Ribbon Thickness Research Articles

The study on surface chemical modification of Fe71.5Cu1Nb3Si13.5B9V2 amorphous alloy ribbons and its piezomagnetic effect

In this paper, a type of smooth even endogeny conversion coat composed of Cu0.86Fe2.14O4 and (Cu0.18Fe0.82)Cu0.82Fe1.18O4 phases was successfully obtained by a conversion reaction on the surfaces of Fe71.5Cu1Nb3Si13.5B9V2 amorphous alloy ribbons. In this way, its ribbon thickness was decreased about 6–8µm equivalently. The phase composition and microstructure of the conversion coat were investigated by XRD and SEM. In addition, the adhesion test of epoxy resin and amorphous alloy ribbon was verified by dipping experiments. It is found that the interface bonding strength between the conversion coat and ribbons is strong comparatively. On one hand, the proper interface between conversion coat and epoxy resin make it easy for ribbons to be encapsulated; on the other hand, the ribbons perform better significant piezomagnetic effect than the untreated ones due to a thinner thickness. This work may be a good basic for the applications of Fe71.5Cu1Nb3Si13.5B9V2 amorphous alloy ribbons in piezomagnetic sensor and other devices based on the piezomagnetism effect.

Influence of the Induction Shape on Hysteresis and Loss Measurements of Soft Magnetic Materials

The frequency dependence of the hysteresis loop of high-pressure torsion treatment (HPT)-deformed Fe75Al25, industrial steel Fe–3wt%Si, bulk Fe–3wt%Si plates, and nanocrystalline VP800 was measured on ring-shaped samples. Applying a sinusoidal or triangular $H(t)$ delivers a strong frequency dependence of the losses. A sinusoidal or triangular $B(t)$ reduces the total loss [this reduction is larger for triangular $B(t)$ ] and the dependence of loss on frequency becomes smaller. Our results are discussed in terms of Bertotti’s loss separation model. For HPT-deformed Fe75Al25, the total loss $W$ linearly varies with the square root of frequency when a triangular $H(t)$ is applied; however, no significant change in the total loss was found for a triangular induction $B(t)$ up to 500 Hz. The hysteresis, classical, and excess loss values of the Fe–3wt%Si steel plates are different from those of bulk Fe–3wt%Si for all $H(t)$ and $B(t)$ shapes due to different microstructures. In nanocrystalline VP800, the contribution of classical eddy current loss to the total core loss is very small due to high resistivity and small ribbon thickness.

Surface and bulk magnetic anisotropy in bilayered CoSiB/FeNbCuSiB and FeNbSiB/FeSiB ribbons

The present study is devoted to the surface and bulk magnetic anisotropy of the bilayered Co72.5Si12.5B15/Fe73.5Nb3Cu1Si13.5B9 and Fe74.5Nb3Si13.5B9/Fe77.5Si7.5B15 ribbons which, completed with microstructure analysis, give the basic complex data prospectively usable for sensor applications. The ribbons prepared by modernized planar flow casting technology were fully amorphous as the X-ray diffraction measurements have confirmed. The thickness of ribbons was about 36 μm while the interlayer thickness reaches typically a few μm as the element distributions at cross-sections have shown. A bending of ribbons leads to changes in both surface and bulk anisotropies detected by the magneto-optical Kerr effect and vibrating sample magnetometer, respectively. An observable difference between both anisotropies is ascribed to the fact that the surface magnetic anisotropy is determined only by magnetostrictive behavior of the corresponding individual layer while the bulk anisotropy depends on integral properties of both layers and the interlayer. Moreover, the magnetic measurements at room and elevated temperatures have shown that the bulk magnetic properties are more markedly influenced by the composition of iron rich layers, FeSiNbCuB or FeSiB, being during the casting in contact with air.

Prediction of Hardness, Yield Strength and Tensile Strength for Single Roll Melt Spinning of 5083 Al-alloy Ribbons

In this paper, an empirical model is applied to predict the hardness, yield strength, and tensile strength of rapid solidified ribbons. The discovered empirical equation is obtained depends upon the experimental results of rapid solidification process for 5083 Al-alloys. The empirical equations predict values and describe the behavior of ribbon with consideration of ribbon thickness, grain size, hardness, yield strength, and tensile strength. The experimental work involves difference operation conditions and the results indicate that orifice diameter, nozzle roll wheel gap, and melting temperature have direct impact on the quality of alloy. Additionally, the results showed that there is a good agreement between experimental and predicted values where the correlation coefficient is 0.99. The experimental show that there is a possibility to produce very thin ribbons with thickness in micrometer by reducing the distance between nozzle and roll wheel, and reduce the orifice diameter of casting. The hardness, and yield strength increased due to increasing the number of small grain size in the ribbons structure and rapidly heat transfer of the small ribbons thickness. Moreover, the optimal melting temperature of this alloy is 925oC which produces high ribbon hardness compared with other melting temperature that used in this research.

EVA(Ethylene Vinyl Acetate) 수지가 태양전지의 장기적인 수명에 미치는 영향에 관한 실험적 연구

Abstract In this study, analysed the characteristics of power drop and surface damage in solar cell through high temperature and humidity test in the 3 case of EVA(ethylen e vinyl acetate) and 2 case ribbon thickness. The solar cells were tested during the 500hr in 85℃ temperature and 85% relative humidity conditions, that excerpted standard of PV Module(KS C IEC-61215 ). Through the EL(Electroluminescence) shots, specimen's surface have partialy damaged. Before and after high humidity and high temperature test, ribbon thickness 200㎛ EVA1 case power drop rate was 8.463%, EVA2 case was 6.667%, EVA3 case was 6.373%. In the ribbon thick ness 250㎛ EVA1 case power drop rate was 6.521%, EVA2 case was 8.517%, EVA3 case was 6.019%. EV A3 case was the lowest power and FF(fill factor) drop rate at the 2 case of ribbon thickness , because EVA3 is laerger than EVA1 and EVA2 in thickness, elongation and tensile strength.Keywords : Solar cell, EVA(ethylene vinyl acetate), High temper ature and high humidity, EL(electroluminescence)

Effect of surface roughness of chill wheel on ribbon formation in the planar flow casting process

The variations of ribbon topography and surface quality with the surface roughness of chill wheel were examined systematically and the average cooling rate during the planar flow casting process was evaluated. The result revealed that an increase in the roughness lengthens the melt puddle and increases the ribbon thickness. A lower roughness was found to induce the appearance of herringbone pattern on the wheel-side ribbon surface and capture more air at the wheel-melt interface to form larger elongated air pockets on the ribbon surface. On the contrary, less air was trapped at a higher roughness and the distribution of air pockets on the ribbon surface was mainly corresponding to the concave spots on the wheel surface. The roughness on the wheel-side ribbon surface increased monotonically with the wheel roughness, while a minimum roughness was observed on the opposite air-side surface exhibiting the smoothest air-side ribbon surface. A higher wheel roughness enhanced the thermal contact resistance at the interface between the ribbon and chill wheel, which reduced the average cooling rate during the casting process and resulted in the occurrence of crystalline structure in the ribbon formation.

Effect of Crucible Parameters on Planar Flow Melt Spinning Process

2D numerical simulation of planar flow melt spinning process was accomplished employing transient analysis of fully coupled fluid flow and heat transfer using CFD software—Ansys Fluent. Fe–B–Si alloy was chosen as the candidate alloy. In the PFMS process, the molten alloy flowed from a crucible through a nozzle slit onto a rotating copper wheel, where a puddle was formed and from which a continuous amorphous ribbon was spun. The objective of the investigation was to examine the melt flow through the crucible nozzle slit on the melt puddle formation and its stability over time as a function of: (a) the effect of gas ejection pressures taken between 0.1 and 0.35 kg/cm2; (b) the nozzle slit widths ranging from 0.3 to 0.5 mm; and (c) the amount of alloy used which was 0.5 kg. Herein, the dynamics of the development of the puddle immediately after melt ejection, the stability of puddle, the ribbon thickness, puddle oscillation and temperature distribution were examined. Simulations indicate that the puddle lengths and ribbon thickness were found to increase linearly with increase in gas ejection pressure; pinning of the liquid puddle at the nozzle edge was found for low gas ejection pressure which caused continuous air entrapment leading to defective amorphous strips. Heat transfer characteristics were also investigated.

Mechanisms of increasing of the magnetic alloy core shunt impedance by applying a transverse magnetic field during annealing

In the J-PARC synchrotrons, Magnetic Alloy (MA) cores loaded RF cavities are employed to achieve a high field gradient. We are successful to increase the shunt impedance of the MA cores for the Main Ring synchrotron RF cavities by reducing the ribbon thickness and applying a transverse magnetic field during annealing. In this paper, we study the effects of transverse field annealing on the MA core shunt impedance by comparing two kinds of MA cores, those are the FT3M core that is annealed without any magnetic fields and the FT3L core that is annealed with a transverse magnetic field. The FT3L core shows the higher shunt impedance than the FT3M core. By applying the transverse magnetic field during annealing, the magnetization processes of the FT3L core occur by mainly magnetization rotations, and consequently the core loss is reduced and the relative complex permeability shows an excellent frequency behavior. The MA core shunt impedance is increased by those improvements of the magnetic properties.

Microstructure characteristics and effect of grain orientation on magnetic properties of Fe63Co32Gd5 alloy ribbons

By using the melt spinning techniques, the Fe63Co32Gd5 alloy ribbons with 15-50 m in thickness and 3-7 mm in width were prepared at the wheel speeds of 15, 20, 25 and 35 m/s. The rapid solidification microstructures were characterized by three layers, the middle layer of which reaches 80% thickness and forms the column grain of (Fe,Co) solid with Gd solution. Grain refinement takes place with the increase of the wheel speed. And after 0.5 h heat treatment at 823 K, the ribbon thickness becomes larger and the middle layer of column grain is very orderly perpendicular to the ribbon plane. The coercivity of quenched and annealed Fe63Co32Gd5 ribbons both have the inflection point at the wheel speed of 20 m/s, and the tendency is declining. The heat treatment processing makes the coercivity become lower by improving the order of (Fe,Co)17Gd2 compound. The saturation magnetization of quenched ribbons increases with the enhancement of wheel speed, whereas that of annealed ones decreases firstly and then increases. The minimum coercivity is 5.30×103 A/m and the maximum saturation magnetization is 163.62 A·m2/kg, which is obtained in the conditions of the wheel speed of 35 m/s and 0.5 h heat treatment at the temperature of 823 K.

Syntheses and corrosion behaviors of Fe-based amorphous soft magnetic alloys with high-saturation magnetization near 1.7 T

Abstract

Thermal and Structural Analysis of Mn49.3Ni43.7Sn7.0 Heusler Alloy Ribbons

The martensitic transformation and the solidification structures of Mn49.3Ni43.7Sn7.0 alloy ribbons prepared by melt-spinning were investigated by means of scanning electron microscopy, X-ray diffraction and differential scanning calorimetry. In those experiments special attention was given to melt spinning processing parameters such as the linear surface speed of the copper wheel rotating, the injection overpressure and the distance between wheel and injection quartz tube. Transformation entropy was found higher when increasing linear surface speed or the distance from injection point to wheel. The resulting samples showed chemical compositions close to the nominal ones and, at room temperature, crystallized in a monoclinic single-phase martensite with 14M modulation (without a significant variation in the cell parameters). Strong dependence of ribbon thickness on processing parameters was found. The average grain size varied between 1.6 and 6.6 μm, while the start temperature of the martensitic temperature varied from 394 to 430 K.

Friedreich ataxia: failure of GABA-ergic and glycinergic synaptic transmission in the dentate nucleus.

Atrophy of large neurons in the dentate nucleus (DN) is an important pathologic correlate of neurologic disability in patients with Friedreich ataxia (FA). Thinning of the DN was quantified in 29 autopsy cases of FA and 2 carriers by measuring the thickness of the gray matter ribbon on stains with anti-glutamic acid decarboxylase, the rate-limiting enzyme in the biosynthesis of γ-amino-butyric acid (GABA). The DN was thinner than normal in all cases of FA, and atrophy correlated inversely with disease duration but not with age at onset or length of the homozygous guanine-adenine-adenine trinucleotide expansions. In 13 of the FA cases, frozen DN tissue was available for assay of frataxin. Dentate nucleus atrophy was more severe when frataxin was very low. Immunohistochemical staining for glutamic acid decarboxylase revealed grumose reaction and preservation of small GABA-ergic neurons in the DN of FA patients. Residual small DN neurons and varicose axons also contained the glycine transporter 2, identifying them as glycinergic. Immunohistochemistry also confirmed severe loss of GABA-A and glycine receptors in the DN with comparable depletion of the receptor-anchoring protein gephyrin. Thus, loss of gephyrin and failure to position GABA-A and glycine receptors correctly may reduce trophic support of large DN neurons and contribute to their atrophy. By contrast, Purkinje cells may escape retrograde atrophy in FA by issuing new axonal sprouts to small surviving DN neurons where they form reparative grumose clusters.

Effects of Manufacturing Parameters in Planar Flow Casting Process on Ribbon Formation and Puddle Evolution of Fe–Si–B Alloy

The effects of manufacturing parameters in the planar flow casting process on the ribbon formation and the puddle stability of Fe78Si9B13 alloy are investigated experimentally. The ribbon morphology, surface quality, and puddle geometry are examined at different conditions and the transient evolution processes of puddle for molten metal passing through a rectangular nozzle are observed. The successful operability window for the production of Fe78Si9B13 ribbon is established and it is found the scope is different from that of Al-based alloy. The trend lines of the alloys on the plane of Reynolds number versus Weber number corresponding to obtain a successful ribbon are established. The ribbon thickness is found to vary with the applied pressure across the crucible and the wheel speed to the power of 0.45 and −0.9, respectively. The formation of small air pockets could be enhanced by increasing the applied pressure difference and wheel speed, or by decreasing the nozzle-wheel gap and the jetting temperature.

Voltage Tunable Magnetoelectric Inductors With Improved Operational Frequency and Quality Factor for Power Electronics

Inductors find widespread use in various applications. Inductors with a large tunability of inductance and quality factor would lead to new paradigm on circuit designs. In this paper, we investigated the effect of ferromagnetic layer thickness on the performance of a magnetoelectric tunable inductor. Using chemical etching, the thickness of Metglas ribbons (2605SA1) can be reduced from 24 to about 8 μm, which dramatically reduces the eddy-current loss at higher frequencies. With the same total thickness, compared with inductor constructed with unthinned Metglas layers (2605CO), the maximum quality factor can be increased for 80%, and the operational frequency range can be extended for 10× to the >10 MHz range. An inductance tunable range of L max /L min = 370% was also achieved together with a significantly enhanced quality factor by ~3. Furthermore, with an inductor constructed with single thin Metglas (2605HB1M) layer, the maximum quality factor can be increased by 150% with single PZT slab and by 235% with double PZT slabs, and the operational frequency range can be extended by 100× with single slab and by 200× with double slabs, which makes these metallic magnetic ribbons tunable inductors competitive with ferrite materials in adaptive inductive power supply systems.

Production of Nanocrystalline (Fe, Co)-Si-B-P-Cu Alloy with Excellent Soft Magnetic Properties for Commercial Applications

With the aim of applying to a magnetic core material, the effect of ribbon thickness on the magnetic properties of a (Fe, Co)-Si-B-P-Cu alloy ribbon was investigated. It is found that the Si addition in (Fe, Co)-Si-B-P-Cu nanocrystalline alloy increased the saturation magnetic flux density (Bs), but degraded the coercivity (Hc), suggesting that the Si addition should be suppressed to a little amount. It is also found that the replacement of Fe with Co is quite effective for obtaining better magnetic properties of Fe-Si-B-P-Cu alloy. Even for the thicker ribbons exceeding 30μm in thickness, the nanocrystalline Fe81.2Co4Si0.5B9.5P4Cu0.8 alloy exhibited low Hc of 7A/m and high Bs of 1.84T. Such excellent magnetic properties were successfully reproduced in 50mm wide ribbons. This regards that the nanocrystallized Co-containing alloy has high applicability to high-efficiency magnetic core material. [doi:10.2320/matertrans.MBW201402]

태양전지 Ribbon 두께와 조성에 따른 Ribbon접합부의 장기 신뢰성 특성에 관한 연구

본 논문에서는 실리콘 태양전지의 Ribbon 접합부에 대한 장기 신뢰성 평가를 위해 Ribbon 두께와 솔더 조성을 달리하여 (A-type:0.2mm/SnPb, B-type:0.25mm/SnPb, C-type:0.2/SnA gPb, D-type:0.25mm/SnAgPb) 열충격 시험을 수행하였다. 열충격 시험 조건은 <TEX>$-40^{\circ}C$</TEX>에서 <TEX>$85^{\circ}C$</TEX>로 각각 15분씩 30분을 1 cycle로 하여 600 cycle을 수행하였다. 그 결과 초기효율은 A-type이 15.0%, B-type이 15.4% 및 C, D-type이 15.8%를 나타냈으며, 열충격 시험 후 초기효율 대비 효율감소율은 A-Type이 13.8%, B- Type이 15.4%, C-Type이 15.3% 및 D-Type이 16.2%을 나타냈다. I-V 특성곡선 및 표면변화를 비교한 결과, 표면의 변화는 큰 차이가 없었으나, A, C-Type의 시편에서는 직렬저항이 증가하였고, C-Type의 I-V 특성곡선 Current 저하 시작점이 A-Type보다 0.05(V)빠르게 나타났다. B, D-Type에서는 직렬저항 증가 및 병렬저항 감소의 복합적인 효율 저하 특성이 나타났으며, Cell 손상도 확인할 수 있었다. SnAgPb계열 솔더를 사용한 시편이 초기 접합성 및 효율 측면에서 우수하였으나, 장기신뢰성에서 취약하였으며, Ribbon 두께가 두꺼울수록 장기신뢰성이 저하되는 것을 확인 할 수 있었다. In this paper, Thermal Shock tests were performed varying the composition of the solder and ribbon thickness (A-type:0.2mm/60Sn40Pb, B-type:0.25mm/60Sn40Pb, C-type:0.2 /62Sn36Ag2Pb, D-type:0.25mm/62Sn36Ag2Pb) for evaluating the long-term reliability about Ribbon junction of Silicon solar cells. Thermal Shock test condition was performed during the 600cycles having <TEX>$-40^{\circ}C{\sim}85^{\circ}C$</TEX> temperature range each 15 minutes; One cycle time was 30min. As a result, the initial efficiency of the A-type, B-type, and C, D-type were showed 15.0%, 15.4% and 15.8% respectively. After thermal shock test, the efficiency decreasing-rate of each type were as follow that A-type was 13.8%, B-Type was 15.4%. C-Type and D-Type was 15.3% and 16.2%, respectively. Also, degradation of surface changes and I-V characteristic curves were showed that the series resistance of the A, C-type was increased. Also, current lowering starting point of C-type shown 0.05volt[v] earlier than that of A-type. And B, D-type shown characteristics of composite lowering efficiency such as increase of series resistance, decrease of parallel resistance and cell damage. Therefore Initial solderability and efficiency of specimens using the solder with SnAgPb were superior. But, It has inferior the long-term reliability. The test was confirmed that as the ribbon thickness increases, long-term reliability of solar cell will decrease.

Colloidal Self‐Assembly of Catalytic Copper Nanoclusters into Ultrathin Ribbons

Metal nanoclusters (NCs) with diameter below 2 nm are promising catalysts in oxygen reduction reactions (ORR). However, the high surface energy of ultra-small clusters leads to structural instability, shedding doubt on practical applications. Herein, we demonstrate a self-assembly method to improve the durability of catalytic metal NCs, employing copper NCs capped by 1-dodecanethiol (DT) to form free-standing ribbons in colloidal solution. By tuning the cooperation between the dipolar attraction between Cu NCs and the van der Waals attraction between DT, the thickness of ribbons is adjusted to a single NC scale. Such free-standing ribbons exhibit excellent catalytic activity and durability in ORR.

Colloidal Self‐Assembly of Catalytic Copper Nanoclusters into Ultrathin Ribbons

AbstractMetal nanoclusters (NCs) with diameter below 2 nm are promising catalysts in oxygen reduction reactions (ORR). However, the high surface energy of ultra‐small clusters leads to structural instability, shedding doubt on practical applications. Herein, we demonstrate a self‐assembly method to improve the durability of catalytic metal NCs, employing copper NCs capped by 1‐dodecanethiol (DT) to form free‐standing ribbons in colloidal solution. By tuning the cooperation between the dipolar attraction between Cu NCs and the van der Waals attraction between DT, the thickness of ribbons is adjusted to a single NC scale. Such free‐standing ribbons exhibit excellent catalytic activity and durability in ORR.

Trail making test performance in youth varies as a function of anatomical coupling between the prefrontal cortex and distributed cortical regions.

While researchers have gained a richer understanding of the neural correlates of executive function in adulthood, much less is known about how these abilities are represented in the developing brain and what structural brain networks underlie them. Thus, the current study examined how individual differences in executive function, as measured by the Trail Making Test (TMT), relate to structural covariance in the pediatric brain. The sample included 146 unrelated, typically developing youth (80 females), ages 9–14 years, who completed a structural MRI scan of the brain and the Halstead-Reitan TMT (intermediate form). TMT scores used to index executive function included those that evaluated set-shifting ability: Trails B time (number-letter sequencing) and the difference in time between Trails B and A (number sequencing only). Anatomical coupling was measured by examining correlations between mean cortical thickness (MCT) across the entire cortical ribbon and individual vertex thickness measured at ~81,000 vertices. To examine how TMT scores related to anatomical coupling strength, linear regression was utilized and the interaction between age-normed TMT scores and both age and sex-normed MCT was used to predict vertex thickness. Results revealed that stronger Trails B scores were associated with greater anatomical coupling between a large swath of prefrontal cortex and the rest of cortex. For the difference between Trails B and A, a network of regions in the frontal, temporal, and parietal lobes was found to be more tightly coupled with the rest of cortex in stronger performers. This study is the first to highlight the importance of structural covariance in in the prediction of individual differences in executive function skills in youth. Thus, it adds to the growing literature on the neural correlates of childhood executive functions and identifies neuroanatomic coupling as a biological substrate that may contribute to executive function and dysfunction in childhood.

Tuning the Planar-Flow Melt-Spinning Process Subject to Operability Conditions

An amorphous structure improves the physical properties of metal and enhances material performance. Planar-flow melt-spinning (PFMS) is a rapid solidification process for producing microcrystalline and amorphous metal ribbons. In PFMS, molten metal is fed through a nozzle onto a rotating wheel where the melt freezes and a continuous ribbon is spun. This study proposes a rapid method for process tuning. Examples were used to determine the applied pressure and wheel speed for designing the ribbon thickness and a wheel-nozzle gap with a preset nozzle size. The determined operating variables are suited to operation conditions, enabling the successful production of continuous ribbon. The proposed method was tested using computational fluid dynamics by treating the liquid metal and ambient air as a two-phase flow using the volume of fluid method. This study used the model to predict the puddle shape and ribbon thickness by fixing the dimensions of the wheel-nozzle gap and nozzle slot and varying the pressure and wheel speed. The results from the simulation confirmed the viability of the method and showed a concerted trend for the ribbon thickness compared with previous studies. In addition, the simulation revealed a fluctuation in the ribbon thickness, which was attributed to the first vibration mode of the puddle that was related to the natural frequency of the liquid inertia balanced by surface tension.