Cubic carbides (titanium, tantalum, niobium, and zirconium carbides) can constitute a significant proportion of so-called cubic and cermet grades, where it is added to substitute a portion of tungsten carbide. It is thus critical to understand and be able to thermodynamically model the cubic carbide systems. In order to do this, the thermodynamic descriptions of lower order systems, such as the Ti-Cr-C system, need to be well studied. To approach this goal, an extensive literature survey of thermodynamic data and phase diagram information on the Ti-Cr-C system, the Ta-Cr-C system, the Nb-Cr-C system and the Zr-Cr-C is presented in this work. Experiments are performed in the Ti-Cr-C system using powder metallurgy and heat treatments. The solubility of Cr in FCC_TiC phase was experimentally measured at 1773K and compared with previous studies showing that the solubility reported earlier is too large. Thereafter, a re-optimization of FCC_TiC and liquid interaction parameters of the Ti-Cr-C system was performed taking into account the experimental data obtained both from previous studies and this work. The Gibbs energy descriptions of the Cr-carbide end members were compared between the one from the in-house database [SandvikTDB] and from other studies. With the new description, the solubility of Cr in FCC_TiC is better described.

The report discusses the destruction of toxic and non-toxic solids, liquids and gases through lasers. In order to completely understand the project first chapters describes the basics about laser and plasma separately, from definition to types, components and categories. Differences between laser and microwave system are covered in this chapter as well. Besides lasers there are different technologies that are currently being used to destroy toxic and non-toxic materials. These technologies were studied and comparison tables are made in order to discern between different destruction technologies. For the destruction of toxic and non-toxic materials through lasers two mathematical models have been developed, molecular dissociation model and plasma exploitation model, and later the experimental work was carried out on one of the toxic material. Mathematical modeling and experimental work is in accordance with each other as discussed in results and discussion. Mathematical model shows that all the materials discussed in the report can be destroyed by lasers but in order to carry further experiments on all other toxic and non-toxic materials, a proposal is made for the laser reactor using CAD model (Solid Edge) and drawing software (AutoCAD). Tables and mathematical calculations have been placed in appendix at the end of the report.

No description available.

Since the investigation of wear particles in rail transport started in late-1910s, the high mass concentration of these particles has raised worries among researchers concerned with air quality. However, effective action has yet to be taken because of lack of relevant knowledge. This thesis provides applicable information for the airborne wear particles in rail transport. Some aspects of their characteristics such as diameter size, mass concentration, number concentration, and morphology of particles were investigated in field tests and laboratory tests.The effects on particle characterisations from different operational conditions in the field tests, and applying different braking materials, conducting tests in different applied loads or sliding velocities in the laboratory tests were studied. The main advantage of conducting laboratory tests was to focus on studying particles from one source. The possibility of repetition, using high sensitive instruments and conducting tests at low costs are the other advantages of laboratory studies. Paper A describes how a pin-on-disc machine was used to reproduce similar real operational conditions during mechanical braking in a train. The results were validated by comparing the field tests results with the laboratory studies. The particles morphology and size distribution were also studied.Paper B presents a summary of field tests results. The effects of curve negotiating and applying braking in different real conditions were investigated with an on-board measurement.The element composition of the particles and their potential sources were also investigated outside of the particles morphologies.Paper C presents comprehensive results from laboratory studies on airborne particles from different braking materials. The differences in the particle characteristics in similar test conditions were attributable to different material compositions and dominant wear mechanisms. A new index was introduced in this paper and is suggested to be used as a qualitative factor with regard to the airborne wear particle emission rate.Paper D is a review of the recent studies of exhaust emission and non-exhaust emission from rail vehicles. A summary of results, measurements, adverse health effects, and proposed or applied solutions are reviewed in this paper. / <p>QC 20110812</p> / JVG F6521

No description available.

The oxide scale created during manufacturing of stainless steel is often removed by a chemical pickling with mixed acid. Various pre-treatments to pickling are also applied to increase the efficiency of the oxide scale removal. Shot blasting is one such pre-treatment, which operates to remove a certain amount of oxide and also to generate cracks and openings for the subsequent pickling. In this work, three materials, AISI 2205, 430 and 304 have been blasted and later exposed to mixed acid. This was conducted to quantify the effect shot blasting has on the subsequent pickling of stainless steel. Three shot products and two blasting parameters were investigated and varied. Shot blasting significantly reduced the oxide scale but was unable to remove the chromium oxide layer closest to the steel surface. No significant difference was observed when comparing the result from the three shot products after blasting. Increasing the particle velocity or the coverage rate further enhanced the pickling but reduced the amount of oxide removed during blasting. These effects are however relative small, so in practise relatively mild conditions seems preferable for economic reasons. Oxide scale containing hematite was difficult to remove by both shot blasting and pickling.

Due to growing demands for steel powder properties and continuous evolution of the powder metallurgy (PM) production it is necessary to apply new investigation technics and research applications for quality investigation of the PM products. In addition, it is important to be able to predict the probable maximum size of inclusions. The industrial scale sampling of steel was made in Höganäs AB. The three dimensional (3D) analysis of non-metallic inclusions obtained by electrolytic extraction (EE) method was applied for metal samples taken from liquid steel before water-atomization and after powder forging process. It was demonstrated that the application of the 3D analysis has a perspective and possibility to be used independently or like a reference during 2D analysis of inclusions in powder metallurgy products. The tundish samples have the maximum total number of inclusions but have smaller size of complex inclusion. The size range of inclusions in the ladle and tundish samples is between 1 and 46 μm. The main type of inclusions is spherical (Si-Ca-Al-Mg-O in composition). The powder forged samples have two main types of non-metallic particles: “gray” carbon saturated (10-250 μm) and “bright” clustered oxide particles (1-37 μm with Cr-Si-Mn-Mg-Al-O in composition). The probable maximum size of inclusions was estimated based on a new particle size distribution (PSD) and the standard extreme value distribution (EVD) methods. Both methods predicted that in 1 kg of metal the maximum size of spherical inclusions is &lt; 15 μm in liquid steel samples and the maximum length of “bright” clustered oxide particles is &lt; 63 μm in powder forged samples. However, the prediction of the maximum size by PSD method showed necessity of the further optimization.

Case hardening distortions are a major problem for gear manufacturers. The aim of the current work is to create a simulation model, able to predict how and when case hardening distortions arise. The results presented in this thesis form a basis for such a model. Two case hardening steels, with base carbon contents of 0.20 and 0.21 % C were studied using dilatometer experiments. One of them was carburized to 0.36, 0.52 and 0.65 % C in order to investigate the influence of carbon content. Experiments were performed during both isothermal and continuous heating and cooling conditions. The results were used to evaluate phase transformations, heat expansion behaviors and phase transformation strains. The expansion behavior of the material was modeled as a function of temperature, carbon content and phase fractions. The phase transformations to martensite and bainite were modeled, using the Koistinen-Marburger equation and a transformation rate equation based on Austin-Rickett kinetics, respectively. Experiments were simulated using the COMSOL Multiphysics software, to verify the model with respect to martensite and bainite transformations, heat expansion behavior and phase transformation strains.

Metal-organic frameworks (MOFs) constructed from metal atoms connected by organic linkers have received extensive attention for greenhouse gas separation in the past decades. Moreover, their large surface area makes them a promising candidate as adsorbents for gas sorption. This project aims to develop MOFs via different synthesis instructions by utilizing  Mg-containing materials, including Commercial MgCO3  and Mesoporous Magnesium Carbonate (Upsalite) as a source of the metal part and four different organic linkers. Water, Ethanol, Methanol, and N, N-dimethylformamide were used as solvents. First, synthesis was performed at room temperature, followed by high temperature using an autoclave and reactor. Then, the successfully synthesized samples were characterized by different characterization methods. These characterization techniques included Powder X-ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), and Infrared Spectroscopy (IR).  Porous properties of the MOFs were tested by gas adsorption techniques, including N2  and CO2 as adsorbate gases. As a result, it was found that synthesized MOFs have a high surface area and porosity to adsorb greenhouse gases and separate CO2 from N2. The highest surface area, N2, and CO2 adsorption amounts were 539 m²/g, 0.32 (mmol/g at 293K,1bar), and 3.31 (mmol/g  at 293K,1bar), respectively. CO2  adsorption is approximately ten times N2  adsorption in almost all MOF synthesized samples. To achieve the best result regarding the high amounts of surface area, N2, and CO2  sorption,  synthesis at room temperature using Commercial MgCO3, H2dhbq linker, and water solvent was the best approach.

In this project a novel chitosan-stearic acid (CS-SA) coating with bee-pollen microcapsules for encapsulation of 2-mecraptobenzothiazole (MBT) as a waterborne formulation for a biocompatible corrosion protection coating was developed and the coating properties was analyzed. Hydrophobic stearic acid (SA) was crosslinked with via a carbodiimide reaction to form micelles and is assembled on the bee- pollen grains and the chitosan matrix was further self-crosslinked using glutaraldehyde (GA). Stearic acid was used to hydrophobically interact with modified pollen and with further crosslinking with the chitosan, which was proven successful by FTIR results. The encapsulation of anticorrosive agent MBT into pollen was successful and examined by UV-Vis spectroscopy, however, the pollen cannot form a fully stable formulation with the chitosan micelle matrix, partially due to its relatively big size (ca. 20 μm), causing problems with forming a proper barrier protection. The size of the grains and the interference of the carbodiimide crosslinking is the most severe problems with the pollen microcapsules. Therefore, no further testing of the corrosive properties could be done, which requires a dense and stable coating to sustain in salty water for the whole measurement period. As the reference coatings without pollen provided much more promising results, especially when crosslinked with GA, the conclusion is that the reactivity of the pollen is proven difficult to crosslink, and choosing a proper size of a microcontainer and the appropriate encapsulation method in the binder matrix is vital and important for developing a corrosion protective coating. / Detta projekt bygger på framställningen och analysen av en tidigare outforskad chitosan-stearinsyra (CS-SA) färg med bi pollen som mikrokapslar för inkapsling av 2-mercaptobenzothiazole (MBT) som en vattenlöslig och biokompatibel anti-korrosions färg. CS-SA var tillverkat med en carbodiimide reaktion för att bilda miceller som ska omslutna pollenkornen, och även ett försök med vidare tvärbindning mellan chitosanen med glutaraldehyde (GA) gjordes. Stearinsyra fick interagera hydrofobiskt med den modifierade pollen och tvärbindes sedan med chitosan, som visade sig vara lyckad med hjälp av FTIR analys. Enkapsuleringen av MBT visade sig med UV-Vis spektroskopi vara lyckad, dock på grund av pollens stora korn (ca 20 μm) orsakade problem med att bilda en stabil barriär mot omgivningen. Storleken av pollen och dess reaktivitet med carbodiimide tvärbindningen är de mest allvarliga problemen med pollen som mikrokapslar, och därav gjordes inga vidare tester av korrosions egenskaperna då detta kräver en täckande och stabil film genom hela mätningen. Då även referensfärgen som gjordes utan pollen gav avsevärt mycket bättre resultat i det avseendet är slutsatsen att reaktiviteten av pollen gör det problematiskt att tvärbinda med chitosan och valet av en kapsel av rätt storlek och hur den inkapslar är avgörande för att utveckla en bra korrosionsskyddande färg.