This page has only limited features, please log in for full access.

Prof. Irena Žmak
University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture

Basic Info


Research Keywords & Expertise

0 Ceramics
0 Composites
0 Recycling
0 neural networks & deep learning
0 sustainabilitiy

Fingerprints

Ceramics
Recycling
Composites
neural networks & deep learning

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Project

Project Goal: Project aims to improve the processes and mechanisms of the university autonomy by increasing the management capacities, accountability and transparency of Western Balkans Universities.

Starting Date:15 January 2021

Current Stage: Contract signed

0 Reads
Project

Project Goal: Exploring the possibility of recycling waste Al2O3 ceramic powder by casting suspensions of monolithic Al2O3 ceramics

Starting Date:01 July 2020

Current Stage: Implementation phase

0 Reads
Project

Project Goal: The overall aim of the project is to support the enhancement of research culture in Kosovo higher education institutions by supporting the enhancement of existing policy and practices as well as establishing and installing new regulations and mechanisms in project beneficiary institutions in Kosovo.

Starting Date:15 November 2019

Current Stage: Implementation phase

0 Reads
Project

Project Goal: Suspensions for the slip casting of micro/nanostructured monolithic Al2O3 and composite Al2O3-ZrO2 advanced ceramics will be investigated, and slip casting and sintering parameters will be optimized. Main advantages of slip casting process are low costs, environmentally friendly process, simplicity and flexibility, potential for uniform particle packing and suitability for the production of parts of intricate shape. The possibility of production of the micro/nanoporous alumina by the replacement of a part of the raw material with the alumina waste obtained by green machining will be investigated. This will result in reducing raw materials costs and enhance waste management, i.e. environmental protection.

Starting Date:01 May 2017

Current Stage: Almost completed

0 Reads
Journal article
Published: 19 August 2021 in Coatings
Reads 0
Downloads 0

In this work, a single-layer TiO2–ZrO2 thin film is deposited on the AISI 316L austenitic stainless steel by the sol–gel process and the dip coating method to improve its corrosion resistance properties. For the sol preparation, titanium isopropoxide and zirconium butoxide are used as the precursors, yttrium acetate hydrate is used for the ZrO2 stabilization, i-propanol as the solvent, nitric acid as the catalyst, acetylacetone as the chelating agent, and the distilled water for the hydrolysis. The deposited films are annealed at 400 °C or 600 °C. Morphology and phase composition of the sol–gel TiO2–ZrO2 films and powders are analyzed by scanning electron microscopy (SEM) equipped with EDX detector and X-ray diffraction (XRD), respectively. The thickness of the sol–gel TiO2–ZrO2 films deposited on the stainless steel is determined by glow discharge optical emission spectrometry (GD-OES). The corrosion behavior of the stainless steel, coated by amorphous films, is evaluated in 3 wt% NaCl and 0.5 mol dm−3 HCl by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. It is found that the sol–gel TiO2–ZrO2 films with the amorphous structure, deposited by the sol–gel process, and calcined at 400 °C significantly enhance the corrosion properties of AISI 316L in both chloride media.

ACS Style

Lidija Ćurković; Helena Otmačić Ćurković; Irena Žmak; Mihone Kerolli Mustafa; Ivana Gabelica. Corrosion Behavior of Amorphous Sol–Gel TiO2–ZrO2 Nano Thickness Film on Stainless Steel. Coatings 2021, 11, 988 .

AMA Style

Lidija Ćurković, Helena Otmačić Ćurković, Irena Žmak, Mihone Kerolli Mustafa, Ivana Gabelica. Corrosion Behavior of Amorphous Sol–Gel TiO2–ZrO2 Nano Thickness Film on Stainless Steel. Coatings. 2021; 11 (8):988.

Chicago/Turabian Style

Lidija Ćurković; Helena Otmačić Ćurković; Irena Žmak; Mihone Kerolli Mustafa; Ivana Gabelica. 2021. "Corrosion Behavior of Amorphous Sol–Gel TiO2–ZrO2 Nano Thickness Film on Stainless Steel." Coatings 11, no. 8: 988.

Journal article
Published: 14 June 2021 in Sustainability
Reads 0
Downloads 0

In this work, alumina (Al2O3) ceramics were prepared using an environmentally friendly slip casting method. To this end, highly concentrated (70 wt.%) aqueous suspensions of alumina (Al2O3) were prepared with different amounts of the ammonium salt of a polycarboxylic acid, Dolapix CE 64, as an electrosteric dispersant. The stability of highly concentrated Al2O3 aqueous suspensions was monitored by viscosity measurements. Green bodies (ceramics before sintering) were obtained by pouring the stable Al2O3 aqueous suspensions into dry porous plaster molds. The obtained Al2O3 ceramic green bodies were sintered in the electric furnace. Analysis of the effect of three sintering parameters (sintering temperature, heating rate and holding time) on the density of alumina ceramics was performed using the response surface methodology (RSM), based on experimental data obtained according to Box–Behnken experimental design, using the software Design-Expert. From the statistical analysis, linear and nonlinear models with added first-order interaction were developed for prediction and optimization of density-dependent variables: sintering temperature, heating rate and holding time.

ACS Style

Darko Landek; Lidija Ćurković; Ivana Gabelica; Mihone Kerolli Mustafa; Irena Žmak. Optimization of Sintering Process of Alumina Ceramics Using Response Surface Methodology. Sustainability 2021, 13, 6739 .

AMA Style

Darko Landek, Lidija Ćurković, Ivana Gabelica, Mihone Kerolli Mustafa, Irena Žmak. Optimization of Sintering Process of Alumina Ceramics Using Response Surface Methodology. Sustainability. 2021; 13 (12):6739.

Chicago/Turabian Style

Darko Landek; Lidija Ćurković; Ivana Gabelica; Mihone Kerolli Mustafa; Irena Žmak. 2021. "Optimization of Sintering Process of Alumina Ceramics Using Response Surface Methodology." Sustainability 13, no. 12: 6739.

Journal article
Published: 23 February 2021 in Open Ceramics
Reads 0
Downloads 0

The implementation of environmentally-friendly manufacturing, which include the reuse and recycling of materials is nowadays crucial in order to meet the circular economy approach. The present study shows the possibility of recycling waste alumina scraps obtained after the green machining step during the manufacturing process of alumina ceramics as a broken ware, which contained small amounts (≤5 ​wt.% in total) of sintering additives in the form of organic binders and MgO. Dense alumina samples containing various amounts of waste alumina powder (0–100 ​wt.%) were produced by spark plasma sintering (SPS) at sintering temperature of 1450 ​°C, dwell time of 5 ​min ​at a 50 ​MPa of uniaxial pressure. The influence of waste alumina content on microstructure, hardness, and fracture toughness was investigated to determine the possibility of recycling broken ware.

ACS Style

Milan Vukšić; Irena Žmak; Lidija Ćurković; Andraž Kocjan. Spark plasma sintering of dense alumina ceramics from industrial waste scraps. Open Ceramics 2021, 5, 100076 .

AMA Style

Milan Vukšić, Irena Žmak, Lidija Ćurković, Andraž Kocjan. Spark plasma sintering of dense alumina ceramics from industrial waste scraps. Open Ceramics. 2021; 5 ():100076.

Chicago/Turabian Style

Milan Vukšić; Irena Žmak; Lidija Ćurković; Andraž Kocjan. 2021. "Spark plasma sintering of dense alumina ceramics from industrial waste scraps." Open Ceramics 5, no. : 100076.

Journal article
Published: 23 January 2021 in Journal of Materials Research and Technology
Reads 0
Downloads 0

The generated process losses such as broken ware from shaping, if not recycled internally, are considered as waste. Furthermore, the collected process losses are provided to external recycling companies or waste disposal facilities. This study investigated the recycling potential of waste alumina powder, which was accumulated during industrial machining of the ceramic green body. The samples containing up to 20 dwb. % (dwb – weight amounts based on dry matter) of powdered waste alumina were prepared by slip casting method and conventionally sintered at various sintering conditions according to Box-Behnken design. Sintered samples were characterized for density, microstructure, hardness, and indentation fracture toughness and compared with samples made of pure commercial alumina. The study shows that the addition of waste alumina up to 20 dwb. % sintered at higher sintering temperature with dwell time 1–3 h did not negatively affect the hardness, nor the indentation fracture toughness of the sintered samples. The enabled recycling potential of waste alumina powder can have direct positive environmental impact, although economic benefits cannot be ignored.

ACS Style

Milan Vukšić; Irena Žmak; Lidija Ćurković; Danko Ćorić; Petra Jenuš; Andraž Kocjan. Evaluating recycling potential of waste alumina powder for ceramics production using response surface methodology. Journal of Materials Research and Technology 2021, 11, 866 -874.

AMA Style

Milan Vukšić, Irena Žmak, Lidija Ćurković, Danko Ćorić, Petra Jenuš, Andraž Kocjan. Evaluating recycling potential of waste alumina powder for ceramics production using response surface methodology. Journal of Materials Research and Technology. 2021; 11 ():866-874.

Chicago/Turabian Style

Milan Vukšić; Irena Žmak; Lidija Ćurković; Danko Ćorić; Petra Jenuš; Andraž Kocjan. 2021. "Evaluating recycling potential of waste alumina powder for ceramics production using response surface methodology." Journal of Materials Research and Technology 11, no. : 866-874.

Journal article
Published: 06 January 2021 in Buildings
Reads 0
Downloads 0

In order to develop the application of the more cost-effective copper-based shape memory alloys (SMAs), rather than nickel–titanium as earthquake energy dissipaters, the influence of ausforming-induced plastic deformation on phase transformations, microstructure, super elasticity and mechanical properties of the shape memory alloy Cu-26Zn-4Al was examined. These specific SMA properties were targeted by applying appropriate parameters of the thermomechanical (the so-called ausforming) process: beta-phase homogenization at 800 °C for 20 min, one-step hot rolling at 800 °C and water quenching. The results showed significant microstructural changes, increased mechanical resistance and change in the phase transformation behavior. The SMA treated by ausforming retained the reversible austenitic–martensitic transformation ability, with the appearance of the super-elastic effect up to 6% of strain recovery. Although some strengthening occurred after hot rolling (an increase in true yield strength of 125 MPa was detected), all phase transformation temperatures were decreased. The smallest decrease was detected for the austenite finish temperature (32.8 °C) and the largest for the martensite finish temperature (42.0 °C), allowing both the expansion and the lowering of the temperature range of super elasticity, which is favorable for construction applications. It is concluded that it is possible to achieve an optimal combination of adequate strength and improved transformation behavior of Cu-Zn-Al alloy by applying the ausforming treatment.

ACS Style

Danko Ćorić; Irena Žmak. Influence of Ausforming Treatment on Super Elasticity of Cu-Zn-Al Shape Memory Alloy for Seismic Energy Dissipaters. Buildings 2021, 11, 22 .

AMA Style

Danko Ćorić, Irena Žmak. Influence of Ausforming Treatment on Super Elasticity of Cu-Zn-Al Shape Memory Alloy for Seismic Energy Dissipaters. Buildings. 2021; 11 (1):22.

Chicago/Turabian Style

Danko Ćorić; Irena Žmak. 2021. "Influence of Ausforming Treatment on Super Elasticity of Cu-Zn-Al Shape Memory Alloy for Seismic Energy Dissipaters." Buildings 11, no. 1: 22.

Journal article
Published: 04 January 2020 in Materials
Reads 0
Downloads 0

In the present work, alumina (Al2O3) foam was prepared by the replica method where a polyurethane (PU) foam (30 pores per inch (ppi)) template was impregnated with a 60 wt.% Al2O3 suspension. Sintered Al2O3 foam was used as substrate for the deposition of sol-gel derived titania (TiO2) film using dip coating. For the preparation of TiO2 sol, titanium(IV) isopropoxide (Ti-iPrOH) was used as the precursor. The common problem of qualification and quantification of a crystalline coating on a highly porous 3D substrate with an uneven surface was addressed using a combination of different structural characterization methods. Using Powder X-ray Diffraction (PXRD) and synchrotron Grazing Incidence X-ray Diffraction (GIXRD) on bulk and powdered Al2O3 foam and TiO2-coated Al2O3 foam samples, it was determined Al2O3 foam crystallizes to corundum and coating to anatase, which was also confirmed by Fourier Transformed Infrared Spectroscopy (FTIR). Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM/EDS) revealed the structural and microstructural properties of the substrate and coating. Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA) were used to clarify the evolution of the porous microstructure. The Al2O3-TiO2 composite was evaluated as a photocatalyst candidate for the degradation of the micropollutant medication memantine. The degradation rate was monitored using a light-emitting diode (LED) lamp operating at electromagnetic (EM) wavelength of 365 nm. The photocatalytic activity of sol-gel-derived TiO2 film immobilized on the Al2O3 foam was compared with commercially available TiO2 nanoparticles, P25-Degussa, in the form of a suspension. The levels of memantine were monitored by High-Performance Liquid Chromatography–Tandem Mass Spectrometry (HPLC–MS/MS). The efficiency and rate of the memantine photodegradation by suspended TiO2 nanoparticles is higher than the TiO2-coated Al2O3 foam. But, from the practical point of view, TiO2-coated Al2O3 foam is more appropriate as a valuable photocatalytic composite material.

ACS Style

Zrinka Švagelj; Vilko Mandić; Lidija Ćurković; Martina Biošić; Irena Žmak; Mattia Gaborardi. Titania-Coated Alumina Foam Photocatalyst for Memantine Degradation Derived by Replica Method and Sol-Gel Reaction. Materials 2020, 13, 227 .

AMA Style

Zrinka Švagelj, Vilko Mandić, Lidija Ćurković, Martina Biošić, Irena Žmak, Mattia Gaborardi. Titania-Coated Alumina Foam Photocatalyst for Memantine Degradation Derived by Replica Method and Sol-Gel Reaction. Materials. 2020; 13 (1):227.

Chicago/Turabian Style

Zrinka Švagelj; Vilko Mandić; Lidija Ćurković; Martina Biošić; Irena Žmak; Mattia Gaborardi. 2020. "Titania-Coated Alumina Foam Photocatalyst for Memantine Degradation Derived by Replica Method and Sol-Gel Reaction." Materials 13, no. 1: 227.

Journal article
Published: 26 December 2019 in Materials
Reads 0
Downloads 0

Alumina (Al2O3) and zirconia (ZrO2) have good overall properties and thus are widely used oxide technical ceramics. The biggest drawback of Al2O3 is its low fracture toughness. In contrast, ZrO2 is relatively tough, but is also much more expensive. In order to improve the alumina toughness, composite ceramics are being developed. Slip casting technology has economic advantages over the conventional hot isostatic pressure technology, but problems may arise when preparing stable highly-concentrated suspensions (slip) for filling the mold. The purpose of this study is to prepare aqueous suspensions using 70 wt. % α-Al2O3, with 0, 1, 5 and 10 wt. % of added t-ZrO2. Suspensions were electrosterically stabilized using the ammonium salt of polymethylacrylic acid, an alkali-free anionic polyelectrolyte dispersant. Also, magnesium oxide in form of magnesium aluminate spinel (MgAl2O4) was used to inhibit the abnormal alumina grain growth during the sintering process. Minimum viscosities were used as stability estimators, where an increase in ZrO2 content required adding more dispersant. After sintering, the Vickers indentation test was used to determine the hardness and the indentation fracture toughness from the measurement of the crack length. Also, the brittleness index (Bi, μm−1/2) was calculated from values of Vickers hardness and the Vickers indentation fracture toughness. It was found that with increasing ZrO2 content the fracture toughness increased, while the hardness as well as the brittleness index decreased. Zirconia loading reduces the crystallite sizes of alumina, as confirmed by the X-ray diffraction analysis. SEM/EDS analysis showed that ZrO2 grains are distributed in the Al2O3 matrix, forming some agglomerates of ZrO2 and some pores, with ZrO2 having a smaller grain size than Al2O3.

ACS Style

Irena Žmak; Danko Ćorić; Vilko Mandić; Lidija Ćurković. Hardness and Indentation Fracture Toughness of Slip Cast Alumina and Alumina-Zirconia Ceramics. Materials 2019, 13, 122 .

AMA Style

Irena Žmak, Danko Ćorić, Vilko Mandić, Lidija Ćurković. Hardness and Indentation Fracture Toughness of Slip Cast Alumina and Alumina-Zirconia Ceramics. Materials. 2019; 13 (1):122.

Chicago/Turabian Style

Irena Žmak; Danko Ćorić; Vilko Mandić; Lidija Ćurković. 2019. "Hardness and Indentation Fracture Toughness of Slip Cast Alumina and Alumina-Zirconia Ceramics." Materials 13, no. 1: 122.

Journal article
Published: 29 May 2019 in Materials
Reads 0
Downloads 0

The green machining of alumina (Al2O3) green bodies generates a certain amount of waste alumina powder. Waste alumina ceramic powder should be disposed of as non-hazardous waste in a legally compliant manner. The influence of additives on the stability of 70 wt.% (≈40 vol.%) alumina-waste alumina water-based suspension was investigated in the presented research. A Box-Behnken three-factor response surface design was used for the preparation of stable highly-concentrated suspensions with the addition of three additives. The optimal amount of each additive was selected according to the obtained results of minimal apparent viscosity: 0.05 wt.% Tiron as dispersant, 0.1 wt.% poly (vinyl alcohol) as binder and 0.2 wt.% magnesium aluminate spinel as abnormal grain growth inhibitor. The analysis of variance was used to identify the contribution of each additive. The zeta potential and sedimentations tests were performed to confirm the suspension stability measurements at different pH values. Alumina particles were optimally dispersed at pH values between 8 and 11. According to the results, the investigated composition of 20 wt.% waste alumina powder (weight content, dry alumina powder), with the addition of optimal amounts of additives, shows a possible application in the production of ceramics by slip casting.

ACS Style

Milan Vukšić; Irena Žmak; Lidija Ćurković; Danko Ćorić. Effect of Additives on Stability of Alumina-Waste Alumina Suspension for Slip Casting: Optimization Using Box-Behnken Design. Materials 2019, 12, 1738 .

AMA Style

Milan Vukšić, Irena Žmak, Lidija Ćurković, Danko Ćorić. Effect of Additives on Stability of Alumina-Waste Alumina Suspension for Slip Casting: Optimization Using Box-Behnken Design. Materials. 2019; 12 (11):1738.

Chicago/Turabian Style

Milan Vukšić; Irena Žmak; Lidija Ćurković; Danko Ćorić. 2019. "Effect of Additives on Stability of Alumina-Waste Alumina Suspension for Slip Casting: Optimization Using Box-Behnken Design." Materials 12, no. 11: 1738.

Journal article
Published: 19 October 2018 in Transactions of FAMENA
Reads 0
Downloads 0

Slip casting is a widely used colloidal technique for consolidation of ceramic powders from a suspension. The colloidal approach ensures homogeneous microstructure of a green body, thereby reducing post-sintering machining and production...

ACS Style

Ivana Sever; Irena Žmak; Lidija Ćurković; Zrinka Švagelj. Stabilization of Highly Concentrated Alumina Suspensions by Different Dispersants. Transactions of FAMENA 2018, 42, 61 -70.

AMA Style

Ivana Sever, Irena Žmak, Lidija Ćurković, Zrinka Švagelj. Stabilization of Highly Concentrated Alumina Suspensions by Different Dispersants. Transactions of FAMENA. 2018; 42 (3):61-70.

Chicago/Turabian Style

Ivana Sever; Irena Žmak; Lidija Ćurković; Zrinka Švagelj. 2018. "Stabilization of Highly Concentrated Alumina Suspensions by Different Dispersants." Transactions of FAMENA 42, no. 3: 61-70.

Conference paper
Published: 01 January 2018 in Proceedings of the 29th International DAAAM Symposium 2018
Reads 0
Downloads 0
ACS Style

Milan Vuksic; Irena Žmak; Lidija Curkovic. Composition Optimization of Alumina Suspensions which Contain Waste Alumina Powder. Proceedings of the 29th International DAAAM Symposium 2018 2018, 1019 -1025.

AMA Style

Milan Vuksic, Irena Žmak, Lidija Curkovic. Composition Optimization of Alumina Suspensions which Contain Waste Alumina Powder. Proceedings of the 29th International DAAAM Symposium 2018. 2018; ():1019-1025.

Chicago/Turabian Style

Milan Vuksic; Irena Žmak; Lidija Curkovic. 2018. "Composition Optimization of Alumina Suspensions which Contain Waste Alumina Powder." Proceedings of the 29th International DAAAM Symposium 2018 , no. : 1019-1025.

Article
Published: 08 August 2017 in Materialwissenschaft und Werkstofftechnik
Reads 0
Downloads 0

In the present study a biowaste, in the form of chicken eggshells, is used for producing a biomaterial – hydroxyapatite by a conventional chemical precipitation method. Hydroxyapatite is a major component of human hard tissues, such as bones and teeth, which makes it a paradigmatic bioactive material. The first step in the synthesis of hydroxyapatite from eggshells is the transformation of their main component calcium carbonate into calcium oxide at 1000 °C. Afterwards, calcium oxide is hydrated in order to produce calcium hydroxide. Hydroxyapatite is then synthesized by the addition of the phosphoric acid. The phase composition of the eggshells is examined by the powder X-ray diffraction. The surface morphology of the sintered product is determined by the scanning electron microscope equipped with the energy dispersive spectrometer. Powder X-ray diffraction and scanning electron microscope analyses confirmed hydroxyapatite as the main phase of the final product. The reuse of chicken eggshells reduces the amount of biowaste, as well as the need for the biowaste management. This investigation shows that the eggshells can be a useful raw material for the synthesis of valuable biomaterials. In dieser Arbeit ist ein konventionelles Fällungsverfahren für die Herstellung eines Biomaterials – Hydroxylapatit aus Bioabfall in der Form von Eierschalen verwendet worden. Hydroxylapatit ist ein wesentliches Biomaterial, weil er ein wichtiger Bestandteil der menschlichen harten Gewebe (Knochen und Zähne) ist. Der erste Schritt bei der Hydroxylapatitsynthese aus den Eierschalen ist die Umwandlung ihrer Hauptkomponente Calciumcarbonat in Calciumoxid bei 1000 °C. Danach wird Calciumoxid hydratisiert, um Calciumhydroxid herzustellen. Hydroxylapatit wird dann durch die Fällungsreaktion mit der Phosphorsäure synthetisiert. Die Phasenzusammensetzung den Eierschalen wird durch Röntgenpulverdiffraktometer untersucht. Die Oberflächenmorphologie des Sinterprodukts wird durch ein Rasterelektronenmikroskop, das mit einem energiedispersiven Spektrometer ausgestattet ist, bestimmt. Die durchgeführten Analysen bestätigen Hydroxylapatit als die Hauptphase des Endprodukts. Die Eierschalenwiederverwendung verringert die Bioabfallmenge sowie die Notwendigkeit für Bioabfallmanagement. Diese Untersuchung zeigt, dass Eierschalen ein nützlicher Rohstoff für die Synthese wertvoller Biomaterialien sein können.

ACS Style

L. Ćurković; Irena Žmak; S. Kurajica; M. E. Tonković; Z. Šokčević; M. Majić Renjo. From eggshells biowaste to hydroxyapatite biomaterial. Materialwissenschaft und Werkstofftechnik 2017, 48, 797 -802.

AMA Style

L. Ćurković, Irena Žmak, S. Kurajica, M. E. Tonković, Z. Šokčević, M. Majić Renjo. From eggshells biowaste to hydroxyapatite biomaterial. Materialwissenschaft und Werkstofftechnik. 2017; 48 (8):797-802.

Chicago/Turabian Style

L. Ćurković; Irena Žmak; S. Kurajica; M. E. Tonković; Z. Šokčević; M. Majić Renjo. 2017. "From eggshells biowaste to hydroxyapatite biomaterial." Materialwissenschaft und Werkstofftechnik 48, no. 8: 797-802.

Article
Published: 08 August 2017 in Materialwissenschaft und Werkstofftechnik
Reads 0
Downloads 0

The purpose of this study was to investigate and analyze fracture toughness (KIc) of yttria stabilized tetragonal zirconia (Y-TZP) dental ceramics by the Vickers indentation fracture test. In order to determine fracture toughness, the Vickers indenter was used under the load of 294.20 N (HV30). The cracks, which occur from the corners of a Vickers indentation, were measured and used for fracture toughness determination, through five mathematical models according to (I) Anstis, (II) Evans and Charles, (III) Tanaka, (IV) Niihara, Morena and Hasselman and (V) Lankford. Morphology of indentation cracking was determined by scanning electron microscope. The most adequate model for determination of fracture toughness (KIc) of yttria stabilized tetragonal zirconia dental ceramics by the Vickers indentation fracture test is Lankford model. Das Ziel der Untersuchung bestand in der Untersuchung und Analyse der durch die Vickers Indenter-Technik ermittelten Bruchzähigkeit (KIc) der Yttrium-stabilisierten Zirkoniumdioxid-Dentalkeramik (Y-TZP). Der Vickerseindringkörper unter der Last von 294,20 N (HV30) wurde benutzt, um die Bruchzähigkeit zu bestimmen. Die Risse, die an den Spitzen der Vickerseindrücke aufgetreten sind, wurden gemessen und für die Bestimmung der Bruchzähigkeit verwendet. Fünf mathematische Modelle wurden eingesetzt: (I) Anstis, (II) Evans und Charles, (III) Tanaka, (IV) Niihara, Morena und Hasselman und (V) Lankford. Die Morphologie der Risse wurde durch Rasterelektronenmikroskopie charakterisiert. Das Lankford-Modell ist das geeignetste Modell für die Bestimmung der Zirkoniumdioxid-Dentalkeramik Bruchzähigkeit mit der Vickers Indenter-Technik.

ACS Style

D. Ćorić; M. Majić Renjo; Irena Žmak. Critical evaluation of indentation fracture toughness measurements with Vickers indenter on yttria-stabilized zirconia dental ceramics. Materialwissenschaft und Werkstofftechnik 2017, 48, 767 -772.

AMA Style

D. Ćorić, M. Majić Renjo, Irena Žmak. Critical evaluation of indentation fracture toughness measurements with Vickers indenter on yttria-stabilized zirconia dental ceramics. Materialwissenschaft und Werkstofftechnik. 2017; 48 (8):767-772.

Chicago/Turabian Style

D. Ćorić; M. Majić Renjo; Irena Žmak. 2017. "Critical evaluation of indentation fracture toughness measurements with Vickers indenter on yttria-stabilized zirconia dental ceramics." Materialwissenschaft und Werkstofftechnik 48, no. 8: 767-772.

Article
Published: 08 August 2017 in Materialwissenschaft und Werkstofftechnik
Reads 0
Downloads 0

EnglishGermanAbstractThe paper presents the preparation of biocomposites from waste seashells as reinforcement and poly(methyl methacrylate), abbreviated as PMMA as the matrix. The used seashells belong to the snow-white Bahamian species of tiger lucine (Codakia orbicularis) from the Island of Coco Cay. Seashells were grinded and homogenized with poly(methyl methacrylate) powder, with the seashell powder content ranging between 2 and 14 wt%, and finally hot pressed. Morphology of prepared composites was analyzed by scanning electron microscopy, and it was determined that the particle distribution was homogenous with no agglomeration. Mechanical properties (microhardness, compressive strength, Young's modulus) of biocomposite materials produced from different amount of waste seashells in poly (methyl methacrylate) were determined and analyzed. The best overall combination of mechanical properties was achieved when 6 wt% of seashell particles below 50 μm size were added to poly (methyl methacrylate).Translation abstractDer Artikel beschreibt die Herstellung von Bioverbundwerkstoffen aus Muschelabfällen als Verstärkung und Polymethylmethacrylat (Kurzzeichen PMMA) als Matrix. Die verwendeten Muscheln gehören der schneeweißen bahamaischen Art Tiger lucine (Codakia orbicularis) von der Insel Coco Cay an. Die Muscheln wurden gemahlen und mit Polymethylmethacrylat-Pulver im Bereich zwischen 2 und 14 Gew.-% homogenisiert, sowie heißgepresst. Die Morphologie vorbereiteter Verbundwerkstoffe wurde durch Rasterelektronenmikroskopie analysiert und es wurde festgestellt, dass die Partikelverteilung ohne Agglomeration und homogen war. Mechanische Eigenschaften (Mikrohärte, Druckfestigkeit, Elastizitätsmodul) der Bioverbundwerkstoffe, hergestellt aus verschiedener Muschelmenge in Polymethylmethacrylat, wurden bestimmt und analysiert. Die insgesamt beste Kombination von mechanischen Eigenschaften wurde bei 6 Gew.-% Muschelpartikeln unter 50 μm Größe erreicht.

ACS Style

Irena Žmak; D. Ćorić; M. Surjak; E. Žalac. Properties of biocomposites from waste seashells and poly(methyl methacrylate). Materialwissenschaft und Werkstofftechnik 2017, 48, 779 -784.

AMA Style

Irena Žmak, D. Ćorić, M. Surjak, E. Žalac. Properties of biocomposites from waste seashells and poly(methyl methacrylate). Materialwissenschaft und Werkstofftechnik. 2017; 48 (8):779-784.

Chicago/Turabian Style

Irena Žmak; D. Ćorić; M. Surjak; E. Žalac. 2017. "Properties of biocomposites from waste seashells and poly(methyl methacrylate)." Materialwissenschaft und Werkstofftechnik 48, no. 8: 779-784.

Article
Published: 08 August 2017 in Materialwissenschaft und Werkstofftechnik
Reads 0
Downloads 0

A nickel matrix with silicon carbide nanoparticles composite coating is prepared by electrodeposition on non-alloyed steel, assisted with an ultrasonic treatment of the galvanic bath. The abrasion and erosion wear resistance of the coating is determined, as well as its micro-hardness. The structure and the composition of the nickel nanocomposite coating is defined using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The corrosion behavior is investigated by the potentiodynamic polarization methods in the 3.5 wt% sodium chloride solution. The results show improved mechanical properties, wear and corrosion resistance as compared to the nickel metallic coating. Eine Nickelmatrix mit Siliciumkarbid-Nanopartikel Komposit-Beschichtung wurde durch galvanische Abscheidung auf unlegiertem Stahl hergestellt. Die galvanische Abscheidung ist durch eine Ultraschallbehandlung des galvanischen Bades unterstützt. Abrasiv- und Erosionsverschleißfestigkeit sowie Mikrohärte der Beschichtung wurden bestimmt. Struktur und Zusammensetzung der Nickel-Nanokomposit-Beschichtung wurden unter Verwendung von Rasterelektronenmikroskopie und energiedispersiver Röntgenspektroskopie untersucht. Das Korrosionsverhalten wurde durch potenziodynamische Polarisationsverfahren in 3,5 Gew% Natriumchlorid-Lösung untersucht. Die Ergebnisse zeigen verbesserte mechanische Eigenschaften, Verschleiß- und Korrosionsbeständigkeit im Vergleich zur Nickel-Metallbeschichtung.

ACS Style

V. Alar; Irena Žmak; I. Stojanović; V. Šimunović; Z. Čeralinac. Abrasion and erosion wear of electrodeposited nickel - silicon carbide nanocomposite coatings. Materialwissenschaft und Werkstofftechnik 2017, 48, 785 -791.

AMA Style

V. Alar, Irena Žmak, I. Stojanović, V. Šimunović, Z. Čeralinac. Abrasion and erosion wear of electrodeposited nickel - silicon carbide nanocomposite coatings. Materialwissenschaft und Werkstofftechnik. 2017; 48 (8):785-791.

Chicago/Turabian Style

V. Alar; Irena Žmak; I. Stojanović; V. Šimunović; Z. Čeralinac. 2017. "Abrasion and erosion wear of electrodeposited nickel - silicon carbide nanocomposite coatings." Materialwissenschaft und Werkstofftechnik 48, no. 8: 785-791.

Journal article
Published: 01 February 2011 in Materials Testing
Reads 0
Downloads 0

The Vickers micro-hardness of three different sea mollusc shell structures has been determined as a function of the indentation load. The following shells from the Adriatic Sea have been investigated: abalone (Haliotis tuberculata), smooth clam (Callista chione), and warty venus (Venus verrucosa). The results show that the measured micro-hardness depends on the load for all of the investigated seashell structures, which indicates the influence of the indentation size effect (ISE). The load dependence of micro-hardness has been analyzed by using the known Meyer's Law, the proportional specimen resistance model (PSR), and the modified proportional specimen resistance model. The best correlation between measured values and used models has been achieved by using the modified PSR model.

ACS Style

Tomislav Filetin; Sanja Šolić; Irena Žmak. The Indentation Size Effect on the Micro-Hardness of Sea Mollusc Shell Structures. Materials Testing 2011, 53, 48 -53.

AMA Style

Tomislav Filetin, Sanja Šolić, Irena Žmak. The Indentation Size Effect on the Micro-Hardness of Sea Mollusc Shell Structures. Materials Testing. 2011; 53 (1-2):48-53.

Chicago/Turabian Style

Tomislav Filetin; Sanja Šolić; Irena Žmak. 2011. "The Indentation Size Effect on the Micro-Hardness of Sea Mollusc Shell Structures." Materials Testing 53, no. 1-2: 48-53.

Journal article
Published: 01 January 2005 in Journal of ASTM International
Reads 0
Downloads 0
ACS Style

Sw Dean; T Filetin; I Žmak; D Novák. Determining Nitriding Parameters with Neural Networks. Journal of ASTM International 2005, 2, 1 .

AMA Style

Sw Dean, T Filetin, I Žmak, D Novák. Determining Nitriding Parameters with Neural Networks. Journal of ASTM International. 2005; 2 (5):1.

Chicago/Turabian Style

Sw Dean; T Filetin; I Žmak; D Novák. 2005. "Determining Nitriding Parameters with Neural Networks." Journal of ASTM International 2, no. 5: 1.