Effect Of Substrate Surface Roughness Research Articles

INFLUENCE OF SUBSTRATE SURFACE ROUGHNESS ON PUSH-OFF STRENGTH FOR FRICTION SURFACING OF LOW CARBON STEEL WITH AA6061-T6 ALUMINIUM ALLOY

Surface roughness plays an essential role in friction surfacing deposition as a smooth substrate surface polishes both consumable and substrate tools, resulting in a lack of deposition. Hence, an attempt is made to investigate the effect of substrate surface roughness while friction surfacing of AA6061-T6 coating on CR01 low carbon steel and its performance is compared through push-off strength. It is revealed that with an increase in substrate surface roughness, more rubbing action occurs between consumable tool and substrate, which results in higher heat generation and reduction in deposition thickness. The grain refinement is observed at the coating region due to dynamic recrystallisation, which results in fine grain microstructure. The substrate with Ra roughness values 1.5-2.5, 5.5-6.5 and 7.5-8.5 µm showed 26, 32 and 45 MPa push-off strength, respectively. Hence, it is inferred that the push-off strength increases substantially with an increase in the substrate surface roughness.

Effect of substrate surface roughness on the microstructure and properties of laser surface cladding of Tribaloy T-400 on mild steel

This study reports a maiden systematic investigation of the effect of substrate surface roughness on the microstructure and relevant mechanical properties following laser surface cladding (LSC) of Co-based Tribaloy T-400 alloy on mild steel substrate. Before LSC, controlled and distinctly different degrees of surface roughness was introduced on the mild steel plates by sandblasting and belt grinding. The roughness of the sandblasted substrate was considerably higher which resulted in significantly higher laser energy absorption during LSC. As a result, although the deposited clads in either case were defect-free and of the same composition, both depth of melting of the substrate and degree of intermixing between the substrate and clad were considerably higher in the clad deposited on the sandblasted substrate. A detailed analysis of the microstructure and composition across the clad and alloyed (or intermixing) zone revealed that substantial change in composition due to solute intermixing, surface alloying, and dilution of Fe-content had completely altered the microstructure, elemental distribution, and phase aggregate of the clad. Co, Mo, and Si-containing MgZn2 type hard primary Laves phase, present in large amounts in the clad deposited on mild steel substrate following belt grinding, was not observed in the clad developed by LSC on the sandblasted substrate. As the high hardness of T-400 clad usually arises due to the presence of a large quantity of primary Laves phase, the clad deposited on mild steel after belt grinding recorded almost 40 % higher hardness and 67 % lower wear rate. In addition, corrosion resistance of the clad deposited after belt grinding was also marginally higher. Thus, surface roughness prior to laser irradiation is an important parameter to ensure the desired microstructure and properties of the clad, besides clad composition and laser process parameters employed in LSC. This important aspect of influence of surface topography on properties of the clad is often ignored or rarely highlighted in LSC of metallic systems.

Novel approach for improving electrochromic and mechanical properties of NiO film: Experiment and molecular dynamics simulation

In this paper, we systematically studied the effect of substrate surface roughness on the electrochromic and mechanical properties of NiO films deposited on FTO conductive glass by magnetron sputtering. Results showed that increasing substrate surface roughness led to an increase in optical contrast of the film and decreased response time. The NiO film deposited on FTO (Ra 20 nm) had the largest optical contrast (54.7 % at 600 nm) and fastest response time (7.0 s and 1.7 s). Moreover, SEM, XPS, and EDS analyses revealed that the resultant increase in nanoporosity with increasing surface roughness was the main reason for this occurrence. The growth process of the NiO film was simulated by molecular dynamics, and the mechanism of the nanoporous structure was explained theoretically. The mechanical test showed that the composite hardness of FRa20 was 4.2 GPa, while the elastic modulus of the NiO film deposited on it was 74.9 GPa, which was better than all the other films. Thus, this study provides a novel and convenient approach for improving the electrochromic and mechanical properties of NiO films.

Fabrication and test of a conceptual first wall containing titanium nitride as a tritium permeation barrier

The control of tritium buildup of plasma-facing components (PFCs) is essential for the safety regulation of tritium and maximizing the efficiency of the reactors. Tungsten (W) is a promising material of PFCs owing to its attractive benefits of high melting point, high thermal conductivity, low tritium retention and low sputtering yield by particles. However, the hydrogen isotope mobility of W is high, which leads to the loss of tritium of the reactor in the fueling cycle. A conceptual first wall with the capacity of tritium prevention was designed and fabricated, which has a sandwich-like structure consisting of a W top layer deposited by chemical vapor deposition (CVD-W), a reduced activation ferritic/martensitic (RAFM) steel called CLF-1 as substrate, and a titanium nitride (TiN) interlayer as a tritium barrier. This work aims to investigate the effects of substrate surface roughness and interlayer thickness, which are essential to the adhesive strength of the sandwich-like structure. Samples with various interlayer thicknesses and substrate roughnesses were prepared and analyzed by using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), the thermal cycling test, and the pull-off test. The results show that proper roughness of the substrate and suitable thickness of the TiN interlayer could crucially contribute to the adhesive strength. Among all the samples, the samples with the substrate roughness of 0.8–1.6 μm and the TiN interlayer thickness of 1.5±0.5 μm have the best adhesive strength. In addition, the gas-driven permeation (GDP) test is employed to evaluate the deuterium permeation resistance of the sandwich-like structure.

Effect of substrate surface roughness on interfacial reaction at Sn-3.0Ag/(001)Cu interface

The high reliability of solder joints is the guarantee for the miniaturization, ultra-high density, multi-functional and high performance of integrated chips. The growth of interfacial intermetallic compounds determined by solder composition, substrates, reflow temperature et al., is the key factor to achieving good bonding. In this paper, the effects of substrate surface roughness on interfacial reaction at Sn-3.0Ag/(001)Cu interface were investigated. Confocal Laser Scanning Microscope (CLSM), Scanning electron microscope (SEM), Electron backscatter diffraction (EBSD) and Shanghai Synchrotron Radiation Facility (SSRF) were used to characterize the interface reaction. Results suggest that higher Ra favors to form thicker IMC layer and more voids, as well as degrades the preferred orientation of IMC. The results have a significant meaning in improving the reliability of solder joints in the real work environment.

Enhanced visible photocatalytic performance of un-doped TiO2 nanoparticles thin films through modifying the substrate surface roughness

Titanium oxide (TiO2) has been widely utilized for application in environmental pollution due to its unique properties. However, large bandgap (3.2 eV) and low surface area of bulk TiO2 are the main properties that limit its photocatalytic applications. In this work, a thin layer of TiO2 (<200 nm) nanoparticles (NPs) on mechanically roughened glass substrates is deposited by a simple sol-gel method followed by a dip-coating process along with fast heating and sintering. The effect of substrate surface roughness on the morphology, hydrophilicity, and optical properties which results in a more electron-hole generation and consequently improved photocatalytic activity was investigated by different characterization techniques. The TiO2 layer on the roughest substrate (RMS = 76.90 nm) showed the smallest average NP size (3 nm) with the highest surface roughness (RMS = 121.00 nm) and hydrophilicity (74.5%) as well as strong optical absorption. This sample photodegraded the pollutant with an efficiency of 85% at a rate of 0.0054 min−1 under the illumination of the vis-light emitting diode (LED)-based source (440 and 590 nm). Therefore, an enhanced photocatalytic activity accompanied by recyclability was achieved by modifying the substrate surface roughness and thermal treatment in the process of synthesis. Conclusively, intrinsic defects and grain boundaries appear which behave as active areas for charge transfer in the photocatalytic process under visible irradiation. This research may provide an insight into the fabrication of highly efficient photocatalysts based on commonly used wide band gap materials to work in the absence of UV light.

Experimental study on bonding behaviour of interface between UHPC and concrete substrate

The aim of this study is to investigate the effect of substrate surface roughness, fibre type, and water-to-binder ratio on the bond behaviour between ultra-high-performance concrete (UHPC) and normal-strength concrete (NSC). In addition, the suitability of different methods for evaluating the surface roughness using a sand-filling method, the height, number, and area of exposed coarse aggregates, and capillary absorption was verified. The results indicated that surface roughness was the most critical factor, followed by the water-to-binder ratio, and finally, the steel fibre type on influencing the bond strength. These methods for evaluating the surface roughness showed good consistency. The bond strength enhancement was mainly attributed to the compact transition zone of UHPC–NSC and the dowel effect of the steel fibres on the substrate surface recess. Based on the experimental bond strength values, an UHPC–NSC shear strength equation was derived, considering the repair surface roughness, and other research data verified the applicability of the proposed equation. Moreover, the NSC area fraction on the UHPC overlay side and the damage index of the composite specimen after debonding had a good linear relationship with the interface performance.

Effect of substrate surface roughness on the wear of molybdenum disulphate coated rolling contact bearings

Abstract The objective of the present experimental work is to investigate the influence of subsurface roughness on the friction and wear performance of high-temperature ball bearing. Bearings, which are used in high-temperature applications, are affected by several operating conditions. Some factors under high-temperature conditions such as short grease life, thin-film thickness at low speed, and insufficient internal clearance can drastically reduce bearing service life due to an increase in surface friction. For this reason, rolling contact bearings are coated with molybdenum disulfide. Before the molybdenum disulfide (MoS2) coating, phosphatization is applied to the bearings. Because the phosphate layer is micro-porous, it assures that molybdenum disulfide is entrapped in the interstitials between the phosphates. Also, phosphate coating provides a much larger surface area for the lubricant to attach to. In this study, several process steps, sandblasting, manganese phosphate coating, molybdenum disulfide coating, friction moment testing, wear testing, wear depth measurement, SEM, and XRD analyses were carried out. Wear tests and friction moment tests were applied to the rings of bearings of varied raceway roughness. This process ultimately provides molybdenum disulfide coated bearings optimum raceway roughness parameters for good wear resistance and optimum boundary lubrication.

Effect of Substrate Surface Roughness on the Tribological Properties of DLC-H Coatings on Tappet Valve

Effect of Substrate Surface Roughness on the Tribological Properties of DLC-H Coatings on Tappet Valve

Investigation of physical and electrical properties of TiN-coated SS316L as bipolar plate of proton exchange membrane fuel cells

ABSTRACT In this research, TiN films were deposited on the SS316L substrate by cathodic arc evaporation technique, to use as bipolar plates in proton exchange membrane fuel cells. The effect of substrate surface roughness and film thickness on the interfacial contact resistance and corrosion properties of the TiN films was investigated. Characterization of deposited films was performed by XRD, XRF, ICR, contact angle, and FESEM equipped with energy-dispersive spectroscopy. Electrochemical and surface properties of deposited films were studied by potentiodynamic scanning, electrochemical impedance spectroscopy, and AFM analysis. It is observed that the surface roughness of the substrate, before deposition, has a significant impact on the final properties of TiN coating, especially when the coating thickness is less than 1.2 µm. All of the coated samples showed better corrosion resistance in comparison to the substrate, and the corrosion current density decreased from 1.65 to 0.16 μA cm–2 when coating thickness increased from 0.6 to 1.5 µm.

Effects of the surface roughness on wetting properties and interfacial reactions between SAC305 solder and Cu substrate with Ni–W–P coating

The SAC305/Ni–W–P/Cu joint system has been investigated in previous studies, and Ni–W–P barrier was suggested to be efficient to inhibit excessive diffusion of atoms. Thus, much attention was drawn to improve the performance of this diffusion barrier, but there were few studies focusing on exploring the effect of substrate surface roughness on interfacial microstructure evolution in the solder joint with Ni–W–P barrier. In this work, copper substrates with different surface roughness were prepared for establishing SAC305/Ni–W–P/Cu joint systems. Results revealed that as roughness of substrate surface increased, sizes of coating grains became larger and the surface of Ni–W–P coatings tended to be rougher. On the other hand, with the decrease of substrate surface roughness, wetting properties of SAC305 solder were remarkably improved and the growth rate of intermetallic compound (IMC) layer would decrease. It is suggested that the roughness of substrate surface had remarkable influences on microstructure of Ni–W–P coating, and hence affected the microstructure evolution of IMC layer.

Perilaku kekasaran permukaan baja AISI 1045 terhadap kekerasan dan laju korosi serta daya lekat permukaan hasil elektroplating

Electroplating is the coating metals with thin layers of other metals by electrolysis to improve the surface properties of materials, especially corrosion resistance. Electroplating is widely used in the automotive, electronics, medical, aerospace, gas, and oil industries. This study will discuss the effect of substrate surface roughness of AISI 1045 steel toward surface roughness, hardness, corrosion rate, and bonding strength of the coating. The surface roughness of the substrate is obtained by grinding process using sandpaper with grades 80, 320, and 1000. In this study, the coating material is Chromium. The electroplating parameters used in this research are 5-volt voltage, current 500 Amperes, and the time of 15 minutes. From this research, it is known that the surface roughness of the substrate material has an influence on the quality of the coating. The lower the surface roughness, improve the roughness, hardness, corrosion rate, and bonding strength. Keywords: electroplating, surface roughness, hardness, corrosion rate, bonding strength.

Fabrication and coating adhesion study of superhydrophobic stainless steel surfaces: The effect of substrate surface roughness

In this study, superhydrophobic 17–4 PH stainless steel surfaces were fabricated for applications in harsh marine environment. The impacts of the substrate's surface roughness on the fabrication and durability of the developed superhydrophobic coating, comprised of a Zn electrodeposited layer capped with 0.05 M stearic acid, were investigated for the first time in this study. Various micron and sub-micron scale finished surfaces with different surface roughness, namely as-received (Ra ~ 4.62 μm), sandblasted (Ra ~ 11.93 μm), and ground (Ra ~ 0.39 μm) surfaces, were fabricated, followed by applying Zn electrodeposited coating to improve the water-repellent properties of the stainless steel substrate. The adhesion durability of the coating and corrosion behavior of the electrodeposited Zn layer were deliberated by studying the combined impacts of the initial surface roughness, and super-hydrophobicity of the surfaces. The cyclic potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) results measured in aerated 3.5 wt.% NaCl electrolyte at room temperature along with salt spray testing highlighted a significantly better uniformity and adhesion durability of the coating on the as-received substrate correlated to its optimum surface roughness. The best coating adhesion was obtained on surfaces with an initial surface roughness of 4.62 ± 0.15 µm. The coated 17–4 pH stainless steel surfaces were also found to be effective in preventing the aggressive chloride ions from approaching the substrate, leading to the improved corrosion performance of the material.

Effect of substrate surface roughness on properties of cold-sprayed copper coatings on SS316L steel

The development of thick pure copper coatings on SS316 substrates with desired properties for Tokamaks is still a challenging task. The solution to this task can help to fulfill the demanding requirements of in-vessel materials for plasma passivation. In the present work, the effect of substrate surface roughness on several properties of cold-sprayed copper coatings was investigated. Effect of post-heat-treatment on the properties of the developed coatings was also studied. The developed coatings were characterized using various techniques viz.; scanning electron microscopy/energy dispersive spectroscopy, X-ray diffraction, optical microscopy, microhardness, nanoindentation, electrical and thermal conductivity measurements, and density and porosity analyses. The novelty of the article includes in-situ micro-tensile testing of the developed coatings to understand their fracture mechanism, which showed multi-crack failure. Moreover, the cracks were found to be originating from the multi-splat boundary junctions, followed by growth along the splat boundaries. Additionally, γ-rays and heavy-nuclei irradiation along with thermal cyclic exposure studies were also performed to elucidate the actual environmental performance of the coatings. The coatings developed on the mirror-finished surface were found to have better mechanical and physical properties as compared to the coatings developed on the rough substrate surface; prior as-well-as post-heat-treatment.

Study of the microstructural control of Ba(Mg1/3Ta2/3)O3 perovskite thermal barrier coating deposited by solution precursor plasma spray

Inductively-coupled plasma spraying was used to deposit Ba(Mg1/3Ta2/3)O3 (BMT) on a titanium alloy substrate. By selecting the appropriate spraying parameter, it was possible to tune the BMT coating microstructure from dense splat-like layers to columns and segmented vertical cracks. Of those parameters, a short spraying distance of 34 mm was the most crucial parameter to form a columnar microstructure. An atomization probe that fed a bimodal droplet size distribution was considered as an important prerequisite to obtain a high-quality columnar structure. Small atomized droplet sizes contribute to the formation of columns, while the large ones ensure a high deposition rate. This is further discussed as part of the column formation mechanism. The effects of substrate surface roughness, precursor concentration and feed rate were studied separately. The surface roughness should be controlled between Ra = 1.3 μm and Ra = 2.7 μm to reduce the intercolumnar gaps. The columnar structure evolves into a segmented vertical cracked one when spraying concentrated precursors (30 wt%). High feed rate (>6 ml/min) can satisfy a series of requirements such as high deposition rate, low intercolumnar gaps and high intracolumnar porosity. Finally, a desired columnar structure with an intracolumnar porosity of 4.3% and an intercolumnar porosity of 9.9% was obtained by spraying a 10 wt% concentration precursor on a finely sand-blasted substrate (Ra = 1.3 μm) at a feed rate of 8 ml/min.

Effect of Substrate Surface Roughness on Microstructure and Mechanical Properties of Cold-Sprayed Ti6Al4V Coatings on Ti6Al4V Substrates

Surface condition, especially surface roughness of substrates, critically influences the adhesion of cold-sprayed titanium alloy coatings. To study this, Ti6Al4V (Ti64) coatings were deposited on Ti64 substrates with increasing surface roughness (Ra) from 0.05 µm (polished surface) to 5.4 µm (water-jet cut surface). It was found that the substrate surface roughness did not significantly affect the porosity, hardness and coating surface roughness because these properties were dependent on the deposition parameters such as propellant gas pressure and temperature and nozzle traverse speed. The adhesion test results showed that smoother substrate surfaces improved the coating bond strength of the cold-sprayed Ti64 coatings from about 7.1 MPa (Ra: 5.4 µm, interface failure) to 68.7 MPa (Ra: 0.05 µm, glue failure). The fracture characteristics of the debonded coating/substrate interfaces revealed that there were more adiabatic shear-induced craters observed on the smoother substrate surfaces. Finite element modeling also showed that the substrate surface features (i.e., peaks and valleys) possibly prevented the intimate contact between the particles and substrate and thus induced the non-uniform distributions of temperature, stress and strain at the particle/substrate interface.

Effects of complex graphite-like carbon coating on gear vibration noise

Abstract In this paper, the effects of substrate surface roughness and the addition of yttrium, cerium and tantalum on thickness uniformity of graphite-like carbon (GLC) coatings on gears were studied by magnetron sputtering method using mosaic targets. And noise reduction effects of gear pump deposited with complex GLC coatings were evaluated at different rotate speeds. The results showed that target-substrate distance, sputtering angle and surface roughness had influences on thickness uniformity of GLC coatings on gear. The introduction of elements Y, Ce and Ta into GLC coatings could effectively improve their thickness uniformity. The complex GLC coating with optimal thickness uniformity on gear exhibited significantly reduction effect for gear noise and the reduction effect for axial vibration was better than that of radial vibrations. Compared with uncoated gears, the noise for the coated gears was decreased by 10 dB at 2000 rpm. Good high-frequency noise reduction was obtained, which could be decreased by 19 dB in the range of 4000–10,000 Hz.

Crosstalk Delay and Stability Analysis of MLGNR Interconnects on Rough Surface Dielectrics

The crosstalk delay and frequency stability of MLGNR interconnects on dielectric materials with rough surfaces are investigated. Two interacting parallel interconnect lines (aggressor and victim) are considered. ABCD matrix model of two port networks is employed to obtain an equivalent single conductor (ESC) circuit model for decoupled victim line. The effect of substrate surface roughness is appropriately included in ESC model. The most common dielectric materials (SiO2, BN and SiC) are considered. By setting up a driver-interconnect-load (DIL) system the crosstalk delay and stability analysis of MLGNR and Cu interconnects are performed. Results show that the crosstalk delay and the stability of MLGNR interconnects oppositely response to the surface roughness of underlying dielectric material. Namely, dielectric materials with rougher surfaces translate to longer crosstalk delays while more stable systems. While MLGNR interconnects on SiO2 have longer crosstalk delay in compare to Cu counterpart, MLGNRs on BN and SiC have shorter crosstalk delay with respect to Cu ones. Therefore, to hold advantage of MLGNR interconnects on SiO2 over Cu counterpart either the SiO2 surface must be more precisely polished or MLGNRs with higher doping concentrations shall be used.

Effects of substrate surface roughness and aluminizing agent composition on the aluminide coatings by low-temperature pack cementation

In this study, a new low-temperature aluminizing process combining surface slurry pre-coating at room temperature with pack cementation process was used to prepare the iron-aluminum alloy coating. The effects of different substrate surface roughness and aluminizing agent composition on the coating surface roughness, phase structure and the thickness of each phase in the coating were studied. The results showed that the average surface roughness of the coating with 2000# substrate and 5% AlCl3 was 2.641 μm. The aluminide coatings under different experimental parameters had the same Fe3Al, FeAl, Fe2Al5 and FeAl3 phase structure. However, the thicknesses of Fe3Al, FeAl and FeAl3 phase layers decreased with the increase of AlCl3 content. Furthermore, the aluminide coating with 2000# substrate and 5% AlCl3 had a bonding strength of 67.60 MPa and outstanding thermal shock resistance. The excellent properties of the iron-aluminum alloy coating made it possible to prepare the top coat on it.

Effects of substrate surface roughness and nano/micro particle additive size on friction and wear in lubricated sliding

Macroscopic wear experiments were complemented by atomistic simulations to study the effect of nano- and micro-scale titanium dioxide particle lubricant additives on friction and wear. The size of the particles and initial roughness of the sliding surfaces were varied to characterize the interrelated effects of these two properties. Results from both experiments and simulations suggest that there is an optimal particle size that will minimize friction and wear for a given surface roughness. Analyses support a previously-proposed mechanism for particle-based additives in which the particles fill in valleys on the sliding surfaces. In this context, particles that are smaller than the characteristic roughness of the surfaces are most likely to perform this function.