94 research outputs found
The effects of deposition parameters on surface morphology and crystallographic orientation of electroless Ni-B coatings
No full textElectroless Ni-B coatings were deposited on AISI 304 stainless steels by electroless deposition method, which was performed for nine different test conditions at various levels of temperature, concentration of NaBH(4), concentration of NiCl(2), and time, using the Taguchi L(9)(3(4)) experimental method. The effects of deposition parameters on the crystallographic orientation of electroless Ni-B coatings were investigated using SEM and XRD equipment. SEM analysis revealed that the Ni-B coatings developed six types (pea-like, maize-like, primary nodular, blackberry-like or grapes-like, broccoli-like, and cauliflower-like) of morphological structures depending on the deposition parameters. XRD results also showed that these structures exhibited different levels of amorphous character. The concentration of NaBH(4) had the most dominant effect on the morphological and crystallographic development of electroless Ni-B coatings
An empirical investigation of Advanced Manufacturing Technology investment patterns: evidence from a developing country
No full textAdvanced manufacturing technology (AMT) investment patterns in developing countries is in need of further investigation, particularly in the light of the conflicting evidence from the literature. This paper provides new evidence on AMT investment patterns from the Turkish automotive industry and develops a taxonomy by exploring the relationships between AMT investment patterns, ownership structure, firm size and performance. Analysis of industry survey data suggests the existence of three groups with different AMT investment strategies. Results suggest that AMT investment patterns are not only significantly correlated with firm performance or ownership, but also reveals significant differences in manufacturing performance across investment patterns. (C) 2013 Elsevier B.V. All rights reserved.Selcuk University Scientific Research Project Fund (BAP)Thanks are due to two reviewers for their valuable comments. In carrying out this research, the third author has been supported by the Selcuk University Scientific Research Project Fund (BAP)
Language Features of the Epic "BULBUL VA GUL"(Nightingale and Flower)
No full textIn this article the linguistic features of the epic "Bulbul va Gul" (Nightingale and Flower) written by Salahiddin Salahi, who lived in the 18th century, are discussed, in particular, the image tools used in the work, monologue, dialogue, proverb, antonym, synonym, repetition, and the language of the author and character. This shows the poet's ability to use the lexical layers of the language. In addition, with the help of this article, we can get information about the state of the literary language of the 18th century
Synergistic effect of bias and target currents for magnetron sputtered MoS2-Ti composite films
No full textIn terms of modification of the properties of MoS2-Ti composite films, especially tribological properties, significant advances have recently been recorded. However, the commercially production of MoS2-Ti composite films is still limited, because the production of desirable MoS2-Ti composite coating is only possible by using closed field unbalanced magnetron systems and by the selection of convenient deposition parameters. This requirement has focused the researchers' attention on optimization of deposition parameters. This study is concentrating on the effect of the bias voltage and the target currents for MoS2-Ti composite films deposited by pulsed magnetron sputtering (PMS). It is found that the bias and the target currents clearly affect the mechanical, structural and tribological properties of MoS2-Ti films
Pulsed-dc bias magnetron sputtered TiB2 ceramic coating
No full textTitanium diboride, TiB2, is well known as a ceramic material with a hexagonal structure which presents various attractive properties, such as high hardness and excellent corrosion, thermal oxidation, and wear resistance. However, one drawback of TiB2 coatings is their poor adhesion to substrate materials due to high compressive residual stress after deposition. The present study aimed to assess whether a PVD-TiB2 coating with both high hardness and sufficiently good adhesion to the substrate and good wear properties can be developed by a closed-field unbalanced magnetron sputtering system using pulsed-dc biasing. The TiB2 coating deposited on AISI M2 steel substrates was characterized in terms of the structural, mechanical and tribological property. From the experimental results, it can be concluded that a closed-field unbalanced magnetron sputtering system using pulsed-dc biasing can be used to produce a TiB2 coating with sufficiently good adhesion (82 N), and high hardness (2300 HK0.01), and low friction (0.34) under given deposition conditions. The deposition conditions, particularly substrate biasing and rotation, which inhibited the formation of (001) orientation, played a role in the coating's lack of superhardness
Characterization of Ti-CN-a:C films prepared by pulsed-dc bias sputtering
No full textThe incapable side of diamond-like carbon films is low adhesion, resulting from high internal stress. The incorporation of buffer layers into the coating structure to relieve stress and to allow crack energy dissipation by plastic deformation in the crack tip is an effective route for improving toughness. Although this approach will result in a partly decreased coating hardness, the gain in tribological properties is more preferred for many applications. In graded coatings, design and joining of the functional regions including sharp interfaces between layers are very important. The desirable properties can provide only through appropriate transition regions produced by using appropriate deposition methods. In this study, Ti-CN-a:C films were deposited on AISI M2 steel substrates by closed-field unbalanced magnetron sputtering using pulsed-dc biasing, and hardness, crystallography, wear, and adhesion properties of the film were investigated. Accordingly, Ti-CN-a: C films grown exhibited an increase of about 30 per cent in hardness according to that of the substrate and low (mu similar to 0.1) and stable friction and good adhesion (L-c = 43 N), whereas the crystallographic development of the film was amorphous. These properties obtained were attributed to using of CN transient layer and pulsed-dc magnetron sputtering technology
STRESS-RELIEF SOLUTIONS FOR BRITTLE TiB2 COATINGS
No full textEngineering applications of TiB2 coatings are limited because of the brittle nature of interfacial bonds on the substrate surfaces, although they have many major properties such as high hardness, high wear and high temperature strength. To overcome this drawback, many researchers have studied over many years and their efforts have taken several forms such as the rotation of substrate, heating treatment during deposition or after deposition, application of positive bias voltage to the substrate, the introduction of transition elements as an interlayer, gradient or multilayer or composite strengthening, and the optimization studies performed by changing deposition process types and/or process parameters such as working gas and bias voltage. The purpose of this paper is to discuss these solutions proposed or developed by researchers against the limited use of TiB2 coatings due to its brittleness and low adhesion. From the results reported in literature, it is concluded that the best solution in order to produce non-brittle TiB2 based film well adherent to substrate is the use of pulsed-dc deposition technology provided that the process parameters are tuned to give an appropriate composition and/or a coating design. Furthermore, the TiB2 based coatings with multiphase layers seem to give better results respect to adherence
Effect of crystallographic orientation on the friction and wear properties of MoxSy-Ti coatings by pulsed-dc in nitrogen and humid air
No full textThis work reports on the structural and wear properties of MoxSy-Ti films, deposited on D2, 52100, and 440C steel substrates by pulsed-dc magnetron sputtering. A closed field unbalanced magnetron sputter ion plating system was used for the deposition process. The mechanical and tribological properties of MoxSy-Ti coated composites onto selected steel substrates were characterized using microhardness test, friction-wear test in atmospheric conditions and in dry nitrogen. The X-ray diffraction (XRD) was used to determine the phase structure. Structural analysis was performed using SEM-EDS. MoxSy-Ti films showed a very dense structure with pronounced basal plane (0 0 2) orientation, which showed the lowest friction coefficient (0.022) in dry nitrogen. The coefficient of friction can be attributed to the oxidation of MoS2 at the wear track to form MoOx that is known to cause an increase in the friction coefficient. In humid air, an oxidative environment, the films had higher coefficient of friction (0.07). and lower wear life (142 500 passes with 2.11 x 10(-6) mm(3)/N m wear rate) than in dry nitrogen, where the wear life was over 250000 passes with the lowest wear rate of 3 x 10(-8) mm(3)/N m. (C) 2004 Published by Elsevier B.V
Human Action Recognition Based on DMMs, HOGs and Contourlet Transform
No full textThis paper proposes a framework for recognizing human actions from depth video sequences by designing a novel feature descriptor based on Depth Motion Maps (DMMs), Contourlet Transform (CT) and Histogram of Oriented Gradients (HOGs). First, CT is implemented on the generated DMMs of a depth video sequence and then HOGs are computed for each contourlet sub-band. Finally, the concatenation of these HOG features is used as a feature descriptor for the depth video sequence. With this new feature descriptor, the l(2)-regularized collaborative representation classifier is utilized to recognize human actions. The experimental results on Microsoft Research Action3D dataset demonstrate that our proposed method can achieve the state-of-the-art performance for human action recognition due to the precise feature extraction of contourlet transform on the DMMs.EICPCI-S(ISTP)[email protected]
Fabrication of antibacterial and hydrophilic electroless Ni-B coating on 316L stainless steel
No full textBiomaterial-associated bacterial infection is one of the most common complications with medical vehicles and implants made of stainless steel. A surface coating treatment like electroless Ni-B deposition, a new candidate to be used in a broad range of engineering applications owing to many advantages such as low cost, thickness uniformity, good wear resistance, may improve the antibacterial activity and physical properties of biomedical devices made of stainless steel. In this study, the antibacterial property of the electroless Ni-B film coated on AISI 316L (UNS S31603) stainless steel is basically investigated. Inhibition halo diameter measurement after incubation at 37 degrees C and 24 h demonstrates the existence of antimicrobial activity of the electroless Ni-B coating deposited on 316L stainless steel over the Escherichia coli test bacteria. The results of X-ray diffraction, scanning electron microscopy, atomic force microscopy and microhardness measurement studies confirms that the coating deposited on the substrate has an uniform amorphous and a harder structure. Besides, the wettability property of the uncoated substrate and the coating was measured as the contact angle of water. The water contact angle reduced about from 97.7 to 69.25 degrees
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