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- Brohede, Ulrika, et al.
(författare)
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A novel graded bioactive high adhesion implant coating
- 2009
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 255:17, s. 7723-7728
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Tidskriftsartikel (refereegranskat)abstract
- One method to increase the clinical success rate of metal implants is to increase their bone bonding properties, i.e. to develop a bone bioactive surface leading to reduced risks of interfacial problems. Much research has been devoted to modifying the surface of metals to make them become bioactive. Many of the proposed methods include depositing a coating on the implant. However, there is a risk of coating failure due to low substrate adhesion. This paper describes a method to obtain bioactivity combined with a high coating adhesion via a gradient structure of the coating. Gradient coatings were deposited on Ti (grade 5) using reactive magnetron sputtering with increasing oxygen content. To increase the grain size in the coating, all coatings were post annealed at 385 degrees C. The obtained coating exhibited a gradual transition over 70 nm from crystalline titanium oxide (anatase) at the surface to metallic Ti in the substrate, as shown using cross-section transmission electron microscopy and X-ray photoelectron spectroscopy depth pro. ling. Using scratch testing, it could be shown that the adhesion to the substrate was well above 1 GPa. The bioactivity of the coating was verified in vitro by the spontaneous formation of hydroxylapatite upon storage in phosphate buffer solution at 37 degrees C for one week. The described process can be applied to implants irrespective of bulk metal in the base and should introduce the possibility to create safer permanent implants like reconstructive devices, dental, or spinal implants.
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| 2. |
- Kubart, Tomas, et al.
(författare)
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A model of DC reactive magnetron sputtering for graded solar thermal absorbers
- 2008
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 100:8, s. 082024-
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Tidskriftsartikel (refereegranskat)abstract
- In this work we present process modelling of reactive in-line sputtering. Although modelling of reactive sputtering is often used, most models are based on assumptions which make them insufficient for use in this case. The presented model takes into account a realistic deposition rate profile and distribution of reactive gas pressure. The model has been applied to reactive sputter deposition of graded solar thermal absorbers. It has been shown that the presented model represents a simple alternative to complex Monte Carlo simulations while still representing all important features of the process.
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| 3. |
- Ning, Yuping, et al.
(författare)
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Optical simulation and preparation of novel Mo/ZrSiN/ZrSiON/SiO2 solar selective absorbing coating
- 2017
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Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 167, s. 178-183
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Tidskriftsartikel (refereegranskat)abstract
- A novel Mo/ZrSiN/ZrSiON/SiO2 solar selective absorbing coating has been investigated, which was prepared by magnetron sputtering on stainless steel substrate. A high solar absorptance of 0.94 and a low thermal emittance of 0.06 at 25 degrees C were achieved. By proportionally decreasing the thicknesses of the ZrSiN, ZrSiON and SiO2 layers, the thermal emittance at 500 degrees C was decreased significantly from 0.19 to 0.12 (Delta epsilon = 0.07) while keeping the solar absorptance unchanged. The coating also showed high thermal stability at 500 degrees C in vacuum, implying that it is a promising candidate for high temperature concentrated solar power (CSP) applications.
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| 4. |
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| 5. |
- Zhao, Shuxi, 1944-, et al.
(författare)
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Angular dependence of coloured absorber coatings
- 2012
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Ingår i: The International Conference on Optical Thin Films and Coating Technology, 15-18 October 2012, Hangzhou, China.
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Konferensbidrag (refereegranskat)abstract
- Angular dependence of coloured absorber coatingsShuxi Zhao1, Dechun Zhu2 and Carl-G.Ribbing1 1) Div. of Solid State Physics, Ångström Laboratory, Uppsala University Box 534, SE-751 21 Uppsala, Sweden2) Dept. of Chemical and Materials Engineering, Hefei University 230022, Hefei, PR. China AbstractInvestigations of angular dependence of thermal solar absorber coatings have been carried out in the Uppsala SSP-division since more than 10 years. In this contribution the angular variation of the optical properties of the recently suggested TiAlN-based coloured absorber is reported. The presence of an interference controlled colour raises a concern that strong irradiscence might make the roof integration of such absorbers aesthetically unsuitable. Using colour coordinates calculated from the measured reflectance spectra we reach the conclusion that the attractive colour seen in normal incidence is only marginally changed by the natural change of angle of incidence for a stationary collector. A second issue to be considered is whether this new absorber surface performs better or worse than earlier cermet absorbers when the solar incidence angle varies. The reflectance of TiAlN, as well as the antireflected TiAlON, as a function of wavelength and angle of incidence has therefore been measured using an integrating sphere with a rotatable sample holder in the centre. For comparison and calibration such measurements, such measurement was also carried out on a freshly sputtered, opaque gold film. The angular variation was fitted using the Incident Angle Modifier Kta, the ratio of the measured absorptance for incidence angle, to that at normal incidence:AbstractInvestigations of angular dependence of thermal solar absorber coatings have been carried out in the Uppsala SSP-division since more than 10 years. In this contribution the angular variation of the optical properties of the recently suggested TiAlN-based coloured absorber is reported. The presence of an interference controlled colour raises a concern that strong irradiscence might make the roof integration of such absorbers aesthetically unsuitable. Using colour coordinates calculated from the measured reflectance spectra we reach the conclusion that the attractive colour seen in normal incidence is only marginally changed by the natural change of angle of incidence for a stationary collector.
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| 6. |
- Zhao, Shuxi, 1944-, et al.
(författare)
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Colour control and selectivity in TiAlN solar-thermal absorbers
- 2011
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Ingår i: Advances in Optical Thin Films IV. Optical Systems Design 2011, 5 September 2011, Marseille, France. - Washington : SPIE - International Society for Optical Engineering. - 9780819487940 ; , s. 81680G-1-81680G-9
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Konferensbidrag (refereegranskat)abstract
- Optical constants for simulations were obtained by R- and T-measurements on TiAlN thin films deposited on Corning 7059 glass. The model parameterized free carrier effects and an inter-band excitation. The calculations demonstrated that the colour effects are due to interference and inter-band absorption around 500 nm in a single layer coating. The peak shifts with the thickness of the thin film which gives a simple way to obtain different colours. Solar absorptance of 86 % can be reached already for a single TiAlN-film on an Al substrate.
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| 7. |
- Zhao, Shuxi, 1944-, et al.
(författare)
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Options for Reststrahlen Materials in Optical Surfaces and Filters
- 2010
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Ingår i: Chinese Optics Letters. - Shanghai, China : Chinese Laser Press. - 1671-7694. ; 8:Supplement 1, s. 119-124
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Tidskriftsartikel (refereegranskat)abstract
- The current potential applications of reststrahlen bands in optical surfaces and components are reviewed. This type of interval with metallic-like high reflectance has been used for monochromatization in infrared and when wavelength selective low emittance is needed for frost prevention or infrared signature reduction. Associated features, including a narrow reflectance minimum for a wide range of angles of incidence, are potentially useful.
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| 8. |
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| 9. |
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| 10. |
- Zhao, Shuxi, 1944-
(författare)
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Spectrally Selective Solar Absorbing Coatings Prepared by dc Magnetron Sputtering
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Spectrally selective solar absorber using composite Ni-NiO as coating materials was studied. Samples were prepared by dc magnetron sputtering unit named Rulle, which is a miniature copy of an industrial roll-coater unit. Using asymmetric location of the oxygen nozzele, it is possible to form the desired metallic concentration distribution along the sputtering zone under optimized conditions. This distribution can be transferred into a graded film profile by moving the substrate, obtaining good spectral selectivity. For specified mechanical settings (such as locations of gas sprays, target and pump positions etc.), the ratio of used oxygen flow to the corresponding critical oxygen flow, RO, is a dimensionless parameter to control the zone specification. The optimal value is around 0.80 for the Rulle. Optimized zone shows properties with two main parts: the metallic composite part of varied nickel volume fraction and the dielectric part. Two parts of the sputtering zone can form a graded absorbing layer with the right ratio of base and middle layer by the moving substrate technique. Distribution of normalized conductivity, NC, along the absorbing sputtering zone is a simple and good specification of zone property. Profile of graded film prepared by the moving substrate technique can be tailored according to NC distribution. XRD and XPS study confirms the NC results. Simulation reveals that absorption should mainly rely on the intrinsic, but less on the interference mechanism. Used metallic volume fraction of Ni-NiO is 0.3 for main absorbing layer. The front surface reflection loss due to high refractive index can be reduced by adding a layer with low refractive index on the top. Simulation shows that three-layer coatings are a good and simple coating structure. High solar absorptance of 0.97 has been achieved with low thermal emittance of 0.05 by theoretical simulation as well as experimentally prepared samples.
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