Influence Of Substrate Roughness Research Articles

Influence of Substrate Roughness and Ceramic Content on Deposition Characteristics of Cold-Sprayed Ti/TiO2 Deposits

Influence of Substrate Roughness and Ceramic Content on Deposition Characteristics of Cold-Sprayed Ti/TiO2 Deposits

Effects of Substrate Roughness on Microstructure and Fatigue Behavior of Plasma Electrolytic Oxidation-Coated Ti-6Al-4V Alloy.

Ceramic coatings were prepared by plasma electrolytic oxidation (PEO) on four different surface roughness’ of Ti-6Al-4V alloys. The effects of substrate roughness on the microstructure and fatigue behavior were investigated. Microstructural characterization was carried out by scanning electron microscopy (SEM) and a laser scanning confocal microscope. In addition, an X-ray diffractometer (XRD) and a U-X360 stress meter were used to analyze the phase composition and residual stress properties of the coatings. The microstructure of coatings revealed the growth mechanism of the coatings. The larger and deeper grooves of the substrate promoted the nucleation and growth of the PEO coating, but the defects (cracks and pores) of the oxide layer became more serious. The fatigue test indicated a significant influence of substrate roughness on the fatigue life under low cyclic stress. The fatigue damage of PEO coatings decreases as the surface roughness of substrates decreases because of the synergistic effect of the coating surface defects and coating/substrate interface roughness. Substrate roughness influences the quality and fatigue performance of the oxide layer.

Influence of substrate roughness on particle adhesion and concentration

Influence of substrate roughness on particle adhesion and concentration

Influence of substrate roughness and bonding agents on the bond strength between old and new concrete

This research aims to study factors affecting the strength of adhesion between old concrete and new concrete. Among the factors that have been studied in this research are the type of bonding material and the roughness of the surface adhesion, four types of bonding materials (EPICHOR-1768, C-Latex, SikaBond-T21, EPICHOR-500) have been selected because they are available in local markets. A wire brush is used in order to increase the roughness of sample surfaces. The pulloff and slant shear tests have been adopted to assess the bonding strength between the test the old and new concrete. 30 cylindrical samples (7 cm diameter) have been examined by pull-off test, also slant shear test was conducted on 40 samples (10 cmx10 cmx30 cm). The obtained results showed that there is an active role for the bonding material as well as the surface roughness to increase the strength of adhesion between the old and new concrete. Also, it showed that the best of these bonding materials is EPICHOR-1768 because of its significant impact in increasing the strength of the adhesion between the old and new concrete where the percentage of increase 124% in the pull-off test and 48% in slant shear test, compared to the reference sample for each test. As well, as a result of roughening the surface by brush, the strength of adhesion reaches 4% increase in the pull-off test and 23% in the slant shear test compared with the reference sample for each test, which demonstrates the importance of surface roughness to increase the bonding strength between the old and new concrete.

Influence of substrate roughness on peeling behavior of DLC coated gear

Influence of substrate roughness on peeling behavior of DLC coated gear

Influence of substrate roughness on the wear behaviour of kinetic spray coating

The purpose of the present study was to explore the importance of different substrate roughness on porosity, hardness and wear properties of NiCr based alloy coatings deposited by kinetic spray technique. Low carbon steel was used as the substrate. Different surface roughness levels were attained using different methods like milling, grit blasting and water jet cutting. Coatings were deposited on these substrates utilizing identical coating parameters and technique. The resultant coatings were then investigated for wear behaviour by using a pin on disc wear testing machine for three loads 10, 20 and 30 N and two speeds 0.5 and 1.5 m/s, keeping the sliding distance a constant. Wear rate of substrates and coatings, porosity measurements and hardness of the coatings were investigated. An indication of the results suggests that substrate surface roughness has an influence on the samples studied. The wear resistance of the coating obtained by grit blasting the surface prior to the coating deposition showed the best result.

Modelling jumping in Locusta migratoria and the influence of substrate roughness

Locusts are widely recognized for their jumping performances. Jumping allows locusts to avoid predators and initiate flight. In this study, jumping performances of Locusta migratoria were modelled with a lumped-parameter theoretical model. Results showed that L. migratoria can reach a maximum take-off velocity of 1.83 m/s and maximum acceleration of 66.72 m/s2, with take-off angle of about 36°. While carrying out such a high performance, locusts are prone to slip when taking off from a smooth ground, especially for locusts with only one hind leg. Experiments have been therefore conducted to test the influence of ground roughness on jumping performance. There was no significant relation between ground roughness and jumping success, and this was due to combined action of rigid claws and adhesive pads ensuring static contact between tarsus and ground. It was noted that large take-off angles might help locusts to jump successfully with only one hind leg left, as well as to achieve better performance on smooth surfaces. The excellent contact ability on surfaces with different roughness gives meaningful insights for jumping robot design.

Influence of substrate roughness on the adhesion and tribological performance of Titanium Nitride coating on AISI H13 steel

ABSTRACTThe aim of this research was to investigate the influence of substrate roughness on the adhesion and tribological performance of thin TiN coatings obtained by physical vapor deposition. For that purpose, substrates of AISI H13 steel with surface finishes of 0.06, 0.28 and 0.90 μm in Ra were coated with TiN under the same coating conditions. The chemical composition of the steel, as well as that of the TiN coating, were obtained using EDS analysis. Adhesion tests were carried out following the procedure of BSi 1071-8 standard while hardness was evaluated by ASTM C 1327-03. On the other hand, dry sliding friction tests were conducted with a pin-on-disk tribometer, according to the ASTM G 99-05 standard. This study showed that the roughness of the coating increases as the substrate roughness increases. Regarding adhesion and hardness, all the samples showed an adhesion class 1 according to the standard and a hardness value of 14.51 GPa. Nevertheless, the highest substrate roughness produced the best adhesion. On the other hand, the lowest values for the friction coefficient and wear behavior were obtained by the sample with the lowest substrate roughness of 0.06 µm. In addition, it was found that friction and wear increase when the substrate roughness increases.

Effects of substrate roughness on the vacuum tribological properties of duplex PEO/bonded-MoS2 coatings on Ti6Al4V

The present study focuses on the influence of substrate roughness on the vacuum tribological properties of PEO/Bonded-MoS2 coatings on Ti-6Al-4V. Four different surface conditions of Ti-6Al-4V coupons, namely Ra being 0.8, 1.6, 3.2 in as-machined conditions, and Ra 1.6 post-treated by sandblasting, were used as substrates. A ball-on-disk tribometer was used to evaluate the vacuum tribological performances of the coated samples. Results showed that the Ra 1.6 sample exhibited the longest anti-wear life, which were attributed to two causes: a hard PEO coating and a special PEO topography with grooves and ridges. The grooves provided ‘reservoirs’ of MoS2, and the ridges acted as hard anti-wear “phases”. The particular wear mechanism and the effects of roughness were proposed and discussed in this study.

The influence of substrate roughness, patterning, curvature, and compliance in peeling problems

Biological adhesion, in particular the mechanisms by which animals and plants ‘stick’ to surfaces, has been widely studied in recent years, and some of the structural principles have been successfully applied to bioinspired adhesives. However, modelling of adhesion, such as in single or multiple peeling theories, has in most cases been limited to ideal cases, and due consideration of the role of substrate geometry and mechanical properties has been limited. In this paper, we propose a numerical model to evaluate these effects, including substrate roughness, patterning, curvature, and deformability. The approach is validated by comparing its predictions with classical thin film peeling theoretical results, and is then used to predict the effects of substrate properties. These results can provide deeper insight into experiments, and the developed model can be a useful tool to design and optimize artificial adhesives with tailor-made characteristics.

Influence of Substrate Roughness on Deposition Mechanism of Cold Sprayed Metallic Coatings

Influence of Substrate Roughness on Deposition Mechanism of Cold Sprayed Metallic Coatings

Influence of substrate roughness on bonding mechanism in cold spray

Abstract In this study, optimization of substrate roughness for enhancing interface bonding state in cold spray for different material combinations is performed. Material combinations are classified into four different particle/substrate impact pairs (i.e., soft/soft, soft/hard, hard/soft and hard/hard) based on their thermos-mechanical and physical properties. Finite Element Analysis (FEA) was employed to simulate the models in relation with constant powder size (25 μm), for estimating impact interface parameters. Experimentally, particles were deposited on different roughened substrates in order to compare the simulation results. Microstructures, deposition efficiencies and bond strengths were obtained for the coatings. On the basis of simulation and experimental results, optimum substrate roughnesses for different cases are suggested for better bonding. The optimum roughness for different material combinations was obtained and found to be the fraction of particle size based on the thermo-mechanical behavior of materials upon impact.

Interface parameters of composite sprayed concrete linings in soft ground with spray-applied waterproofing

The presence of a spray-applied waterproofing membrane between the primary and secondary lining layers is important to the behaviour of a composite sprayed concrete lined (SCL) tunnel in soft ground. In order to confirm the feasibility of the composite shell lining concept, the structural adequacy of the concrete-membrane interfaces under the effects experienced in a typical tunnel needs to be investigated.This paper presents a series of laboratory tests on samples cut from composite sprayed concrete panels, to which uniaxial compression, direct tension and direct shear loadings are applied over both short- and long-term timeframes under conditions of ambient atmospheric humidity. Test results show that the interfaces are capable of resisting significant compression, tension and shear in both short- and long-term. Failures under these actions should not occur in a typical shallow SCL tunnel, and a degree of composite action between primary and secondary layers should be expected. Influence of substrate roughness and membrane thickness on the measured interface properties has been quantified. Overall, this investigation confirms the existence of composite action for composite sprayed concrete linings in soft ground, and provides parameters based on test results for further research and design.

The Influence of Substrate Roughness on the Surface Condition of WC-Co Coatings Obtained Using the Supersonic Method

Thermal spraying process is one of the main methods of obtaining the protective coatings. Coating quality largely depends on the proper selection of coating materials, technology and spraying equipment and the method of substrate preparation. The article presents the problem of the effect of surface preparation process on selected properties of the coating produced by supersonic thermal spraying – HVOF. Blast cleaning and supersonic thermal spraying processes were characterized. The influence of blasting parameters on the resulting surface profile and selected properties of the coating, such as roughness, porosity and structure were determined by means of surface profilometry, light microscopy and digital image analysis.

Influence of substrate roughness on adhesion of TiN coatings

Titanium-nitride coatings were prepared by ion beam assisted deposition. In order to provide adequate adhesion between TiN films and steel substrates, ion beam mixing of Ti atoms with atoms of steel base was applied prior to deposition. The effect of substrate surface roughness on adhesion strength of TiN coatings was evaluated in this research. A scratch test was used to characterize the adhesive properties of the coatings. Optical microscopy was employed to examine scratch-induced channels, while atomic force microscopy was used to determine sample roughness prior and after the deposition of TiN coatings. It has been revealed that adhesion increases with increase in substrate roughness.

Role of surface wettability and roughness in emulsion separation

Droplet interaction with a surface placed in an immiscible liquid surrounding is very important for liquid–liquid separation. This study investigates the influence of filter surface energy (14–43mN/m), micro- and nanoscale surface roughness on wetting, mobility and coalescence of isooctane droplets (5–10μl) in immiscible water surrounding and explains their role in emulsion separation performance of nanoparticle coated filters. In water, coalescence among the oil droplets primarily takes place at filter surface. Despite different interfacial energies in air and water surrounding, the influence of substrate roughness on droplet mobility is same in both the surroundings. For effective separation of oil-in-water emulsion with a surface filter, it should be super hydrophilic, oriented vertically and have pore size smaller than the dispersed droplet size. In addition, the influent side of a surface filter should possess sufficient micro- and nanoscale surface roughness to provide high mobility, coalescence of the oil droplets and thereafter their easy detachment. For effective separation of oil from water a coalescing filter should be hydrophobic–oleophilic, oriented vertically with rough fibers surface to offer strong adhesion with the oil droplets and thereby high coalescence efficiency.

Influence of substrate roughness on structure and mechanical property of TiAlN coating fabricated by cathodic arc evaporation

The aim of the present research was to investigate the influence of different substrate roughness on structure and mechanical properties of Titanium Aluminium Nitride (TiAlN) coatings. Tungsten carbide rectangular block was used as substrate. Different surface roughness was achieved by using grinding discs with different grain sizes and diamond polishing powder, and TiAlN coatings were deposited on these substrates under the same preparation technique and parameters. Morphologies of substrates and coatings, crystal structure, thickness and mechanical properties of coatings were investigated using optical microscope, AFM, XRD, CSM scratch tester and tribometer. It was shown that surface morphology of cathodic arc TiAlN coating was mainly affected by the morphology of the substrate surface and the coating growth process. The influence of substrate roughness on crystal structure and thickness of the coatings could be ignored. With the decreasing of the substrate roughness, the adhesion force between coating and substrate increased. Three stresses model was applied to interpret this result. The wear resistance of the coating was also improved with decreasing the substrate roughness.

Influence of steel substrate roughness on morphology and mesostructure of TiO 2 porous layers produced by template-assisted dip coating

Mesoporous titania films were prepared by template-assisted dip coating on 1.4301 stainless-steel substrates processed by grinding and spark erosion to different degrees of roughness. The influence of substrate roughness on the morphology and mesostructure of deposited films was studied. Textures produced by grinding with roughness R a ranging from 0.10 to 0.78 μm did not noticeably affect the pore structure as confirmed by similar pore size and a single cubic mesophase formed on grinded steel. Grinding had a modest effect on the film integrity which manifested in fractures developed in the texture depressions. Greater roughness of the steel produced by spark erosion affected the micelle self-assembly process yielding two different mesophases on a substrate of 1.08 μm roughness, and resulting in a predominant loss of templated mesostructure on a rougher ( R a = 2.69 μm) substrate surface. Film surface area expressed as m 2 BET per m 2 of the substrate planar dimensions increased with substrate roughness. Higher roughness resulted in higher photocatalytic activity of crystalline films when tested in methylene blue decomposition. Given that a moderate surface texture had a negligible effect on the film mesostructure, introducing controlled substrate roughness may serve as a technique to enhance the total film surface area.

Theoretical and experimental approaches of bacteria‐biomaterial interactions

AbstractAbout the influence of substrate roughness and spray particle size on the adhesion of thermal spray coatingsBacterial adhesion to surfaces is a complicated process influenced by many factors including the bacteria (surface energy and charge, molecular details), the substratum surface (chemical composition, roughness, configuration, surface energy and charge) and environmental factors (serum proteins, flow conditions, temperature, bacterial concentration, time of exposure, antibiotics). The models that have been proposed for the quantitative prediction of bacteria‐material interactions are based on colloidal theories and macromolecular binding considerations. Two categories of techniques used in calculating bacterial adhesion strength and bacteria‐material interactions have been proposed: those that utilize fluid flowing against adherent bacteria and those that manipulate single bacteria (atomic force microscopy and optical tweezers), and are concisely reviewed.

202 プラズマ溶射皮膜の密着強度に及ぼす基材表面粗さの影響(OS6(1) コーティング部材の寿命管理・延伸)

202 プラズマ溶射皮膜の密着強度に及ぼす基材表面粗さの影響(OS6(1) コーティング部材の寿命管理・延伸)