which is used as a separating layer between the conductor and the Permalloy elements. When Ti/Au/Ti is used to improve adhesion of the dielectric layer, it is found that resistance changes are even larger than in Ti/Au. The use of intermediate layers of palladium does not alleviate the problem. High-speed operational testing reported elsewhere has demonstrated that non-planar processing results are equivalent to those obtained from planar processing. This is shown in scanning electron micrographs to be a result of achieving excellent step coverage where Permalloy elements overlap the conductor.

Modified Alloy Layers in Tinplate

SummaryThe corrosion resistance of tinplate depends partly on the intermetallic compound layer formed at the iron-tin interface. The shape and size of the crystallites forming the layer are important features. In commercial tinplate, the compound forms as discrete crystallites nucleated from the steel. Methods of altering the alloy coverage of the steel substrate by changing the number of available nuclei and direction of growth of the compound using pickling, preplate, barrier and intermediate plating treatments are discussed, with special reference to the use of intermediate layers within the tin deposit.

The shock-to-detonation transition in solid explosives

The development of a shock wave and its subsequent growth-to-detonation is considered to be a necessary step in the initiation of detonation in any explosive. Using this argument as a basis, it is logical to study in detail, the development of impulse-initiated detonations, to establish the dependence of the growth-to-detonation process on physical, chemical, and geometric variables which appear to be of importance. In this paper, experiments on shock initiation of cast and pressed explosives are discussed. Plane shocks developed by explosive plane-wave generators, and degraded to desired peak amplitudes by the use of intermediate layers of inert materials, were used to initiate detonation in the test explosive sample. The velocity of the shock in each sample was measured as a function of distance into the explosive and as a function of initial shock amplitude. Initial shock pressures ranged from 28 to 140 kilobars. Explosives discussed are TNT and various cyclotols. Both cast and pressed charges were used. In cast charges other than TNT the shock velocity remained essentially constant for a period of time, the length of which depended on the initial shock amplitude, and then rapidly accelerated to normal, steady state detonation velocity. In pressed charges it was found that in the rapid rise, the shock velocity temporarily exceeded the steady detonation value, but decayed thereafter to that of the normal steady detonation. In cast TNT the velocity was found to rise to a value intermediate to that of the initial shock and the final detonation, where it persisted for a time before growth to the normal detonation value. The over-all results can be explained by a hydrodynamic model in which pressure build-up, due to chemical reaction behind the shock, reinforces the shock front as it proceeds through the charge. On the other hand, the detailed results cannot be explained by thermal reactions in homogeneous domains, but require the concept of hotspot initiation. In the discussion our findings will be compared with the work of others who have used various impact and gap-test configurations. Some of the problems and differences of opinion which have arisen in the interpretation of shock initiation will be discussed.