Wyniki wyszukiwania - BazTech

1

Stanowisko do pomiaru przewodności elektrycznej próbek stopów metali o małych gabarytach

Grzenik Michał, Kubiczek Krzysztof, Kampik Marian

Przegląd Elektrotechniczny

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2022

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R. 98, nr 12

23--26

PL

W artykule przedstawiono metodę i stanowisko do pomiaru przewodności elektrycznej próbek metali w kształcie prostopadłościanu o nieregularnych wymiarach geometrycznych. Oszacowana niepewność pomiaru przewodności wynosi około 5% (k=1).

EN

The article presents a method and a measurement system for measuring the electrical conductivity of metal samples in the shape of a cuboid with irregular geometrical dimensions. The estimated uncertainty of the conductivity measurement is approximately 5% (k=1).

2

Material investigations on poly(ethylene glycol) diacrylate-based hydrogels for additive manufacturing considering different molecular weights

Klimaschewski Sven F., Küpperbusch Janine, Kunze Annika, Vehse Mark

Journal of Mechanical and Energy Engineering

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2022

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Vol. 6, No 1

33--41

EN

The aim of this case study is to generate several poly(ethylene glycol) diacrylate-based hydrogels using additive manufacturing processes. The interest here is in determining different material properties. The test specimens are produced using a commercial stereolithography system. For this purpose, three formulations are prepared. The basis in each case is PEGDA with average molecular weights of 700 Mn, 575 Mn and 250 Mn. A photoinitiator and a UV absorber are added to ensure spatial and temporal cross-linking. Furthermore, the formulations are tested for their material properties according to ISO standards using tensile, compression and hardness tests. An equivalence can be found in the tensile and compression tests. The results with the molecular weights of 700 Mn and 575 Mn show values close to each other. However, the results of the material tests with the molecular weight of 250 Mn are ten times higher. The Shore A hardness values also correlate with the previous tests. These results between molecular weight and material property are particularly striking. A novel aspect of this method could be that the properties determined of these tailor-made high-performance polymers can be applied to different areas of application in an organism.

3

Kontrola właściwości fibrobetonu przeznaczonego na prefabrykowane elementy stałej obudowy tunelu pod Świną

Jurczak Robert

Mosty

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2021

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nr 4

74--77

PL

W artykule przedstawiono badania prowadzone przez laboratorium GDDKiA nad fibrobetonem przeznaczonym do wykonania prefabrykowanych elementów stanowiących stałą obudowę tunelu pod Świną.

4

Cavitation erosion resistance influence of material properties

Zakrzewska D. E., Krella A. K.

Advances in Materials Science

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2019

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Vol. 19, nr 4(62)

18--34

EN

The cavitation erosion is the phenomena that causes degradation of fluid flow machinery components due to repetitive implosion of cavitation bubbles adjacent to the solid surface. Cavitation erosion is a complex phenomenon, which includes not only hydrodynamic factors of liquid, but also properties of erodible material e.g. microstructure, hardness or Young modulus. In order to reduce the negative impact of erosion on machine components, there are many methods to increase cavitation erosion resistance. The paper discusses the correlations between structural and mechanical properties and the resistance to cavitation erosion (CER) of pure materials, their alloys and coatings. Methods to increase CER have also been described - using heat / thermo-chemical treatment and application of coatings by various methods.

5

Inferring material properties in robotic bone drilling processes

Gil Jorge Juan, Díaz Iñaki, Accini Fernando

Acta of Bioengineering and Biomechanics

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2019

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Vol. 21, no. 3

109--118

EN

Recent innovations in robotics have enabled the development of automatic bone drilling tools which allows surgeons to improve the precision of their surgical operations. However, these tools still lack valuable tactile information about the material properties of the bone, preventing surgeons from making decisions while operating. The aim of this work is to explore whether robotic drilling tools can infer bone condition on the basis of certain key measures, particularly thrust force. Methods: To infer material properties in robotic bone drilling processes 1) a complete database of experimental operations with an automatic bone drilling tool is implemented and 2) binary logistic regression models are developed to estimate the type of material from the observed values (mainly the central tendency of the thrust force). This work compares three different materials: bovine bone specimens, porcine bone specimens and FullCure 720, which is a general-purpose resin with, a priori, much less feed resistance. The DRIBON automatic bone drilling tool developed at CEIT is used for the experiments. Results: The classification matrices derived using the logistic models show that it is possible to recognize a bovine bone vs. a porcine bone with a relatively high success rate rate (approximately 90%). In contrast, it is possible to recognize bone material vs. another material (in our case a resin) with a 100% of success. These results are successfully implemented in a new hand-held version of DRIBON. Conclusions: We propose a method and devise a novel hand-held tool which show that robotic systems can effectively infer bone material properties.

6

Modern approach to materials currently used in transmission gears

Matczak J., Matczak K.

Autobusy : technika, eksploatacja, systemy transportowe

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2018

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R. 19, nr 6

586--590, CD

EN

The article discusses the materials currently used for transmission elements as an alternative to traditionally used bearing, alloy and special steels, for carburizing and for improvement. The material properties were presented, the possibilities of their implementation were discussed, as well as the advantages and disadvantages of their application. A comparative analysis of the proposed materials was made. The possible development directions have been indicated.

PL

W artykule omówiono materiały współcześnie stosowane na elementy przekładni jako alternatywa dla tradycyjnie stosowanych stali łożyskowych, stopowych, specjalnych, do nawęglania oraz do ulepszania. Przedstawiono właściwości materiałów, omówiono możliwości ich implementacji, a także wskazano zalety i wady, wynikające z ich zastosowania. Dokonano analizy porównawczej zaproponowanych materiałów. Wskazano możliwe kierunki rozwoju.

7

Struktura i własności materiałów kompozytowych magnetycznie miękkich o osnowie silikonowej wzmacnianych nanokrystalicznymi proszkami stopu kobaltu

Konieczny J.

Przetwórstwo Tworzyw

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2014

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[R.] 20, nr 2 (158)

182--186

PL

W artykule przedstawiono wyniki badań mikrostruktury, własności mechanicznych i magnetycznych materiałów kompozytowych, magnetycznie miękkich o osnowie silikonowej. Proszki metalowe otrzymano w wyniku mielenia taśm metalowych o strukturze amorficznej oraz nanokrystalicznej ze stopu Co68Fe4Mo1B13,5Si13,5. Wykazano, że na własności mechaniczne jak i fizyczne bardzo silnie oddziałuje udział metalowego proszku.

EN

The article presents the investigation results of microstructure, mechanical and magnetic properties of soft magnetic composite materials with silicone matrix. Metal particles obtained by high energy ball milling of the metal ribbons of amorphous and nano-crystalline structure of the alloy Co63Fe4Mo1B13,5Si13,5. It was shown that the mechanical properties as well as physical influences strongly the powder metal part.

8

Influence of fiber type and the layer thickness on the stress distribution in composite pipe

Krysiak P., Błachut A., Gąsiorek P., Kaleta J.

Interdisciplinary Journal of Engineering Sciences

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2014

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Vol. 2, no. 1

17--20

EN

In this work authors presented distribution of circumferential stress in wound composite structures made from different layers. The cylindrical shape specimens were made from layers which have different elastic moduli. Manufactured specimens underwent strength test to obtain distribution of circumferential stress as a function of radius. Circumferential strain on outside surface was measured by fiber optic strain gauge. In order to verify the experimental results were made microscopy specimens, obtained material properties by homogenization method and calculated the strain using analytical approach. In the end, authors compared results obtained from both methods.

9

Właściwości materiałów kompozytowych typu flow modyfikowanych nanocząstkami srebra i złota

Sokołowski K., Szynkowska M. I., Łukomska-Szymańska M., Pawlaczyk A., Kowalski Z., Sobczak A., Sokołowski J.

Przemysł Chemiczny

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2013

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T. 92, nr 6

1032--1037

10

Revisiting the Reflected Caustics Method : the Accurate Shape of the “Initial Curve”

Markides Ch. F., Kourkoulis S. K.

Engineering Transactions

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2013

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Vol. 61, iss. 4

265–-287

EN

The shape of the “initial curve”, i.e. the locus of material points, which if properly illuminated provide (under specific conditions) the “caustic curve”, is explored. Adopting the method of complex potentials improved formulae for the shape of the “initial curve” are obtained. Application of these formulae for two typical problems, i.e. the mode-I crack and the infinite plate with a finite circular hole under uniaxial tension, indicates that the “initial curve” is in fact not a circular locus. It is either an open curve or a closed contour, respectively, the actual shape of which depends also on the in-plane displacement field.

11

Wybrane właściwości nowego kompozytu o osnowie z poli(ε-kaprolaktamu) (PA6)

Moraczewski K., Rytlewski P., Żenkiewicz M., Karasiewicz T., Stepczyńska M.

Przetwórstwo Tworzyw

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2012

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[R.] 18, nr 5

474-477

PL

W artykule przedstawiono wyniki badań wybranych właściwości nowego kompozytu o osnowie z PA6 przeznaczonego do autokatalitycznego metalizowania z wykorzystaniem nowoczesnych technik laserowych. Wyznaczono jego wytrzymałość na rozciąganie (σM), naprężenie przy zerwaniu (σB), wydłużenie względne przy maksymalnym naprężeniu (εM), wydłużenie względne przy zerwaniu (εB), udarność (uC), moduł zachowawczy (E'), współczynnik tłumienia (K), temperaturę zeszklenia (Tg) oraz odporność termiczną.

EN

There are presented some results of selected properties of the new PA6 composite intended for autocatalytic metallization using modern laser techniques. Tensile strength (σM), tension at break (σB), elongation at a maximum stress (εM), elongation at break (εB), impact strength (uC), storage modulus (E'), damping coefficient (K), glass transition temperature (Tg) and thermal resistance of the new composite were determined.

12

Ocena wpływu wybranych parametrów termoformowania na rozkład grubości ścianki wyrobu

Rojek M., Szymiczek M., Wróbel G.

Przetwórstwo Tworzyw

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2012

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[R.] 18, nr 6

699-702

PL

W artykule przedstawiono wpływ wybranych parametrów termoformowania próżniowego na rozkład grubości ścianki wyrobu. Na podstawie założonych parametrów procesu przeprowadzono analizę porównawczą. Wykonano obliczenia rozkładu grubości ścianki modelowego wyrobu dla wybranych materiałów polimerowych, które zweryfikowano eksperymentalnie.

EN

The article presents the influence of selected parameters of vacuum thermoforming on wall thickness distribution of the product. On the basis of assumed parameters of the process, the comparative analysis was conducted. The calculations of the wall thickness were performed for selected polymer materials, which were experimentally verified.

13

Influence of Sportswear Fabric Properties on the Health and Performance of Athletes

Hassan M., Qashqary K., Hassan H. A., Shady E., Alansary M.

Fibres & Textiles in Eastern Europe

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2012

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Vol. 20, no. 4 (93)

82--88

EN

The main goal of this work was to study the Influence of sportswear fabric properties on the physiological responses and performance of athletes. The influence of three different types of sportswear fabrics on the physiological response and performance of volunteers in sports conditions was investigated. The fabrics and garments tested were made of 100% cotton, a 65/35 polyester/cotton blend and 100% polyester fibres. Seven volunteer were selected to wear the sportswear during the physical exercise assigned and their physiological responses were tested. The results of the study show a statistically significant effect on the athletes' physiological responses and performance parameters measured for the different types of sportswear tested. The sample with 100% polyester produced the best physiological responses and performance from the athletes. This effect can be related to better moisture management, which reflects the amount of relative water vapour permeability (68%) and lower thermal conductivity. This will enhance the body's temperature regulation leading to increase athletes' cardiorespiratory fitness and performance. The results also show the high correlation between the sportswear fabrics properties and athletes' physiological responses and performance, except the relationship between the end-tidal partial pressure of oxygen (PETO2) and fabric thickness (h), air permeability (AP) and thermal resistance (r), which are not highly correlated. The other correlation values vary between (š0.62 and (š1).

PL

Badano właściwości ubiorów sportowych na fizjologiczną odpowiedź oraz wytrzymałość organizmu. Przebadano trzy rożne rodzaje ubiorów wykonanych z 100% bawełny, mieszanki 65/35 poliester/bawełna oraz 100% poliestru. Wytypowano 7 ochotników, którzy w przygotowanych ubiorach wykonywali zaprogramowane ćwiczenia a następnie poddano ich badaniom. Wyniki opracowano statystycznie i wykazano, że najkorzystniejsze właściwości posiada odzież wykonana ze 100% poliestru. Wynik ten można tłumaczyć lepszymi właściwościami transportu wilgoci wynikającymi z poziomu przepuszczalności pary wodnej i niższą przewodnością termiczną. Właściwości te wpływają na zachowanie się organizmu a zwłaszcza na sprawność układu krążeniowo-oddechowego, a tym samym wydolność organizmu. Wykazano korelację pomiędzy właściwościami ubioru a wydolnością organizmu za wyjątkiem korelacji pomiędzy grubością materiału a wydechowym cieśnieniem parcjalnym tlenu (PETO2) oraz przepuszczalnością powietrza i opornością cieplną.

14

The Influence of Geometry of the Specimen and Material Properties on the Q-Stress Value Near the Crack Tip for SEN(T) Specimen

Graba M.

Acta Mechanica et Automatica

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2011

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Vol. 5, no. 2

27-34

EN

In the paper the short theoretical backgrounds about elastic-plastic fracture mechanics were presented and the O’Dowd-Shih theory was discussed. Using ADINA System program, the values of the Q-stress determined for various elastic-plastic materials for SEN(T) specimen – single edge notched plates in tension – were presented. The influence of kind of the specimen, crack length and material properties (work-hardening exponent and yield stress) on the Q-parameter were tested. The numerical results were approximated by the closed form formulas. Presented in the paper results are complementary of the two papers published in 2007 (Graba, 2007) and in 2010 (Graba, 2010), which show and describe influence of the material properties and crack length for the Q-stress value for SEN(B) and CC(T) specimens respectively. Presented and mentioned papers show such catalogue of the Q-stress value, which may be used in engineering analysis for calculation of the real fracture toughness.

15

PVD and CVD gradient coatings on sintered carbides and sialon tool ceramics

Dobrzański L. A., Staszuk M.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 43, nr 2

552--576

EN

Purpose: The main objective of the work is to investigate the structure and properties of multilayer gradient coatings produced in PVD and CVD processes on sintered carbides and on sialon ceramics, and to define the influence of the properties of the coatings such as microhardness, adhesion, thickness and size of grains on the applicable properties of cutting edges covered by such coatings. Design/methodology/approach: The investigation studies pertaining to the following have been carried out: the structures of the substrates and coatings with the application of transmission electron microscopy; the structure and topography of coating surfaces with the use of electron scanning microscopy; chemical composition of the coatings using the GDOES and EDS methods; phase composition of the coatings using X-ray diffraction and grazing incident X-ray diffraction technique (GIXRD); grain size of the investigated coatings using Scherrer’s method; properties of the coatings including thickness, microhardness, adhesion and roughness; properties of the operating coatings in cutting trials. The models of artificial neural networks have been worked out which involve the dependencies between the durability of the cutting edge and properties of the coatings. Findings: Good adhesion of the coatings to the substrate from sintered carbides is connected with the diffusive mixing of the components of the coating and substrate. In the case of PVD coatings obtained on sialon ceramics, the highest adhesion to the substrate (Lc=53-112 N) has been demonstrated by the coatings containing the AlN phase of the hexagonal lattice having the same type of atomic (covalence) bond in the coating as in the ceramic substrate. The damage mechanism of the investigated coatings depends to a high degree on their adhesion to the substrate. The durability of cutting edges covered by the investigated coatings depends principally on the adhesion of the coatings to the substrate, and to a lesser degree on the other properties. Practical implications: While selecting a proper coating material on ceramic cutting edges, it is advisable to remember that the coatings having the same type of atomic bond as the ceramic substrate have higher adhesion to the substrate. Another relevant aspect of the research presented in the paper is the fact that the adhesion of the coatings contributes significantly to the durability of the cutting edge, whereas the microhardness of the coatings, their thickness and grain size have a slightly lower influence on the durability of the tool being coated. Originality/value: The paper presents the research involving the PVD and CVD coatings obtained on an unconventional substrate such as sialon ceramics. Furthermore, to define the influence of coating properties on the durability of cutting edges, artificial neural networks have been applied.

16

Material behavior under dynamic mono- and biaxial loading

Meyer L. W., Herzig N., Pursche F., Abdel-Malek S.

Engineering Transactions

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2010

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Vol. 58, iss. 3/4

119-129

EN

This paper gives an overview of different testing methods and the mechanical material behavior including mono-axial and multi-axial testing under high rate loading. Special emphasis is laid on difficult loading conditions and loading states such as a high temperature and high strain loading (? > 1200?C, ? > 1) and multiaxial impact tests. The impact behavior of selected materials is shown and compared for di?erent loading conditions. Furthermore, a distinction is made between virgin and manufactured material behavior (e.g. welding) or pre-damaged materials. Specifically, if the influence of the manufacturing history is investigated. Under certain loading states the impact material properties show a dramatic difference compared to the virgin state of the material. Some examples of different material behavior under the conditions previously mentioned are given.

17

Structural alteration of collagen fibres - spectroscopic and mechanical studies

Gąsior-Głogowska M., Komorowska M., Hanuza J., Ptak M., Kobielarz M.

Acta of Bioengineering and Biomechanics

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2010

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Vol. 12, no. 4

55-62

EN

Fourier Transform Near Infrared Raman Spectroscopy has been used to monitor the molecular changes of collagen in a tendon subjected to strain. In the Raman spectrum of the unstrained tendon, some protein bands, mainly assigned to collagen, can be observed: amide I (1666 cm–1) and III (1266 and 1248 cm–1) vibrational modes and skeletal (C–C) stretching vibrations (816 and 940 cm–1). The position of these bands is changing with the increasing strain values. It is concluded that elastin and non-helical domains of collagen are initially involved in the load transfer and triple helices of collagen are gradually joining this process.

18

Corrosion behaviour of metallic biomaterials used as orthodontic wires

Ziębowicz A., Walke W., Barucha-Kępka A., Kiel M.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 27, nr 2

151-154

EN

Purpose: The aim of the work was evaluation of the corrosion resistance of the commercial metallic orthodontic wires from different manufacturers in simulated intra-oral environment. Design/methodology/approach: Corrosion resistance tests were carried out in artificial saliva at the temperature 37 ± 1° C with the use of the VoltaLab ® PGP 201 system for electrochemical tests. The saturated calomel electrode (SCE) was applied as the reference electrode and the auxiliary electrode was a platinum foil. The evaluation of pitting corrosion was realized by recording of anodic polarization curves with the use of the potentiodynamic method. In order to evaluate crevice corrosion resistance the samples were polarized in the potential equal to 0.8 V by 900 seconds. Findings: Results of corrosion resistance tests of the CrNi, NiTi and CuNiTi wires showed comparable data of parameters obtained in the artificial saliva. Research limitations/implications: The obtained results show the influence of artificial saliva on the electrochemical corrosion of orthodontic wires. In order to demonstrate the higher risk of corrosion, which can have two consequences: a loss of the physical properties and the release of Ni ions (which have been shown to be toxic and the cause of allergic reactions) - additional research on fatigue corrosion should be carried out. Originality/value: The analysis of the obtained results show that that commonly used materials for making orthodontic wires (because of their interesting properties - elasticity and shape memory) can be used in different orthodontic treatment stages to correct numerous clinical conditions. The most favorable characteristics were observed for the new NiTi samples (American Orthodontics).

19

Infiltracja porowatych materiałów metodą CVI

Jonas S., Kluska S., Drygalska E., Walasek E., Czyżewska A., Krupa G.

Inżynieria Materiałowa

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2008

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Vol. 29, nr 6

760-763

PL

Chemiczna infiltracja z fazy gazowej (Chemical Vapour Infiltration - CVI) jest skuteczną metodą modyfikacji mikrostruktury porowatych materiałów. Metoda ta pozwala na wypełnienie porów otwartych wysokoogniotrwałymi związkami, takimi jak węgliki, azotki, borki i tlenki. W pracy zastosowano tę metodę do modyfikacji węglikiem krzemu przemysłowych wyrobów węglowo-grafitowych i korundowych materiałów ogniotrwałych produkowanych w Polsce. Skoncentrowano się na początkowych etapach procesu infiltracji z jednej strony dlatego, że zjawiska związane ze specyfiką procesu osadzania mogą decydować o dalszych etapach zagęszczania, z drugiej, dla niektórych zastosowań, np. zwiększonej odporności na korozję, ścieranie, nie jest konieczne maksymalne wypełnienie pustych przestrzeni. Dla określenia zmian mikrostruktury badanych tworzyw zastosowano mikroskopię elektronową SEM, mikroanalizę rentgenowską EDS, dyfrakcję rentgenowską XRD, ultradźwięki, metodę BET, porozymetrię rtęciową. Wykonano badania odporności na korozję infiltrowanych tworzyw oraz określono ich wytrzymałość mechaniczną. Uzyskane wyniki mogą stanowić użyteczną bazę do projektowania technologii modyfikacji tych materiałów takimi związkami, jak: węglik krzemu, azotek krzemu, pirografit, krzem.

EN

Chemical vapour infiltration (CVI) is a effective method for microstructure modification of porous materials. This method allows to infiltrate open pores by high refractory compounds such as carbides, nitrides, borides and oxides. In the work was to use this method for modification of carbon industrial materials and aluminia refractories by SiC. The products are manufactured in Poland. The authors focused on initial stage of infiltration. The phenomena connected with the initial stages of infiltration may determine following densification process. On the other hand, for some applications as corrosion resistance improvements the maximal filing of material is not needed. For the investigation into the changes of the samples microstructure were used: SEM, EDS, XRD, ultrasounds propagation velocity, BET, mercury porosimetry. Corrosion resistance and mechanical strength measurement of infiltrated materials were carried out. The results are a useful base for development of technology of these materials modified with such compounds as silikon carbide, silicon nitride, pirographite or silicon.

20

Crack initiation in steel parts working in boilers and steam pipelines

Renowicz D., Cieśla M.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 21, nr 2

49-52

EN

Purpose: The purpose of this paper is to identify the influence of loading history and the processes of material degradation on the crack initiation and on durability under thermo-mechanical fatigue conditions. Design/methodology/approach: Based on the operation data, the conditions of laboratory examinations of specimens were determined. A specialist apparatus unit was used for the examination, enabling the simulation of any spectrum of mechanical load and temperature changes. Findings: The material durability criterion has been defined based on an energy related approach to the problem of crack initiation in steels which work under thermal fatigue conditions. Research limitations/implications: In the case discussed, i.e. a pipeline part, the present criteria should be expanded with critical values describing the total length of cracks initiated on the internal surface of a specimen. Practical implications: The paper refers to the research on steel 10H2M (10CrMo.910) used in the conventional boilers, superheaters and pipelines in power plants. Originality/value: Originality of the paper is the methodology of the lifetime prediction of steam pipeline parts working in thermo-mechanical fatigue conditions.