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Final project report - CRADA with United Solar Technologies and Pacific Northwest Laboratory (PNL-021): Thin film materials for low-cost high performance solar concentrators

Description: The objectives of this project were as follows: To develop and evaluate promising low-cost dielectric and polymer-protected thin-film reflective metal coatings to be applied to preformed continuously-curved solar reflector panels to enhance their solar reflectance, and to demonstrate protected solar reflective coatings on preformed solar concentrator panels. The opportunity for this project arose from a search by United Solar Technologies (UST) for organizations and facilities capable of applying reflective coatings to large preformed panels. PNL was identified as being uniquely qualified to participate in this collaborative project.
Date: March 1, 1995
Creator: Martin, P.M.; Affinito, J.D.; Gross, M.E. & Bennett, W.D.
Partner: UNT Libraries Government Documents Department

Improved manufacturing techniques for RF and laser hardening of missile domes. Phase I. Technical report

Description: This report summarizes key results and accomplishements during the first year of a Manufacturing Methods and Technology project to adapt an existing Pacific Northwest Laboratory (PNL) optical coating capability developed for high-power fusion-laser applications to the case of rf and laser hardening of plastic missile domes used by the US Army (MICOM). The primary objective of the first year's work was to demonstrate rf hardening of Hellfire and Copperhead 1.06-micron missile domes by use of transparent conductive Indium Tin Oxide (ITO) coatings. The project thus involved adaptation of a coating material and process developed for flat glass components used in fusion lasers to the case of hemispherical or conical heat-sensitive plastic domes used on laser-guided missiles. Specific ITO coating property goals were an electrical sheet resistance of 10 Ohms/square, a coated-dome transmission of 80% or more at 1.06 micron wavelength (compared to 90% for a bare dome), and good adhesion. The sheet resistance goal of 10 Ohms/square was expected to result in an rf attenuation of 30 dB at the frequencies of importance.
Date: July 1, 1982
Creator: Pawlewicz, W.T.; Mann, I.B.; Martin, P.M.; Hays, D.D. & Graybeal, A.G.
Partner: UNT Libraries Government Documents Department

Development of damage resistant sputtered oxide optical coatings for use at 248 NM

Description: This report summarizes the results of a six-month effort to develop damage-resistant Kr*F laser mirrors by using and refining reactive sputter deposition techniques for the fabricaton of multilayer oxide optical coatings. Mirror performance goals included a reflectivity of 99% at 248 nm and a laser damage threshold of 5 J/cm/sup 2/ for 20 ns pulses. Oxide multilayer coating combinations selected for development were SiO/sub 2//Al/sub 2/O/sub 3/, SiO/sub 2//HfO/sub 2/ and SiO/sub 2//Y/sub 2/O/sub 3/. Selection was based on review and compilation of the optical properties of oxide materials reported in the recent literature. Twenty-eight coatings of selected designs were fabricated on LLNL substrates for laser damage testing by LLNL. Forty other coatings were fabricated on PNL substrates for optical, microstructural and topographical characterization by PNL aimed at optimization of their performance. Specimens for damage testing consisted of single layers of Al/sub 2/O/sub 3/, HfO/sub 2/ and Y/sub 2/O/sub 3/ in thicknesses of lambda/2, 3lambda/2 and 2lambda at 248 nm plus high reflectors of the design LL (HL)/sup m/ HLL.
Date: October 1, 1981
Creator: Pawlewicz, W.T.; Martin, P.M.; Hays, D.D. & Mann, I.B.
Partner: UNT Libraries Government Documents Department

Recent developments in reactively sputtered optical thin films

Description: Highlights of a multiyear effort to develop new or improved thin film optical coating materials through the use of reactive sputtering techniques are presented. Reactive sputtering is shown to be an extremely versatile technique capable of synthesizing broad classes of materials in a straightfoward manner. The exceptional utility of sputtering for preparation of hard coatings such as oxides, nitrides and novel materials based on Si and Ge is described. Some of these coating materials cannot be made by conventional evaporative techniques. Reactive sputtering is shown to allow precise control of coating composition, microstructure and the resulting optical properties. Examples of multilayer coatings such as all-dielectric and dielectric-enhanced mirrors made from reactively sputtered materials are included, and simple yet elegant fabrication techniques are introduced. The reactive sputtering technique and equipment used specifically for optical coatings are briefly described, and comparison is made with the conventional evaporative approach.
Date: December 1, 1981
Creator: Pawlewicz, W.T.; Martin, P.M.; Hays, D.D. & Mann, I.B.
Partner: UNT Libraries Government Documents Department

Advanced process development for high reflector coatings on solar concentrator panels. Final letter report

Description: Objectives were to develop and demonstrate the manufacturing process for vacuum deposition of low-cost thin-film high reflectance coatings onto large solar concentrator panels; demonstrate thin-film deposition processes for commercialization of this technology by United Solar Technologies (UST); apply reflective coatings to solar concentrator panels for prototype application by UST.
Date: October 1, 1996
Creator: Martin, P.M.; Stewart, C.D.; Bennett, W.D. & Johnston, J.W.
Partner: UNT Libraries Government Documents Department

Vacuum deposited polymer/metal films for optical applications

Description: Vacuum deposited Polymer/Silver/Polymer reflectors and Tantalum/Polymer/Aluminum Fabry-Perot interference filters were fabricated in a vacuun web coating operation on polyester substrates with a new, high speed deposition process. Reflectivities were measured in the wavelength range from 0.3 to 0.8{mu}m. This new vacuum processing technique has been shown to be capable of deposition line speeds in excess of 500 linear meters/minute. Central to this technique is a new position process for the high rate deposition of polymer films. This polymer process involves the flash evaporation of an acrylic monomer onto a moving substrate. The monomer is subsequently cured by an electron beam or ultraviolet light. This high speed polymer film deposition process has been named the PML process -- for Polymer Multi-Layer. Also, vacuum deposited, index matched, polymer/CaF{sub 2} composites were fabricated from monomer slurries that were subsequently cured with LTV light. This second technique is called the Liquid Multi-Layer (or LML) process. Each of these polymer processes is compatible with each other and with conventional vacuum deposition processes such as sputtering or evaporation.
Date: April 1, 1995
Creator: Affinito, J.D.; Martin, P.M.; Gross, M.E.; Coronado, C. & Greenwell, E.
Partner: UNT Libraries Government Documents Department

Test of two prototype high-temperature superconducting transmission cables

Description: Two 500-A class prototype high-temperature superconducting cables have been constructed by Southwire Company and tested at Oak Ridge National Laboratory (ORNL). In the first cable, no insulation was used to separate the individual HTS tapes. In the second cable, Kapton tape was used to insulate the HTS tapes between successive layers for the study of AC loss and current distribution. The cables were tested with both DC and AC currents in liquid nitrogen from 77 to 69 K. Both cables achieved DC critical current, I{sub c} greater than 500 A. A calorimetric technique that measures the cable temperature rise under ac currents was used to measure the ac loss of the cables. The un-insulated cable showed a cryoresistive behavior under the 60 Hz AC currents. The insulated cable started to show measurable loss at current where there was corresponding resistive loss.
Date: October 1, 1996
Creator: Lue, J.W.; Lubell, M.S.; Kroeger, D.M.; Martin, P.M.; Demko, J.A.; Jones, E.C. et al.
Partner: UNT Libraries Government Documents Department

Multilayer coatings on flexible substrates

Description: Thin-film optical and non-optical multilayer coatings are deposited onto flexible substrates using a vacuum web coater developed at Pacific Northwest Laboratory. The coater`s primary application is rapid prototyping of multilayer (1) polymer coatings, (2) polymer/metal coatings, (3) ceramic/metal coatings, and (4) hybrid polymer, ceramic, and metal coatings. The coater is fully automated and incorporates polymer evaporation and extrusion heads, high-rate magnetron sputtering cathodes, and e-beam evaporation sources. Polymer electrolytes are deposited by extrusion techniques. Flexible plastic, metal, and ceramic substrates can be coated using roll-to-roll or closed-loop configurations. Examples of multilayer optical coatings demonstrated to date are solar reflectors, heat mirrors, Fabry-Perot filters, and alpha particle sensors. Nonoptical coatings include multilayer magnetic metal/ceramic and lamellar composites.
Date: April 1, 1995
Creator: Martin, P.M.; Affinito, J.D.; Gross, M.E.; Coronado, C.A.; Bennett, W.D. & Stewart, D.C.
Partner: UNT Libraries Government Documents Department

Electrodeposition of high-T{sub c} superconductor material for microsensor fabrication

Description: Thin films of YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) superconductor precursor were synthesized using electrodeposition. The YBCO precursor thin films were deposited on Ag foils using pulsed potential deposition conditions of 10 s at -4 V and 10 s at -1 V (vs Ag reference electrode). The post-annealed films showed zero electrical resistance at 60 K. The procedures for fabricating a high precision micro-sensor using YBCO superconductor, for measuring weak magnetic fields are outlined. The micro-sensor templates were patterned using x rays and precursor films were deposited into the features. 8 figs, 10 refs.
Date: December 31, 1996
Creator: Natarajan, A.; Wang, W.; Ma, E.; Bhattacharya, R.N.; Khann-Malek, C.; Paranthaman, M. et al.
Partner: UNT Libraries Government Documents Department

Epitaxial Growth of Yb<sub>2</sub>O<sub>3</sub> Buffer Layers on Biaxially Textured-Ni (100) Substrates by Sol-Gel Process

Description: In order to develop an alternative buffer layer architecture using the sol-gel process to produce YBCO (YBa2Cu307+) coated conductors, Yb203 has been chosen as the candidate material. Buffer layers of fi03 were epitaxkdly grown on biaxially textured-Ni (100) substrates by the sol gel process for the first time. The ~03 precursor solution was prepared from an alkoxide sol-gel route in 2-xnetho~ethanol and was deposited on textured-Ni (100) substrates by either spin coating or dip coating methods. The amorphous film was then processed at 1160oC under flowing (96%)MH2(4%) gas mixture for one hour. The fi03 iihn exhibited a strong c-axis orientation on the Ni (100) substrates. The phi and omega scans indicated good in plane and out of plane orientations. The X-ray (222) pde figure showed a cube-on-cube epitaxy. High current YBCO films were grown on the Y&03 sol-gel buffered-Ni substrates.
Date: April 5, 1999
Creator: Beach, D.B.; Chirayil, T.G.; Christen, D.K.; Feenstra, R.; Goyal, A.; Kroeger, D.M. et al.
Partner: UNT Libraries Government Documents Department

Solution processing of YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} thin films

Description: The aim of this work was to develop a non-vacuum chemical deposition technique for YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} (YBCO) coated conductors on rolling-assisted biaxially textured substrates (RABiTS). The authors have chosen the metal-organic decomposition (MOD) and sol-gel precursor routes to grow textured YBCO films. In the MOD process, yttrium 2-ethylhexonate, barium neodecanoate, copper 2-ethylhexonate and toluene were used as the starting reagents. YBCO films processed by the MOD method on SrTiO{sub 3} (100) single crystal substrates were consisted of c and a-axis oriented materials. These films also contained some amount of the random phase. The c and a-axis oriented materials were epitaxial on SrTiO{sub 3} substrates. Films have a T{sub c,onset} of 89K and the best superconducting transition temperature of 63K. Films pyrolyzed at 525 C and subsequently annealed at 780 C in a p(O{sub 2}) of 3.5 {times} 10{sup {minus}4} atm contained YBCO phase predominantly in a-axis orientation. In the sol-gel route, yttrium-isopropoxide, barium metal, copper methoxide and 2-methoxyethanol were used as the starting reagents. Sol-gel YBCO films on SrTiO{sub 3} substrates were epitaxial and c-axis oriented.
Date: December 1997
Creator: Singhal, A.; Paranthaman, M.; Specht, E. D.; Hunt, R. D.; Beach, D. B.; Martin, P. M. et al.
Partner: UNT Libraries Government Documents Department

Fabrication of High Current YBa<sub>2</sub>Cu<sub>3</sub>O(sub>7-y</sub>) Coated Conductors Using Rolling-Assisted Biaxially Textured Substrates

Description: High critical current YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-y</sub> (referred to as YBCO) coated conductors were fabricated with a layer sequence of YBCO/YSZ/CeO<sub>2</sub>/Ni. The cube (100) texture in the starting Ni substrates was obtained by cold rolling followed by recrystallization. A thin CeO<sub>2</sub> (Cerium Oxide) layer with a thickness of 100-200 Å was grown epitaxially on the biaxially textured-Ni substrates using an e-beam evaporation technique. This was followed by the growth of a thick (<= 0.77 µm) YSZ (Yttria Stabilized Zirconia) layer using either e-beam evaporation or rf magnetron sputtering. The e-beam CeO<sub>2</sub> film had a dense microstructure. The microstructure of the e-beam YSZ film was porous whereas the sputtered YSZ film was dense. The YBCO films were grown by pulsed laser deposition on both e-beam and sputtered YSZ layers. A transport critical current density of ~ 1 x l0<sup>6</sup> A/cm<sup>2</sup> at 77 K was obtained for ~ 0.8 µm thick YBCO Rims on both YSZ surfaces in zero field. To demonstrate the quality and compatibility of the e-beam CeO<sub>2</sub> layers; YBCO films were also grown on CeO<sub>2</sub>-buffered YSZ (100) single crystal substrates using e-beam co-evaporated Y-BaF<sub>2</sub>-Cu precursors followed by a post-annealing process. A transport critical current density of over 1 x lO<sup>6</sup>A/cm<sup>2</sup> at 77 K was obtained on a ~ 0.3 µm thick YBCO film in zero field.
Date: June 1, 1999
Creator: Christen, D.K.; Feenstra, R.; Kroeger, D.M.; Lee, D.F.; List, F.A.; Martin, P.M. et al.
Partner: UNT Libraries Government Documents Department

Demonstration of High Current Density YBCO Coated Conductors on RE<sub>2</sub>O<sub>3</sub>-Buffered Ni Substrates with Two New Alternative Architectures

Description: In continuation of our effort to develop single buffer layer architectures for YBCO (YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-<font face="symbol">g</font>) coated tape conductors, we have studied RE<sub>2</sub>O<sub>3</sub> (RE = Y, and rare earths) as candidate materials. Three types of crystal structures including the preferred cubic phase are known for the rare earth oxides. High quality simple cubic RE<sub>2</sub>O<sub>3</sub> buffer layers were grown epitaxiahy on {100}<001> textured Ni substrates using both reactive evaporation and sol-gel processing. Detailed X-ray studies have shown that the Y<sub>2</sub>O<sub>3</sub>, Eu<sub>2</sub>O<sub>3</sub>, Gd<sub>2</sub>O<sub>3</sub>, and Yb<sub>2</sub>O<sub>3</sub> were grown with a single epitaxial orientation. SEM micrographs indicated that both e-beam and sol-gel grown films were dense, continuous and crack free. High J<sub>c</sub> YBCO films were grown on RE<sub>2</sub>O<sub>3</sub>-buffered Ni substrates with sputtered cap layers. Two new alternative buffer layer architectures were developed. A high J<sub>c</sub> of 1.8 MA/cm<sup>2</sup> at 77 K and self-field was obtained on YBCO films with a layer sequence of YBCO (pulsed laser deposition)/Yb<sub>2</sub>O<sub>3</sub> (sputtered)/Y<sub>2</sub>O<sub>3</sub> (e-beam)/Ni. Also, a high J<sub>c</sub> of over 1 MA/cm<sup>2</sup> at 77 K and self-field was obtained on YBCO films with a layer sequence of YBCO (ex-situ BaF<sub>2</sub> process)/CeO<sub>2</sub> (sputtered)YSZ sputtered)/RE<sub>2</sub>O<sub>3</sub> (sol-gel or e-beam)Ni. The performance of sol-gel grown buffers approached the quality of e-beam grown buffers.
Date: July 12, 1999
Creator: Beach, D. B.; Chirayil, T. G.; Christen, D. K.; Cui, X.; Feenstra, R.; Goyal, A. et al.
Partner: UNT Libraries Government Documents Department