Metal Tape Research Articles

Hydrodynamics and heat and mass transfer during formation of thin metal glass tape

The mathematical model of hydrodynamic and heat transfer processes in a system, which rotates a disk, a metal tape, an environment, is developed. The adequacy of both the mathematical model and the computing algorithm is confirmed by comparison the computing results with the laboratory experiment. It has been shown that increase of the disc’s rotational speed reduces the thickness of the amorphous metal tape.

Tilted BaHfO3 nanorod artificial pinning centres in REBCO films on inclined substrate deposited-MgO coated conductor templates

We grow BaHfO3 (BHO) nanorods in REBa2Cu3O7−x (REBCO, RE: Gd or Y) thin films on metal tapes coated with the inclined substrate deposited (ISD)-MgO template by both electron beam physical vapour deposition and pulsed laser deposition. In both cases the nanorods are inclined by an angle of 21°–29° with respect to the sample surface normal as a consequence of the tilted growth of the REBCO film resulting from the ISD-MgO layer. We present angular critical current density (Jc) anisotropy as well as field- and temperature-dependant Jc data of the BHO nanorod-containing GdBCO films demonstrating an increase in Jc over a wide range of temperatures between 30 and 77 K and magnetic fields up to 8 T. In addition, we show that the angle of the peak in the Jc anisotropy curve resulting from the nanorods is dependent both on temperature and magnetic field. The largest Jc enhancement from the addition of the nanorods was found to occur at 30 K, 3 T, resulting in a Jc of 3.0 MA cm−2.

Processing and characterization of Tb2O3-ZrO2 insulation coatings by sol-gel technique for high temperature applications

This paper covers a new insight into high-temperature Tb2O3-ZrO2 insulation coatings on Ag substrate for magnet technologies. Sol-gel methods used to produce Tb2O3-ZrO2 insulation layers are described, emphazing key parameters. The thermal, structural, microstructural, and electrical properties of Tb2O3-ZrO2 coatings on Ag metallic tape substrates were discussed in our research. It was found that commercial Ag and AgMg sheathed Bi-2212-long-length tapes would be insulated with pure ZrO2 and Tb2O3-ZrO2 coatings and then the coated tapes could be wound to fabricate an electromagnet.

BaFe2(As1−xPx)2 (x = 0.22−0.42) thin films grown on practical metal–tape substrates and their critical current densities

We optimized the substrate temperature (Ts) and phosphorus concentration (x) of BaFe2(As1−xPx)2 films on practical metal–tape substrates for pulsed laser deposition from the viewpoints of crystallinity, superconductor critical temperature (Tc), and critical current density (Jc). It was found that the optimum Ts and x values are 1050 °C and x = 0.28, respectively. The optimized film exhibits and along with a high self-field Jc at 4 K (∼1 MA cm−2) and relatively isotropic Jc under magnetic fields up to 9 T. Unexpectedly, we found that lower crystallinity samples, which were grown at a higher Ts of 1250 °C than the optimized Ts = 1050 °C, exhibit higher Jc along the ab plane under high magnetic fields than the optimized samples. The presence of horizontal defects that act as strong vortex pinning centers, such as stacking faults, are a possible origin of the high Jc values in the poor crystallinity samples.

Effect of annealing high-dose heavy-ion irradiated high-temperature superconductor wires

Heavy-ion irradiation of high-temperature superconducting thin films has long been known to generate damage tracks of amorphized material that are of close-to-ideal dimension to effectively contribute to pinning of magnetic flux lines and thereby enhance the in-field critical current. At the same time, though, the presence of these tracks reduces the superconducting volume fraction available to transport current while the irradiation process itself generates oxygen depletion and disorder in the remaining superconducting material. We have irradiated commercially available superconducting coated conductors consisting of a thick film of (Y,Dy)Ba2Cu3O7 deposited on a buffered metal tape substrate in a continuous reel-to-reel process. Irradiation was by 185MeV 197Au ions. A high fluence of 3×1011ions/cm2 was chosen to emphasize the detrimental effects. The critical current was reduced following this irradiation, but annealing at relatively low temperatures of 200°C and 400°C substantially restore the critical current of the irradiated material. At high fields and high temperatures there is a net benefit of critical current compared to the untreated material.

High-performance FeSe0.5Te0.5 thin films fabricated on less-well-textured flexible coated conductor templates

We report on the transport properties of FeSe0.5Te0.5 (FST) thin films fabricated on less-well-textured flexible coated conductor templates with LaMnO3 (LMO) as buffer layers using pulsed laser deposition. The LMO buffer layers exhibit large in-plane misalignment of ∼7.72°, which is unfavorable for cuprate-coated conductors due to the high grain boundaries. The FST thin films show a superconducting transition temperature of 16.8 K, higher than that of bulk materials due to the compressive strain between LMO and FST. Atomic force microscopy observations reveal that island-like features appear at the surfaces of both LMO and FST, confirming the island growth mode. A self-field transport critical-current density of up to 0.43 MA cm−2 at 4.2 K has been observed in FST thin films, which is much higher than that in powder-in-tube processed FST tapes. The films are capable of carrying current densities of over 105 A cm−2 in the whole applied magnetic field up to 9 T, showing great potential for high-field applications. The results indicate that, for FST, highly textured metal tapes are not needed to produce coated conductors with high performance, which is of great advantage over cuprate-coated conductors.

Effect of Annealing Temperature and Spin Coating Speed on Mn-Doped ZnS Nanocrystals Thin Film by Spin Coating

ZnS:Mn nanocrystals thin film was fabricated at 300°C and 500°C via the spin coating method. Its sol-gel was spin coated for 20 s at 3000 rpm and 4000 rpm with metal tape being used to mold the shape of the thin film. A different combination of these parameters was used to investigate their influences on the fabrication of the film. Optical and structural characterizations have been performed. Optical characterization was analyzed using UV-visible spectroscopy and photoluminescence spectrophotometer while the structural and compositional analysis of films was measured via field emission scanning electron microscopy and energy dispersive X-ray. From UV-vis spectra, the wavelength of the ZnS:Mn was 250 nm and the band gap was within the range 4.43 eV–4.60 eV. In room temperature PL spectra, there were two emission peaks centered at 460 nm and 590 nm. Under higher annealing temperature and higher speed used in spin coating, an increase of 0.05 eV was observed. It was concluded that the spin coating process is able to synthesize high quality spherical ZnS:Mn nanocrystals. This conventional process can replace other high technology methods due to its synthesis cost.

Investigation on quench initiation and propagation characteristics of GdBCO coil co-wound with a stainless steel tape as turn-to-turn metallic insulation.

This paper investigates the quench initiation and propagation characteristics of a metallic insulation (MI) coil by conducting thermal quench tests for a GdBCO single-pancake coil co-wound with a stainless steel tape as the turn-to-turn MI. The test results confirmed that the MI coil exhibited superior thermal and electrical stabilities compared to the conventional coils co-wound with organic insulation material because the operating current could flow along the radial direction due to the existence of a turn-to-turn contact when a local hot spot was generated. The results of the quench test at a heater current (Ih) of 12, 13, and 14 A indicate that the MI coil possesses a self-protecting characteristic resulting from the "current bypass" through the turn-to-turn contact. However, the test coil was not self-protecting at Ih = 15 A because the Joule heat energy generated by the radial current flow was not completely dissipated due to the characteristic resistance of the metallic insulation tape and the non-superconducting materials, including the substrate, stabilizer, and buffer layers within the high-temperature superconductor (HTS) tape. Even though the MI coil possesses superior thermal and electrical stability relative to those of conventional HTS coils co-wound with an organic material as turn-to-turn insulation, it is essential to consider the critical role of the Joule heat energy resulting from the operating current and stored magnetic energy as well as the characteristic resistances in order to further develop self-protective 2G HTS magnets.

High-Performance Flexible Thin-Film Transistors Based on Single-Crystal-like Silicon Epitaxially Grown on Metal Tape by Roll-to-Roll Continuous Deposition Process.

Single-crystal-like silicon (Si) thin films on bendable and scalable substrates via direct deposition are a promising material platform for high-performance and cost-effective devices of flexible electronics. However, due to the thick and unintentionally highly doped semiconductor layer, the operation of transistors has been hampered. We report the first demonstration of high-performance flexible thin-film transistors (TFTs) using single-crystal-like Si thin films with a field-effect mobility of ∼200 cm2/V·s and saturation current, I/lW > 50 μA/μm, which are orders-of-magnitude higher than the device characteristics of conventional flexible TFTs. The Si thin films with a (001) plane grown on a metal tape by a "seed and epitaxy" technique show nearly single-crystalline properties characterized by X-ray diffraction, Raman spectroscopy, reflection high-energy electron diffraction, and transmission electron microscopy. The realization of flexible and high-performance Si TFTs can establish a new pathway for extended applications of flexible electronics such as amplification and digital circuits, more than currently dominant display switches.

Effects of Sputtering Parameters on AlN Film Growth on Flexible Hastelloy Tapes by Two-Step Deposition Technique.

AlN thin films were deposited on flexible Hastelloy tapes and Si (100) substrate by middle-frequency magnetron sputtering. A layer of Y2O3 films was used as a buffer layer for the Hastelloy tapes. A two-step deposition technique was used to prepare the AlN films. The effects of deposition parameters such as sputtering power, N2/Ar flow rate and sputtering pressure on the microstructure of the AlN thin films were systematically investigated. The results show that the dependency of the full width at half maximum (FWHM) of AlN/Y2O3/Hastelloy on the sputtering parameters is similar to that of AlN/Si (100). The FWHM of the AlN (002) peak of the prepared AlN films decreases with increasing sputtering power. The FWHM decreases with the increase of the N2/Ar flow rate or sputtering pressure, and increases with the further increase of the N2/Ar flow rate or sputtering pressure. The FWHM of the AlN/Y2O3/Hastelloy prepared under optimized parameters is only 3.7° and its root mean square (RMS) roughness is 5.46 nm. Based on the experimental results, the growth mechanism of AlN thin films prepared by the two-step deposition process was explored. This work would assist us in understanding the AlN film’s growth mechanism of the two-step deposition process, preparing highly c-axis–oriented AlN films on flexible metal tapes and developing flexible surface acoustic wave (SAW) sensors from an application perspective.

Ultrasonic Identification of Weld Defects Made by Butt Welding with Hot Plate on Plastic Pipelines

This article describes usage of ultrasonic method TOFD for testing of welds on plastic pipelines welded with butt fusion with hot plate. As an artificial defects were selected cold fusion and inclusion in the weld area, by using metallic tape and wire as a mentioned defects. To test defects was necessary to use wedges with water as a bonding agent. Results of testing are proof of usefulness of this method. It can severely reduce risks of accidents caused by unidentified defects, which can occur in welded joints. Since plastic pipelines are used even in nuclear industry as a replacement for metal pipelines for its resistance against radiaton decay, it is necessary to implement similar testing regulations to avoid fatal incidents and method like TOFD and Phased Array ultrasonic testing can prevent such failures.

Characterization of Steel-Ta Dissimilar Metal Builds Made Using Very High Power Ultrasonic Additive Manufacturing (VHP-UAM)

Ultrasonic additive manufacturing is a solid-state additive manufacturing technique that utilizes ultrasonic vibrations to bond metal tapes into near net-shaped components. The major advantage of this process is the ability to manufacture layered structures with dissimilar materials without any intermetallic formation. Majority of the published literature had focused only on the bond formation mechanism in Aluminum alloys. The current work pertains to explain the microstructure evolution during dissimilar joining of iron and tantalum using very high power ultrasonic additive manufacturing and characterization of the interfaces using electron back-scattered diffraction and Nano-indentation measurement. The results showed extensive grain refinement at the bonded interfaces of these metals. This phenomenon was attributed to continuous dynamic recrystallization process driven by the high strain rate plastic deformation and associated adiabatic heating that is well below 50 pct of melting point of both iron and Ta.

Characterisation of Al–Ti dissimilar material joints fabricated using ultrasonic additive manufacturing

Ultrasonic additive manufacturing (UAM) is a solid state manufacturing process for joining thin metal tapes using principles of ultrasonic metal welding. The process operates at low temperatures, enabling dissimilar material welds without generating harmful intermetallic compounds. In this study, a 9 kW UAM system was used to create joints of Al 1100 and commercially pure titanium. Viable process parameters were identified through pilot weld studies via controlled variation of weld force, amplitude and weld speed. Push-pin delamination tests and shear tests were performed, comparing as-built, heat treated and spark plasma sintering treated samples. Heat treated and spark plasma sintering treated samples yielded mechanical strengths over twice that of as-built samples. Electron backscatter diffraction measurements show that deformation and grain refinement only take place in the aluminium layers. Heat treated samples exhibit a thin intermetallic layer, which is hypothesised as constraining the interface, leading to the improved strength.

A (RE)BCO Pancake Winding With Metal-as-Insulation.

In this paper, we report preliminary experimental results on protection study of two REBCO pancake coils based on the metal-as-insulation (MI) winding technique, a variant of the no-insulation (NI) winding technique, in which a metallic tape is cowound. Against the more-proven NI technique, our results demonstrate that the MI technique, too, is quite viable for HTS pancake coils with the following features: 1) nearly self-protecting;2) significantly smaller charging-delay time constant; and 3) better control of coil parameters. It also permits stable operation at 97% of a quench current. We present 77-K results of NI and MI pancakes: first, comparing the advantages and drawbacks of the two winding techniques and, second, dealing with stability and quench parameters. Finally, using a simple circuit model, we quantitatively show that metallic tape thickness has little detrimental effect on the self-protecting feature of the MI pancakes.

Self-heating technique of metallic substrate for reel-to-reel and double-sided deposition of YBa2Cu3O7−δ films

A new, simple, and highly efficient heating technology for metal tape substrates is proposed and applied to reel-to-reel and double-sided film deposition. In this technology, direct electrical current (I DC) is conducted into the metal layer of oxide-buffered metal substrate to induce heat. Different substrate surface temperatures were achieved by varying I DC from 22 to 25 A. At these temperatures, a series of 1-μm-thick and 5-cm-long YBa2Cu3O7−δ (YBCO) films were fabricated on ion-beam-assisted deposition (IBAD) templates through metal organic chemical vapor deposition. X-ray diffraction analysis on the samples revealed that the YBCO film changed its growth mode from mixed a-axis and c-axis to purely c-axis with increasing I DC. The optimal out-of-plane and in-plane texture reached ~1.4° and 3.5°, respectively. A 30-m-long and 500-nm-thick single-sided YBCO-coated conductor was also prepared through reel-to-reel deposition using the proposed heating method. The fabricated conductor presented homogeneous crystallization and texture and exhibited a critical current density at self-field and 77 K (J c 77K, 0T ) of 2.8–3.2 MA/cm2. Moreover, 500-nm-thick YBCO films were fabricated simultaneously on both sides of the double-sided IBAD template. The two sides of films demonstrated uniform texture and J c 77K, 0T of 3.2 MA/cm2. Results demonstrated that the proposed substrate heating technology can be used for reel-to-reel and double-sided deposition of YBCO-coated conductors.

TATRA: a versatile high-vacuum tape transportation system for decay studies at radioactive-ion beam facilities

A compact and versatile tape transport system for the collection and counting of radioactive samples from radioactive ion beam facilities has been developed. It uses an amorphous metallic tape for transportation of the activity. Because of this material, the system can hold very good vacuum, typically below 10−7mbar.

Improve Static Performance Identification Of Inductive Proximity Sensor For a Mobile Robot

Nowadays, inductive proximity sensor and mobile robot are one of the most interesting topics attracting scientists. With enhancement techniques from using sensor for controlling mobile robots which can be developed more in the future. Additionally, measuring of static performance of inductive proximity sensor is also essential because the testing and navigation systems perform more exactly by result information from the experiment by assaying the output signal. In this paper, the hand-made measurement system is used to verify again the static performance of proximity sensor with ferrous, non-ferrous and alloy metal tape. Simultaneously, improve static properties of typical tape metal through the relationship between the output signal and the sensing distance of sensor. According to theoretical basis, the relationship of the static parameters can be determined such as: thickness of metal, sensing distance, dimension of metal, and so on. The testing results have shown the output signal of proximity sensor in the model and theory is not similar. The final data will accommodate some information about the relationship of the thickness of metal tape and the sensing distance of proximity sensor, the different affects of position sensor and optimum operation range of mobile robot.

Microstructures of YBa2Cu3Oy Layers Deposited on Conductive Layer-Buffered Metal Tapes

REBa2Cu3Oy (REBCO; RE: rare-earth elements)-coated conductors (CCs) have high potential for use in superconducting devices. In particular, REBCO CCs are useful for superconducting devices working at relatively high temperatures near 77K. The important issues in their applications are high performance, reliability and low cost. To date, sufficient performance for some applications has almost been achieved by considerable efforts. The establishment of the reliability of superconducting devices is under way at present. The issue of low cost must be resolved to realize the application of superconducting devices in the near future. Therefore, we have attempted several ways to reduce the cost of REBCO CCs. The coated conductors using a Nb-doped SrTiO3 buffer layer and Ni-plated Cu and stainless steel laminate metal tapes have recently been developed to eliminate the use of electric stabilization layers of Cu and Ag, which are expected to reduce the material cost. Good superconducting properties are obtained at 77K. The critical current density (JC) at 77K under a magnetic self-field is determined to be more than 2x106 A/cm2. The microstructures of the CCs are analyzed by transmission electron microscopy to obtain a much higher quality. By microscopic structure analysis, an overgrowth of the buffer layer is observed at a grain boundary of the metal substrate, which is one of the reasons for the high JC.

DNA profiles from fingermarks: A mock case study

Environmental factors and subsequent PCR inhibitors may affect the ability to retrieve DNA from handled objects. A poor quality DNA profile results from low DNA template or modifications imposed on the template (damage or degradation) prior to amplification. In this study, we show that direct PCR has the ability to amplify ‘touch’ DNA from uncleaned, handled, substrates following exposure to various environmental conditions. A variety of items (n=90), ranging from metal cartridge cases, glass, tape and wood were touched briefly (less than 15s) by 4 volunteers, exposed to the environment overnight, and in one case for 8 days, and tested for the presence of surviving DNA. Informative DNA profiles were obtained from 49 out of the 90 items (a success rate of 54%), with glass having the highest rate of DNA recovery.

The method of “double thickness” for studying heat transfer from metal tapes to liquid nitrogen

To study heat transfer from a metal surface, the method of “double thickness” is proposed, in which the heating of the central region of a conductor and its average temperature are measured. As a result, the surface temperature is determined directly under stationary cooling. The method was tested to measure the characteristics of the heat transfer from a stainless steel tape to liquid nitrogen.