Analysis of Tungsten-Alumina Nanocomposite Thin Films on SS304 Substrate

2021 ◽  
Vol 903 ◽  
pp. 125-132
Author(s):  
T.R. Mohan Kumar ◽  
P.V. Srihari ◽  
Sahas ◽  
M.S. Krupashankara

Higher solar absorptance and lower thermal emittance are the key factors for solar collectors. The use of thin films that are having mechanically resistant coatings are common practice in industries. The primary motivation of carrying this research work is to lower thermal emittance and maximize solar absorptance on SS304 substrate material. W-Al2O3 composite coatings are developed using magnetron sputtering process by considering the process parameters. The experimental plan is achieved based on Taguchi L9 orthogonal under various levels for deposition parameters. The tungsten and alumina thin films deposited using a co-sputtering were characterized using 410 - solar instrument for measuring solar absorptance and ET 100 Emissometer for measuring thermal emittance. The optimization for process parameters on thermal emittance and absorptance were carried out. It was found that for deposition parameters of DC power 750W, RF power 1050W and Argon gas flow rate of 250 sccm, absorptance of 0.758 with thermal emittance of 0.061 is observed with deposition was carried out on SS304 substrates.

2017 ◽  
Vol 31 (07) ◽  
pp. 1750059 ◽  
Author(s):  
Zhengguo Shang ◽  
Dongling Li ◽  
She Yin ◽  
Shengqiang Wang

Since molybdenum (Mo) thin film has been used widely recently, it attracts plenty of attention, like it is a good candidate of back contact material for CuIn[Formula: see text]Ga[Formula: see text]Se[Formula: see text]S[Formula: see text] (CIGSeS) solar cells development; thanks to its more conductive and higher adhesive property. Besides, molybdenum thin film is an ideal material for aluminum nitride (AlN) thin film preparation and attributes to the tiny (−1.0%) lattice mismatch between Mo and AlN. As we know that the quality of Mo thin film is mainly dependent on process conditions, it brings a practical significance to study the influence of process parameters on Mo thin film properties. In this work, various sputtering conditions are employed to explore the feasibility of depositing a layer of molybdenum film with good quality by DC reactive magnetron sputtering. The influence of process parameters such as power, gas flow, substrate temperature and process time on the crystallinity and crystal orientation of Mo thin films is investigated. X-ray diffraction (XRD) measurements and atomic force microscope (AFM) are used to characterize the properties and surface roughness, respectively. According to comparative analysis on the results, process parameters are optimized. The full width at half maximum (FWHM) of the rocking curves of the (110) Mo is decreased to 2.7[Formula: see text], and the (110) Mo peaks reached [Formula: see text] counts. The grain size and the surface roughness have been measured as 20 Å and 3.8 nm, respectively, at 200[Formula: see text]C.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
M. Marton ◽  
M. Vojs ◽  
E. Zdravecká ◽  
M. Himmerlich ◽  
T. Haensel ◽  
...  

To meet various application requirements, it is important to enable an improvement of a-C structure and properties, such as hardness, adhesion, and wear resistance. In this study, we used the Raman spectroscopy to investigate the a-C thin films structure dependence on the different deposition parameters. The effect of nitrogen, argon, and hydrogen gas flow rate was analyzed to determine the influence on the film properties. The change in the gas type, combination, and flow had a significant influence on the D and G bands of the a-C Raman spectra. The addition of N2into the chamber promoted the sp2creation, while with adding hydrogen the layer contained more sp3bonds. The depositions of a-C thin films were carried out in pulsed arc discharge vacuum installation. Micro-Raman measurements of the deposited materials were performed using an ISA Dilor-Jobin Yvon-Spex Labram confocal system with 632.8 nm radiation from a He-Ne laser using a back-scattering geometry.


2001 ◽  
Vol 697 ◽  
Author(s):  
Mark Walter ◽  
Srikant Nekkanty ◽  
Elizabeth Cooke ◽  
Gary Doll

AbstractBoron carbide (BC) is well known as a coating material that is important for a wide range of technological applications. The applicability of boron carbide stems from the fact that it is a very hard material with high lubricity, high elastic modulus, low specific gravity, and good chemical stability. Disadvantages, however, include extreme brittleness and sometimes poor adhesion. Recently, a reactive sputtering involving boron carbide targets and hydrocarbon gases has been used to produce novel nano-composite boron carbide thin films comprised of BC nano-crystals embedded in a matrix of hydrogenated amorphous carbon (DLC). The microstructure of these thin films is similar to that of other metal carbide/DLC nano-composite films. The present paper discusses the results of Vickers indentation experiments carried out on four different samples of boron carbide/DLC coatings that were sputtered deposited onto 52100 steel disks. The four different samples resulted from four different levels of hydrocarbon gas flow during processing. Acoustic emission data was recorded simultaneously with the indentation experiments. The indentations and the associated crack patterns were observed using scanning electron microscopy.


1998 ◽  
Vol 553 ◽  
Author(s):  
T. Eisenhammer ◽  
H. Nolte ◽  
W. Assmann ◽  
J. M. Dubois

AbstractSolar selective absorbers for thermal energy applications can be realized with films of quasicrystal forming alloys. Absorbers were produced by sputtering thin films of AlCuFe and AlCuFeCr. Alumina and floatglass were used as dielectric antireflective coatings, which are necessary for the required optical properties. For applications, several aspects are of importance: high solar absorptance and low thermal emittance have to be achieved. Moreover, the coatings have to show good adhesion and stability with respect to oxidation in air at elevated temperatures and exposure to humidity and condensation of water. The present study emphasizes these aspects, especially degradation stability, for coatings deposited on technical copper foils with large roughness. Oxidation stability is achieved easily, while humidity stability depends strongly on the choice of materials. The combination AlCuFeCr/floatglass turned out to be stable, while the combination AlCuFe/alumina is destroyed rapidly.


Author(s):  
Hamidreza Alemohammad ◽  
Ehsan Toyserkani

Laser assisted maskless micro-deposition (LAMM) is a recently developed technology for deposition of thin films with micro-scale feature sizes. It can be used for deposition of a large number of materials such as, electronic inks/pastes, conductive polymers, insulators, adhesives, and biological materials. This process is a combination of liquid atomization, micro-deposition and laser sintering. The present study is concerned with the process characterization for the deposition of silver thin films on silica. The deposited material is in the form of nano-particles dispersed in liquid, known as nano-past. In the present research work, deposition patterns are produced with different process parameters. Afterwards, the effects of process parameters, e.g., laser power and laser scanning speed, are investigated by examining the quality of the deposited material.


2006 ◽  
Vol 514-516 ◽  
pp. 1140-1144 ◽  
Author(s):  
Ana P. Piedade ◽  
Guenis Gomez ◽  
M. Teresa Vieira ◽  
Mariana Staia

In this research work, sputtering was used to deposit silver thin films under different deposition parameters, namely by changing deposition pressure, substrate bias and discharge gas. The main objective of the present work was to study the influence of the textured grain in the mechanical behaviour of the modified surfaces. The deposition rate, chemical composition (EPMA), morphology (SEM) and hardness were also assessed. In the slide alternating wear tests, where poly(tetrafluoroethylene) (PTFE) was used as counterbody, the loads varied from 10 to 30 N. One of the major conclusions of this work is that the thin films with the strongest (111) preferential crystallographic orientation correspond to the highest deposition rate. These sample present higher hardness and lower wear coefficient if compared with other orientations


2016 ◽  
Vol 254 ◽  
pp. 164-169 ◽  
Author(s):  
Dragos Toader Pascal ◽  
Viorel Aurel Şerban ◽  
Gabriela Marginean

Process parameters play a crucial role in the final characteristics and properties of every product. The current work focuses mainly on improving the vacuum furnace brazing process for tungsten carbide reinforced Ni-based alloy (NiCrBSi) metallic composite coatings, by establishing the best set of parameters adapted to this specific chemical composition. In order to determine the optimum parameters, a fine adjustment of a typical vacuum brazing process was performed. The melting interval of the filler metal was identified by means of Differential Thermal Analysis. Morphology, microstructure and metallurgical bond of the cladding to the substrate material were investigated by Scanning Electron Microscopy and Light Microscopy combined with a Porosity Analysis Software. The process optimization resolved the initial problem of fractures and crack initiation, making possible to achieve high quality hardfacing coatings with a low degree of porosity (approximately 1 %).


Author(s):  
O. S. Fatoba ◽  
A. M. Lasisi ◽  
S. A. Akinlabi ◽  
E. T. Akinlabi ◽  
A. A. Adediran

Abstract The study experimentally investigates the effects of Ytterbium Laser System process parameters on the resultant microstructure of Ti-6Al-4V grade 5 alloy and reinforcement powders. The deposition process was conducted employing a 3 kW (CW) Ytterbium Laser System (YLS-2000-TR) machine, coaxial to the reinforcement powder. The laser scanning speed and power were varied between the intervals of 0.8–1.0 m/min and 900–1000 W. All other parameters kept constant were the rate of gas flow, the spot diameter, and the rate of powder flow. Metallurgical studies were conducted where all the samples microstructure was characterized by employing Scanning Electron Microscopy (SEM) and Optical Microscopy (OM). The results showed that a minimum porosity was achieved at high laser power complemented with low powder feed rate. The microstructure formed was dominated by columnar grains and martensitic needle-like structures with a formation of beta phase. It was observed that the microstructure was influenced significantly by the two laser speed modes, and the laser power. The grain size and phase structure were influenced significantly by the laser power; increasing it had resulted in larger grains, and a coarser microstructure. The results also showed that the residual stresses of the optimized specimens were compressive.


Author(s):  
M. Grant Norton ◽  
C. Barry Carter

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.


Author(s):  
Karren L. More

Beta-SiC is an ideal candidate material for use in semiconductor device applications. Currently, monocrystalline β-SiC thin films are epitaxially grown on {100} Si substrates by chemical vapor deposition (CVD). These films, however, contain a high density of defects such as stacking faults, microtwins, and antiphase boundaries (APBs) as a result of the 20% lattice mismatch across the growth interface and an 8% difference in thermal expansion coefficients between Si and SiC. An ideal substrate material for the growth of β-SiC is α-SiC. Unfortunately, high purity, bulk α-SiC single crystals are very difficult to grow. The major source of SiC suitable for use as a substrate material is the random growth of {0001} 6H α-SiC crystals in an Acheson furnace used to make SiC grit for abrasive applications. To prepare clean, atomically smooth surfaces, the substrates are oxidized at 1473 K in flowing 02 for 1.5 h which removes ∽50 nm of the as-grown surface. The natural {0001} surface can terminate as either a Si (0001) layer or as a C (0001) layer.


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