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    Effect of Diamond-Like-Carbon Coating on 3D Surface Roughness
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    Abstract:
    Companies that coat their products with DLC often have strict surface roughness goals. This research investigates the surface roughness properties of uncoated and DLC coated specimens in an effort to know what uncoated surface roughness is needed to obtain a certain DLC coated surface roughness. Therefore, a model describing the relationship between uncoated and DLC coated surface roughness is needed. If this relationship can be estimated, the cost of surface finishing can be minimized by avoiding any unnecessary processes. A total of 7 specimens were tested before and after coating process with a non-contact surface roughness measurement microscope. Mathematical relationships are found between the DLC coated surface roughness and uncoated surface roughness. An experimental methodology was described for applying the findings to other coating methods and materials as the mathematical relationships found in this study are specific to the coating process and materials used.
    Keywords:
    Diamond-like carbon
    Companies that coat their products with DLC often have strict surface roughness goals. This research investigates the surface roughness properties of uncoated and DLC coated specimens in an effort to know what uncoated surface roughness is needed to obtain a certain DLC coated surface roughness. Therefore, a model describing the relationship between uncoated and DLC coated surface roughness is needed. If this relationship can be estimated, the cost of surface finishing can be minimized by avoiding any unnecessary processes. A total of 7 specimens were tested before and after coating process with a non-contact surface roughness measurement microscope. Mathematical relationships are found between the DLC coated surface roughness and uncoated surface roughness. An experimental methodology was described for applying the findings to other coating methods and materials as the mathematical relationships found in this study are specific to the coating process and materials used.
    Diamond-like carbon
    Citations (0)
    Summary Surface roughness is an essential rock parameter affecting petrophysical properties that are surface sensitive such as characterization of pore structure and wettability. For instance, Wenzel’s contact angle formula for rough surfaces requires knowledge of the surface roughness, and surface roughness is expected to speed up the aging of cores in crude oil for wettability restoration. In addition, proper quantification of surface roughness is critical for obtaining representative, roughness-independent, pore sizes for applications such as prediction of permeability and interpretation of capillary pressure curves. Intuitively, a surface is better characterized in 2D than in 1D. This 2D study is a continuation and enhancement of the previous 1D work, recently published in the SPE Journal (Ma et al. 2021). In this current paper, a comprehensive investigation of 1D vs. 2D surface roughness measurements is conducted to evaluate and cross validate the two approaches. In this study, surface roughness is measured on 26 carbonate rock samples by laser scanning confocal microscopy (LSCM), where both the 1D absolute increment surface roughness, Sr, and the 2D interfacial area ratio of surface roughness, Sdr, are reported. As expected, the results indicate that surface roughness characterized by 2D Sdr has a greater dynamic range than the 1D Sr measurement, i.e., the 2D Sdr provides a more representative characterization of surface roughness. A detailed account of methodologies, assumptions, limitations, validation, and applications of the 1D and 2D surface roughness characterization is documented in this paper. To extract the roughness features present on rock grain surfaces, effects of de-spiking and filter length, used to eliminate pore-size effects, are investigated. For specific applications of surface roughness corrected pore-size estimation from nuclear magnetic resonance (NMR) measurements, differences in length scales of surface roughness are compared between LSCM measurement and that derived from NMR diffusion-T2 plus BET (Brunauer-Emmett-Teller) surface area. The surface roughness-corrected NMR pore-size distribution is also validated against the pore-size distribution obtained from the measurement of micro-computed tomography (CT) scanning.
    Petrophysics
    Characterization
    Capillary pressure
    Citations (4)
    Though superliquid-repelling surfaces are universally important in the fields of fundamental research and industrial production, the understanding and development of these surfaces to impacting liquid droplets remain elusive, especially the changes of wettability states. Surface roughness is required to obtain superliquid-repelling surfaces. However, the effect of surface roughness on the transition of these surfaces' wettability states is uncertain. Herein, we unveiled the relationship of surface roughness on regulating the wettability states of superliquid-repelling surfaces with randomly distributed rough structures through experiment and calculations. The roughness was controlled via regulating the size of surface rough structures, which were formed by a facile coating method. The results indicated that the surface rough structures could impact the value of the polar component (γsp) and then impact the wettability states of superliquid-repelling surfaces. Quantitatively, when the increment of surface roughness was low, the decrement of γsp was low and the wettability state of the superliquid-repelling surface was superhydrophobicity. When the increment of surface roughness was high, the decrement of γsp was high and the wettability state of the superliquid-repelling surface converted to superamphiphobicity. The findings will shed light onto the development of superliquid-repelling surfaces in future studies.
    Wetting transition
    Surface roughness of part was vital to its application.40Cr material was irradiated by large scale pulse electron beam with orthogonal experiment and the surface roughness was checked.The results indicate that the surface roughness of 40Cr is changed by different electron beam parameters.Surface roughness of part increases or decreases in terms of electron beam parameter.The samples with high and low surface roughness are tested with electron beam respectively.The results show that the surface roughness decreases with irradiation numbers increasing in high original surface roughness,contrary surface roughness increases with irradiation numbers increasing in low original surface roughness.It is analysed that the surface roughness is influenced in two opposite sidedness when it is modified on the surface with pulsed electron beam.
    Electron beam processing
    Citations (0)
    Abstract Surface light scattering enables contactless and fast measurements of surface roughness. A surface inclination alters the direction of the scattering beam and thus the measured surface roughness is calculated from the detected intensity distribution. Hence, an accurate sensor–surface alignment is necessary. In order to achieve tilt-independent roughness measurements, a model-based evaluation approach for polychromatic speckle patterns is presented. By evaluating the shape of the superposed speckles, which occur for polychromatic illumination, with regard to the distance to the scattering centre, surfaces with an Sa roughness value in the range of 0.8–3.2 μm are measurable. Experimental investigations demonstrate that the influence of a surface tilt up to ± 1.25° on the roughness measurement is reduced by 90%. As a result, the robustness of the polychromatic speckle roughness measurement is improved, which allows to speed up the adjustment of the measurement system or the surface sample, respectively.
    Robustness
    Citations (15)
    The influence of surface roughness on performance of machinery parts and assessment principle of surface roughness were summarized. Several surface roughness measurement methods were described. Attentions were paid to surface roughness measurement by profilometer.
    Surface Metrology
    Citations (0)
    The following topics are dealt with: filled polymers; permittivity; electric breakdown; space charge; resins; power cable insulation; ageing; nanocomposites; partial discharges; XLPE insulation.
    Dielectric strength
    Electric breakdown
    Electrical treeing
    Insulation system
    Abstract Surface roughness is an essential rock parameter affecting petrophysical properties that are surface sensitive such as characterization of pore structure and wettability. For instance, Wenzel's contact angle formula for rough surfaces requires knowledge of the surface roughness, and surface roughness is expected to speed up aging of cores in crude oil for wettability restoration. In addition, proper quantification of surface roughness is critical for obtaining representative, roughness-independent, pore sizes for applications such as prediction of permeability and interpretation of capillary pressure curves. Intuitively, a surface is better characterized in 2D than in 1D. This 2D study is a continuation and enhancement of the previous 1D work, recently published in the SPE Journal (Ma et al., 2021). In this current paper, a comprehensive investigation of 1D versus 2D surface roughness measurements is conducted to evaluate and cross validate the two approaches. In this study, surface roughness is measured on 26 carbonate rock samples by laser scanning confocal microscopy (LSCM), where both the 1D absolute increment surface roughness, Sr, as well as 2D interfacial area ratio of surface roughness, Sdr, are reported. As expected, results indicate that surface roughness characterized by 2D Sdr has a greater dynamic range than the 1D Sr measurement, i.e., the 2D Sdr provides a more representative characterization of surface roughness. A detailed account of methodologies, assumptions, limitations, validation and applications of the 1D and 2D surface roughness characterization is documented in this paper. To extract the roughness features present on rock grain surfaces, effects of de-spiking and filter length, used to eliminate pore size effects, are investigated. For specific applications of surface roughness corrected pore size estimation from nuclear magnetic resonance (NMR) measurements, differences in length-scales of surface roughness are compared between LSCM measurement and that derived from NMR diffusion-T2 plus BET surface area. The surface roughness-corrected NMR pore-size distribution is also validated against the pore-size distribution obtained from measurement of micro-CT scanning.
    Petrophysics
    Characterization
    Citations (2)