Nanostructured hydroxyapatite (HAP) was prepared by a wet precipitation method using Ca(NO 3 ) and KH 2 PO 4 as the main material and NH 3 as the precipitator under ultrasonic irradiation. The Ca/P ratio was set at 1.67 and the pH maintained at a minimum of 9. The temperature conditions and ultrasound influences were investigated using X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Fourier Transform Infrared Spectroscopy (FT-IR). The results showed that Nano-HAP can be obtained by this method and the particles were achieved to around 30nm.
ÔØ Å ÒÙ× Ö ÔØOptical and mechanical characterization of novel cobalt-based metal oxide thin films synthesized using sol-gel dip-coating method This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 AbstractNew cobalt-based metal oxide thin films (M x Co y O z with M = Mn, Cu, Ni) have been deposited on commercial aluminium and glass substrates using sol-gel dip-coating method.The as-deposited films were characterized by a wide range of complementary techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Spectrophotometry and Nanoindentation techniques. A light absorption study for coatings on glass substrates within a wavelength range of 300-1100 nm was also conducted. Topographical and morphological investigations showed the presence of nano-sized, grain-like particles in the copper-cobalt oxide coatings, which consequently had the roughest surface among the three coatings. All coatings on glass substrate exhibited higher absorption of ultraviolet (UV) light compared to visible light, while coatings on aluminium substrate generally had low reflectance (< 50 %) of UV light, moderate reflectance (< 80 %) of visible light and high reflectance (up to 100 %) of infrared light. Implications of optical properties as a function of film thickness controlled by dip-heating cycles were discussed. The elastic modulus (E) and hardness (H) of thin film samples compared with standalone commercial aluminium substrate were also measured.
ÔØ Å ÒÙ× Ö ÔØTailoring the physicochemical and mechanical properties of optical copper cobalt oxide thin films through annealing treatment This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 Abstract Sol-gel dip-coated optical coatings, copper-cobalt oxides on aluminium substrates, were thermally treated at different annealing temperatures in the range 500 -650 °C. The resulting films were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis-NIR spectrophotometry and nanoindentation techniques. The crystallinity of CoCu 2 O 3 enhanced significantly, with increasing annealing temperature from 500 to 650 °C, while the electronic structure and bonding states of the copper-cobalt oxides matrix remained unchanged. UV-Vis-NIR analysis showed that the solar absorptance (α) of the coatings changed with increasing of annealing temperature and an optimum α (84.4%) was achieved at 550 °C, which also coincides to the maximum tensile residual stress of the coating.Nanoindentation tests exhibited an increasing trend in both the hardness (H) and elastic modulus (E) of the coatings with increase in annealing temperature, although a slight decrease in the H/E ratio was also observed. The experimental studies were complemented by Finite Element Modelling (FEM). The results showed that, under mechanical loading, the stress and plastic deformation were concentrated within the coating layers. As such, the likelihood of delamination of the coating layer upon unloading would be reduced.
steel substrates via closed field unbalanced magnetron sputtering technology. These were investigated using XRD, SEM, XPS, UV-Vis, FTIR and nanoindentation techniques. Analysis of the optical properties showed the solar absorptance, in the visible range, of the Ti x M 1ÀxÀy N y films improved significantly from 51% to 81% with AlSi-doping and an increase of solar absorptance of up to 66% was recorded from films doped with Al. Moreover, the Al doping can reduce the thermal emittance in the infrared range from 6.06% to 5.11%, whereas doping with AlSi reduces the emittance to ca. 3.58%. The highest solar selectivity of 22.63 was achieved with TiAlSiN films. Mechanical studies showed enhanced hardness by $32%; enhanced yield strength by $16% and enhanced plastic deformation by $110% of Al and AlSi doped TiN matrix. IntroductionA spectrally selective surface is, generally, used to improve the photothermal conversion performance and, as such, it possesses two characteristics: high absorptance, a in the visible region of solar spectrum (0.3 to 2.5 mm) and low emittance, 3, (i.e., high reection) in the infra-red (IR) region ($2.5 mm) at operating temperatures. An excellent selective surface maximises the absorption of incoming photons in the visible region and minimises photon emission through thermal radiation in the IR energy region. Such a surface can be designed by an absorber-reector assembly. In such an approach, the reector is coated with a highly absorbing layer over the visible solar spectrum, while the infrared region is made transparent. Various types of metal nitrides based selective solar surfaces such as TiN, ZrN, HfN, TiAlN, TiAlON, NbAlN, NbAlON, MoAlN, and WAlN have been investigated by numerous groups.1-11 Over the past few years, transition metal nitride based thin lms have attracted signicant research interest as selective solar surfaces in solar thermal conversion devices. Generally, the energy conversion performance of a selective solar surface depends on the lm materials, lm design and fabrication technique used. A multi-layer lm stack with mixture of metal nitride, metal oxide and metal oxynitride lms e.g., TiAlN/AlON, and TiAl/ TiAlN/TiAlON/TiAlO has been explored for the potential commercial development of selective solar surfaces.3,12 TiAlN/ TiAlON/Si 3 N 4 selective absorbers have been produced on various substrates such as copper, nickel, stainless steel, glass and nimonic alloys.13 However, these materials are yet to be commercialized for solar energy conversion applications. View Article OnlineView Journal | View Issue solar selective surface applications, transition metal oxides based thin lms also received signicant research interests. 15-19Various synthesis methods such as evaporation, electrodeposition, chemical conversion, chemical vapour deposition and magnetron sputtering have been employed in manufacturing selective solar surfaces. Owing to its advantages in large area deposition, dry, clean and environment friendly, magnetron sputtering technique is widely used for syn...
Optical properties and thermal durability of copper cobalt oxide thin film coatings with integrated silica antireflection layer, Ceramics International, http://dx.doi.org/10.1016/j. ceramint. 2014.08.012 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. antireflection (AR) layer have been deposited on the top of aluminum substrates using a simple sol-gel dip-coating method. Reflectance spectra of the coatings were generated using spectroscopic methods while the coatings were subjected to an accelerated thermal durability test. The addition of silica changed the reflectance spectra of coatings within the wavelength range of 0.3-15.4 µm. The absorptance decreased with the increase of the withdrawal rate in range of 10-40 mm/min, while the emittance increased with the increase of the withdrawal rate. The optimum optical parameters for this study were absorptance, α S = 84.96%; emittance, ε T = 5.63% corresponding to the coating with a silica AR layer at withdrawal rate of 10 mm/min. The coatings with the silica AR layer were shown to be thermally durable in which no discernible 'cracking' phenomenon was observed. The degradation of the coatings with the silica AR layer was predominantly governed by temperature changes rather than exposure time.
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