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Drying rate during industrial coating application is important to understand because drying a coated paper requires energy. If an unnecessary high amount of energy is used to dry paper, a fast evaporation rate can be achieved which can result in defects of the coated surface.   In this bachelor’s thesis, temperature profile during industrial coating application was studied. An industrial pilot trial on a coating machine was implemented at UMV coatings at Säffle, Sweden. Two boards with grammages of 210 and 350 gsm were used, where cardboard 210 gsm was precoated on the backside with two different precoatings. Where the two precoating differed in latex content and type of Hydrocarb. Board 350 gsm was not precoated. Temperatures between 65 to 85 oC were achieved in the drying section, depending on which substrate that was used.  Laboratory tests were also performed to investigate the relationship between surface temperature and dry content of a substrate during drying. As the temperature and time increased, did also the surface temperature and dryness of the samples. It was assumed that the temperature readings from the pilot coater could be correlated to the dry content of coating color.    The results from the study showed that by decreasing the dry content in a coating, a higher surface temperature was obtained during industrial- and laboratory drying due to the increase in heat transfer rate. Results showed also that when fraction of clay in a coating was decreased, a higher evaporation rate and higher surface temperature was obtained during drying.

<p>At solid oxide fuel cell (SOFC) operating temperatures (650^oC--800^oC), the chromia scale growth on the interconnect surface and chromium poisoning of cathode can lead to performance degradation of the whole cell. A spinel coating can be effective for blocking chromium outward diffusion to overcome this issue. In this thesis, two spinel-forming systems, Zn-Mn-O and Co-Cu-Mn-O were studied to identify a suitable coating.</p> <p>In-situ high temperature XRD was used to identify the phases in the Zn-Mn-O system between 600^oC and 1300^oC. The results showed that cubic spinel phase was stable only at high temperatures (above 1200^oC) and when the temperature decreases, the cubic phase tends to deform to tetragonal structure. In addition, the conductivity results showed low conductivities (below 3 S/cm) at SOFC operating temperature. Thus, the Zn-Mn-O system is not suitable for SOFC interconnect coatings.</p> <p>Another potential coating material analyzed was the Co-Cu-Mn-O system. This system exhibited promising conductivity values. Electrodeposition was used to apply Co-Cu-Mn-O coatings on both ferritic stainless steel and chromium-based alloy (Cr-5Fe) followed by oxidation in air at 800^oC. The spinel coating formed nicely on the stainless steel substrate. However, on the chromium plate, nitride formation, blistering and metal isolation were the common problems that occurred during the oxidation process. In order to improve the quality of coating on the chromium alloy, different heat treatments were explored, such as annealing in reducing atmosphere, oxidation in pure oxygen / mixed gas and decreasing the oxidation temperature. The objective of modifying the heat treatment was to produce adherent, dense coatings.</p> / Master of Applied Science (MASc)

Friction in machining is a complex phenomenon that can directly affect cutting productivity and product quality. Currently, different coatings are developed for machining applications which can increase tool life in the machining processes. Since performing a real machining test to quantify the friction is expensive and time-consuming, developing a bench scale testing method to simulate the friction in machining can reduce the cost and help researchers and industries select a suitable coating for their specific applications. The goal of this work was to study the adhesion between the tool and workpiece material under machining conditions by simulating them using a heavy-load high-temperature tribometer. A high normal load was applied to plastically deform the workpiece material. The contact zone was then heated up using a resistance heating method. The normal load should be in the range that can generate a plastic flow on the surface of the workpiece material prior to seizure. Three groups of in-house coatings were tested to study the effects of coating deposition parameters on the coefficient of friction. The results of these tests showed that the coating with the lowest bias voltage and highest Nitrogen pressure had the best tribological performance. As a next step, three different commercial coatings were selected. Super duplex stainless steel was chosen as the workpiece material and the tribometer tests were performed. To validate the tribometer results real machining tests and tool wear analysis were performed. AlTiNOS+ WC/C was observed to be a lubricious coating which reduced the cutting force and coefficient of friction during the running-in stage. However, the low hardness of the coating provided little abrasion resistance and was removed after the first pass. AlTiNOS+ TiB2 demonstrated a good combination of hardness and lubricity associated with improved coating tribological performance as well as wear resistance. / Thesis / Master of Applied Science (MASc)

Recently, Zn-XAl-YMg coatings have emerged as lighter-weight substitutes for traditional Zn-based coatings for the corrosion protection of steels; however, little is currently known concerning the interactions between the oxides present on advanced high strength steel (AHSS) surfaces and the Zn-Al-Mg bath. In the current contri- bution, the selective oxidation and reactive wetting of a series of C-Mn AHSS were determined with the objective of providing a quantitative description of this pro- cess. The process atmosphere pO2 was varied using dew points of −50◦C, −30◦C and −5◦C. The surface oxide chemistry and morphology were analysed by means of SEM and XPS techniques. Reactive wetting of the selectively oxidized surfaces using a Zn-1.6 wt.% Al-1.6 wt.% Mg bath was monitored as a function of annealing time at 60 s, 100 s and 140 s at 800◦C. The resulting bare spot defects in the Zn-1.6 wt.% Al-1.6 wt.% Mg coating were assessed by means of SAM-AES and FIB, while coating adhesion was analysed by 180◦ bend tests. Annealing the steel substrates resulted in the formation of surface MnO, which varied based on pO2 and Mn alloy content, and that this MnO greatly reduced the wettability of the steel by the Zn-1.6 wt.% Al- 1.6 wt.% Mg bath, resulting in bare spot defects. It was determined that the reactive wetting of the steel substrate was dependant on the oxide morphology and oxidation mode, which was a function of both alloying content of Mn in the steel and annealing pO2 process atmosphere (dew point). Finally, it was concluded that the bare spot area percentage on the coated panels was statistically invariant for annealing times of between 60 s and 140 s at 800◦C. / Thesis / Master of Applied Science (MASc) / Metallic coatings are applied to steels that are not naturally corrosion resistant. The aim of this research was to determine how well a coating containing zinc, aluminum and magnesium adhered to high strength automotive steel. It was deter- mined that manganese oxides formed on the steel during heating prior to applying the metallic coating. The manganese oxides prevented good adhesion between the steel and the coating, resulting in bare spot defects in the coating. The bare spot defects are undesirable as they leave the steel exposed and therefore susceptible to corrosion and are unsightly when painted.

Thin film coatings of (Cao.6Mg0.4)Zr4(P04)6 (CMZP) and Mg stabilized AhTiOs ( Mg-Ah Ti05 ) on dense SiC substrates were investigated using sol-gel coating techniques. The thickness and quality of both CMZP and Mg-Ah Ti05 coatings were found to depend on the solution concentration and lift rate. Double coatings were applied to obtain homogeneous and crack-free coatings. The quality of double coatings was influenced by different first and second coating thickness. The CMZP coated samples were fired in controlled atmospheres to have the pure CMZP phase. Unhydrolyzed solution of Mg-AhTiOs was utilized instead of hydrolyzed solution to improve the quality of Mg-AhTiOs coatings. Aging process was found to improve the quality of CMZP and Mg-Ah TiOs coatings. SiC samples coated with CMZP and Mg-Ah TiOs exhibited good thermal shock resistance and greatly improved the high temperature alkali corrosion resistance. / Master of Science

The corrosion protection service life extension provided by epoxy-coated reinforcement (ECR) was determined by comparing ECR and bare bar from 10 bridge decks built between 1981 and 1995. The objective was to determine the corrosion protection service life time extension provided by ECR field specimens with various degrees of coating adhesion: disbonded, partially disbonded, and wholly bonded coatings. The size and length distributions of cracks in Virginia bridge decks were investigated to assess the frequency and severity of cracks. Correlation of cracks with chloride penetration was used to characterize the influence of cracking on deck deterioration. Cracks influence the rate of chloride penetration, but the frequency and width distributions of cracks indicate that cracks are not likely to shorten the overall service life of most bridge decks in Virginia. Altogether, 141 drilled cores, 102 mm (4 inches) in diameter, were employed in this study. For each of the decks built with ECR, 10 to 12 cores were drilled through a top reinforcing bar adjacent to the previous study core locations. In addition, approximately 3 cores were drilled through a top reinforcing bar at a surface crack location. Laboratory testing involved nondestructive monitoring using advanced electrochemical techniques to periodically assess the corrosion state of the steel bars during cyclic exposure to chloride-rich solution over 22 months of treatment. Time of corrosion initiation and time of cracking (where applicable), as well as chloride content of the concrete before and after treatment, were used in the analysis. Less than 25 percent of all Virginia bridge decks built under specifications in place since 1981 is projected to corrode sufficiently to require rehabilitation within 100 years, regardless of bar type. The corrosion service life extension attributable to ECR in bridge decks was found to be approximately 5 years beyond that of bare steel. / Ph. D.

Novel poly(imide siloxane) copolymers were prepared and developed as high performance fiber coatings. These copolymers were synthesized and characterized extensively as a function of chemical composition. The polyimides were then utilized to coat prototype fibers which were subsequently evaluated regarding thermal stability, thermal behavior, and hydrophobicity. The polymer series included poly(imide siloxane)s which were prepared in two steps, the first involving the generation of soluble poly(amic acid} intermediates which were then cyclodehydrated by heating in a coamide solution, at temperatures ranging from 140 to 170°C, resulting in soluble polymer which exhibited excellent thermal and mechanical properties. Because of the different nature of the imide and siloxane, a two phase microstructure developed at relatively low block molecular weight. X-ray photoelectron spectroscopy (XPS) and contact angle measurements indicated that the surface of the copolymer films was dominated by siloxane. A series of coating solutions was prepared, controlling the solution concentration, solvent, and viscosity. Polybenzimidazole and Kevlar aramid multifilament yarns were immersion coated, dried, and evaluated. Due to the surface segregation of siloxane, these coated fibers advantageously displayed lower moisture sorption as measured in three environments of different humidities. Thus, the coating acted as a hydrophobic barrier. These coated fibers were also evaluated by thermogravimetric analysis (TGA) which displayed that the dynamic thermo-oxidative stability was improved. Finally, thermal expansion coefficients were measured in order to determine coating integrity or matrix/resin integrity under thermal stress. / M.S.

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.

The synthesis of epoxide containing block and alternating copolymers has been investigated in this research. Poly(ethylene oxide-2-ethyl-2-oxazoline) (PEO) copolymers have been synthesized with poly(ethylene oxide) macroinitiators ranging from O.75K-40K. Monohydroxy functionalized PEO oligomers have been synthesized with potassium tert-butoxide as an initiator in tetrahydrofuran, and in the bulk. The PEO oligomers were reacted with 4-(chloromethyl) benzoyl chloride to yield a 4-(chloromethyl) benzoate functionalized PEO oligomer quantitatively. This oligomer was further reacted in the melt with sodium iodide to result in 4-(iodomethyl) benzoate functionalized PEO oligomers. The iodo adduct (macroinitiator) initiated the polymerization of 2-ethyl-2-oxazoline, the second block of the diblock copolymer. The formation of the poly ( ethylene oxide-2-ethyl- 2-oxazoline) copolymer resulted in materials ranging from 20 - 80 weight percent poly(2-ethyl-2-oxazoline) (PEOX). These materials were water soluble with PEOX as a strong hydrogen bonding block in the copolymer. The diblock copolymers may have potential uses in particle stabilization, and coating applications. / Ph. D.