Theoretical modeling for laser cleaning of micro-particles from solid surface

1997 ◽  
Vol 501 ◽  
Author(s):  
Y. F. Lu ◽  
W. D. Song ◽  
M. H. Hong ◽  
D. S. H. Chan ◽  
T. S. Low
Keyword(s):  
Thermal Expansion ◽  
Solid Surface ◽  
Adhesion Force ◽  
Substrate Surface ◽  
Substrate Material ◽  
Laser Wavelength ◽  
Laser Cleaning ◽  
Micro Particles ◽  
Theoretical Predictions ◽  
Substrate Surfaces

ABSTRACTIn laser cleaning of micro-particles from solid surface, the adhesion force between the particles and the substrate surface and the thermal expansion of both particles and substrate play important roles in determining the threshold laser fluence. Taking Van der Waals force and cleaning force due to fast thermal expansion of particles and substrate surface induced by pulsed laser irradiation into account, a cleaning model was established for removal of tiny particles from substrate surfaces. The cleaning condition and cleaning threshold can be obtained from this model. This model can qualitatively and quantitatively predict how the laser cleaning process depending on laser incident direction, laser wavelength, particle size, particle material and substrate material. Theoretical predictions have been verified by the experimental results. Laser cleaning of micro-particle has wide applications in microelectronics and magnetic recording industries.

Laser cleaning of micro-particles from a solid surface — theory and applications

1998 ◽  
Vol 54 (1-3) ◽  
pp. 181-185 ◽  
Author(s):  
Yong-Feng Lu ◽  
Wen-Dong Song ◽  
Teck-Seng Low
Keyword(s):  
Solid Surface ◽  
Laser Cleaning ◽  
Surface Theory ◽  
Micro Particles

A Theoretical Model for Steam Laser Cleaning

1998 ◽  
Vol 526 ◽  
Author(s):  
Y. F. Lu ◽  
Y. Zhang ◽  
W. D. Song ◽  
T. S. Low
Keyword(s):  
Theoretical Model ◽  
Liquid Film ◽  
Solid Surface ◽  
Laser Fluence ◽  
Adhesion Force ◽  
Thin Liquid Film ◽  
Laser Cleaning ◽  
Superheated Liquid ◽  
Cleaning Efficiency ◽  
The Difference

AbstractA theoretical model for removal of tiny particles from solid surface covered with a thin liquid film by laser cleaning is established by taking adhesion force and cleaning force into account. When pulsed laser irradiates on the solid surface coated with a thin liquid film, a sheet of liquid near the liquid/substrate interface can be superheated through thermal diffusion. The rapid growth of vapor bubbles inside the superheated liquid can generate transient stress wave with high pressure, large enough to expel micron and sub-micron particles from the contaminated surface. By calculating the adhesion force and cleaning force, the cleaning threshold of laser fluence can be predicted from this theoretical model. The difference between cleaning force and adhesion force increases quickly along with the laser fluence and leads to higher cleaning efficiency.

Self-Assembled Nanostructures on VSe2Surfaces Induced by Cu Deposition

2005 ◽  
Vol 11 (5) ◽  
pp. 456-471 ◽  
Author(s):  
Erdmann Spiecker ◽  
Stefan Hollensteiner ◽  
Wolfgang Jäger ◽  
Hans Haselier ◽  
Herbert Schroeder
Keyword(s):  
Electron Microscopy ◽  
Substrate Surface ◽  
Intercalation Compound ◽  
Electron Beam Evaporation ◽  
Substrate Material ◽  
Electronic Charge ◽  
Lateral Dimension ◽  
Cu Nanowires ◽  
Roof Structure ◽  
Substrate Surfaces

Analytical transmission electron microscopy (TEM) and scanning electron microscopy (SEM) have been applied for the characterization of evolution, lateral arrangements, orientations, and the microscopic nature of nanostructures formed during the early stages of ultrahigh vacuum electron beam evaporation of Cu onto surfaces of VSe2layered crystals. Linear nanostructure of relatively large lateral dimension (100–500 nm) and networks of smaller nanostructures (lateral dimension: 15–30 nm; mesh sizes: 500–2000 nm) are subsequently formed on the substrate surfaces. Both types of nanostructures are not Cu nanowires but are composed of two strands of crystalline substrate material elevating above the substrate surface. For the large nanostructures a symmetric roof structure with an inclination angle of ∼30° with respect to the substrate surface could be deduced from detailed diffraction contrast experiments. In addition to the nanostructure networks a thin layer of a Cu-VSe2intercalation phase of 3R polytype is observed at the substrate surface. A dense network of interface dislocations indicates that the phase formation is accompanied by in-plane strain. We present a model that explains the formation of large and small nanostructures as consequences of compressive layer strains that are relaxed by the formation of rooflike nanostructures, finally evolving into the observed networks with increasing deposition time. The dominating contributions to the compressive layer strains are considered to be an electronic charge transfer from the Cu adsorbate to the substrate and the formation of a Cu-VSe2intercalation compound in a thin surface layer.

Composite intermediate layer for CVD diamond film on steel substrate

MRS Advances ◽  
2017 ◽  
Vol 2 (41) ◽  
pp. 2211-2216 ◽  
Author(s):  
Andre Contin ◽  
Getúlio de Vasconcelos ◽  
Djoille D. Damm ◽  
Vladimir J. Trava-Airoldi ◽  
Raonei A. Campos ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Diamond Film ◽  
Steel Substrate ◽  
Substrate Surface ◽  
Composite Layer ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Substrate Material ◽  
Film Deposition ◽  
Carbon Solubility

ABSTRACTThe union of the unique diamond properties with steel (most common substrate material) provides a new solution for machine parts under critical mechanical conditions and severe environmental. However, CVD diamond coating directly on steel comes with several issues. The fundamental reasons for the lack of adhesion are an iron catalytic effect, the high carbon solubility in iron and high mismatch in thermal expansion coefficient of diamond and steel. The use of interlayer may solve these issues acting as a diffusion barrier, for both iron and carbon, and match thermal expansion coefficients. Several articles describe the PVD deposition or electroplated interlayer. In the present study, the diamond film coated steel with an intermediate barrier deposited by laser cladding process. In this novel technique, laser irradiation melts the powder (preplaced) and the substrate surface to create the coating on a steel substrate. We used the SiC/Ti and SiC/Cu powder mixtures to create the intermediate barrier. Diamond film deposition was carried out in an HFCVD reactor (Hot Filament Chemical Vapor Deposition). The samples characterization included X-ray Diffraction (XRD); Field Emission Gun - Scanning Electron Microscopy (FEG-SEM) and Raman Scattering Spectroscopy (RSS). Results showed that laser incidence dissociated partially the SiC powder, forming FeSi, Cu3Si phases. Further, the composite layer assisted the high thermal stress relief in steel/diamond interface.

Recent Progress On The Modeling Of Laser Surface Cleaning

2000 ◽  
Vol 617 ◽  
Author(s):  
Y.F. Lu ◽  
W. D. Song ◽  
B.S. Lukyanchuk ◽  
M.H. Hong ◽  
W.Y. Zheng
Keyword(s):  
Recent Progress ◽  
Substrate Surface ◽  
Near Field ◽  
Surface Cleaning ◽  
Laser Cleaning ◽  
Cleaning Efficiency ◽  
Optical Resonance ◽  
Near Field Effect ◽  
Substrate Surfaces

AbstractLaser cleaning has emerged to effectively remove contaminants from solid surfaces. In this paper, recent progress on laser cleaning has been studied. First, a cleaning model is established for removal of particles from substrate surfaces. The model not only explains the influence of fluence on cleaning efficiency, but also predicts the cleaning thresholds. Following that, the optical resonance and near field effect are discussed for transparent particles with a size of α ∼ λ (radiation wavelength) which strongly influences the intensity distribution in the contacted area (substrate surface). The characterization of ejected particles during laser cleaning is finally investigated. It is found that the particle distribution curves closely fit to Gaussian curve.

Morphologies of Nonadherent Al2O3 and Matching Substrate Surfaces

1972 ◽  
Vol 30 ◽  
pp. 524-525
Author(s):  
C. S. Giggins ◽  
J. K. Tien ◽  
B. H. Kear ◽  
F. S. Pettit
Keyword(s):  
Electron Microscopy ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Substrate Surface ◽  
Morphological Features ◽  
Thermally Induced ◽  
Oxide Spallation ◽  
Oxidation Resistant ◽  
Induced Stresses ◽  
Substrate Surfaces

The performance of most oxidation resistant alloys and coatings is markedly improved if the oxide scale strongly adheres to the substrate surface. Consequently, in order to develop alloys and coatings with improved oxidation resistance, it has become necessary to determine the conditions that lead to spallation of oxides from the surfaces of alloys. In what follows, the morphological features of nonadherent Al2O3, and the substrate surfaces from which the Al2O3 has spalled, are presented and related to oxide spallation.The Al2O3, scales were developed by oxidizing Fe-25Cr-4Al (w/o) and Ni-rich Ni3 (Al,Ta) alloys in air at 1200°C. These scales spalled from their substrates upon cooling as a result of thermally induced stresses. The scales and the alloy substrate surfaces were then examined by scanning and replication electron microscopy.The Al2O3, scales from the Fe-Cr-Al contained filamentary protrusions at the oxide-gas interface, Fig. 1(a). In addition, nodules of oxide have been developed such that cavities were formed between the oxide and the substrate, Fig. 1(a).

Fast forced liquid film spreading on a substrate: flow, heat transfer and phase transition

2010 ◽  
Vol 656 ◽  
pp. 189-204 ◽  
Author(s):  
ILIA V. ROISMAN
Keyword(s):  
Heat Transfer ◽  
Phase Transition ◽  
Stokes Equations ◽  
Substrate Surface ◽  
Reynolds Numbers ◽  
Drop Impact ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Theoretical Predictions ◽  
Viscous Drop

This theoretical study is devoted to description of fluid flow and heat transfer in a spreading viscous drop with phase transition. A similarity solution for the combined full Navier–Stokes equations and energy equation for the expanding lamella generated by drop impact is obtained for a general case of oblique drop impact with high Weber and Reynolds numbers. The theory is applicable to the analysis of the phenomena of drop solidification, target melting and film boiling. The theoretical predictions for the contact temperature at the substrate surface agree well with the existing experimental data.

scholarly journals Tunable Adhesion of a Bio-Inspired Micropillar Arrayed Surface Actuated by a Magnetic Field

2018 ◽  
Vol 86 (1) ◽  
Author(s):  
Xingji Li ◽  
Zhilong Peng ◽  
Yazheng Yang ◽  
Shaohua Chen
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Rotation Angle ◽  
Adhesion Force ◽  
Practical Applications ◽  
Section Shape ◽  
Theoretical Predictions ◽  
Large Elastic Deformation ◽  
The Difference

Bio-inspired functional surfaces attract many research interests due to the promising applications. In this paper, tunable adhesion of a bio-inspired micropillar arrayed surface actuated by a magnetic field is investigated theoretically in order to disclose the mechanical mechanism of changeable adhesion and the influencing factors. Each polydimethylsiloxane (PDMS) micropillar reinforced by uniformly distributed magnetic particles is assumed to be a cantilever beam. The beam's large elastic deformation is obtained under an externally magnetic field. Specially, the rotation angle of the pillar's end is predicted, which shows an essential effect on the changeable adhesion of the micropillar arrayed surface. The larger the strength of the applied magnetic field, the larger the rotation angle of the pillar's end will be, yielding a decreasing adhesion force of the micropillar arrayed surface. The difference of adhesion force tuned by the applied magnetic field can be a few orders of magnitude, which leads to controllable adhesion of such a micropillar arrayed surface. Influences of each pillar's cross section shape, size, intervals between neighboring pillars, and the distribution pattern on the adhesion force are further analyzed. The theoretical predictions are qualitatively well consistent with the experimental measurements. The present theoretical results should be helpful not only for the understanding of mechanical mechanism of tunable adhesion of micropillar arrayed surface under a magnetic field but also for further precise and optimal design of such an adhesion-controllable bio-inspired surface in future practical applications.

Determination of Spread Activation Energy and Assessment of Wetting Behavior of Solders on Metallic Substrates

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
K. N. Prabhu ◽  
G. Kumar
Keyword(s):  
Surface Roughness ◽  
Operating Temperature ◽  
Substrate Surface ◽  
Substrate Material ◽  
Metallic Substrates ◽  
Wetting Behavior ◽  
Substrate Surface Roughness ◽  
Exponential Power ◽  
Kinetics Of

The effects of substrate material, substrate surface roughness, and operating temperature on the wetting behavior of Sn–37Pb, Sn–3.5Ag, and Sn–9Zn eutectic solders on metallic substrates were investigated. Solder spreading kinetics was successfully represented by the exponential power law (EPL): ϕ=exp(−Kτn). The EPL parameter K has the significance of accelerating the kinetics of relaxation while the parameter n represents the resistance to spreading process (spread resistance parameter). EPL parameters exhibited a decreasing trend with an increase in surface roughness. Estimated activation energies for solder spreading were found to be in between those reported for inert and highly reactive spreading systems.

Asymmetric Cracking in Znse/ZnSxSel−x Superlattices Grown by Molecular Bean Epitaxy

1987 ◽  
Vol 102 ◽  
Author(s):  
Richard J. Dalby ◽  
John Petruzzello
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thermal Expansion ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Lattice Mismatch ◽  
Sulfur Concentration ◽  
Transmission Electron ◽  
Theoretical Predictions ◽  
Superlattice Layer

ABSTRACTOptical and transmission electron microscopy have been used to study cracks appearing in ZnSe/ZnSxSe1−x (x ∼ 0.38) superlattices grown by Molecular Beam Epitaxy. It Is shown that when a fracture occurs it is confined, in most cases, to the superlattice and propagates along <011> cleavage directions in these <001> oriented epilayers. Cracks were not observed in all superlattices and their onset is discussed in relation to sulfur concentration, overall superlattice height, individual superlattice layer thicknesses, and stress, tensile or compressive, due to lattice mismatch and thermal expansion differences between buffer layer and superlattice. It was found that by adjusting the controllable parameters, cracks in the superlattices could be eliminated. Orientation and density of these features have been related to asynnmetric cracking associated with the zincblende structure of these II-VI materials. Experimental results are shown to be in agreement with theoretical predictions of critical heights for the onset of cracking.

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