Wyniki wyszukiwania - BazTech

1

Characterization of Ca Precipitation in Al-Mg Alloys Containing a Trace of Ca During Homogenization

Ha Seong-Ho, Shin Young-Chul, Kim Bong-Hwan, Yoon Young-Ok, Lim Hyun-Kyu, Lim Sung-Hwan, Kim Shae K.

Archives of Metallurgy and Materials

|

2021

|

Vol. 66, iss. 4

959--962

EN

In this study, precipitation of Ca in Al-Mg alloys containing a trace of Ca during homogenization was investigated using a transmission electron microscope (TEM) and calculated phase diagrams. TEM result indicated that the Ca-based particles found in the examined sample are Ca7Mg7.5Si14. From the calculation of Scheil-Gulliver cooling, it was found that the Ca was formed as Al4Ca and C36 laves phases with Mg2Si and Al13Fe4 from other impurities phase during solidification. No Ca-Mg-Si ternary phase existed at the homogenization temperature in the calculated phase diagram. From the phase diagram of Al-Al4Ca-Mg2Si three-phase isothermal at 490°C, it was shown that Ca7Mg6Si14 phase co-exists with Al, Mg2Si and Al4Ca in the largest region and with only Al and Mg2Si in Al4Ca-poor regions. It was thought that the Ca7Mg6Si14 ternary phase was formed by the interaction between Mg2Si and Al4Ca considering that the segregation can occur throughout the entire microstructures.

2

Assessment of changes in microstructure and hardness of bearing steel for operation at a high temperature caused by short-term overheating

Łęczycki Krzysztof, Gronek Sebastian

Journal of KONBiN

|

2020

|

Vol. 50, iss. 4

89--110

EN

The paper presented research results of the impact of short-term overheating of samples collected from the outer bearing ring suitable for the operation at elevated temperature installed in the turbine engine on the microstructure and hardness of the material. The samples were annealed at the following temperatures: 500, 600, 700, 800, 900 and 1000°C; and then cooled in still air. Microstructure examinations were conducted under metallographic microscope and transmission electron microscope.

PL

W publikacji przedstawiono wyniki badań wpływu krótkotrwałego nagrzewania próbek pobranych z pierścienia zewnętrznego łożyska przeznaczonego do pracy w podwyższonej temperaturze z silnika turbinowego na mikrostrukturę oraz twardość jego materiału. Próbki wygrzewano w temperaturach: 500, 600, 700, 800, 900 i 1000°C, następnie studzono na spokojnym powietrzu. Badania mikrostruktury przeprowadzono, wykorzystując mikroskop metalograficzny oraz transmisyjny mikroskop elektronowy.

3

A field study on the possible attachment of DPM and respirable dust in mining environments

Gaillard Sallie, Sarver Emily, Cauda Emanuele

Journal of Sustainable Mining

|

2019

|

Vol. 18, iss. 2

100--108

EN

Typcial monitoring procedures for diesel particulate matter (DPM) in mines include the collection of filter samples using particle size selectors. The size selectors are meant to separate the DPM, which is generally considered to occur in the submicron range (i.e.,<0.8 μm), from larger dust particles that could present analytical interferences. However, previous studies have demonstrated that this approach can sometimes result in undersampling, therefore, excluding significant fractions of the DPM mass. The excluded fraction may represent oversized DPM particles, but another possibility is that submicron DPM attaches to supramicron dust particles such that it is effectively oversized. To gain insights into this possibility, a field study was conducted in an underground stone mine. Submicron, respirable, and total airborne particulate filter samples were collected in three locations to determine elemental carbon (EC) and total carbon (TC), which are commonly used as analytical surrogates for DPM. Concurrent with the collection of the filter samples, a low-flow sampler with an electrostatic precipitator was also used to collect airborne particulates onto 400-mesh copper grids for analysis by transmission electron microscope (TEM). Results indicated that, while typical submicron sampling did account for the majority of DPM mass in the study mine, DPM-dust attachment can indeed occur. The effect of exposure to such attached particulates has not been widely investigated.

4

Synthesis of Cu and Ce co-doped ZnO nanoparticles: crystallographic, optical, molecular, morphological and magnetic studies

Rawat M., Singh J., Singh J., Singh C., Singh A., Kukkar D., Kumar S.

Materials Science Poland

|

2017

|

Vol. 35, No. 2

427--434

EN

In the present research work, crystallographic, optical, molecular, morphological and magnetic properties of Zn1-xCuxO (ZnCu) and Zn1-x-yCeyCuxO (ZnCeCu) nanoparticles have been investigated. Polyvinyl alcohol (PVA) coated ZnCu and ZnCeCu nanoparticles have been synthesized by chemical sol-gel method and thoroughly studied using various characterization techniques. X-ray diffraction pattern indicates the wurtzite structure of the synthesized ZnCu and ZnCeCu particles. Transmission electron microscopy analysis shows that the synthesized ZnCu and ZnCeCu particles are of spherical shape, having average sizes of 27 nm and 23 nm, respectively. The incorporation of Cu and Ce in the ZnO lattice has been confirmed through Fourier transform infrared spectroscopy. Room temperature photoluminescence spectra of the ZnO doped with Cu and co-doped Ce display two emission bands, predominant ultra-violet near-band edge emission at 409.9 nm (3 eV) and a weak green-yellow emission at 432.65 nm (2.27 eV). Room temperature magnetic study confirms the diamagnetic behavior of ZnCu and ferromagnetic behavior of ZnCeCu.

5

Rapid capture and exemplary detection of clinical pathogen using surface modified fluorescent silica coated iron oxide nanoparticles

Chitra K., Annadurai G.

Biocybernetics and Biomedical Engineering

|

2014

|

Vol. 34, no. 4

230--237

EN

Rapid, sensitive and selective detection of pathogenic bacteria is very important for treat- ment of diseases like foodborne illness, sepsis and bioterrorism. The silica coated iron oxide nanoparticles (SIO) were synthesized using simple, cost-effective method and used for the rapid capture and detection of clinical pathogen. The surface modification of nanoparticles was carried out using 3-aminopropyltriethoxy silane. The scanning electron microscopy image results showed the slightly agglomerated spherical shaped nanoparticles. Transmis-sion electron microscope result showed the polydispersed particles in the size ranges from 5 to 12 nm. The EDAX results confirmed the coating of silica with iron oxide particles. The SAED pattern confirmed the crystalline nature of iron oxide nanoparticles and also indicated the presence of silica. The FTIR spectrum of the nanoparticles confirmed the functional groups of the iron oxide and surface modified fluorescent silica coated iron oxide nano-particles (SFSIO). This work provides a very effective method for controlling the growth, capture and detection of pathogenic bacteria.

6

Kinetyka wydzielania oraz właściwości stali maraging po krótkotrwałym starzeniu

Marcisz J., Garbarz B., Adamczyk M., Stępień J.

Prace Instytutu Metalurgii Żelaza

|

2012

|

T. 64, nr 4

18-22

PL

W pracy podjęto badania skutków wczesnych etapów umacniania wydzieleniowego ultrawysokowytrzymałych stali maraging MS350 i MS550. Badano zmiany struktury i właściwości w początkowych stadiach starzenia. Wyniki badań będą wykorzystane do modyfikacji technologii wytwarzania wyrobów ze stali maraging.

EN

In this paper, testing of the effects of early stages of precipitate strengthening of ultra-highstrength maraging steels MS350 and MS550 was presented. The changes in structure and properties in the initial stages of ageing were tested. Test results will be used for modification of the technology for manufacturing of maraging steel products.

7

Oznaczenie stężenia struktur azbestowych w powietrzu – nowa metoda

Rożkowicz M.

Biuletyn Państwowego Instytutu Geologicznego

|

2012

|

nr 450

83--90

PL

Azbest jest toksycznym minerałem, który powoduje wyniszczające efekty zdrowotne u ludzi. Z powodu jego toksyczności konieczne jest posiadanie skutecznych metod do wykrywania i kwantyfikacji azbestu w środowisku. Przez lata opracowano wiele metod, jednak każda z tych metod ma swoje mocne i słabe strony. Publikacja przedstawia kompleksową metodę kontroli stężeń struktur azbestowych w powietrzu. Metoda zawiera procedury: lokalizacji punktów pobierania próbek, pobierania próbek z powietrza, przygotowania próbek do analizy, identyfikacji struktur na podstawie cech morfologicznych, chemicznych, strukturalnych, zliczania struktur w próbce i wyznaczania stężenia struktur azbestowych w powietrzu.

EN

Asbestos is a toxic mineral known to produce debilitating health effects in humans. Because of its toxicity, it is necessary to have effective methods to detect asbestos in the environment. Over the years, a number of methods have been developed, but each method has its own strengths and weaknesses. The paper presents the composite method for the control of concentrations of asbestos structures in the air. The method involves the following procedures: location of sample collection points, collection of air samples, preparation of samples for analysis, identification of structures based on morphological, chemical and structural features, counting of asbestos structures in the sample and determination of concentrations of asbestos structures in the air.

8

Structure of gradient coatings deposited by CAE-PVD techniques

Dobrzański L. A., Staszuk M., Konieczny J., Lelątko J.

Journal of Achievements in Materials and Manufacturing Engineering

|

2007

|

Vol. 24, nr 2

55-58

EN

Purpose: The main aim of this research was investigation of the gradient and multicomponent coatings structure deposited by cathode arc evaporation physical vapor deposition (CAE-PVD) on a SiAlON substrate. Design/methodology/approach: The structure of investigated coatings was characterized by scanning and transmission electron microscopy. Chemical composition was determined by energy dispersive spectroscopy (EDS) method. Investigation of surface roughness was done. Findings: The results of the investigations of microstructure, chemical compositions and surface morphology of gradient TiAIN and multicomponent AlSiCrN coatings deposited by PVD techniques are given in the paper. The linear analyses of chemical compositions on cross-sections of the investigated coatings are given. In the gradient coatings the chemical composition changes continuously at the cross-section. The result of the investigations of thin foils performed with use of transmission electron microscope and selected a diffraction are given also. Research limitations/implications: In future the examination will progress for mechanical properties, e.g. microhardness, adhesion strength and abrasive wear resistance as well as for the technological machining test. Originality/value: Future examinations will progress for mechanical properties, e.g. microhardness, adhesion strength and abrasive wear resistance as well as technological machining tests.

9

TEM study of iridium silicide contact layers for low Schottky barrier MOSFETs

Łaszcz A., Czerwiński A., Ratajczak J., Kątcki J., Breil N., Larrieu G., Dubois E.

Archives of Metallurgy and Materials

|

2006

|

Vol. 51, iss. 4

551-554

EN

An influence of annealing temperatures (300, 400 and 500°C) on the iridium silicide formation in the Ir/Si structure was analysed by means of the transmission electron microscopy (TEM). The silicide layer is formed by the solid-state reaction between 15 nm thick Ir metallisation and a Si layer during the rapid-thermal-annealing (RTA) process for 120 s. The silicide layers are used as source/drain contacts for a novel technology of low Schottky barrier MOSFETs on SOI. For this reason the high quality of the silicide/Si interface and the silicide structure are essential for the electrical properties of the device. The studies enabled the determination of the silicide layer thickness, the layer morphology, and the silicide/Si interface roughness as well as the identification of the silicide phase. Annealing of the Ir/Si structure at 300 and 400°C caused formation of an amorphous iridium silicide layer between the iridium layer and the silicon substrate. At the highest annealing temperature (500°C) the whole Ir layer completely reacted with Si, forming a crystalline iridium silicide layer. A diffraction analysis showed that the silicide layer consists of the dominant IrSi orthorhombic phase and another silicide phase with higher content of silicon (IrSix). The IrSix is placed between IrSi and Si. It indicates that during solid-state reaction at 500°C the Si diffusion is predominant.

PL

Wpływ różnych temperatur wygrzewania (300, 400 i 500°C) na proces tworzenia się krzemku irydu w strukturze Ir/Si był badany za pomocą transmisyjnej mikroskopii elektronowej (TEM). Warstwa krzemkowa tworzy się podczas wygrzewania przez 120 s metoda RTA 15 nm warstwy irydu osadzonej na podłożu krzemowym. Tak wytworzone warstwy krzemkowe stosowane są jako źródło/dren kontakty w nowoczesnej technologii tranzystorów typu MOSFET na podłożach SOI. Uzyskanie najlepszych parametrów elektrycznych tranzystorów zależy od struktury krzemku jak i bardzo gładkiej granicy fazowej krzemek/Si. Badania przy użyciu TEM polegają na określeniu grubości i morfologii warstw krzemkowych, gładkości granicy fazowej krzemek/Si, jak również ustaleniu rodzaju struktury krystalicznej tworzącego się krzemku irydu. Wygrzewanie struktury w temperaturze 300 i 400°C powoduje tworzenie się amorficznej warstwy krzemku irydu pomiędzy warstwą irydu a podłożem krzemowym. W najwyższej temperaturze wygrzewania (500°C) cała warstwa irydu reaguje z krzemem, tworząc krystaliczną warstwę krzemku irydu. Analiza dyfrakcyjna wykazała, że warstwa krzemkowa składa się z dominujacej fazy IrSi o budowie rombowej oraz innej fazy krzemku irydu zawierającej więcej krzemu (IrSix) i położonej pomiędzy faza IrSi a podłożem krzemowym. Wynik ten wskazuje, że podczas reakcji w 500°C dyfuzja Si jest dominująca.

10

Elektrochemiczne osadzanie na podłożu Cu wielokrotnych nanowarstw Ag-Ni z kąpieli cyjankowych i kwaśnych.

Banaszkiewicz A., Cimochowski D.

Inżynieria Materiałowa

|

2002

|

R. XXIII, nr 5

380-383

PL

W niniejszej pracy przeprowadzono elektrolityczne osadzanie na podłożu miedzi wielokrotnych naprzemiennych warstw Ag (osadzanych z kąpieli cyjankowych) oraz Ni (osadzanych z kąpieli kwaśnych). Ustalono optymalny potencjał osadzania (-1000 mV w stosunku do nasyconej elektrody kalomelowej), przy którym osadzane warstwy były ciągłe i przyczepne do podłoża. Przy pomocy mikroskopu skaningowego zaobserwowano naprzemienne warstwy o grubości 50 nm każda. Podjęto próby obserwacji tych warstw na transmisyjnym mikroskopie elektronowym przy pomocy techniki triafolowych replik celowanych napylanych węglem i złotem. Uzyskano dobre odwzorowanie powierzchni, ale nie natrafiono na obserwowanych fragmentach replik na obszary obejmujące wielokrotne warstwy. Technika ta po jej dopracowaniu rokuje nadzieje na obserwację supersieci o grubości warstw rzędu 1 nm.

EN

In this paper electrochemical deposition of Ag-Ni multilayers on the Cu substrate from cyanide and acid baths is presented. Optimal deposition potential (-1000 mV SCE) was determined, at which deposited layers were of good quality and adherence. Using scanning electron microscope, multilayers of 50 nm thick were observed. Some efforts were made to observe those layers in STM using the triafole replica technique (vacuum sputtered with carbon and gold). Satisfying representation of the surface was obtained but in the observed fragments one could not find superlattices. Nevertheless, after ameliorating, this technique may let us observe superlattices built from layers 1 nm thick.

11

XTEM-study of ceramic-metal joints: SiC/Mo, Si3N4/Mo.

Jezierska E., Jezierski S., Jakubowski J., Senkara J.

Inżynieria Materiałowa

|

1998

|

R. XIX, nr 4

723-726

EN

Joining of SiC and Si3N4 to molybdenum was carried out using Ag-Cu-In brazing alloy containing Ti as an active addition. In the present investigation a novel approach to the examination of ceramic-metal interfaces by means of cross-sectional transmission electron microscopy (XTEM) is described. The identification of the reaction products in an active zone of the joints was done and the detailed structure of multiphase interfacial region is presented. XTEM investigations were performed using Jeol microscopes; JEM 100B and JEM 3010, equipped with energy dispersive spectrometer (EDS). TEM samples were prepared by mechanical dimpling and ion beam thinning of real cross-sections of joints.