Catálogo de publicaciones - libros

Solution deposition of coated conductors shows potential to be the lowest cost process toward workable coated conductors, but is confronted with several issues. Among these are the need for demonstration of high in multimicron thicknesses, and the need for scale-up of the crystallization anneal. While a value of 91 A/cm width has been obtained from a 6 layer, 0.7 MA/cm, 1.3 m diol-derived YBCO film, a method for fabricating yet thicker films of higher is certainly desired. It is hoped the delayed water introduction method, and improvements in crystallization kinetics will play a role in this development. Of key concern is development of a process to enable YBCO crystallization of layers greater than 0.3 m without significant -axis content; this remains an issue for both solution deposited and evaporated BaF process films. An additional area of concern is the scale-up of the crystallization anneal, and ability of the anneal to remove reaction products uniformly from the film. It is hoped that the parallel studies of evaporated BaF process film crystallization and scale-up will prove applicable to solution deposition due to the similarity of crystallization mechanisms in these processes.

The recent progress on the development of LPE process for fabricating coated conductors was reviewed. In order to prevent the reaction between liquid and metal, it was clarified that the combination of MgO or NiO buffer layer and MgO- or NiO-saturated liquid are both effective. There is difference in the influence of buffer material-addition to liquid for growth of the 1 LPE layer. Although the MgO addition affect little to the Y-solubility and of 123, NiO addition makes the able temperature range for Y123 growth decrease due to decrease of and increase of crystallization temperature of the low temperature phase. Additionally, it was found that the suitable selection of RE for each layers to suppress dissolution of the 1 layer at dipping for the 2 layer, which means stable growth of the 2 layer. Consequently, the double layered LPE structure successfully realized on metal substrates, which reveal high superconducting performance. Then, the suitable constructions for the LPE coated conductors were confirmed as that lower growth temperature for the 2 LPE layer should be selected than of the 1 LPE layer material. Additionally, a higher material than Y123 such as Nd- or Sm-system has to be selected for the 1 LPE layer in the NiO saturated system.

Next stage, the textured substrates such as the MgO deposited by using ISD technique or NiO fabricated by the SOE method will be applied to obtain high and . Furthermore, the process has to be extended to the long tape processing in parallel with improving and .

Jet Vapor Deposition holds much promise for high rate, low cost manufacture of HTS tape. At low rates, JVD has proven its ability to deposit multicomponent oxides such as the ferrites and ferroelectrics, as well as HTS buffer layers and sandwiches of CeO and YSZ. For more demanding future production, the versatile “e-jet” JVD source offers powerful advantages: high rate deposition of manyHTS oxides, synthesis from elemental metals or bulk HTS oxides, easy replenishment of lost oxygen, control of crystallinity via low energy, extreme-high ion current bombardment, and control of surface reaction conditions on rolled, textured Ni substrates. Added to these advantages is the absence of environmental threat; there are no toxic precursors or products in JVD. For economic, continuous manufacture, the JVD stripcoater features a simple but unique air-to-vacuum seal that enables reel-to-reel production in a low cost, small footprint system. Accelerating work at Jet Process Corporation is aimed at realizing these advantages for HTS production.

The Combustion Chemical Vapor Deposition (CCVD) technique presents an attractive route for the deposition of low-cost, practical lengths of second-generation coated superconductors. CCVD-deposited buffer layers on textured nickel substrates have enabled high-performance superconductors of greater than 1 MA/cm. Thin films of YBCO deposited by CCVD exhibit excellent materials characteristics (epitaxy, composition, and microstructure) and electrical properties on single crystal substrates with critical current densities greater than 1MA/cm. The CCVD technology is very amenable to scale-up as has been demonstrated by the fabrication of 1 and 10 m lengths of buffered nickel. The incorporation of ccvd superconductor depositions can also be easily realized. Because of the inexpensive chemical and capital equipment costs, CCVD is well-positioned to fabricate commercial quantities of YBCO-coated conductor that meet DOE’s cost target of $10/kA-m.

The development of the ISD method has made it possible to deposit a film with in-plane alignment on a polycrystalline metal substrate and achieve a value ten times higher than normal PLD tape. We also confirmed that the resulting mechanical properties and other practical properties are improved. Since the ISD method can be used with metal substrates, which are inexpensive and easily made into long tape material, it is believed that it will be a very powerful method for future mass production.

The recent progress on the development of LPE process for fabricating coated conductors was reviewed. In order to prevent the reaction between liquid and metal, it was clarified that the combination of MgO or NiO buffer layer and MgO- or NiO-saturated liquid are both effective. There is difference in the influence of buffer material-addition to liquid for growth of the 1 LPE layer. Although the MgO addition affect little to the Y-solubility and of 123, NiO addition makes the able temperature range for Y123 growth decrease due to decrease of and increase of crystallization temperature of the low temperature phase. Additionally, it was found that the suitable selection of RE for each layers to suppress dissolution of the 1 layer at dipping for the 2 layer, which means stable growth of the 2 layer. Consequently, the double layered LPE structure successfully realized on metal substrates, which reveal high superconducting performance. Then, the suitable constructions for the LPE coated conductors were confirmed as that lower growth temperature for the 2 LPE layer should be selected than of the 1 LPE layer material. Additionally, a higher material than Y123 such as Nd- or Sm-system has to be selected for the 1 LPE layer in the NiO saturated system.

Next stage, the textured substrates such as the MgO deposited by using ISD technique or NiO fabricated by the SOE method will be applied to obtain high and . Furthermore, the process has to be extended to the long tape processing in parallel with improving and .

Solution deposition of coated conductors shows potential to be the lowest cost process toward workable coated conductors, but is confronted with several issues. Among these are the need for demonstration of high in multimicron thicknesses, and the need for scale-up of the crystallization anneal. While a value of 91 A/cm width has been obtained from a 6 layer, 0.7 MA/cm, 1.3 m diol-derived YBCO film, a method for fabricating yet thicker films of higher is certainly desired. It is hoped the delayed water introduction method, and improvements in crystallization kinetics will play a role in this development. Of key concern is development of a process to enable YBCO crystallization of layers greater than 0.3 m without significant -axis content; this remains an issue for both solution deposited and evaporated BaF process films. An additional area of concern is the scale-up of the crystallization anneal, and ability of the anneal to remove reaction products uniformly from the film. It is hoped that the parallel studies of evaporated BaF process film crystallization and scale-up will prove applicable to solution deposition due to the similarity of crystallization mechanisms in these processes.

The recent progress on the development of LPE process for fabricating coated conductors was reviewed. In order to prevent the reaction between liquid and metal, it was clarified that the combination of MgO or NiO buffer layer and MgO- or NiO-saturated liquid are both effective. There is difference in the influence of buffer material-addition to liquid for growth of the 1 LPE layer. Although the MgO addition affect little to the Y-solubility and of 123, NiO addition makes the able temperature range for Y123 growth decrease due to decrease of and increase of crystallization temperature of the low temperature phase. Additionally, it was found that the suitable selection of RE for each layers to suppress dissolution of the 1 layer at dipping for the 2 layer, which means stable growth of the 2 layer. Consequently, the double layered LPE structure successfully realized on metal substrates, which reveal high superconducting performance. Then, the suitable constructions for the LPE coated conductors were confirmed as that lower growth temperature for the 2 LPE layer should be selected than of the 1 LPE layer material. Additionally, a higher material than Y123 such as Nd- or Sm-system has to be selected for the 1 LPE layer in the NiO saturated system.

Next stage, the textured substrates such as the MgO deposited by using ISD technique or NiO fabricated by the SOE method will be applied to obtain high and . Furthermore, the process has to be extended to the long tape processing in parallel with improving and .