Papers by Keyword: Interlayer

Abstract: A IrO₂ anode on titanium substrate with iridium–titanium oxide interlayer (Ti/ TiO₂-IrO_x/IrO₂) was prepared through repeating brushing-drying-calcinating procedure. The TiO₂-IrO_x interlayer was prepared using a mixture of TiN nanoparticles and H₂IrCl₆ solution as the coating solution. The Ti/TiO₂-IrO_x/IrO₂ had high catalytic activity, good catalytic stability and long service life. It was suitable for the application of electrochemical depolymerization of chitosans. The experimental results showed that chitosan could be effectively degraded using the Ti/ TiO₂-IrO_x/IrO₂ as the anode. The influence of the current density on the degradation of chitosans was complicated. The power supply type obviously influenced on the degradation.

Abstract: Ti₃Al intermetallic alloy is a light and high-temperature resistant material which substitutes for superalloy. It is promising for wide use in aerospace yield. In this paper, the Ti₃Al alloy was joined by diffusion bonding with and without Ti-6-4 alloy interlayer respectively. Diffusion bonding quality and shear strength of the joints were measured and compared. The results show that there was almost no defect found in joints with interlayer and maximum shear strength is 523 MPa in conditions of 940°C and 2.5 MPa pressure for 1.5h. In contrast, defect rate (percentages of sum of defects length in optical micrograph) of joints without interlayer exceeds 80% and maximum shear strength is only 150 MPa in same conditions. According to fracture analysis, the ductile fracture occurred at Ti-6-4 interlayer of joint with interlayer. Fracture of joint without interlayer belongs to mixed type of ductile fracture and brittle fracture.

Abstract: The explosive welding is a non-conventional technique gaining popularity due to its ability to join dissimilar metals. The technique is very successful in achieving area joining by using the controlled energy of explosives which creates a metallurgical bond between two similar or dissimilar materials. This paper explains the technique of explosive welding for joining SS304 and AA6061 using pure aluminum (2 mm) as an interlayer. The joining was done in two stages. The explosive used is a mixture of Trimonite and salt having velocity of detonation (VOD) in the range of 1500-1600 m/sec. Ultrasonic testing showed good bonding over more than 80%. Micro-hardness variations as compared to parent materials have been evaluated along with microstructure study done to analyze the interface characteristics. SEM/EDS also have been used to check the presence of any possible brittle phases. Both the interfaces are found to be laminar, continuous, uniform and free from micro-cracks.

Abstract: This paper explains the technique of explosive welding for joining SS304 and Al 6061 using Copper interlayer. The joining was done in two stages. In the first stage SS304 (thickness: 20 mm) was joined to Copper (thickness: 3mm). Second stage involved joining of SS-Cu plate to Al 6061 (thickness: 8 mm).The paper presents detailed discussion on important parameters required for explosive welded process. The most important parameter is minimum and maximum flyer plate velocity required for creating the impact. Collision angle and angle of impact are also discussed. Another important parameter is the Velocity of detonation (VOD) of explosive to be used. The explosives used have VOD of the order of 2500 m/s and 1600 m/sec. Since the explosive welding process involves formation of jet between two surface, therefore surface conditions of the base and flyer plate like its flatness, roughness and cleanliness which are very critical for proper joining have been discussed in this paper. Chisel test (which is considered to be most rugged test) was conducted on the joint. The test confirmed successful joining.The paper explains how use of trimonite expands the weldability window in comparison to NGU when used for direct SS to Al alloy welding.It also compares the results obtained by use of two different powder explosives to obtain the same tri-layered plate via two different routes. The results are particularly interesting because both the explosives have substantial difference in their properties such as Velocity of Detonation, Gurney Characteristic Velocity, density and homogeneity which can be used as advantages from different angles of views.

Abstract: Adhesion, hardness and surface morphology are important properties of thin film coated by PVD. Interlayer lying between substrate and coating layer plays an important role on these properties. In this research, type and thickness of interlayer for Cr-Zr-N film are varied to investigate their effect on properties of film. Cr, Zr and mixed Cr+Zr interlayer were selected for this research. Thickness of interlayer was varied by varying coating time from 5 to 45 min. The effect of interlayer on formation of Cr-Zr-N film was analyzed by XRD. Surface morphology was observed by OM, SEM and AFM. Hardness and adhesion were measure by nanoindentation tester and scatch tester. This research found that for surface morphology and hardness, Cr+Zr is the most appropriate interlayer while Zr interlayer provides the best adhesion properties.

Abstract: Rotary Friction welding is a process of solid state joining, broadly in shaft and pipe weld, in the field of automobile, defence, aeronautical, chemical and nuclear environment assembly pipe lines. Due to its some distinctive advantages similar to ease of fabricate, environmentally sociable, high fabrication value and appropriate for similar, dissimilar metal joint. Now a day’s Titanium alloy and stainless steel materials are very popular material in industrial application due to its high mechanical potency, and non-corrosive in nature. In this study an attempt was made to join commercial rod of Ti-6Al-4V and Stainless steel304L with some methods and evaluates the joint strength. Different intermediate metals are taking on in this process and the outcomes are witnesses. From that study the best method of in-between metal was analyzed by carry out mechanical and metallurgical test.

Abstract: Carbon nitride coatings doped with tungsten were deposited on high speed steel disks by unbalanced DC magnetron sputtering using nitrogen-argon mixture gas. The coatings were deposited on three different types of interlayer (Ti, Ti/TiN and Ti/TiC), and the tungsten target current was varied from 0 to 0.9 A. Surface morphology of the coatings were measured by roughness testing and scanning electron microscopy (SEM). In addition, the chemical composition and depth profile were analyzed by X-ray Diffraction (XRD) analysis, Raman spectroscopy, and glow discharge spectroscopy (GDS). Finally, the hardness (H) and elasticity (E) were measured by nanoindentation and a Rockwell indentation test, while the tribological properties were tested using a pin-on-disk tribometer. After all, the coatings were measured by cutting testing of tuning inserts and micro-drillers. It is found that all of the coatings are amorphous and have a thickness of approximately 1.5 μm. Moreover, the nitrogen content is around 30 at%, while the tungsten content varies in the range of 0-9 at%. In addition, the hardness values are in the range of 15-20 GPa and the elasticity varies from 236 to 274 GPa. A good correlation is observed between the wear resistance and the indentation adhesion level. Furthermore, it is found that the hardness is not significantly correlated to the tungsten content and the coatings deposited on the Ti/TiC interlayer have greater adhesion. Finally, the coatings generally have a very low coefficient of friction (0.01-0.3) and a wear coefficient as low as 10^-6 mm³/Nm, and the CN/TiC coating reduced 41% and 43% of flank wear in the cutting testing of turning inserts and micro-drillers respectively.

Abstract: Due to its excellent thermal physical properties, tungsten is used as structural material in divertor components of fusion reactors. With the rapid development of the technology, the joining of W to reduced activation ferritic/martensitic steel is required for use as a component according to the design of helium cooled high performance divertors. However, W and steel have remarkable differences in their coefficients of thermal expansion, which results in a large residual stress in the joints during the manufacturing and service and consequently leads to failure of the joint. In order to obtain a sound W/steel joint, an appropriate interlayer material inserted between tungsten and steel is necessary to solve the above-mentioned problem. A brazing process, using a Ni–based foil–type filler and a Nb slice as intermediate materials, was carried out in vacuum at 1150 °C for 30 min to investigate the joining of tungsten and steel. The microstructures, chemical composition, hardness and strength of the joint were investigated by scanning electron microscopy (SEM), electron probe microanalysis (EPMA), nanoindentation and tensile strength measurement, respectively. The results show that brazing of W and steel was successfully carried out using a Nb interlayer. The bonding interfaces were bonded well. The average tensile strength of 284 MPa was obtained and all specimens fractured in W near the joining seam, in a brittle fracture mode. The nanoindentation test results indicated that the high hardness of 23 GPa were produced at the W/Ni–based filler brazed seams due to the formation of the Boron–riched phase.

Abstract: Pb_xCd_1-xS quantum dots (QDs) was successfully deposited on TiO₂ mesoporous film as TiO₂ mesoporous photoanode using successive ionic layer adsorption and reaction (SILAR) method for quantum dot sensitized solar cells (QDSSCs). Quantum dot sensitized solar cells (QDSSCs) were prepared by sandwiching the TiO₂ mesoporous photoanode with Cu₂S counter electrode. Single layer of Pb_xCd_1-xS, PbS and CdS and multilayer of PbS/CdS/ZnS as well as multilayer PbS/Pb_xCd_1-xS/CdS/ZnS were prepared for characterizations. The characterizations including X-ray Diffraction Spectroscopy (XRD), Field Emission Scanning Electron Microscopy (FESEM), UV-visible spectrophotometer and Current-density voltage (J-V) measurement were carried out to study the effects of number of SILAR cycles of Pb_xCd_1-xS interlayer for molar fraction, x of 0.2 in QDSSCs. Pb_xCd_1-xS interlayer with four SILAR cycles is incorporated between PbS and CdS layer will increase the efficiency in QDSSCS.

Abstract: Inserting a porous samaria-doped ceria (SDC) interlayer between yttria-stabilized zirconia (YSZ) electrolyte and anode is an effective method to enhancing the performance of intermediate-temperature solid oxide fuel cells (IT-SOFCs). In this work, the microstructure and morphology of the SDC interlayer were optimized by varying its thickness and sintering temperature. Results show that the SDC interlayer fabricated by utilizing once screen printing method and then sintered at 1300 °C for 2 h obtains the best electrochemical performance. The resulting polarization resistance and anodic overpotential (at a current density of 0.05 Acm^-2) were 0.84 Ωcm² and 0.07 V at 800 °C in H₂, reduced by factors of 4.7 and 5.6, respectively, when compared with the LSCM anode without the SDC interlayer.