O presente trabalho tem como objetivo contribuir para o conhecimento da morfologia, microestrutura e modulação composicional (perfil da composição química) de recobrimentos NbN/CrN multicamadas nanoestruturados com diferentes periodicidades (entre 4 e 20 nm) depositado por PVD pela técnica de arco catódico. Foi alcançada espessura total do recobrimento de 30 ?m mantendo-se a homogeneidade da periodicidade ao longo de toda a espessura. Análises de difração de Raios-X, aliadas a modelamento computacional (difração dinâmica), e análise de microscopia eletrônica de transmissão (MET), permitiram a determinação da periodicidade das multicamadas e a espessura das camadas individuais de NbN e CrN e análise qualitativa da coerência entre as camadas. O modo de varredura (SMET) acoplado com espectroscopia de perda de energia de elétrons (EELS), permitiu medir a variação da composição química ao longo das nano-camadas individuais. A análise por EELS mostrou que, mesmo para a menor periodicidade estudada - 4nm, não há eliminação da modulação composicional. Assim, um modelo de Análise de Elementos Finitos (FEA) foi utilizado para avaliar a componente das tensões residuais intrínsecas ao longo das multicamadas, alimentado com o cáculo da deformação do parâmetro de rede, que pela Lei de Vergards varia em função da modulação química, ao longo das camadas de NbN e CrN. A microindentação instrumentada e o teste de riscamento mostraram aumento de dureza e maior resistência ao risco com a redução da periodicidade das multicamadas nanoestruturadas de NbN/CrN. O cruzamento dos resultados das diversas técnicas empregadas permitiu análise detalhada da estrutura e morfologia destes recobrimentos e a influência das periodicidades na modulação química das camadas individuais, possibilitando o desenvolvimento de um modelo qualitativo. Este aprendizado irá permitir a deposição de recobrimentos multicamadas nanoestruturados com melhor controle das propriedades mecânicas objetivadas em função da aplicação final do produto. / The present work aims at contributing to the knowledge, microstructure and compositional modulation (Chemical composition profile) of NbN/CrN multilayer nanostructured coatings with different periodicities (between 4 and 20nm) deposited by cathodic arc technique. It was reached a total coating thickness of 30 ?m preserving the periodicity homogeneity along the thickness. X-Ray Diffraction analisys, combined with computational modeling (dinamic diffraction) and Transmission Eletron Microscopy analysis (TEM), allowed the multilayer periodicity determination, the individual NbN and CrN layer thicknesses as well as the qualitative analysis of coherency among layers. The scanning mode (STEM) combined with Electron Energy Loss Spectroscopy (EELS), allowed the measurement of the chemical composition variation along the individual nanolayers. The EELS analysis showed that, even for the lowest periodicity studied - 4nm, there is no elimination of the compositional modulation. Thus, the Finite Element Analysis model (FEA) was used to evaluate the intrinsic residual stress component along the multilayers, fed with the lattice parameter deformation calculation, which, by Vegards Law varies as a function of the chemical modulation, along the NbN and CrN layers. The instrumented microindentation and the Scratch test showed hardness increase and higher scratch resistance as periodicity decreases on the nanostructured multilayer of NbN/CrN. The cross-linking data of the several techniques employed enabled a detailed analysis of the structure and morphology of such coatings and the influence of the periodicities on the individual layer chemical modulation, allowing the development of a qualitative model. This learning will allow multilayer nanostructured coatings deposition with a better control of desired mechanical properties as a function of the final product application.

The effect of hydrogen charging current density and tensile strain rate on the mechanical properties of X80 pipeline steel were investigated by slow strain rate test (SSRT), Charpy impact test, and scanning electron microscopy (SEM) in this thesis. The results show that both the ultimate tensile strength and elongation to failure of X80 steel were deteriorated significantly after charging with hydrogen. With a strain rate of 5 x 10-5 s-1, the relative tensile strength and plasticity loss of X80 steel had no significant change within the range of assumed hydrogen partial pressures at room temperature. At room temperature, X80 steel had no apparent variation in ultimate tensile strength and elongation, except at the strain rate of 10-6 s-1. Specimens obtained the greatest relative tensile strength loss and plasticity loss when strained at 10-6 s-1 with a current density of 4.6 mA/cm2. The fracture morphology of two test groups of X80 steel exhibited significant brittle rupture when tested with dynamic hydrogen charging. The impact energy of X80 was not affected by hydrogen charging. Different current density also had no influence on the results of the impact test.

Solar selective coatings based on carbon transition metal carbide nanocomposite absorber layers were designed. Pulsed filtered cathodic arc was used for depositing amorphous carbon: metal carbide (a-C:MeC, Me = V, Mo) thin films. Composition and structure of the samples were characterized by ion beam analysis, X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. The optical properties were determined by ellipsometry and spectrophotometry. Three effective medium approximations (EMA), namely Maxwell-Garnett, Bruggeman, and Bergman, were applied to simulate the optical behaviour of the nanocomposite thin films. Excellent agreement was achieved between simulated and measured reflectance spectra in the entire wavelength range by using the Bergman approach, where in-depth knowledge of the nanocomposite thin film microstructure is included. The reflectance is shown to be a function of the metal carbide volume fraction and its degree of percolation, but not dependent on whether the nanocomposite microstructure is homogeneous or a self-organized multilayer. Solar selective coatings based on an optimized a-C:MeC absorber layer were designed exhibiting a maximum solar absorptance of 96% and a low thermal emittance of ~5 and 15% at 25 and 600ºC, respectively. The results of this study can be considered as predictive design tool for nanomaterial-based optical coatings in general.

Ett stort industriellt problem när det gäller metalliska material är korrosion. En metod för att förhindra korrosion är genom en elektrokemisk process som kallas katodiskt skydd vilket kan utföras på två olika sätt: Katodiskt korrosionsskydd med påtryckt ström (ICCP) eller offeranod (SACP). SACP är baserat på oxidation av de mindre ädla metalliska offeranoderna som vanligtvis är gjorda av zink- och aluminiumlegeringar. Det finns ett stort behov av att forska på andra alternativ för dessa anoder eftersom metallerna som används vis SACP släpper ut tungmetaller i havsvatten. Ledande polymerer (CP) har intressanta och kontrollerande elektriska och elektrokemiska egenskaper vilket gör dem till ett miljövänligt alternativ vid val av anod för SACP.  I följande studie var de utvalda ledande polymererna poly(3,4-etylendioxytiopend)polystyrensulfat (PEDOT:PSS) och polypyrrole-SDS (PPy-SDS). PEDOT:PSS syntetiserades och PPy-SDS köptes. Deras beteende i artificiellt havsvatten analyserades I syfte att bestämma utvecklingen av polymerstrukturen och egenskaper samt eventuella förändringar i havsvattenegenskaperna. Inga av dessa polymerer visade förändringar i den molekylära strukturen till skillnad från den kristallinga strukturen som påverkades. Dessutom släppte inte PPy-SDS ut och komponenter i vattnet till skillnad från PEDOT:PSS som genomgick mekanisk sönderfall vid kontakt med konstgjort havsvatten.  För att förbättra konduktiviteten, post-dopning med metanol och svavelsyra utfördes på PEDOT:PSS vilket inte var fallet när post-dopning med metanol utfördes, det var dock inte möjligt att få en konduktivitet av PEDOT:PSS post-doped  med svavelsyra.  Elektrod tillverkningsmetod utfördes och undersöktes i denna studie. Metoderna inkluderade komprimering från 3000bar till 6000bar vid olika temperaturer och olika geometrier av elektrod. Temperaturen hade en positiv effekt på polymerernas ledningsförmåga. / A major industrial issue when it comes to metallic materials is corrosion. One method to prevent corrosion to occur is by an electrochemical process called cathodic protection which is done in two different ways: impressed current cathodic protection (ICCP) or sacrificial anode cathodic protection (SACP). SACP is based on oxidation of the less noble metal which usually is made of zinc and aluminum alloys. The environmental concerns of these anodes due to the release of heavy metals in the seawater induced a strong need to explore other alternatives. Then, conductive polymers (CP) with their interesting and controllable electrical and electrochemical properties represent an opportunity to investigate as an eco-friendly anodic material.  In the following study, two conductive polymers were chosen: poly(3,4-ethylenedioxythiopende)polystyrene sulfonate (PEDOT:PSS) and polypyrrole-SDS (PPy-SDS). The former was synthesized, while the latter was purchased. Their behavior as polymer powders in artificial seawater was analyzed with the aim to determine the evolution of polymer structure and properties as well as any change in the seawater characteristics. Neither of these polymers showed changes in the molecular structure contrary to the crystalline structure which was affected. Furthermore, PPy-SDS did not release any components to the water unlike PEDOT:PSS which went through mechanical disintegration when in contact with artificial seawater.  To improve the conductivity of PEDOT:PSS post-doping with methanol and sulfuric acid were performed. The obtained results did not show the expected effect which need further optimization of post-doping conditions.  Electrode fabrication method was proposed and investigated in this study. The methods included compression from 3000bar to 6000bar at different temperatures and different geometries of electrode. The temperature had a positive effect on the conductivity of the polymers without an impact on their structure.

Through history, iron has mainly been used as reinforcement in concrete. Contemporary building technology would not have been possible without reinforced concrete, however, from a global perspective, many concrete buildings have begun to encounter reinforcement corrosion, mainly due to chlorides and carbonation. When the chlorides come into contact with the reinforcing bars, a chemical reaction begins, which causes the iron to oxidize and begin to corrode. In a humid environment when the reinforcement corrodes, the iron expands and bursts the concrete from inside, which in turn results in cracks occurring in the concrete structure. In an environment with lack of oxygen, it often occurs that non expanding rust products form that are not defected on the concrete surface occurs through discoloring or spalling. This type of damage is not detected ocularly and therefore forms a more serious type of injury. This type of rust is a silent type of damage that can cause deteriorated bearing capacity in the construction, since the cross-sectional area of the reinforcement in the concrete decreases. Sweco has been involved in a couple of projects where there have been huge problems due to corrosion of reinforcement. The damages that emerged leading to the repairs of these type of damage costing large sums. This report is based on previous projects, articles, literature studies, reports and interviews. Interviews have been conducted with competent people who have shared their valuable opinions, knowledge and experiences. In order to stop ongoing corrosion of reinforcement and also repair the damage, several alternative solution and repair measures have been devolped. Some of the most relevant suggestions in this report is to remove the damaged concrete and then re-cast or alternatively cast in cathodic protection or a combination of these. / Genom historien har man främst använt sig av järn som armering i betong. Samtidens byggteknik hade inte varit möjlig utan armerad betong, dock behöver man vara uppmärksam på armeringskorrosion framför allt på grund av klorider och karbonatisering. När kloriderna kommer i kontakt med armeringsjärnen påbörjas en kemisk reaktion som leder till att järnen oxiderar och börjar korrodera. I fuktig miljö när armeringen korroderar, expanderar järnen och spränger betongen inifrån vilket i sin tur resulterar i att sprickor uppstår i betongkonstruktionen. I syrefattiga miljöer uppstår det oftast svartrost som är den typ av skada som uppstår inuti en betongkonstruktion. Denna typ av skada upptäcks inte okulärt och blir därför en allvarligare typ av skada. Svartrost är även den typ av skada som kan förorsaka försämrad bärighet i konstruktionen eftersom tvärsnittsarean hos armeringen i betongen minskar. Sweco har varit inblandade i ett par projekt där det har förekommit enorma problem på grund av armeringskorrosion. Skadorna som har uppstått på grund av armeringskorrosion har lett till att reparationerna av dessa skador har varit kostsamma. Denna rapport är baserad på tidigare projekt, artiklar, litteraturstudier, rapporter samt intervjuer. Intervjuer har genomförts med kompetenta personer som har delat med sig av sina värdefulla åsikter, kunskaper och erfarenheter för att få en bättre uppfattning av konsekvenserna som uppstår på grund av armeringskorrosion. För att stoppa pågående armeringskorrosion och även reparera skadorna, har reparationsåtgärder i denna rapport tagits fram. Några utav de mest relevanta förslag på åtgärder i denna rapport är att ta bort den skadade betongen för att sedan gjuta på nytt, alternativt gjuta in katodiskt skydd eller en kombination av dessa.

[pt] A corrosão é a patologia mais recorrente no concreto armado, responsável por custos elevados na recuperação das estruturas afetadas. Além dos custos diretos como os materiais utilizados na recuperação, a mão de obra especializada, substituição de peças ou equipamentos afetados, existem os custos indiretos como a paralização da utilização da estrutura, mobilização de moradores em caso de edificações residenciais, perda de produção em caso de edificação industriais, entre outros. Encontrar e apresentar meios para o combate e a prevenção da corrosão é de extrema importância. A proteção catódica tem se apresentado nas últimas décadas como uma forma eficaz de combate a corrosão, não só paralisando o processo corrosivo totalmente, mas também prevenindo o surgimento de novos pontos. Seu uso vem sendo aplicado cada vez mais em estruturas de concreto armado, como pontes, cais, edifícios industriais e residenciais e túneis. Diversos materiais vêm sendo testados e aprovados, possibilitando a flexibilização e a adaptação do melhor sistema para cada estrutura. Relatos de casos com uso da proteção catódica tem mostrado a sua eficácia mesmo depois de anos de instalação. Essa dissertação apresenta a proteção catódica, seus sistemas de uso, casos em que foi instalada, um experimento com proteção catódica por corrente impressa para a restauração de uma ferramenta de aço, além de um modelo computacional desenvolvido para o dimensionamento de anodos galvânicos para estruturas de concreto armado. / [en] Corrosion is the most recurrent pathology in reinforced concrete, responsible for high costs in the recovery of affected structures. In addition to direct costs such as materials used in the recovery, specialized labor, replacement of affected parts or equipment, there are indirect costs such as the interruption of use of the structure, mobilization of residents in case of residential buildings, loss of production in case of industrial buildings, among others. Finding and introducing means to combat and prevent corrosion is extremely important. Cathodic protection has been presented in the last decades as an effective way to combat the corrosion, as it not only paralyzes the corrosive process completely, but also preventing the combat to new points. Its use has been increasingly applied in structures such as bridges, industrial and residential buildings, and tunnels. Various materials have been tested and approved, adaptation system for flexibility and adaptation to better each structure. Case reports with the use of cathodic protection have had attention even after years of installation. This dissertation presents cathodic protection, its systems of use, cases in which it was installed, an experiment with cathodic protection by impressed current for the restoration of a steel tool, as well as a computational model developed for the design of galvanic anodes for reinforced concrete structures.

Made available in DSpace on 2017-07-21T19:26:06Z (GMT). No. of bitstreams: 1 Bruna Corina Kurelo.pdf: 9097435 bytes, checksum: 9e2ea56fd2dfc2427ab47a5b071d8244 (MD5) Previous issue date: 2013-04-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nitriding by glow discharge (DL) and a new technique called luminous glow discharge with cathodic cage (DLGC) were techniques widely employed today for surface treatment. In the present work were investigated nanoscale tribo-mechanical properties of three grades:austenitic stainless steel (AISI 316), Martensitic (AISI 420) and supermartensitic (HP13Cr) subjected to treatments by DL and DLGC techniques. Martensitic steels have been previously heat-treated in 1025 C (AISI 420) and 1100C (HP13Cr) with subsequent rapid cooling in oil. The three classes of steels have been nitrided using the following parameters of temperature – time : 350 C/6 h, 400 C/6 h e 450 C/6 h (to DL and DLGC). The nitriding treatments were held in atmospheres of N2/H2 in the proportions of 20 %-80 % (in volume) to DL and 80 %-20 % (in volume) to DLGC. For the characterization of the samples were employed the techniques of x-ray diffraction (DRX), scanning electron microscopy (SEM), optical microscopy (OM), atomic force microscopy (AFM) and Energy Dispersive X-ray Spectrometry (EDS). The mechanical properties were evaluated by instrumented indentation (II), and, with the same equipment, the nano scratch tests. In the samples treated by DL the temperature influence the formation of different stages (γN or αN, γ'-Fe4N, ε-Fe2 + xN, CrN). In the treatments carried out at low temperature (350 C) the predominant phase formed is γN to austenitic steel AISI 316 and phases γ' and ε for martensitic steels HP13Cr and AISI 420, due to difference in solubility and diffusivity of nitrogen in the austenite and martensite phases.Nitriding treatments by DL cause the effect of chromium depletion to all steels in the temperature of 450°C. To DLGC treatments occurs the formation of ε phase regardless of temperature. By this way higher temperatures favor the formation of the phases γN and αN. In treatments by DLGC, hardness of the deposited layer measured by II remained, regardless of steel, next to that of the reference sample. The hardness of the modified layers existing below the films produced by DLGC is next the hardness of the layers produced by DL but no border effect and low roughness. In treatments by DL, the hardness increased from 2,5 GPa up to 15,5 GPa for steel AISI 316. The estimated thicknesses of modified surfaces treated by DL are superior to those of the layers deposited and modified by DLGC at same parameters. The scratch resistance of modified surfaces by DL increases to any conditions of treatment. The greatest value of critical load of scratch resistance obtained (126.7 ± 32.1 mN) for the layers deposited by DLGC is too low for typical applications expected of these steels. However, further analyzes are necessary in the modified layer to check the applicability of this technique for these steels.The conditions of excellence found for DL technique can provide an increase in the useful life of the parts treated in the media, where they are employed that require good mechanical and tribological properties. / Dentre as várias técnicas empregadas na atualidade para tratamento de superfícies, destaca-se a nitretação por Descarga Luminosa (DL) e uma nova técnica denominada nitretação iônica por DL com Gaiola Catódica (DLGC). No presente trabalho investiga-se as propriedades tribo-mecânicas em nanoescala de três classes de aços inoxidáveis: austenítico (AISI 316), martensítico (AISI 420) e supermartensítico (HP13Cr) submetidos a tratamentos pelas técnicas de DL e DLGC. Os aços martensíticos foram previamente tratados termicamente em 1025 °C (AISI 420) e 1100 °C (HP13Cr) com posterior resfriamento rápido em óleo. Os três aços foram nitretados nas seguintes condições de temperatura/tempo: 350 °C/6 h, 400 °C/6 h e 450 °C/6 h (DL e DLGC). As nitretações foram realizadas em atmosferas de N2/H2 nas proporções de 20 %-80 % para DL e 80 %-20 % para DLGC. As superfícies foram caracterizadas pelas técnicas de difração de raios X (DRX), microscopia eletrônica de varredura (MEV), microscopia de força atômica (MFA) e espectroscopia de raios X por energia dispersiva (EDS). As propriedades mecânicas foram avaliadas por indentação instrumentada (II), e, com o mesmo equipamento, realizaram-se os ensaios de nanorisco. Na técnica de DL ocorre influência da temperatura de tratamento na formação das diferentes fases (γN ou αN, γ’-Fe4N, ε- Fe2+xN, CrN); nos tratamentos realizados a baixa temperatura (350 °C) predomina a formação da fase γN para o aço austenítico AISI 316 e das fases γ’ e ε para os aços HP13Cr e AISI 420, de estrutura martensítica, devido a diferença de solubilidade e difusividade de nitrogênio nas diferentes fases austenita e martensita. Os tratamentos de nitretação por DL causam o efeito da depleção do cromo em quaisquer dos aços na temperatura de 450 C. Nos tratamentos por DLGC ocorre a formação da fase independentemente da temperatura. Entretanto temperaturas mais altas propiciam a formação das fases γN e αN. Nos tratamentos por DLGC, a dureza da camada depositada medida por II permaneceu, independentemente do aço, próxima à da amostra de eeferência. A dureza das camadas modificadas existentes abaixo dos filmes produzidos por DLGC é próxima a dureza das camadas produzidas por DL mas sem efeito de borda e com baixa rugosidade. Nos tratamentos por DL, a dureza elevou-se de 2,5 GPa a até 15,5 GPa para o aço AISI 316. As espessuras estimadas para as camadas modificadas de amostras tratadas por DL são superiores às das camadas depositadas e modificadas de amostras tratadas por DLGC nos mesmos parâmetros. A resistência ao risco das superfícies modificadas por DL aumenta para quaisquer condições de tratamento. O maior valor de carga crítica de resistência ao risco (126,7 ± 32,1 mN) obtido para as camadas depositadas por DLGC é um valor muito baixo para as aplicações típicas esperadas desses aços. No entanto, são necessárias análises complementares na camada modificada para verificar a aplicabilidade dessa técnica para estes aços. As condições de excelência encontradas para a técnica de DL podem proporcionar um aumento da vida útil das peças tratadas nos meios onde são empregadas que exigem boas propriedades mecânicas e tribológicas.

Este trabalho tem por objetivo avaliar os efeitos do hidrogênio em três diferentes tipos de aços de alta resistência mecânica. São descritos os fenômenos de introdução, difusão e aprisionamento de hidrogênio (H) dentro dos metais, em conjunto com os diferentes tipos de danos provocados devido à presença do hidrogênio. Os materiais de estudo são aços da família Advanced High Strength Steels (AHSS): aços Dual Phase (DP 1000 e DP 1200) e aço Martensítico (M 190). A introdução de hidrogênio nos materiais foi realizada através de carregamento catódico, o qual é representativo para as condições industriais a que se destinam. De modo a avaliar a influência do H nas propriedades mecânicas dos aços, os seguintes ensaios foram propostos: ensaio de carregamento com H, para determinar o conteúdo total de H (saturação) e conteúdo de H difusível (suscetibilidade a fragilização); ensaio de tração ao ar, para determinar a tensão no final da região elástica e resistência à tração na região do entalhe e ensaio de tração com carga constante em ambiente hidrogenado, para avaliar os efeitos provocados pela presença do H e determinar o patamar abaixo do qual o H não apresenta efeito crítico sobre o material. Os efeitos provocados pela aplicação de diferentes densidades de correntes (0,2 – 1,0 mA/cm²) foram avaliados nos ensaios de quantificação de H difusível. Conforme os resultados obtidos todos os aços apresentaram perdas na resistência mecânica à tração quando em ambiente hidrogenado, ou seja, sofreram fragilização por H. Os aços DP 1200 e M 190 (de microestrutura predominantemente martensítica) foram fortemente afetados, conforme evidenciado pela notável queda nos valores de tensão necessários para provocar a falha. Por outro lado, o aço DP 1000, de menor resistência mecânica, demonstrou menor suscetibilidade à fragilização, o que é atribuído a menor permeabilidade do H na microestrutura austenítica. / This work aims to evaluate the effects of hydrogen in three high- strength steel grades. The phenomena of hydrogen (H) entry, transport and trapping inside the metals, together with the different types of damages due to the presence of hydrogen are presented. The study materials are a range of AHSS steel grades: Dual Phase Steel (DP 1000 and DP 1200) and Martensitic Steel (M 190). The hydrogen entry was performed by cathodic charging, which is suitable for industrial applications. In order to evaluate the influence of H on the steel mechanical properties, the following tests were done: H charging, to measure total H content (saturation point) and diffusible H content (embrittlement susceptibility); uniaxial tensile test of uncharged samples to determine notched tensile strength values and the strength levels at the end of elastic region and constant load tensile testing carried out in hydrogen environment, to determine the threshold values where hydrogen has an effect on the material. DP 1200 and M 190 were strongly affected by H pre-charging, as shown by the significant drop in stress required to break them. On the other hand, DP 1000 showed a lower embrittlement susceptibility, which is attributed to its lower mechanical strength. The current densities effects (0.2 up to 1.0 mA/cm²) were evaluated during H charging to measure diffusible H content. All steels showed a drop in the tensile strength i.e. experienced hydrogen embrittlement. Steels with higher tensile strength, as DP 1200 and M 190, showed a much bigger drop that is related to the favorable characteristics of martensitic microstructure regarding to the hydrogen permeability and diffusivity.

<p>Idén till detta arbete uppstod som en följd av att vi på den fartygsförlagda praktiken upptäckt att kunskapen om katodiskt korrosionsskydd är mycket bristfällig hos många ombordanställda. Vi har även gjort en mindre undersökning bland yrkesverksamma maskinister för att se hur kunskapsnivån inom detta område ligger ombord. Undersökningen visar att vår hypotes om kunskapsnivån stämde till stor del. Ytterliggare ett skäl till att vi studerat det här området är att vi själva har velat fördjupa oss i ämnet, då våra egna erfarenheter endast varit att skriva av siffror från en display. Vår huvudfrågeställning har varit, Hur fungerar katodiskt korrosionsskydd ombord på fartyg? För att få svar på denna frågeställning har vi bedrivit litteraturstudier inom ämnet. De teoretiska kunskaperna har vi samlat från internet och böcker. De praktiska kunskaperna har vi fått från tidigare praktikperioder samt under praktik på MS Silja Galaxy under perioden december 2008 till januari 2009.</p> / <p>The idea for this exam paper arose under our onboard training periods. Under these periods we understood that the knowledge in cathodic corrosion protection was poor among the engine personal. We have also made a minor survey among marine engineers to see how the knowledge in this area is onboard. The survey shows that our hypothesis on the level of knowledge corresponded to a large extent. Further reason why we studied this area is that we wanted to deepen us in this subject, when our own experience only was to write numbers from a display. Our main question has been how cathodic corrosion protection work at ships. In order to answer this question, we conducted literature studies in the subject. The theoretical knowledge we have gathered from internet and books. The practical knowledge we have gained from previous training periods and during onboard training on MS Silja Galaxy in December 2008 to January 2009.</p>

Idén till detta arbete uppstod som en följd av att vi på den fartygsförlagda praktiken upptäckt att kunskapen om katodiskt korrosionsskydd är mycket bristfällig hos många ombordanställda. Vi har även gjort en mindre undersökning bland yrkesverksamma maskinister för att se hur kunskapsnivån inom detta område ligger ombord. Undersökningen visar att vår hypotes om kunskapsnivån stämde till stor del. Ytterliggare ett skäl till att vi studerat det här området är att vi själva har velat fördjupa oss i ämnet, då våra egna erfarenheter endast varit att skriva av siffror från en display. Vår huvudfrågeställning har varit, Hur fungerar katodiskt korrosionsskydd ombord på fartyg? För att få svar på denna frågeställning har vi bedrivit litteraturstudier inom ämnet. De teoretiska kunskaperna har vi samlat från internet och böcker. De praktiska kunskaperna har vi fått från tidigare praktikperioder samt under praktik på MS Silja Galaxy under perioden december 2008 till januari 2009. / The idea for this exam paper arose under our onboard training periods. Under these periods we understood that the knowledge in cathodic corrosion protection was poor among the engine personal. We have also made a minor survey among marine engineers to see how the knowledge in this area is onboard. The survey shows that our hypothesis on the level of knowledge corresponded to a large extent. Further reason why we studied this area is that we wanted to deepen us in this subject, when our own experience only was to write numbers from a display. Our main question has been how cathodic corrosion protection work at ships. In order to answer this question, we conducted literature studies in the subject. The theoretical knowledge we have gathered from internet and books. The practical knowledge we have gained from previous training periods and during onboard training on MS Silja Galaxy in December 2008 to January 2009.