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Dissertations / Theses on the topic 'Coating processes'

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Published: 4 June 2021
Last updated: 30 July 2024

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1

Eckermann, Jurgen. "Optimising high speed coating processes." Thesis, Swansea University, 2012. https://cronfa.swan.ac.uk/Record/cronfa42471.

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The coil coating process of strip steel is a continuous and highly automated process in which the aim is to apply a paint layer of uniform thickness onto metal sheet at high operational speed. However, the performance of the coil coating process has been limited due to the occurrence of coating defects, such as ribbing and fat edges, which leads ultimately to a reduction in the operational speed of coating. Therefore, in order to enhance coating productivity, the complex flow behaviour of commercial paints needs to be fully understood. Consequently, the main objective of this work was to obtain rheological parameters for the commercial paints using rotational Rheometers, Capillary Break-up Rheometer and Capillary Extrusion Rheometer to allow the characterisation of the complex flow behaviour. This research project was tailored over its course to generate a solid knowledge foundation of the rheological properties of polyester resin based paints prior to the defining of different experimental procedures so as to guarantee the reproducibility of the data measured with various Rheometers. Once these rheological characteristics were fully understood for one paint, the project was moved forward by selecting other commercially available paints which were similarly analysed to allow a comparison of the various rheological behaviours. One key finding was that the commercial paints behaved in either a Newtonian or a Non Newtonian fashion. The Non Newtonian paints possessed a high internal microstructure which was reflected in the degree of elasticity exhibited, whereas the Newtonian paint did not seem to exhibit any elasticity. Furthermore, a mutual, ideal operability window for the Capillary Break up Rheometer could be derived from data which was systematically collected by varying the input parameters including opening time, stretch profile and Hencky strain. Capillary Extrusion Rheometer provided extensional and shear information at very high strain rates. At the end, a steady state flow curve for both shear and extensional viscosity could be determined for a strain rate range of 10-1 to 5 x 104, which is unique for the polyester resin based paints analysed in this work.
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2

Chen, Desong. "Modelling and control of zinc coating." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314906.

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3

Carter, G. C. "The modelling and analysis of coating processes." Thesis, University of Leeds, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355375.

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4

Rowe, Charles William. "Bulk coating processes with sodium silicate slurries." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10604.

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5

Popescu, Catalin Nicolae. "Modeling and control of extrusion coating." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/13700.

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6

Pandey, Preetanshu. "Studies to investigate variables affecting coating uniformity in a pan coating device." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4469.

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Thesis (Ph. D.)--West Virginia University, 2006.
Title from document title page. Document formatted into pages; contains xiv, 122 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 107-116).
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7

Ehiasarian, Arutiun Papken. "Development of PVD coating processes informed by plasma diagnostics." Thesis, Sheffield Hallam University, 2002. http://shura.shu.ac.uk/19603/.

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Physical vapour deposition technologies have been on the fast track of development for the last two decades due to their ability to meet demands for special materials and performance tools. The ever increasing complexity of the required coating microstructure and chemical composition can be achieved only by the development of PVD technology and in particular plasma sources for vapour generation that can provide the necessary tools. This thesis describes plasma diagnostic studies of plasma discharges, developments of plasma sources and deposition of CrN coatings. Initially the project investigated vacuum arc plasma discharges used in the Hauzer HTC1000/ABS industrially sized coater. The attention was concentrated to the plasma pretreatment by low energy (1200 - 3600 eV) Cr ion implantation into substrates, which contributed to an enhanced adhesion of subsequently deposited TiAIN coatings. Optical emission spectroscopy (OES), electrostatic probes, and time-of-flight (TOF) spectroscopy were used to study the interactions of the arc plasma with the gas atmosphere in the chamber. It was shown that increasing the pressure of Ar gas had a strong effect on the composition of the generated metal ion flux as the density of highly charged metal species reduced significantly to the benefit of gas ionisation. The mechanisms behind these observations are discussed and supported by further experiments. Based on the plasma diagnostic results, a novel two-stage pretreatment method was developed which allowed an enhanced adhesion due to faster sputter cleaning of the substrate surface and more efficient metal ion incorporation in the substrate material. In the final stages of the project a novel high power pulsed magnetron sputtering (HIPIMS) process utilising peak power densities of 3000 Wcm[-2] was investigated. OES studies showed the first evidence of doubly charged Cr and Ti ions generated by the HIPIMS discharge. Peak plasma densities of 10[13] cm[-3] were measured and, in the case of Cr, metal ions were found to constitute 30% of the total deposition flux to substrates. The influence of power on the plasma density, plasma composition and time evolution of the plasma was studied in detail using OES and electrostatic probes. The conditions for glow-to-arc transition were investigated. CrN coatings (thickness 2 mum) were deposited for the first time using HIPIMS of Cr in a nitrogen atmosphere. The microstructure observed in transmission electron microscopy cross sections was highly dense and droplet free and contributed to an excellent corrosion and wear resistance superior to 20 mum thick electroplated hard Cr, and CrN coatings deposited by arc and unbalanced magnetron sputtering. The HIPIMS discharge was used also for pretreatment of substrates with metal ions analogous to the one performed previously with arc discharge. High adhesion was achieved as indicated by the scratch test critical load value Lc = 85 N.Finally, at an intermediate stage of the PhD project, an alternative source providing metal ionisation was studied. It was based on a radio frequency (RF) powered coil that was inductively coupled to a magnetron sputtering discharge. Energy resolved mass spectroscopy and OES in a laboratory-sized version of the plasma source revealed elevated metal ion densities and high ion energies of the order of 60 eV. This source was upscaled, installed, and tested successfully in the industrially sized Hauzer coater. The ion-to-neutral ratio at the substrate position could be increased 5-fold for a similar increase in RF power.
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8

Mathers, Philip. "The effect of acoustic standing waves on vacuum coating technology." Thesis, Cranfield University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263535.

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9

Sudsakorn, Kandis. "The effect of particle size on the amount of coating received during a batch fluidized bed coating operation." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=612.

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Thesis (M.S.)--West Virginia University, 1999.
Title from document title page. Document formatted into pages; contains x, 98 p. : ill. (some col.) Includes abstract. Includes bibliographical references (p. 63-68).
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10

Pallay, Krista Joy. "Surface Modifications to Mitigate Refractory Degradation in High-Temperature Black Liquor Gasifiers." Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10488.

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Ceria (CeO2), chromia (Cr2O3), yttria-stabilized zirconia (Y2O3-ZrO2), and sodium cerium oxide (Na2CeO3) were used as barrier coatings on Ufala, an alumina-based ceramic refractory, to determine if they were effective at increasing the life of the refractory in a high-temperature black liquor gasification environment. The ceria, chromia, and yttria-stabilized zirconia coatings were applied at atmospheric pressure using a coating applicator at the Institute of Paper Science and Technology at the Georgia Institute of Technology. The sodium cerium oxide coatings in addition to the three other coating types were applied under atmospheric pressure at C3 International Technologies in Alpharetta, GA. The coated refractory, as well as a set of uncoated refractory used for baseline analysis, were tested using molten synthetic smelt at 1000C for 36 hours. Uncoated refractory samples were also tested for 12, 72, 120, and 168 hours in order to make a kinetic reaction rate determination. The refractory were analyzed using gravimetric and dimensional analysis, X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy to determine the severity of the physical changes that occurred after exposure to molten smelt. The data gathered from these experiments were not able to conclude that barrier coatings are sufficient to impede corrosion of the Ufala refractory material in molten smelt.
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11

Jiba, Zetu. "Coating processes towards selective laser sintering of energetic material composites." Diss., University of Pretoria, 2019. http://hdl.handle.net/2263/79246.

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This research aims to contribute to the safe methodology for additive manufacturing (AM) of energetic materials. Coating formulation processes were investigated to find a suitable method that may enable selective laser sintering (SLS) as the safe method for fabrication of high explosive (HE) compositions. For safety and convenience reasons, the concept demonstration was conducted using inert explosive simulants with properties quasi-similar to the real HE. Coating processes for simulant RDX-based microparticles by means of PCL and 3,4,5- trimethoxybenzaldehyde (as TNT simulant) are reported. These processes were evaluated for uniformity of coating the HE inert simulant particles with binder materials to facilitate the SLS as the adequate binding and fabrication method. The critical constraints being the coating effectiveness required, spherical particle morphology, micron size range (>20 μm) and a good powder deposition and flow, and performance under SLS to make the method applicable for HEs. Of the coating processes investigated, suspension system and single emulsion methods gave required particle near spherical morphology, size and uniform coating. The suspension process appears to be suitable for the SLS of HE mocks and potential formulation methods for active HE composites. The density was estimated to be comparable with the current HE compositions and plastic bonded explosives (PBXs) such as C4 and PE4, produced from traditional methods. The formulation method developed and the understanding of the science behind the processes paves the way toward safe SLS of the active HE compositions and may open avenues for further research and development of munitions of the future.
Dissertation (MSc)--University of Pretoria, 2019.
Chemical Technology
MSc
Unrestricted
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12

Pajkić, Željko. "Atmospheric pressure microwave plasma assisted coating processes for particulate materials /." Aachen : Shaker, 2009. http://d-nb.info/993180701/04.

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13

Ku, Shaari Ku Zilati. "Coating uniformity on a pharmaceutical tablet an experimental study and finite volume modeling of droplet impact behavior /." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5528.

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Thesis (Ph. D.)--West Virginia University, 2007.
Title from document title page. Document formatted into pages; contains xv, 141 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 132-135).
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14

Sandadi, Sandeepa. "In-situ, near real-time acquisition of particle movement in rotating drum coating equipment." Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=2759.

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Thesis (M.S.)--West Virginia University, 2003.
Title from document title page. Document formatted into pages; contains xiii, 137 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 101-103).
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15

Mitchell, K. "The scale-up, modelling and optimisation of aqueous film coating processes." Thesis, University of Bradford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503590.

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16

Galhenage, Teluka Pasan. "Surface Optimization of Siloxane-Polyurethane Marine Coatings for Improved Fouling-Release Properties." Diss., North Dakota State University, 2016. https://hdl.handle.net/10365/29092.

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Biofouling has been an economically and environmentally costly problem to mankind ever since they set sail. Biofouling causes frictional drag leading to slow vessel speeds, and increased fuel costs. Antifouling (AF) coatings containing biocides have been used for decades, however, since some biocides have shown undesired effects towards the environment, a non-toxic solution to combat fouling is desired. Subsequently, fouling release (FR) coatings quickly gained acceptance as a non-toxic approach to contend with biofouling. Unlike AF coatings, FR coatings not necessarily prevent settlement of organisms, they permit weak adhesion which is easily released by water shear or light grooming. The siloxane-polyurethane (SiPU) coatings based on the concept of self-stratification is a non-toxic and durable approach to prepare FR coatings. In this work, several approaches were considered to optimize surface properties of SiPU coatings. Incorporation of phenyl-methyl silicone oils led to improved FR properties towards several marine organisms in laboratory assays and in ocean field immersion. Enhancement in FR properties may be attributed to slowly exuding silicone oil providing surface lubricity, weakening the adhesion of marine organisms. Addition of diphenyldimethyl siloxane in to SiPU coatings at different ratios resulted in micro-scale surface topographical features which negatively affected microfouling-release while several coatings displayed good FR performance towards macrofouling organisms. In another study, decreasing the acid group content helped to improve FR performance towards barnacles, but FR performance towards diatoms were compromised. Novel amphiphilic siloxane-polyurethane (AmSiPU) coatings from polyisocyanate pre-polymers modified with polydimethyl siloxane and polyethylene glycol displayed excellent FR properties towards several marine organisms during laboratory assays. These AmSiPU coatings show promise as contenders to commercial FR standards. Initial development of SiPU coatings with hydrophilic surfaces showed promise, as the coatings showed rapidly rearranging surfaces with comparable FR performance to commercial standards which claim hydrophilic surface properties. During freshwater field immersion trials, SiPU coatings displayed excellent mussel FR performance up to 3 years. Surface analysis suggested that solvent content affected self-stratification and morphology of SiPU coatings. The SiPU coating system is a highly tunable, tough, environmentally friendly, and practical FR solution which can evolve along with non-toxic commercial marine coatings.
Office of Naval Research (Grant number N00014-12-1-0482)
SSPC
Valpar
American Coatings Association
North Dakota State University. College of Science and Mathematics
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17

Kulpa, Matthew. "A vibrational study of gear pumps and gear pump drives /." Online version of thesis, 1991. http://hdl.handle.net/1850/11048.

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18

Bunker, Daniel Thomas. "The Influence of drying rate on the pore volume distribution of clay coatings." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/5783.

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19

Erasmus, Deidre Felicia. "Investigating the potential for the application of lean manufacturing in the can coating plant at Duco Coatings." Thesis, Nelson Mandela Metropolitan University, 2008. http://hdl.handle.net/10948/949.

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Companies are constantly expected to be more competitive while working in an environment in which time and cost are limited, thereby preventing such companies from taking the time required to be responsive. It is, therefore, important that companies understand that conventional knowledge and methods will not serve unless there is a concerted focus on improvement of organisational performance toward fulfilling increased expectations, not just maintaining that which is comfortable. A more sustainable approach may be the introduction of lean manufacturing techniques. The lean manufacturing process is one that continuously strives to eliminate waste, thereby increasing the percentage of time that may be devoted to value-adding activities. Lean manufacturing principles were applied in the Can Coating Plant of Duco Speciality Coatings. This study was intended to identify waste in the current production process in the Can Coating Plant and then to use lean tools and principles to eliminate such waste. Implementation of these lean tools proved to result in a leaner and more value-adding process. The new process rendered a positive result on Duco Coating’s costs, quality and product performance. Recommendations on further improvements were also offered.
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20

Lee, Hyungsuk. "Development of parylene/PDMS bi-layer coating and characterization using nanoindentation." Diss., Online access via UMI:, 2006.

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Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Materials Science and Engineering Program, 2006.
Includes bibliographical references.
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21

Gupta, Barun Shankar. "Development of a coating technology for wood plastic composites." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Fall2006/b_gupta_082806.pdf.

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22

Pajkic, Zeljko [Verfasser]. "Atmospheric Pressure Microwave Plasma Assisted Coating Processes for Particulate Materials / Zeljko Pajkic." Aachen : Shaker, 2009. http://d-nb.info/1126378542/34.

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23

Leggett, Suzanne McCarthy. "Volatile organic compound emission reduction strategies for industrial printing and coating processes." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264655.

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24

Ku, Shaari Ku Zilati. "Modeling of product variability in fluidized bed coating equipment." Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=2774.

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Thesis (M.S.)--West Virginia University, 2003.
Title from document title page. Document formatted into pages; contains xiv, 137 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 106-109).
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25

Wang, Da-yung. "Simultaneous chrominizing-aluminizing of iron and iron-base alloys /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487325740721186.

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26

Lee, Jaebeom. "Laser produced SiOâ‚‚/TiOâ‚‚ coating on stainless steel substrate with sol-gel processes." Thesis, Robert Gordon University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400605.

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27

Starikov, V. V. "Oxide films with electret properties as coating for medical implant." Thesis, Lviv Polytechnic National University, 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/43966.

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28

Chen, Dong. "Preparation and characterization of silver coated metallodielectric spheres /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?CHEM%202005%20CHEN.

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29

Prasad, Ajit. "Influence of processing variables on the mechanical properties of SiC fibers prepared by chemical vapor deposition." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/19651.

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30

TARGOVE, JAMES DONALD. "THE ION-ASSISTED DEPOSITION OF OPTICAL THIN FILMS." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184166.

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The columnar microstructure of most thermally evaporated thin films detrimentally affects many of their properties through a reduction in packing density. In this work, we have investigated ion-assisted deposition as a means of disrupting this columnar growth for a number of coating materials. A Kaufman hot-cathode ion source bombarded thermally evaporated films with low-energy (< 1000 eV) positive ions during deposition in a cryopumped box coater. We have investigated MgF₂, Na₃AIF₆, AIF₃, LaF₃, CeF₃, NdF₃, Al₂O₃, and AIN. Argon ion bombardment of the fluoride coatings increased their packing densities dramatically. We achieved packing densities near unity without significant absorption for MgF₂, LaF₃, and NdF₃, while Na₃AIF₆, AIF₃, and CeF₃ began to absorb before unity packing density could be achieved. Fluorine was preferentially sputtered by the ion bombardment, creating anion vacancies. The films adsorbed water vapor and hydroxyl radicals from the residual chamber atmosphere. These filled the vacancy sites, eliminating absorption in the visible, but the oxygen complexes caused increased absorption in the ultraviolet. For LaF₃ and NdF₃, a sufficient amount of oxygen caused a phase transformation from the fluoride phase to an oxyfluoride phase. The refractive indices of Al₂O₃ films increased with ion bombardment. Values as high as 1.70 at 350 nm were achieved with bombardment by 500 eV oxygen ions. Since all of the Al₂O₃ films had packing densities near unity and were amorphous, we postulate that the increase in refractive index was due to a change in amorphous networking. Aluminum nitride was deposited by bombarding thermally evaporated aluminum with nitrogen ions. Films with N:Al ratios of 0.5-1.5 could be deposited by varying the deposition conditions. Films with low absorption for wavelengths longer than 1 μm could be deposited. Annealing the films at 500°C eliminated absorption at wavelengths longer than 500 nm.
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31

Bhatia, Aashish. "Encapsulation of particles using brittle coatings for subterranean applications." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=1179.

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Thesis (M.S.)--West Virginia University, 1999.
Title from document title page. Document formatted into pages; contains x, 74 p. : ill. Includes abstract. Includes bibliographical references (p. 70-71).
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32

Akhtar, Mst Alpona. "Hydrophobicity of Magnetite Coating on Low Carbon Steel." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1248389/.

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Superhydrophobic coatings (SHC) with excellent self-cleaning and corrosion resistance property is developed on magnetite coated AISI SAE 1020 steel by using a simple immersion method. Roughness measurement, scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), contact angle measurement (CAM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), potentiodynamic polarization test, electrochemical impedance spectroscopy (EIS), and qualitative characterization of self-cleaning behavior, antifouling property and durability of the coatings are assessed. A water contact angle as high as 152o on the coated surface with excellent self-cleaning and resistivity to corrosion and good longevity in atmospheric air is obtained. Self-cleaning test results prove that these surfaces can find applications in large scale production of engineering materials. Potentiodynamic polarization tests and EIS tests confirm that the superhydrophobic low carbon steel surfaces have better resistance to corrosion compared to bare steel and magnetite coated steel in 3.5% NaCl solution. But the longevity of the coated steel surfaces in 3.5% salt solution is limited, which is revealed by the immersion durability test. However, hydrophobic coatings (HC) have better stability in normal tap water, and it can stay unharmed up to 15 days. Finally, hydrophobic coatings on low carbon steel surface retains hydrophobic in open atmosphere for more than two months. Results of this investigation show surface roughness is a critical factor in manufacturing hydrophobic steel surfaces. Higher contact angles are obtained for rougher and more uniform surfaces. A linear mathematical relationship (y =6x+104; R2 = 0.93) is obtained between contact angle (y) and surface roughness (x).
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33

Graham, David W. "Corrosion resistant chemical vapor deposited coatings for SiC and Si3N4." Thesis, Virginia Tech, 1993. http://hdl.handle.net/10919/44944.

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Silicon carbide and silicon nitride turbine engine components are susceptible to hot corrosion by molten sodium sulfate salts which are formed from impurities in the engine's fuel and air intake. Several oxide materials were identified which may be able to protect these components from corrosion and preserve their structural properties. Ta20, coatings were identified as one of the most promising candidates. Thermochemical calculations showed that the chemical vapor deposition(CVD) of tantalum oxide from O2 and TaCI5 precursors is thermodynamically feasible over a range of pressures, temperatures, and reactant concentrations. The deposition of Ta205, as a single phase is predicted in regions of excess oxygen, where the reaction is predicted to yield nearly 100% efficiency.

CVD experiments were carried out to deposit tantalum oxide films onto SiC substrates. Depending on the deposition conditions, a variety of coating morphologies have been produced, and conditions have been identified which produce dense, continuous Ta205 deposits. Preliminary corrosion tests on these coatings showed no apparent degradation of the CVD deposited tantalum oxide coatings.

The feasibility of depositing ZrTi04 as a coating material was also investigated based on thermochemical considerations. Since no data were available for this material, thermodynamic values were estimated. Thermochemical calculations indicated the chemical vapor deposition of zirconium titanate from O2, ZrCl4, and TiCl4 occurs over a range of temperatures in a very narrow region of the phase diagram. Deviations from the single phase region predicted the codeposition of either Zr02 or Ti02 with ZrTi04.

These results suggested that the chemical vapor deposition of ZrTi04 may be difficult from a process handling perspective. Additionally, the process is predicted to be very inefficient, leaving substantial amounts of unreacted chlorides in the reactor exhaust.


Master of Science
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34

Ahmad, Haifa G. "Studies and modelling of high temperature diffusion processes in selected high performance structural coating systems." Thesis, Northumbria University, 2010. http://nrl.northumbria.ac.uk/1587/.

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The central theme of the work undertaken in this thesis involved modelling of diffusion – numerical and microstructural – occurring during high temperature exposure of selected materials and coatings. The materials and coatings and their high temperature treatments included carburization of steel (nonsteady-state diffusion of iron carburized at 950o C after 7.1 hours), a two component Cu-Ni diffusion couple subjected to diffusion anneal at 1054oC for 300 hours, a three component Pt-Ni-Al solid alloy subjected to oxidation and diffusion anneal, Multicomponent Ni -aluminide and Pt-aluminide coatings on MAR M002 subjected to 150 hours of diffusion treatment at temperature 1273K, a Jr and Jr/Pt Low-activity aluminide / MAR M002 system at 1100oC after 100 hours, aluminise coating on low alloy steels at 650oC, Jnnovatial coatings- Ti45Al8Nb coated with Al2Au subjected to air oxidation at 750oC for 1000 hours, and Ti45Al8Nb coated with TiAlCrY subjected to air oxidation at 750oC for 500 hours. Such coatings are being increasingly used to protect materials against high temperature (600-1000oC) degradation by oxidation. The demands for using such coatings have arisen because of the need to increase the efficiency by increasing the operation temperature in many areas of technological applications such as power operation, aero engines, and energy conversion systems and in processing industries. However the one of the major obstacles to use these coatings to prevent high temperature oxidation of materials is the degradation of the coatings due to the coating/substrate interdiffusion. Jnterdiffusion of critical elements from the coating to the substrate will deplete the protective scale forming elements in the coating.
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35

Gurfinkel, Castillo Mariano Enrique. "Modelling and parallel simulation of three-dimensional ribbing instability in symmetric forward-roll coating processes." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/36518.

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36

Bukula, Nwabisa Asanda. "Optimisation of clearcoat viscosity." Thesis, Nelson Mandela Metropolitan University, 2016. http://hdl.handle.net/10948/4814.

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Modern automobiles are painted with basecoat, technology which is either metallic, solid colour or pearlescent. This requires protection from chemicals, scratching, weathering and UV light by applying a protective top coat (clearcoat) over the basecoat. For the clearcoat to cure into a hard protective shell it undergoes an irreversible crosslinking process. This usually takes place over the first four to five hours, depending on the formulation and weather conditions. The speed of crosslinking can be enhanced by temperature. Pot life is important as it can affect the overall quality of the painted surface. If crosslinking occurs too quickly, before the clearcoat is applied onto the surface, the clearcoat cannot be used to produce a good quality finish. The “expired” mixture is thus discarded. If used, the quality of the finished product cannot be guaranteed to last, and the paintwork may have to be redone. This often means removing the underlying paint and primer as well with the clearcoat film. Besides the time lost, the discarded clearcoat mixture often lands in the landfill, polluting ground water and the environment. It is thus important from the point of view of both the environment preservation and waste management, that as much clearcoat as possible is used without being wasted. It was proven in an earlier study (BSc Hon Formulation Science Treatise, 2011) that adding eugenol to a clearcoat mixture after crosslinking had started could reduce its viscosity, which is an indicator of crosslinking progress. Crosslinking subsequently resumed at a lower rate than in traditional blends. If stored away from oxygen and high temperatures, this blend could maintain optimum viscosity indefinitely. In this follow up study an optimum formulation was developed using D - optimal experimental design. It sought to extend the pot life to avoid waste to spray painters while saving the environment from pollution. The formulation that gave the desired viscosity after five hours of pot life was adopted. It was hypothesised that the optimum formulated clearcoat mixture would have a longer pot life than its traditional counterparts, and that it would perform just as well as the traditional clearcoat mixtures. To study the rate of crosslinking (disappearance of functional groups and appearance of the urethane bond), FTIR spectrometry was performed on a mixture produced from the optimized formula in comparison to that of a traditional mixture (the control). The rate of disappearance of functional groups was found to be lower in the eugenol mixture than in the control mixture. After six hours, eugenol was added into the control mixture, and this seemed to reduce the viscosity with the re-emergence of functional groups in the mixture. After 24 hours of crosslinking, an FTIR scan was done on the solid sample and this revealed that the eugenol mixture had crosslinked fully, with no detectable functional groups in the sample.
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37

Madhavan, Nair Rajeev. "Studies of laser-based, solid freeform fabrication and coating processes using nanoscale and functionally-graded materials." [Ames, Iowa : Iowa State University], 2007.

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38

Elhoriny, Mohamed [Verfasser]. "Development of Coupled Offline Robot Trajectory Generation and Coating Simulation for Thermal Spray Processes / Mohamed Elhoriny." Aachen : Shaker, 2017. http://d-nb.info/1159836779/34.

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39

Tabbara, Hani. "Numerical investigations of thermal spray coating processes : combustion, supersonic flow, droplet injection, and substrate impingement phenomena." Thesis, University of Southampton, 2012. https://eprints.soton.ac.uk/348993/.

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The aim of this thesis is to apply CFD methods to investigate the system characteristics of high speed thermal spray coating processes in order facilitate technological development. Supersonic flow phenomena, combustion, discrete droplet and particle migration with heating, phase change and disintegration, and particle impingement phenomena at the substrate are studied. Each published set of results provide an individual understanding of the underlying physics which control different aspects of thermal spray systems. A wide range of parametric studies have been carried out for HVOF, warm spray, and cold spay systems in order to build a better understanding of process design requirements. These parameters include: nozzle cross-section shape, particle size, processing gas type, nozzle throat diameter, and combustion chamber size. Detailed descriptions of the gas phase characteristics through liquid fuelled HVOF, warm spray, and cold spray systems are built and the interrelations between the gas and powder particle phases are discussed. A further study looks in detail at the disintegration of discrete phase water droplets, providing a new insight to the mechanisms which control droplet disintegration, and serves as a fundamental reference for future developments of liquid feedstock devices. In parallel with these gas-particle-droplet simulations, the impingement of molten and semi-molten powder droplets at the substrate is investigated and the models applied simulate the impingement, spreading and solidification. The results obtained shed light on the break-up phenomena on impact and describe in detail how the solidification process varies with an increasing impact velocity. The results obtained also visually describe the freezing induced break-up phenomenon at the splat periphery.
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40

NOE', CAMILLA. "Make it greener: Exploring novel biobased materials in photopolymerization processes." Doctoral thesis, Politecnico di Torino, 2022. http://hdl.handle.net/11583/2962960.

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41

Wengeler, Lukas [Verfasser]. "Coating and drying processes for functional films in polymer solar cells - from laboratory to pilot scale / Lukas Wengeler." Karlsruhe : KIT Scientific Publishing, 2014. http://www.ksp.kit.edu.

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42

García-Verdugo, Zuil Ana, and Martín Amanda Herrero. "Additive manufacturing and radio frequency filters : A case study on 3D-printing processes, postprocessing and silver coating methods." Thesis, KTH, Industriell produktion, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280572.

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Additive manufacturing (AM) is an attractive way to shorten development time, reduce product weight and allow the manufacturing of more complex products than by conventional manufacturing processes. The problem arises when the previous traditional manufacturing requirements need to be fulfilled by AM as well as the volume production capability. This investigation is done together with Ericsson to evaluate the possibilities of the different AM technologies, post-processing methods and silver coating processes to guarantee the specifications of radiofrequency (RF) filters. Here, minimal RF signal insertion losses are targeted. Since insertion losses are dependent on surface roughness, surface smoothness is sought as well. Ericsson simulation software uses correction factors to account for surface roughness, however there are some inconsistencies between the simulated and actual surface roughness that is allowed in the parts. In AM parts, surface roughness is not easy to control since it depends on parameters related to feedstock, process and machine properties. Commonly, most AM components do not comply with requirements of lower surface roughness values. Therefore, parts need to be smoothened before silver plated; this step is necessary to ensure the electrical conductivity in this specific application. These finishing processes add costs to the final product and increase time to market. Firstly, a comprehensive study was carried out to better understand the landscape of AM technologies, postprocessing and silver coating methods. Secondly, the different processes are assessed with the help of selection matrices, considering the products requirements. The components to print are two RF filters with different shapes and dimensions but similar requirements. The CAD design is modified depending on each AM process and directly affects the results. Afterwards, the design of an experimental plan is carried out; the number of samples of each part comparing AM technologies, feedstock, different suppliers (3D printing and post-processing) is obtained. Due to budget and time restrictions, the parts were printed using Multi Jet Fusion and Selective Laser Melting processes. After printing, tolerances and surface roughness were measured. This thesis results in the selection of suitable AM technologies and post-processing methods for RF filters. For MJF printed cavities at 0˚, 30˚ and 90˚ orientation, the best results for this application are obtained at 30˚ providing a good balance between sharp detail and smooth surfaces. In the case of SLM, waveguides are printed at 0˚ and 30˚. 30˚ waveguides present lower surface roughness values than the 0˚ ones as inner support material is needed at 0˚ orientation. SLM cavities were printed at 30˚ in seek of asymmetry between faces, resulting in higher surface roughness in the downfacing face.
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43

Samuel, Sonia Banerjee Rajarshi. "Surface engineering and characterization of laser deposited metallic biomaterials." [Denton, Tex.] : University of North Texas, 2007. http://digital.library.unt.edu/permalink/meta-dc-3618.

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44

Ghasemi, Hamid-Reza M. R. "Fundamental studies of the tribological behavior of thin polymeric coatings in fretting contact using infrared and photo/video techniques." Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/39591.

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Direct measurements of surface temperatures produced during fretting contact are an unknown area in the discipline of tribology; in addition, the possible effects of such temperatures on the behavior of protective anti-fretting coatings (e.g., polymeric) have never been investigated. An oscillating contact device was designed and built to study fretting contact behavior in tribological processes. The contact geometry consisted of a stationary spherical test specimen loaded against a vibrating sapphire disk driven by an electromagnetic shaker. Surface temperatures generated by frictional heating were measured during fretting contact using an infrared microscope. A photo/video technique was developed to view the fretting contact interface during an experiment and to measure the size and distribution of real area(s) of contact. The effects of size and distribution of the areas on the experimental surface temperatures for polymer-coated steel spheres-on- sapphire were investigated. Archard's theoretical model was also modified to account for multiple contact areas, and the calculated surface temperatures were compared to the experimental results. Polymeric coatings - including polystyrene (PS), polymethylmethacrylate (PMMA), polysulfone (PSO), polyvinylchloride (PVC), and polyvinylidenechloride (PVDC) were studied at a given load (20 N), frequency (150 Hz), amplitude (100 JLm), and film thickness (55 p.m). The surface temperatures generated were generally low and below the glass transition temperatures of the rigid polymers studied. The magnitude of the surface temperatures was found to be particularly dependent on the size and distribution of real area(s) of contact. The most extensive studies were performed using polystyrene coatings. Effects of load, frequency, amplitude, and film thickness on surface temperature rise and the size and distributions of real area of contact were examined. In addition, uncoated steel specimens were studied under various loads and fretting amplitudes. The observed formation of iron oxide at low surface temperature (60°C) tribologica1 experiments was explained in terms of exoelectron emission. There were considerable differences observed in the behavior of polymeric coatings under various fretting conditions. The fretting behavior of the coatings was explained in terms of mechanical and thermo-elastic effects. Thermo-elastic predictions of size distributions of real contact areas (patches) showed good agreement with the observed photo/video studies. A mechanism was proposed for tribological behavior and fretting protection of polystyrene coatings.
Ph. D.
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45

GUERRIERO, Elisa. "Development of processes, qualification, and de-risking for the Ariel primary mirror." Doctoral thesis, Università degli Studi di Palermo, 2022. http://hdl.handle.net/10447/564365.

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The work carried out in the Ph.D. program focused on developing the optics design of the Atmospheric Remote-Sensing Infrared Exoplanet Large Survey (Ariel) telescope, an optical/infrared mission of the European Space Agency (ESA), whose primary mirror is an off-axis paraboloid mirror measuring 1.2 · 0.7m. The novelty of the telescope is that both the mirrors and the telescope structure will be made of aluminium, and the primary mirror will be made of bare aluminium without a thick hard coating. The choice is mainly due to the thermo-mechanical properties of the material, and the usage of the same material for the whole structure will allow better heat exchange between the mirror and the optical bench. Furthermore, the cost of aluminium is lower than other materials commonly used for infrared optics (Silicon carbide, Beryllium, or Zerodur). This thesis is part of the de-risking activity of the mission to bring the telescope elements, and in particular, the primary mirror to the required Technology Readiness Level (TRL); here are described the problems that arose for the use of aluminium, the testing and development of processes to make this material performant with activities carried out at Media Lario S.r.l. (ML) Most of the work was focused on the processes considered most risky: Heat Treatment (HT), Diamond Turning (DT), Polishing, and Thin Silver (Ag) Coating. The second part of the thesis is devoted to some managerial aspects of the project, aspects particularly relevant for a complex mission such as Ariel. The general management of the payload consortium is under the responsibility of the Rutherford Appleton Laboratory (RAL), while the Italian management is under the responsibility of the Università di Firenze with the Isti tuto Nazionale Di Astrofisica (INAF) team. In this phase, the focus was on producing verification documents for ESA and RAL and managing the search for companies to perform further tests and treatments of the aluminium.
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König, Olivia Maria [Verfasser]. "Development of a bioactive coating for the specific gene silencing of pathogenetic processes after intravascular stent implantation / Olivia Maria König." Tübingen : Universitätsbibliothek Tübingen, 2020. http://d-nb.info/1217249281/34.

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47

Vargas, Hernandez Jesus. "Structural and Morphological modification of TiO2 doped metal ions and investigation of photo-induced charge transfer processes." Thesis, Le Mans, 2017. http://www.theses.fr/2017LEMA1018/document.

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Le travail de thèse porte sur les méthodes de synthèse de nanostructures de dioxyde de titane et de leurs études physicochimiques afin de préciser les corrélations entre la morphologie, le dopage métallique, les caractéristiques structurales avec l'efficacité photocatalytique. Le grand intérêt pour les nanomatériaux TiO2 réside dans la mise au point de nouvelles sources d'énergie ou la conservation de l’environnement par des processus photocatalytiques. Cependant, la limitation principale de TiO2 est du au large gap électronique (eV ~3,2) du polymorphe Anatase. Ainsi, un des objectifs importants pour l'amélioration de l’efficacité des nanomatériaux TiO2 est d'augmenter leur photoactivité en décalantla création de paires d'électron-trou de l’UV à la gamme du visible. D'ailleurs, on a montré que l'utilisation de nanostructures 1D de TiO2 (nanotubes) a amélioré la collection de charges, en favorisant leur transport dans les structures 1D, qui par conséquent réduit au minimum la recombinaison et prolonge les durées de vie des électrons.La première partie de ce travail est dédiée à la synthèse des nanopoudres TiO2 dopées par des ions métalliques (Ag, Cu, Eu) préparés par sol-gel. Même avec différents éléments de dopage qui apparemment peuvent adopter le même état de valence (2+) (Cu2+, Ag2+, Eu2+), différents comportements ont été démontrés pour l'incorporation efficace de ces ions dans la structure de TiO2. L'anomalie entre les rayons ioniques des différents éléments utilisés module le rapport du dopage substitutionnel. Ceci est en effet réalisé pour Cu2+ mais dans moins d'ampleur pour Ag2+ tandis que les ions d'europium forment une ségrégation de phase Eu2Ti2O7. La dégradation de colorants de bleu de méthylène (MB) a étéaméliorée légèrement avec les échantillons dopés Ag. La raison a été attribuée aux clusters métalliques Ag qui ont été en effet mis en évidence à travers leur bande d’absorption plasmonique. La deuxième partie porte sur des couches minces de TiO2 dopés (Cu, Ag, et Eu) qui ont été élaborés par sol-gel et spin-coating et dipcoating. Les paramètres optimaux ont été obtenus pour réaliser les films cristallins mais présentant une organisation mésoporeuse qui dépend également du processus de dopage. Des études de Photocatalyse ont été également réalisées et l'efficacité des films ont été comparées en fonction des éléments dopants. La troisième partie de la thèse est liée à la modification morphologique des nanoparticules pour former des nanotubes à l'aide de la méthode hydrothermale sous pression contrôlée. Un plan d'expérience basé sur la méthode Taguchi a été utilisé pour la détermination des paramètres optimaux.Les nanotubes TiO2 augmentent la surface spécifique en comparaison avec les nanoparticules. La dégradation de bleu deméthylène par les nanotubes a montré une efficacité photocatalytique plus élevée qu’avec les nanopoudres TiO2 pures etdopés Ag
The thesis work is focused on the synthesis methods of titanium dioxide nanostructures and their physico-chemical studies in order to point out the correlations between the morphology, metal doping, structural features with the photocatalytic efficiency. The great interest on TiO2 nanomaterials deals with new sources of energy or in the environment preservation through the photocatalytic properties. However, the main limitations is due to the wide band gap (~3.2 eV) of the anatase polymorph. Thus, a major objective for improvement of the performance of TiO2 nanomaterials is to increase theirphotoactivity by shifting the onset of the electron-hole pairs creation from UV to the visible range. Moreover, it was found that using onedimensional (1-D) TiO2 (nanotubes) improved the charge collection by 1D nanostructures which consequently minimizes the recombination and prolongate the electron lifetimes. The first part of this work is focused on the synthesis of TiO2 nanopowders doped with metallic ions (Ag, Cu, Eu) prepared by Solgel. Even with different doping elements which apparently can adopt the same valence state (2+) such as (Cu2+, Ag2+,Eu2+), different behaviors were demonstrated for the effective incorporation of these ions in the host structure of TiO2. The discrepancy between ionic radii of the different used elements modulates the ratio of the substitutional doping. This is indeed achieved for Cu2+ but in less extent for Ag2+ while Europium ions form segregated phase as Eu2Ti2O7. The experiments on the degradation of methylene blue (MB)dyes have shown slight improvement with Ag-doped samples. The reason was tentatively attributed to the Ag clusters which were indeed demonstrated through their plasmon optical band. The second part of the work concerns thin films of TiO2 doped (Cu, Ag, and Eu) which were elaborated by spin coating and dip coating. The optimal parameters were obtained to achieve crystalline films but presenting mesoporous organisation which also depends on the doping process. Photocatalysis investigations were also realized and the efficiency of the films compared as function of the doping elements.The third part of the thesis is related to the morphological modification from nanoparticles to nanotubes by using the hydrothermal method with controlled pressure. An experimental design based on Taguchi Method was employed for the determination of the optimal parameters. TiO2 nanotubes increase the surface area in comparison with TiO2nanoparticles. TiO2 nanotubes were tested for the methylene blue degradation and show a higher photocatalytic efficiency than TiO2 nanopowders and TIO2 doped with Ag
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48

Van, den Dungen Eric T. A. "Self-healing coatings based on thiol-ene chemistry." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1274.

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Thesis (PhD (Chemistry and Polymer Science)--University of Stellenbosch, 2009.
The work presented in this dissertation describes the development of self-healing coatings based on thiol-ene chemistry. The approach was to synthesize capsules with thiol and ene compounds separately encapsulated. These capsules were embedded in various coating formulations and upon the formation of a crack with a razor blade, these capsules ruptured. This caused the healing agent to flow into the crack via capillary action and the thiol-ene healing mechanism was initiated. This resulted in recovery of the damaged coating and provided continued protection to the substrate. Pentaerythritol tetrakis(3-mercaptopropionate) (TetraThiol), 1,6-hexanediol diacrylate (DiAcrylate) and 1,6-hexanediol di-(endo, exo-norborn-2-ene-5-carboxylate) (DiNorbornene) are the thiol and ene compounds used in this study. Kinetic experiments indicated that both TetraThiol-DiAcrylate and TetraThiol-DiNorbornene monomer pairs undergo rapid polymerization and form a network within minutes upon exposure to UV radiation and with the addition of a photoinitiator. The TetraThiol-DiNorbornene monomer pair also showed a high rate of polymerization without the addition of a photoinitiator and/or exposure to UV radiation. Styrene-maleic anhydride (SMA) copolymers and chain-extended block copolymers with styrene (P[(Sty-alt-MAh)-b-Sty]) were synthesized via Reversible Addition-Fragmentation chain Transfer (RAFT)- mediated polymerization. These copolymers were used as surfactant in miniemulsification for the synthesis of core-shell particles with TetraThiol as the core material. It appeared that P[(Sty-alt-MAh)-b-Sty] block copolymers, sterically stabilized via the addition of formaldehyde, provide optimal stability to the core-shell particles. DiNorbornene is encapsulated via miniemulsion homopolymerization of styrene and well-defined, stable nanocapsules were obtained. TetraThiol and DiAcrylate microcapsules were synthesized via in-situ polymerization of urea and formaldehyde. Microcapsules with a particle size of one to ten micrometers and with a very smooth surface were obtained. These microcapsules and nanocapsules were embedded in poly(methyl acrylate) (PMA), styrene-acrylate and pure acrylic films and the self-healing ability of these coatings, after introduction of a crack with a razor blade, was assessed.
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49

Vanat, Karen Juliana. "Influência da temperatura de pré-aquecimento sobre a morfologia e ciclos térmicos de revestimentos YSZ." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1967.

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Revestimentos resistentes à elevadas temperaturas, como os revestimentos do tipo barreira térmica (TBC), são compostos por uma camada cerâmica superior (Top Coat) sobre um revestimento de ligação metálico (Bond Coat), e são normalmente aplicados por aspersão térmica para a proteção de componentes de turbinas. Para que o revestimento aplicado a estes componentes seja eficiente, é preciso analisar os fatores influentes sobre o desempenho dos revestimentos, como por exemplo, a temperatura de pré-aquecimento do substrato. O objetivo geral deste trabalho foi estudar a influência da temperatura de pré-aquecimento do substrato sobre a morfologia e comportamento de revestimentos cerâmicos de zircônia estabilizada com ítria (YSZ), submetidos a ciclos térmicos de aquecimento seguido de resfriamento forçado. A aplicação do revestimento cerâmico foi realizada pelo processo de aspersão térmica a plasma ao ar (APS), sobre substrato de uma liga de Ni previamente revestido, por um Bond Coat constituído de uma superliga de níquel aspergida termicamente pelo processo de chama de alta velocidade (HVOF). Analisou-se a influência da temperatura de pré-aquecimento do substrato (Bond Coat) sobre a porosidade, morfologia, microdureza, bem como a aderência e tenacidade à fratura da interface do revestimento Top Coat antes e após os ensaios de ciclos térmicos de oxidação. Observou-se que o aumento da temperatura de pré-aquecimento promoveu uma diminuição da porosidade do revestimento, bem como um aumento da aderência e uma maior microdureza do revestimento. A maior temperatura de pré-aquecimento promoveu também um aumento da tenacidade à fratura na interface metal/cerâmica. Observou-se que a oxidação cíclica promoveu a sinterização do revestimento Top Coat e alterações na microestrutura do revestimento Bond Coat, resultando na diminuição da porosidade e consequente aumento da tenacidade à fratura da interface Top Coat/Bond Coat. Este efeito foi mais pronunciado para as amostras de menor temperatura de pré-aquecimento do substrato.
High temperature resistant coatings, such as thermal barrier coatings (TBC), are composed of a ceramic layer (Top Coat) deposited on a metallic layer Bond Coat, these coatings are normally applied by thermal spray techniques to protect these components. In order to improve the coating properties, it is necessary to analyze the influence of the different processing parameters on the performance of the coatings, for example, the preheating temperature of the substrate. The general objective of this research was to study the influence of preheating temperature of the substrate on the morphology and behavior of ytrria stabilized zirconia (YSZ) ceramic coatings, submitted to thermal cycles. The ceramic coating deposition was carried out by air plasma thermal spraying process (APS) on a Ni substrate.alloy pre-coated with a Bond Coat constituted of a Ni superalloy thermally sprayed by high velocity oxy-fuel process (HVOF). Preheating temperature influence was analyzed on the YSZ porosity, as well as the coating morphology, microhardness, tensile adhesion resistance and interface fracture toughness of the Top Coat, before and after thermal cycling oxidation tests. It was observed that increasing the preheating temperature decreases the YSZ porosity, improving the coating adhesion and microhardness increase. This pre heating temperature increase promoted a greater fracture toughness on the YSZ/Bond Coat interface. The cyclic oxidation reduced the porosity of the Top Coat and promoted some metallurgical changes on the Bond Coat, resulting in the fracture toughness increase in the Top Coat/Bond Coat interface. This effect was more pronounced on samples with minor substrate preheating temperature.
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50

Jarray, Ahmed. "Mesoscopic modeling, experimental and thermodynamic approach for the prediction of agglomerates structures in granulation processes." Phd thesis, Toulouse, INPT, 2015. http://oatao.univ-toulouse.fr/15112/1/jarray.pdf.

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Wet granulation process requires the addition of a coating agent or binder, typically composed of surfactants, water, plasticizers and fillers. In dry granulation however, the coating agent is added to the system in the form of fine solid particles. Our goals are to investigate the particles behaviour and agglomeration mechanism in dry and aqueous systems at the micro and meso scales, and also, to develop predictive methodologies and theoretical tools of investigation allowing to choose the adequate binder and to formulate the right coating solution. In this study we chose materials widely used in food and pharmaceutical industries, including; coating agents such as Hydroxypropyl-methylcellulose (HPMC) and Ethyl cellulose (EC), binders such as Polyvinylpyrrolidone (PVP) and Microcrystalline cellulose (MCC), hydrophobic filler such as Stearic acid (SA) and plasticizer such as Polyethylene glycol (PEG). A successful granulation requires good affinity between host and guest particles. In this context, in the first part of this work, two approaches to predict the binder-substrate affinity in dry and in aqueous media were compared; one based on the work of adhesion and the other based on the ideal tensile strength. The concept of ideal tensile strength was extended to ternary systems and applied for granulation in aqueous media. The developed approaches were thereafter tested for various systems (composed of PVP, MCC, HPMC, SA, EC, PEG and water) and compared to experimental observations. Approaches yielded results in good agreement with the experimental observations, but the work of adhesion approach might give more accurate affinity predictions on the particles affinity than the ideal tensile strength approach. Both approaches predicted that HPMC is a good binder for MCC. Results also indicated that PEG has a good affinity with HPMC and SA. In a second part of our work, we used mesoscale simulations and experimental techniques to investigate the structure of agglomerates formed in aqueous colloidal formulations used in coating and granulation processes. For the simulations, dissipative particle dynamics (DPD) and a coarse-grained approach were used. In the DPD method, the compounds were described as a set of soft beads interacting according to the Flory-Huggins model. The repulsive interactions between the beads were evaluated using the solubility parameter (δ) as input, where, δ was calculated by all-atom molecular simulations. The mesoscale simulation results were compared to experimental results obtained by Cryogenic-SEM, particle size distribution analysis and DSC technique. According to the DPD simulations, HPMC polymer is a better stabilizing agent for SA than PVP and MCC. In addition, HPMC is able to cover the SA particle with a thick layer ant to adsorb in depth into its inner core, preventing SA agglomeration and crystal growth. But, for high amounts of SA (above 10% (w/w)), HPMC is unable to fully stabilize SA. We also found that PEG polymer diffuses inside HPMC chains thereby extending and softening the composite polymer. Experimental results presented similar trends; particle size distribution analysis showed that in the presence of HPMC, for low percentages of SA (below 10% (w/w)), the majority of SA particles are below 1 μm in diameter. SEM images revealed that HPMC surrounds SA crystals with a hatching textured film and anchors on their surface.
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