Influence Of Substrate Surface Roughness Research Articles

Influence of substrate surface roughness on the thermal emissivity of titanium carbide coatings on graphite

This study focused on the impact of substrates shape on the heat radiationcharacteristics of a coating made of titanium carbide, TiC, deposited over a graphite basis. The TiC coating emissivity increase by 29.65% at 1050?C and by 37.45% at 1650?C when graphite, substrate surface roughness, was decreased from 3.01 ?m to 0.73 ?m. Simultaneously, the TiC coating?s spectrum emissivity on the graphite substrate indicated the material?s clear characteristic heat radiation. These findings demonstrated that the coating and substrate interacted to determine the coating?s heat radiation properties. A simplified coating model created to consider how the shape of the substrate affects the coating?s ability to conduct heat. Ultimately, the rough form of the substrate led to a decrease in the coating?s heat radiation characteristics and an enhancement in energy loss at the interface.

Effect of substrate roughness on the nucleation and growth behaviour of microwave plasma enhanced CVD diamond films – a case study

The influence of substrate surface roughness on the nucleation and growth of diamond films by chemical vapour deposition (CVD) is investigated. Silicon substrates were grinded with six different grit sizes of abrasive papers with a rotating wheel. Si was also etched by Ar+ ions to produce average surface roughness Ra = 11.29 nm on the mirror polished side (Ra = 1.17 nm). A comparison of the results of the effect of substrate roughness, on the growth behaviour of nanocrystalline diamond (NCD) films, by using both the resonant cavity and the linear antenna CVD systems, are presented here. Scanning electron microscopy (SEM) images and Raman spectroscopy reveal that under both the linear antenna and the resonant cavity microwave plasma CVD conditions, grown films are NCD. The diamond nanocrystals sizes vary from 80 to 180 nm, grown by both the reactors after few hours of deposition, irrespective of the substrate roughness, whereas their quality (defined by the relative percentage ratios of the Raman sp3 peak intensity to the non-sp3 peak intensity) varies from 33% to 45%, depending on the substrate surface roughness. Such nanocrystals grew into plate-like flat 1–6 μm size diamond grains after prolonged hours (64–69 h) of CVD growth. It is found specifically that the roughness created by the argon plasma treatment of the silicon substrate surfaces effectively enhances the nucleation and growth behaviour of the diamond films.

Influence of Substrate Surface Roughness on Synthesized Diamond Films by Flame Combustion on Ti Substrate for Dental Implants

The flame combustion method enables the synthesis of diamonds via acetylene-oxygen gas flame combustion in ambient air, and this method has various advantages over other methods. However, most diamond films synthesized by this method delaminate because of thermal stress during cooling. Titanium (Ti) has recently been utilized as a dental implant in the dental industry. In this study, to improve the strength, wear resistance, and biocompatibility of dental implant surfaces, diamond films were synthesized on a Ti substrate, a dental implant material, by the flame combustion method. Moreover, to obtain high-quality diamond films and achieve good adhesion on the Ti substrate, as a pretreatment of the substrate to prevent delamination, scratch processing, in which a substrate is ground with emery paper in one direction, was performed to roughen the surface. The surface roughness of the Ti substrates was varied by scratching with emery paper of #180, #400, and #1500 grain sizes. According to these results, diamond films were synthesized on the Ti substrate surface by flame combustion. The surface morphology of the synthesized films could be altered by varying the scratching process using emery paper. Delamination of the synthesized films during the scratching process with emery paper #180 (Case A) and #400 (Case B) grain size was completely prevented. However, delamination occurred during the scratching process with a grain size of emery paper #1500 (Case C). To investigate the reason for this result, the surface roughness of the pretreated Ti substrate was observed, and it affected the surface roughness of pretreated Ti substrate affected the surface morphology and delamination of the synthesized diamond films.

Influence of Substrate Surface Roughness and Post Heat Treatment on Interfacial Strength of Plasma-sprayed Hydroxyapatite Coatings

Influence of Substrate Surface Roughness and Post Heat Treatment on Interfacial Strength of Plasma-sprayed Hydroxyapatite Coatings

Influence of Substrate Surface Roughness on Copper Coating Formation Behavior on Graphites by Low Temperature Plasma Spraying

Influence of Substrate Surface Roughness on Copper Coating Formation Behavior on Graphites by Low Temperature Plasma Spraying

Influences of Ni–5 at.%W Alloy Substrates on the Epitaxial Growth and Surface Morphologies of CeO2 Films Deposited by PLD

We fabricated CeO2 films using pulsed laser deposition (PLD) for YBa2Cu3O7−δ coated conductors on Ni–5 at.%W alloy substrates and investigated the effect of Ni–5 at.%W tapes on the epitaxial growth and surface morphologies of CeO2 deposited on various substrates at various temperatures ranging from 650 to 770 °C. The texture and microstructure of substrates and CeO2 films were measured by X-ray diffraction (XRD), optical microscope (OM), field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM). It was found that the texture and microstructure of Ni–5 at.%W substrates, such as Ni(111), grain size, the depth of grain boundary grooves and surface roughness, affected the growth of CeO2 films. Especially, the depth of grain boundary grooves of substrates resulted in high intensity of CeO2(111) peak and high surface roughness of CeO2 films. We also found that high growth temperature effectively reduced the influence of substrate surface roughness on the epitaxial growth of CeO2 films. CeO2 films with high in-plane and out-of-plane alignments (Δφ=5.54°, Δω=3.40°) were obtained under optimum condition.

Enhanced deposition of cubic boron nitride films on roughened silicon and tungsten carbide–cobalt surfaces

We report the influence of substrate surface roughness on cubic boron nitride (cBN) film deposition under low-energy ion bombardment in an inductively coupled plasma. Silicon and cemented tungsten carbide–cobalt (WC–Co) surfaces are roughened by low-energy ion-assisted etching in a hydrogen plasma, followed by deposition in a fluorine-containing plasma. Infrared absorption coefficients are measured to be 22,000cm−1 and 17,000cm−1 for sp2-bonded BN and cBN phases, respectively, for our films. For the silicon substrates, the film growth rate and the cBN content in the film increase with increasing the surface roughness, while the amount of sp2BN phase in the film shows only a small increase. A larger surface roughness of the substrate results in a smaller contact angle of water, indicating that a higher surface free energy of the substrate contributes to enhancing growth of the cBN film. For the WC–Co substrates, the film growth rate and the cBN content in the film increase similarly by roughening the surface.

The influence of substrate surface roughness on microstrip transmission line loss using conventional analyses and length‐scale fractal analysis

AbstractTwo components of conductor topography can impact conductor loss for signals in the GHz frequency range: conductor–ceramic interface roughness and conductor edge angle. This study is an experimental investigation of the influence of these conductor topographies on conductor loss in microstrip circuits produced by thick‐film technology. The aluminum nitride ceramic substrates have different surface roughnesses due to different surface finish processes. The substrate surfaces were characterized using conventional and length‐scale fractal analysis. The conductor–ceramic interface was measured with a contact profilometer. The conductor edge angle and conductor edge profile were measured optically. It was found that there is a direct correlation between conductor loss and conductor edge angle, whereas there is an inverse correlation between loss and substrate roughness or relative length of the conductor–ceramic interface. This is the opposite result to the conventional expectation of surface roughness effects on conductor loss. There is also a negative correlation between conductor edge angle and surface roughness or relative length. The loss behavior can be explained by the interaction of the conductor paste with the surfaces during processing. The paste tends to spread more on the smoother surfaces, and thus creates an elongated edge of diminishing cross‐section and a small edge angle. This leads to greater conductor loss. Copyright © 2009 John Wiley & Sons, Ltd.

Influence of substrate topography on the growth and magnetic properties of obliquely deposited amorphous nanocolumns of Fe–Ni

We investigated the influence of substrate surface roughness on the structural and magnetic properties of obliquely deposited amorphous nanocolumns of Fe–Ni. Experiments showed that the surface roughness of the substrate greatly determines the morphology of the columnar structures and this in turn has a profound influence on the magnetic properties. Nucleation of Fe–Ni nanocolumns on a smooth silicon substrate was at random, while that on a rough glass substrate was defined by the irregularities on the substrate surface. It has been found that magnetic interaction between the nanocolumns prepared on a silicon substrate was due to their small inter-column separation. Well separated nanocolumns on a glass substrate resulted in exchange isolated magnetic domains. The size, shape and the distribution of nanocolumns can be tailored by appropriately choosing the surface roughness of the substrate. This will find potential applications in thin film magnetism.

Ge growth on self-affine fractal Si surfaces: influence of surface roughness

We have studied the influence of substrate surface roughness on the growth of Ge on self-affine fractal Si surfaces. Self-affine fractal surfaces can be prepared by irradiating surfaces of solid materials with an energetic ion beam, which modifies the surface morphology predominantly via an erosion process. By tuning the ion beam energy, surface parameters such as surface roughness (σ0) and correlation length (ξ), can be controlled. Values of σ0 and σ0/ξ affect the effective free energy of the surface. When materials are grown on surfaces with different values of surface roughness parameters, the morphology of the deposited layer is expected to be influenced. In comparison with an earlier study where 2 MeV Si ion irradiation was used, we have produced surfaces with larger values of σ0 and σ0/ξ by irradiating the surfaces with 45 keV Si ions. We have made a comparison for Ge growth on Si surfaces irradiated with 2 MeV and 45 keV Si ions and have observed remarkably different growth behaviour. Upon Ge deposition, in the former case, the surface roughness decreases at smaller length scales and remains practically unchanged at larger length scales. This indicates that Ge has grown preferentially within the valleys of the rough surface. In the latter case, where σ0 is large and ξ is small on the substrate surface, the roughness increases at all length scales by almost a factor of 2, upon Ge deposition, indicating the lack of preferential growth within the surface valleys. Following Ge deposition, in the former case the roughness exponent increases from 0.82 to 0.99, while in the latter case it remains practically unchanged (∼0.83). Roughness parameters of the substrate surface are found to have a significant influence on the morphology of the overlayers.

An investigation of the effect of surface roughness and coating thickness on the friction and wear behaviour of a commercial MoS 2–metal coating on AISI 400C steel

The objective of the present experimental work was to investigate the influence of substrate surface roughness and coating thickness on the friction and wear behaviour of AISI 440C steel-coated with MoST under pure sliding with oil lubrication. An AISI 52100 bearing steel ball was slid at 0.5 m/s against the coated steel disc using an applied normal load of 50 N. This gave a mean Hertzian pressure of 0.75 GPa. Friction and wear maps were constructed from the experimental data. Wear resistance was greatest when a coating thickness of 1 μm was used and when the substrate surface roughness (Ra) was 0.1 μm or below.

Porosity of Electroless Nickel Coatings Investigated Using Different Porosity Tests and Their Application

SummaryThe porosity of electroless nickel coatings on mild steel substrates having different substrate surface roughness and coating thickness was investigated using NSS (Neutral Salt Spray), ferroxyl, and SO2 tests. In addition the influence of substrate surface roughness and coating thickness upon the properties of electroless nickel coatings was studied.It was found that all porosity tests showed the same tendency for the porosity of electroless nickel coatings to decrease with decreasing substrate surface roughness and increasing coating thickness. The use of the SO2 and ferroxyl test have the advantage over the NSS test as a routine quality control procedure in that they are both quicker to carry out and easier to interpret. A relationship between porosity, substrate surface roughness and coating thickness was established which might be used as an industrial quality control tool.

35. Ion and plasma etching

We report the influence of substrate surface roughness on cubic boron nitride (cBN) film deposition under low-energy ion bombardment in an inductively coupled plasma. Silicon and cemented tungsten carbide–cobalt (WC–Co) surfaces are roughened by low-energy ion-assisted etching in a hydrogen plasma, followed by deposition in a fluorine-containing plasma. Infrared absorption coefficients are measured to be 22,000 cm−1 and 17,000 cm−1 for sp2-bonded BN and cBN phases, respectively, for our films. For the silicon substrates, the film growth rate and the cBN content in the film increase with increasing the surface roughness, while the amount of sp2BN phase in the film shows only a small increase. A larger surface roughness of the substrate results in a smaller contact angle of water, indicating that a higher surface free energy of the substrate contributes to enhancing growth of the cBN film. For the WC–Co substrates, the film growth rate and the cBN content in the film increase similarly by roughening the surface.