This thesis work is part of the BTH research lab, focusing on developing the early product development, by analyzing how to integrate the manufacturing process with the early design process. A known problem in the manufacturing industry is the knowledge gap between the designers and the manufacturing process. Where in the early stages of the product development a knowledge regarding the manufacture process is needed. This is in many cases ignored by the designers because it is commonly thought that the responsibility of selecting the manufacturing processes for a product falls upon the manufacturers, despite the fact that the manufacturing processes in reality is highly dependent upon the design choses such as materials, size, shape, finishing and tolerances of the product. To mitigate this problem a variations of product ‘team’ approaches have been used where the idea is to involve a multitude of people with the necessary experience to produce a ‘production friendly product’. Those approaches have a few drawbacks mainly the problem of finding people with the relevant experiences or that the expertise only covers the manufacturing processes already used in the organization, losing the opportunity to benefit from any alternative manufacturing process. This thesis focuses on how the welding manufacturing technic, analysis can be integrated into the design process with the help of a digital model? To improve the communications between the manufacturers and designers, two excel files were developed. The first excel file aimed at the manufacturers where they can present the specific machines used in the workshop. Focusing on specific machine and workshops instead of on the general welding method will give the designers a better understanding of the feasibility of producing their design in a specific workshop instead of focusing on a specific manufacturing method. The second excel file is aimed at calculating and comparing the weld methods where the cost and requirements are derived for general welding methods and compared with the machine specifications gathered from the manufacturers using the first excel file. To assess the excel files, a parametrized CAD model of the rear engine turbine structure was developed, and three different cases were used to evaluate the developed excel files. The values used are presented in Appendix A: Table 11–15, and were gathered from public sources. Values were also approximated using regression analysis. / Avhandlingen är en del av BTH research lab och fokuserar på det tidiga produktutvecklingsstadiet. Närmare kontrolleras hur produkttillverkningsprocessen kan integreras in i det tidiga produktutvecklingsstadiet. Ett känt problem för detta område är skillnaden på kunskapen som designer och tillverkaren besitter under det tidiga produktutvecklingsstadiet, då kunskapen om tillverkningsprocessen inte existerar. Vanligtvis tar inte produktutvecklare hänsyn till detta, eftersom ansvaret för valet av tillverkningsprocessen bedöms falla på tillverkaren. Trots att tillverkningsprocessen beror på många aspekter som bestäms under designprocessen som till exempel materialval, geometrin, efterbehandlingar och toleranser på produkten. För att minimera problemet involverar industrin en stor variation av människor med kompetens och erfarenhet, som sedan kan tillverka en produkt rätt anpassad för tillverkningsprocessen. Dock har denna lösning några nackdelar, då det kan vara svårt att hitta människor med rätt erfarenhet, men då man fokuserar på ett tillverkningssätt så kan företaget gå miste om fördelarna med alternativa tillverkningsprocesser. Denna avhandling fokuserar på hur analysen av svetstillverkningstekniken kan integreras in i designprocessen med hjälp av en digital modell. För att förbättra kommunikationen mellan tillverkare och designer har 2 Excel filer utvecklats. Den första Excel filen är riktat mot tillverkarna där dem kan nämna maskinerna som finns tillgängliga i deras verkstad. Den andra Excel filen är till för att kunna göra en kostnadskalkyl och jämföra dem olika tillverkningsmetoderna med hjälp av maskinspecifikationerna som fanns presenterade i den första Excel filen. För att utvärdera Excel filerna, har en parametrisk CAD modell skapats och 3 fall har använts för att testa de utvecklade CAD modellera. Värdena som använts i detta examensarbete finns i Appendix A: Table 11–15 och är hämtade från allmänt tillgängliga källor. Värden uppskattades också med hjälp av regressionsanalyser.

This project was ordered by Sandvik Materials Technology and was performed by a group of students at Uppsala university. The purpose of the project was to study precipitation behavior and structure stability in six advanced heat resistant alloys. Each sample were subjected to a creep rupture test in 600 or 700°C depending on the alloy type. Two parts of each alloy where examined; one part which had been affected by creep and another part which was unaffected by creep. A literature study was performed first to gain knowledge of the scientific theory utilized in this project, namely creep, precipitation hardening, and about the different materials which were analyzed. Preliminary results for the phase composition of the materials were obtained from a Thermo-Calc (TC) simulation. The SEM-images showed nothing noteworthy for any sample due to the roughness of the sample surfaces. The EDS-analysis showed chromium depletion in the centers of the aged samples of HT9 and Sanicro® 75X. Other minority phases such as Cr23C6 in Sanicro®70, P-phase and a titanium nitride phase in sanicro® 60X, VB in Esshete 1250 and Sigma-phase in 4C54 were identified using EDSmapping. It was found that when using XRD to analyze the phase compositions of small samples it is impractical to have the samples cast in bakelite beforehand. The XRD-results obtained in this project showed that more than 90% of the XRD diffractogram for every sample was graphite, which made the identification of minority phases impossible. The quality of the LOM-images varied greatly between samples, for 4C54 grain sizes were measured in all images, for Esshete 1250 grain sizes were measured for the crept sample, and for Sanicro® 60X measurements could only be taken from one image. Most of the sample preparation was insufficient to achieve the test results necessary for complete microstructural analysis and phase analysis of the samples. The mistakes in the practical steps of the project were noted and improvements for these mistakes are presented in the conclusion.

The major challenges currently facing the mining industry are related to the growing trend to deal with deeper ore bodies and consequently increasing complex ores. This has led to the development of new approaches to tackle incoming issues by integrating different parts of the value chain in order to offer appropriate solutions. One of these is the geometallurgical approach, which seeks to integrate geology and mineral processing to optimize ore beneficiation. This assessment can be carried out using a methodology called "Particle Tracking" that basically allows to go a step forward in the study of the phenomena occurring during ore beneficiation from the common assessment by size to the particle level. In other words, this methodology enables to incorporate to the analysis mineral liberation and the different mineral phases in particles. This is essentially what is described in literature as “Particle based approach”. This way, streams are regarded as a set of particles that have different properties and therefore their deportment throughout beneficiation vary accordingly. The purpose of this work was to apply “particle tracking” to samples from Pyhäsalmi beneficiation plant in central Finland. Rougher and scavenger flotation cells of the copper circuit were the main focus of this study. Mineral liberation analysis was used over samples of feed, concentrate and tailings for both rougher and scavenger. Mass balance and reconciliation were performed for bulk streams, streams divided by size and particle classes (classification of particles based on liberation degree) using HSC10 software from Outotec. The main findings show that recovery of chalcopyrite in rougher is above 80% over all size fractions, highest recovery is achieved at 90 µm and most liberated chalcopyrite particles present in the ore were reported to rougher concentrate. In case of scavenger, recovery to concentrate is reduced to a highest value of 66% between 60 µm to 80 µm with pronounced variation over size fractions. Most of chalcopyrite bearing minerals reported to scavenger concentrate are binary (two mineral phases) and complex (more than two mineral phases). Final tailings exhibit minimum amount of chalcopyrite, which is a good indicator of the efficiency of the copper circuit. In terms of recovery of chalcopyrite bearing particles, rougher reported to the first concentrate mainly liberated, binary and complex particles. An interesting finding was that complex particles to the first concentrate showed a particular high recovery. The second rougher concentrate mostly reported liberated and binary particles. As for scavenger, the first concentrate mostly reported liberated and complex particles while the second concentrate mainly reported complex particles. Final tailings exhibit essentially complex particles linked to coarse size fraction and the bulk grade of chalcopyrite for that stream was found to be noticeably low. / <p>The presentation was made through the zoom platform</p>

This thesis covers fundamental aspects of process control when growing titanium oxide nanoparticles in a reactive sputtering process. It covers the influence of oxygen containing gas on the oxidation state of the cathode from which the growth material is ejected, as well as its influence on the particles oxidation state and their nucleation. It was found that a low degree of reactive gases was necessary for nanoparticles of titanium to nucleate. When the oxygen gas was slightly increased, the nanoparticle yield and particle oxygen content increased. A further increase caused a decrease in particle yield which was attributed to a slight oxidation of the cathode. By varying the oxygen flow to the process, it was possible to control the oxygen content of the nanoparticles without fully oxidizing the cathode. Because oxygen containing gases such as residual water vapour has a profound influence on nanoparticle yield and composition, the deposition source was re-engineered to allow for cleaner and thus more stable synthesis conditions. The size of the nanoparticles has been controlled by two means. The first is to change electrical potentials around the growth zone, which allows for nanoparticle size control in the order of 25-75 nm. This size control does not influence the oxygen content of the nanoparticles. The second means of size control investigated was by increasing the pressure. By doing this, the particle size can be increased from 50 – 250 nm, however the oxygen content also increases with pressure. Different particle morphologies were found by changing the pressure. At low pressures, mostly spherical particles with weak facets were produced. As the pressure increased, the particles got a cubic shape. At higher pressures the cubic particles started to get a fractured surface. At the highest pressure investigated, the fractured surface became poly-crystalline, giving a cauliflower shaped morphology.

Over time the level of inoculant will decrease due to fading and this needs to be compensated bymore additions of inoculant. When casting CGI400 at Scania a one-step method is used, and the inoculant additions are based on the last ladle from the previous oven. Longer stops in production will result in the previous oven not being representable and more inoculant should be added. A method to establish the inoculation level of the base iron in the oven would make it easier to control the process. This study was about inoculation measurements with the help of thermo- analysis of the melt in the oven to get a better understanding how it fluctuates between ovens and changes over time. The study is also about how to implement this tool into production in a foundry. With the help of thermo- analytic measurements, the inoculation level of the melt was established, and the method was also used to see how the level of inoculant changed over. To establish the inoculation additions needed, the saturation point of inoculant was investigated. The results from the study shows that the starting level of inoculant is too low in the melt it also shows that the inoculation level fluctuates over time. The conclusions that can be drawn from this study is that thermos analysis can be used in production to establish the inoculation level, but moremeasurements needs to be conducted to determine its accuracy. / Över tid så minskar ympnivån i en smälta på grund av fading och detta måste kompenseras med mertillsatser av ymp. Vid gjutning av CGI400 på Scania används en en-stegs metod där man baserar ymptillsatsen i skänken på vad ympnivån var i sista skänken från den tidigare ugnen. Vid längre produktionsstopp kommer inte ympnivån från ugnen innan vara representativ utan mer ymp måste tillsättas. En metod för att bestämma ympnivån av basjärnet i ugnen skulle göra det lättare att styra processen. Denna studie handlar om ympmätning med hjälp av termisk analys i bas smälta för att få en bättre förståelse för hur den fluktuerar mellan ugnar och ändras över tid. Studien handlar också om hur man ska kunna applicera denna mätmetod i produktionen på ett gjuteri. Med hjälp av termo analytiska mätningar skulle grundnivån av ymp i smältan bestämmas och även för att se hur nivån ändrades över tiden. För att bestämma tillsatsen av ymp som borde tillföras undersöktes mättnadspunkten av ymp och hur den kunde tillsättas i skänk. Resultaten från studien visar att grundnivån av ymp är för låg och resultaten visar också att nivån av ymp fluktuerar både upp och ner ökar tid vilket inte var vad man hade förväntat sig och även det finns flera faktorer som kan påverka nivån. Slutsatsen som kan dras är att termisk analys kan användas i produktion för att bestämma ympnivån, men mer mätningar behövs för att bestämmadess noggrannhet.

Case hardened Uddeholm Orvar® Superior (Orvar) has the potential to replace currently used materials in shafts inside transmissions, which would lower the overall weight and thus result in lower fuel consumption while maintaining the necessary mechanical properties. However, previous studies have failed to reliably carburize the steel during the case hardening process. The case contains tempered martensite, which has high wear resistance, hardness, and good fatigue properties, and will be affected by the absence of the additional carbon. The presence of passive oxide layers such as chromia and silica is believed to inhibit the carburization, this by their impact of the adsorption and diffusion. One suggested solution is a preoxidation step before the carburization, to promote the formation of iron oxides which are preferential for carburization due to higher diffusion. To evaluate the impact of preoxidation different times, temperatures, and cooling methods were used and analyzed by LOM, XRD, SEM, and hardness measurements. The results indicate that reliable carburization can be obtained by preoxidation performed at 600 °C for 24 hours followed by immediate case hardening. / Sätthärdat Uddeholm Orvar® Superior (Orvar) har potential att ersätta nuvarande material i drivaxlari växellådor, detta skulle minska vikten och därmed sänka bränslekonsumtionen medan de nödvändiga mekaniska egenskaperna behålls. Tidigare studier har emellertid misslyckats med att tillförlitligt uppkola stålytan under sätthärdningen. Ytan består utav tempererad martensit som har hög slitstyrka, hårdhet, och bra utmattningsegenskaper, och påverkas utav avsaknaden av tillfört kol. Närvaron av passiva oxidskikt som kiseldioxid och kromoxid tros hindra uppkolningen, detta på grund utav deras påverkan på adsorption och diffusion. En föreslagen lösning är ett föroxideringssteg innan sätthärdningen, för att gynna bildandet utav järnoxider vilka är fördelaktiga för uppkolningen på grund utav högre diffusion. För att utvärdera påverkan av föroxideringen användes olika tider, temperaturer, och kylningsmetoder som blev analyserade utav LOM, XRD, SEM, och hårdhetsmätningar. Resultaten indikerar att tillförlitlig uppkolning kan uppnås med föroxideringutförd vid 600 °C i 24 timmar följt utav omedelbar sätthärdning.

Firstly, an existing thermodynamic model for the predicting of martensite start temperature of commercial steels has been improved to include more elements such as N, Si, V, Mo, Nb, W, Ti, Al, Cu, Co, B, P and S and their corresponding composition ranges for Martensitic transformation. The predicting ability of the existing model is improved considerably by critical assessment of different binary and ternary systems i.e. CALPHAD approach which is by wise selection of experimental data for optimization of the interaction parameters. Understanding the degree of variation in multi-component commercial alloys, various ternary systems such as Fe-Ni-X and Fe-Cr-X are optimized using both binary and ternary interaction parameters. The large variations between calculated and the experimental values are determined and reported for improvements in thermodynamics descriptions.Secondly, model for the prediction of Epsilon martensite start temperature of some commercial steels and shape memory alloys is newly introduced by optimizing Fe-Mn, Fe-Mn-Si and other Fe-Mn-X systems considering the commercial aspects in the recent development of light weight steels alloyed with Al and Si.Thirdly, the effect of prior Austenite grain size (pAGS) on martensite start temperature is introduced into the model in the form of non-chemical contribution which will greatly influence the Gibbs energy barrier for transformation. A serious attempt has been made to describe the dependency of transition between lenticular and thin-plate martensite morphologies on the refinement of prior Austenite grain size.Finally, the model is validated using a data-set of 1500 commercial and novel alloys. Including the newly modified thermodynamic descriptions for the Fe-based TCFE9 database by Thermo-Calc software AB, the model has the efficiency to predict the martensite start temperature of Multi-component alloys with an accuracy of (±) 35 K. The model predictability can be further improved by critical assessment of thermodynamic factors such as stacking faults and magnetism in Fe-Mn-Si-Ni-Cr systems.

Calcium treatment is an established operation in the production of steels. Most importantly, it serves to modify detrimental inclusions in the melt for improved castability and superior product properties. Due to calcium’s low melting point and high vapour pressure, its addition to liquid steel is challenging and yields are generally low. The current standard method for addition is cored wire feeding, in which a calcium-bearing compound is injected into the melt inside a sacrificial metal tube. The depth at which the compound is released has a pronounced impact on its yield and depends on the rate at which the wire is injected. A mathematical model is constructed to predict the time after which release occurs and thus estimate injection depth. It is based on one-dimensional heat transfer and respects phase change effects, i.e., solidification of melt on the cold wire surface and subsequent melting of the wire and compound. Equations are derived using the finite difference method and the model is solved numerically using an implicit method. The model is applied to two different steel grades – one austenitic (AISI 316L), one super-duplex (SAF 2507) – and predictions are tested for the former grade in a 75-ton industrial ladle furnace. Results indicate that a decreased feeding rate (&lt;100 m/min) leads to better calcium yield. Positive effects were also observed with downward melt stirring and a good slag coverage. Improved yield can lead to savings in process and material cost. The results also provide insights into the cored wire feeding process which may be useful for future process development, both for calcium and other additions. / Kalciumbehandling är en etablerad process vid tillverkning av stål. Framförallt används den för modifieringen av skadliga inneslutningar i smältan för att förbättra gjutbarheten och produktegenskaper. På grund av kalciums låga smältpunkt och höga ångtryck är det svårt att tillsätta det till flytande stål och utbytet är i allmänhet låg. Den nuvarande standardmetoden för tillsats är inmatning av tråd, där ett kalciumhaltig ämne matas in i smältan inuti en metallhölje som smälter bort. Djupet på vilket ämnet frigörs påverkar utbytet och beror på hur snabbt tråden matas. En matematisk modell konstrueras för att beräkna den tid efter vilken frisättning sker. Den bygger på endimensionell värmeöverföring och tar hänsyn till fasförändringseffekter, dvs. stelning av smältan på den kalla trådytan och smältning av tråd och kalciumämne efteråt. Ekvationer härleds med hjälp av finita differensmetoden och modellen löses numeriskt med hjälp av en implicit metod. Modellen tillämpas på två olika stålsorter – en austenitisk (AISI 316L) och en superduplex (SAF 2507) – och förutsägelser testas för den förstnämnda sorten i en 75-tons industriell skänkugn. Resultaten visar att en minskad matningshastighet (&lt; 100 m/min) leder till ett ökat kalciumutbyte. Positiva effekter observerades med nedåtgående smältomrörning och god slaggtäckning. Ett förbättrat utbyte kan leda till besparingar i fråga om process- och materialkostnader. Resultaten ger också insikter i processen för inmatning av tråd, vilket kan vara användbart för framtida processutveckling, både för kalcium och andra tillsatser.

The landfilling of slag obtained from the high alloyed Electric Arc Furnace (EAF) steel making process, constitutes an environmental treat for society as well as an economical problem for the companies producing it, due to the costs related to waste management practices. Conventional methods of slag recycling are abundantly used among the steelmaking business, but due to their particular physical properties, high- alloyed EAF slags cannot be properly valorized. Moreover, the pickling process that high-alloyed EAF steels undergo to, generates acidic wastewaters, that need to be collected and neutralized, before they can be recirculated into the natural water streams. For such a task, steel mills currently utilize slaked lime (a Ca rich mineral) to raise the pH and to remove any metal particles dissolved into the wastewaters. Slag contains high amount of Ca; therefore, it has already been tested as a slaked lime replacement. In fact, previous studies conducted at the Material Science and Engineering department at KTH Royal Institute of Technology showed, on a laboratory scale, that slag has the potential to replace lime for the neutralization and purification of the acidic wastewaters. This Master’s thesis project aims at upscaling the volumes of wastewaters to be tested, about 70 to 90 folds of the one from previous research, bridging the gap between laboratory tests and the industrial scale. The thesis is divided into three tranches, a first part where a water-salt solution conductivity trials were carried out, to model the behavior or slag dispersion in the acidic wastewaters. After the results obtained from the conductivity trials, neutralization trials with slag and the lime product currently in use by the company, were carried out at the neutralization plant in Outokumpu Stainless, Avesta (Sweden). The neutralization trials were carried out with 70 and 90 liters of acidic wastewaters and in order to perform the trials on site, the slag sample was dried and later sieved to a particle size of less than 350μm. Moreover, data was analyzed and compared to previous studies in order to have a clearer understanding regarding the neutralization efficiency of the slag, especially whether or not the technology would had worked on upscaled volumes. Additionally, the project checked if it was possible to find a generalized relationship between the mass of slag and volume of wastewaters required for the neutralization process. Slag demonstrated to be able to buffer the pH to the target values of 9, while also showing an almost linear trend compared to previous studies. The reaction progress between slag, lime, and the acidic wastewaters was also analyzed. / Deponering av slagg som erhållits från den höglegerade ljusbågsugn (EAF) stålframställningsprocessen utgör en miljömässig behandling för samhället och ettekonomiskt problem för de företag som producerar den på grund av kostnaderna för avfallshantering. Konventionella metoder för återvinning av slagg används i storutsträckning bland stålindustrin, men på grund av deras speciella fysiska egenskaper kan höglegerade EAF-slaggen inte värderas ordentligt. Dessutom produceras sura avloppsvatten av betningsprocessen som höglegerade EAF-stål genomgår som sedan måste samlas in och neutraliseras innan de kan återcirkuleras i det naturliga vattnet. För en sådan uppgift använder stålfabriker för närvarande släckt kalk (ett Ca-rikt mineral) för att höja pH-värdet och för att avlägsna alla metallpartiklar som löses upp i avloppsvattnet. Slaggen innehåller hög mängd Ca och därför har den testats som en ersättning till släckt kalk. Tidigare studier utförda vid avdelningen materialvetenskap och teknik vid Kungliga Tekniska Högskola visade på laboratorieskala att slagg har potential att ersätta kalk för neutralisering och rening av sura avloppsvatten. Detta examensarbete syftar till att skala upp volymerna av avloppsvattnet som ska testas till cirka 70–90 gånger av den från tidigare forskning, och därav fylla ut bryggan mellan laboratorietester och industriell skala. Avhandlingen är uppdelad i tre delar, Första delen innehåller försök på ledningsförmåga i en vatten-saltlösning som genomfördes för att modellera beteende eller slaggspridning i sura avloppsvatten. Efter de resultat som erhållits från konduktivitetsmätningarna genomfördes neutraliseringsförsök med slagg och kalk som för närvarande används av företaget vid neutraliseringsanläggningen i Outokumpu Stainless, Avesta (Sverige). Neutraliseringsförsöken genomfördes med 70 och 90 liter sura avloppsvatten och för att utföra experimenten på plats torkades slagg provet och siktades senare till en partikelstorlek på mindre än 350 μm. Dessutom analyserades data och jämfördes med tidigare studier för att få en tydligare förståelse för slaggens neutraliseringseffektivitet, särskilt huruvida tekniken skulle ha fungerat på större volymer, och även om det också var möjligt att hitta ett generaliserat samband mellan mängden slagg och volym avloppsvatten som krävs för neutraliseringsprocessen. Slagget visade sig kunna buffra pH till målvärdena 9, samtidigt som den visade en nästan linjär trend jämfört med tidigare studier. Reaktionsförloppet mellan slaggkalk och de sura avloppsvattnen analyserades också.

Electroplated zinc-alloy coatings have been used on fasteners in the automotive industry for many years. The coating often consists of three layers: a zinc-alloy layer, a passivation layer and a sealer or top-coat. The coating layers affect the functional properties of the fastener (mainly the corrosion resistance, friction coefficient and electrical conductivity), and the aim of this thesis has been to increase the understanding of how these functional properties are affected by the properties of the coating. The corrosion resistance, friction coefficient and electrical conductivity of several different fasteners have been tested. Variations in these properties are connected with morphological and chemical properties of the electro-deposited zinc-alloy coating, passivation layer and sealer/top-coat of the fasteners. Measurement methods include scanning electron microscope and energy dispersive x-ray spectroscopy (SEM-EDX), light optical microscope (LOM), x-ray fluorescence (XRF), glow discharge optical emission spectroscopy (GD-OES), broad ion beam (BIB) and Fourier transform infrared spectroscopy (FTIR). From the results it can be concluded that the surface structure of zinc-nickel layers differs significantly from supplier to supplier. Screws with a thicker and rougher zinc-nickel surface structure displays higher friction values, but lower electrical resistance values. Optimisation of both of these properties is thus challenging. The distribution and surface structure of the outmost top-coat layer also differs between suppliers, but no connection between this and the functional properties of the screw has been found. The corners of the screw heads are often lacking a proper zinc-alloy coating, and this is also where corrosion is initiated. In general, the zinc-nickel alloy coating systems are performing better and display less corrosion spreading effects than the zinc-iron or pure zinc systems in terms of corrosion. / Elektropläterade zinklegeringsbeläggningar har använts på fästelement inom bilindustrin under många år. Beläggningen består ofta av tre skikt: ett zinklegeringsskikt, ett passiveringsskikt och en ”top-coat”, eller ”sealer”. Beläggningsskikten påverkar fästelementens funktionella egenskaper (främst korrosionsbeständighet, friktionskoefficient och elektrisk ledningsförmåga) och syftet med denna avhandling har varit att öka förståelsen för hur dessa funktionella egenskaper påverkas av ytbeläggningens egenskaper. Korrosionsmotståndet, friktionskoefficienten och den elektriska ledningsförmågan hos flera olika fästelement har mätts. Variationer i dessa egenskaper kopplas till de morfologiska och kemiska egenskaperna hos den elektropläterade zinklegeringsskiktet, passiveringsskiktet och top-coat-skiktet hos fästelementen. Mätmetoder inkluderar svepelektronmikroskop och röntgenspektroskopi (SEMEDX), ljusoptiskt mikroskop (LOM), röntgenfluorescens (XRF), optisk strålningsspektroskopi (GD-OES), bred jonstråle (BIB) och Fourier-transformerad infraröd spektroskopi (FTIR). Av resultaten kan man dra slutsatsen att ytstrukturen hos zink-nickelskiktet skiljer sig avsevärt från leverantör till leverantör. Skruvar med tjockare och hårdare zink-nickelytstruktur visar högre friktionsvärden, men lägre elektriska resistansvärden. Optimering av båda dessa egenskaper är således utmanande. Distributionen och ytstrukturen hos det yttersta top-coat-skiktet skiljer sig också mellan leverantörer, men ingen samband mellan detta och skruvens funktionella egenskaper har hittats. Skruvhuvudets hörn saknar ofta en lämplig zinklegeringsbeläggning, och det är också där korrosion initieras. I allmänhet fungerar zink-nickellegeringsbeläggningssystemen bättre och visar mindre spridningseffekter i termer av korrosion än zinkjärn eller rena zinksystem.