Yazar "Boyraz, Tahsin" seçeneğine göre listele
Listeleniyor 1 - 18 / 18
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Characterization of microstructural and thermal properties of steatite/cordierite ceramics prepared by using natural raw materials(ELSEVIER SCI LTD, 2011) Gokce, Hasan; Agaogullari, Duygu; Ovecoglu, M. Lutfi; Duman, Ismail; Boyraz, TahsinSteatite/cordierite ceramics were fabricated by using a combined method of high-energy ball milling, cold pressing and sintering. Steatite and cordierite powders were separately synthesized from natural raw materials such as kaolinite and talc. The powder blends containing different amounts of cordierite (5, 10 and 20 wt.%) were wet-milled for 1 h in a vibratory ball-mill (Fritsch (TM) Pulverisette 7 Premium Line), using zirconia vial and balls. After drying, powders were compacted to cylindrical preforms with a diameter of 12.7 mm by uniaxial pressing at 300 MPa. The green compacts were sintered at 1200-1350 degrees C for 2 h under air. Phase, microstructural and thermal characterizations of the sintered materials were carried out by using X-ray diffraction technique (XRD), thermogravimetry/differential thermal analyzer (TG/DTA) and scanning electron microscope (SEM). Densities, open porosity and water absorption values of sintered bodies were measured by Archimedes method. Thermal expansion coefficient (CTE) measurements were conducted by a dilatometer. (C) 2010 Elsevier Ltd. All rights reserved.Öğe Correlation between bending strength and porosity in vermiculite added ceramic bodies(Hanyang University, 2024) Önen, Umut; Boyraz, TahsinIn this study focused on the production, characterization and bending strength-porosity relationship of vermiculite-added floor tiles, porcelain and sanitary ware bodies. The materials used in this study are calcined vermiculite, quartz, clay, kaolin, feldspar and porcelain powder as ceramic raw materials. Calcined vermiculite was incorporated into the ceramic bodies at concentrations of 0.10% and 20% by weight, following a heat treatment at 1050°C for 1 hour. The mixtures underwent homogenization in alumina ball mills operating at 60 rpm for 24 hours and were subsequently shaped via uniaxial dry pressing at 100 MPa. The resulting pressed samples were then subjected to sintering at temperatures ranging from 1050 to 1150°C for 1 hour. Evaluation of the fabricated samples included analysis of microstructure using scanning electron microscopy (SEM), phase analysis via X-ray diffraction (XRD), and assessment of mechanical properties through 3-point bending tests. Additionally, physical properties such as percentage shrinkage, water absorption, porosity, and density were measured. The results demonstrated that higher concentrations of calcined vermiculite resulted in improvements in the properties of the ceramic bodies. After the characterization results, the bending strength-porosity relationship was examined. Correlation coefficient, t-test and p values were calculated. There is a strong negative correlation with the correlation coefficient at-0.898,-0.875 and-0.907 for floor tiles, porcelain and sanitary ware respectively. © 2024, Hanyang University. All rights reserved.Öğe Fabrication and characterization of aluminium titanate and mullite added Porcelain ceramics(KOREAN ASSOC CRYSTAL GROWTH, INC, 2019) Akkus, Ahmet; Boyraz, TahsinIn this study, aluminium titanate (AT, Al2TiO5) and mullite (M, 3Al(2)O(3)center dot 2SiO(2)) ceramics were synthesized by reaction sintering from Al2O3, SiO2 and TiO2 powders which consisted of homogenization by wet ball milling followed by sintering AT and M in air at 1550 degrees C for 2 hrs and 1400 degrees C for 2 hrs, respectively. AT and M in different amounts (0 and 20 wt. %) were mixed with Porcelain (P). AT and M reinforced porcelain ceramics were prepared by the powder metallurgy route. After drying, the powders were compressed to preforms of 56x12x10 mm by uniaxial pressing at 200 MPa. The green compacts were sintered at 1100-1200 degrees C for 1-5 hr under air. Investigations were carried out, on the effect of addition of AT and M in terms of physical properties, microstructure, XRD phases, as well as wear and mechanical properties of AT and M-reinforced porcelain ceramic composites. Phase and microstructural characterizations of the sintered materials were carried out by using X-ray diffraction technique (XRD) and scanning electron microscope (SEM). The Micro Vickers hardness testing was performed using the Shimadzu HMV-MIII hardness tester.Öğe Fabrication and Characterization of Mullite Reinforced CeO2 Added ZrO2 Ceramics(2022) Hafızoğlu, Mehmet Akif; Akkuş, Ahmet; Boyraz, TahsinIn this study, mullite (3Al2O3.2SiO2) and 10 mol % ceria added zirconia (10 mol % CeO2 - 90 mol % ZrO2) ceramic powders were synthesized by conventional ceramic production processing route. The mixtures were prepared by mechanical alloying method in acetone environment with zirconia ball mill. Mullite and ceria added zirconia ceramic powders were synthesized in air at 1600 oC for 3 h and 1300 oC for 2 h, respectively. Then, the ceramic phases formed were made ready to form ceramic - ceramic composites by crushing, grinding and sieving processes. Then 0 and 10% by weight mullite added ceria doped zirconia mixtures were prepared by powder metallurgy method. The prepared mixtures were wet milled with zirconia ball mill for 24 h and sieved. After drying, the powders were compacted by uniaxial pressing at 200 MPa. The green compacts were sintered at 1500-1600 oC for 1-5 h in air conditions using a heating rate of 5 oC min-1 in a high temperature furnace. Then, microstructure (SEM), phase analysis (XRD), mechanical (hardness, 3-point bending and wear) and physical properties (% shrinkage, water absorption, porosity and density) tests were performed on the ceramic composites. In this study, whether there is a phase change in the ZrO2 - CeO2 mixture at high sintering temperatures and the effect of mullite additive on the properties of this mixture was investigated.Öğe Humidity sensitivity characteristics of BaTiO3 ceramics with PMMA additive at various working temperatures(KOREAN ASSOC CRYSTAL GROWTH, INC, 2010) Ertug, Burcu; Boyraz, Tahsin; Addemir, OkanBarium titanate samples were prepared by a traditional powder metallurgy method. High-purity powders were mixed by ball-milling in order to produce powder mixtures. The resultant mixtures were dried, sieved and were uniaxially pressed into green samples. Green samples were then sintered at 1200-1500 degrees C for 6 h in air to form a barium titanate phase. The average grain size and microstructural features were determined for each composition. The effects of porosity and working temperatures on the barium titanate ceramics were investigated by microstructural analysis and electrical conductivity measurements and the results were evaluated in terms of porosity.Öğe Investigation Of The Effect Of Vermiculite (Yıldızeli/Sivas) Addition On The Properties Of Sanitaryware Ceramic(2022) Boyraz, Tahsin; Önen, Umut; Tapik, ŞabanSanitaryware is the generic term used to describe items which traditionally were made from pottery. i.e. toilets, washbasins, pedestals, bidet, urinals, sinks, bathtubs installed within a bathroom or washroom. Sanitaryware products are primarily made of clay, kaolin, feldspar and quartz but they may also include small quantities of other raw materials. Its high gloss, stain resistant surface is ideal for use in both bath-rooms and kitchens. Vermiculite, a mineral in which the hydromicas group occurs naturally, becomes a high-efficiency thermal insulation material when heated above 300 ?. The expanded vermiculite can be used as a filler for heat insulating materials due to its unique properties, low bulk density, low thermal conductivity, relatively high melting point, chemical inertia, durability and environmental safety. In this study, the effects of vermiculite obtained from Yıldızeli/Sivas region on sanitaryware body properties were investigated. The materials used in this study are calcined vermiculite, quartz, clay, kaolin and feldspar ceramic raw materials. Sanitaryware compositions were prepared by using kaolin-feldspar-quartz ternary equilibrium diagram according to the appropriate recipe from the raw material. In accordance with this purpose; prepared sanitaryware bodies %0, 10 and 20 by weight calcined vermiculite (1050 oC 1 hour) was added to formed the body compositions. The samples were coded as S20V1100 (S: Sanitaryware; 20V: 20% vermiculite addition and 1100: 1100 °C firing temperature). Mixtures homogenized in Alumina ball mills (60 rpm, 24 hours) were shaped by uniaxial dry pressing (100 MPa). Then, the prepared pressed samples were fired at 1050-1100 and 1150 °C for 1 hour. Microstructure (SEM), phase analysis (XRD), mechanical (hardness, 3-point bending) and physical properties (% shrinkage, water absorption, porosity and density) tests were performed on the sanitaryware bodies produced. The obtained data were presented in graphs and tables and commented. Accordingly, the properties of the vermiculite doped specimens were successfully developed and the optimum parameters were clearly shown. According to the results, it has been shown that sanitaryware properties are improved with the increase of calcined vermiculite.Öğe Investigation of wear properties of CaO, MgO added stabilized zirconia ceramics produced by different pressing methods(KOREAN ASSOC CRYSTAL GROWTH, INC, 2018) Akkus, Ahmet; Boyraz, TahsinStabilized zirconia has superior high temperature properties such as high tolerance for thermal shock, low thermal conductivity, mechanical properties, elevated melting point, good phase stability and excellent oxidation resisNtance. The present paper describes the fabrication and wear behaviour of 8 mole% CaO, 4 mole % CaO-4 mole% MgO and 8 mole% MgO - stabilized zirconia (ZrO2) based composites fabricated by the conventional ceramic production process. CaO/MgO added stabilized zirconia ceramics were fabricated by using a combined method of ball milling, cold press-cold isostatic pressing and sintering. The powder blends containing different amounts of % 8 mole CaO/MgO were wet-milled for 1 hr in a vibratory ball-mill using zirconia vial and balls. After drying, powders were compacted to cylindrical preforms with a diameter of 12.7 mm by uniaxial pressing at 300 MPa and by cold isostatic pressing at 300 MPa. The green compacts were sintered at 1600 degrees C for 3 hrs under air. Phase and microstructural characterizations of the sintered materials were carried out by using X-ray diffraction technique (XRD) and scanning electron microscope (SEM). The Micro Vickers hardness testing was performed using the Shimadzu HMV-MIII hardness tester. Plint brand abrasion tester was used for the abrasion tests of ceramics. As a result, it has been observed that the hardness is increased by increasing the amount of MgO and the ceramics produced by cold isostatic pressing are harder.Öğe Microstructural and Mechanical Properties of Hot-pressed (B4C, SiC)/TiB2 Composites(GOLLER VERLAG GMBH, 2012) Akarsu, Ali Cem; Gokce, Hasan; Ertug, Burcu; Addemir, A. Okan; Ovecoglu, M. Lutfi; Boyraz, TahsinThe overall characteristics of the starting powders were determined, namely microstructure, partitle size, phase composition. The pre-forming step and the parameters of the hot pressing were given in detail. (B4C, Sic)/TiB2 composites were succesfully fabricated by hot-pressing at 2250 degrees C for 2 h under a pressure of 130 MPa. The Matrix phase was B4C-SiC including TiB2 (2 and 4 vol.-%) as additive. The microstructural features of the fabricated Composites were examined by SEM. Relative densities of the composites ranged between 89 and 93,5 %. According to Vickers microhardness tests and flexure strength measurements, highest hardness obtained was 2200 Hv and flexure strength results have values up to 275 MPa. It was concluded that TiB2 reinforcement improved the flexure strength and microhardness of hot pressed B4C-SiC composites. It was concluded that the novel compositions presented here are candidate materials for body armor or blasting nozzle applications.Öğe Mullit Takviyeli CaO Katkılı ZrO2 Seramiklerinin İmalatı ve Karakterizasyonu(Osman SAĞDIÇ, 2021) Hafızoğlu, Mehmet Akif; Akkuş, Ahmet; Boyraz, TahsinBu çalışmada, mullit (3Al2O3.2SiO2) ve %11 mol kalsiyum oksit katkılı zirkonya (%11 mol CaO - %89 mol ZrO2) seramik tozları geleneksel seramik üretim yöntemi ile sentezlenmiştir. Karışımlar, zirkonya bilyalı değirmende aseton ortamında mekanik alaşımlama yöntemiyle hazırlanmıştır. Tozlar karıştırılmadan önce 110 ºC'de 24 saat etüvde kurutulmuştur. Al2O3, SiO2, CaO ve ZrO2 tozlarının stokiyometrik oranlarından oluşan tozların aseton ortamında bilyeli değirmende homojenize edildikten sonra geleneksel sinterleme yöntemiyle Mullit (3Al2O3.2SiO2) ve %11 mol kalsiyum oksit katkılı zirkonya (CaO-ZrO2) seramik tozları sentezlenmiştir. Mullit ve %11 mol kalsiyum oksit katkılı zirkonya seramik tozları sırasıyla 1600 oC'de 3 saat ve 1300 oC'de 2 saat sentezlenmiştir. Daha sonra oluşan seramik fazlar kırma, öğütme ve eleme işlemleri ile seramik - seramik kompozitleri oluşturmaya hazır hale getirilmiştir. Daha sonra ağırlıkça %0 ve %10 mullit (M) takviyeli kalsiyum oksit katkılı zirkonya (CaZ) karışımları toz metalurjisi yöntemiyle hazırlanmıştır. Hazırlanan karışımlar zirkonya bilyalı değirmende 24 saat yaş öğütülmüş ve elenmiştir. Kurutulduktan sonra, tozlar 200 MPa'da tek eksenli presleme ile 56x12x10 mm'lik preformlara sıkıştırılmıştır. Devamında, yüksek sıcaklıklı bir fırında 5 oC/dak ısıtma hızı kullanılarak hava koşullarında 1500-1600 oC'de 1-5 saat sinterlenmiştir. Daha sonra mullit takviyeli kalsiyum oksit katkılı zirkonya seramik kompozitler üzerinde mikroyapı (SEM), faz analizi (XRD), mekanik (sertlik, 3 nokta eğme ve aşınma) ve fiziksel özellikler (% küçülme, su emme, gözeneklilik ve yoğunluk) testleri yapılmıştır. Bu çalışmada, yüksek sinterleme sıcaklıklarında ZrO2 - CaO karışımında faz değişimi olup olmadığı ve mullit katkı maddesinin bu karışımın özelliklerine etkisi araştırılmıştır. Elde edilen veriler grafik ve tablolar halinde sunulmuş ve yorumları yapılmıştır.Öğe Mullit Takviyeli MgO Katkılı ZrO2 Seramiklerinin İmalatı ve Karakterizasyonu(Osman SAĞDIÇ, 2021) Hafızoğlu, Mehmet Akif; Boyraz, Tahsin; Akkuş, AhmetBu çalışmada, mullit (3Al2O3.2SiO2) ve %10 mol magnezya katkılı zirkonya (%10 mol MgO - %90 mol ZrO2) seramik tozları geleneksel seramik üretim yöntemi ile sentezlenmiştir. Karışımlar, zirkonya bilyalı değirmende aseton ortamında mekanik alaşımlama yöntemiyle hazırlanmıştır. Tozlar karıştırılmadan önce 110 ºC'de 24 saat etüvde kurutulmuştur. Al2O3, SiO2, MgO ve ZrO2 tozlarının stokiyometrik oranlarından oluşan tozların aseton ortamında bilyeli değirmende homojenize edildikten sonra geleneksel sinterleme yöntemiyle Mullit (3Al2O3.2SiO2) ve %10 mol magnezya katkılı zirkonya (MgO-ZrO2) seramik tozları sentezlenmiştir. Mullit ve %10 mol magnezya katkılı zirkonya seramik tozları sırasıyla 1600 oC'de 3 saat ve 1300 oC'de 2 saat sentezlenmiştir. Daha sonra oluşan seramik fazlar kırma, öğütme ve eleme işlemleri ile seramik - seramik kompozitleri oluşturmaya hazır hale getirilmiştir. Daha sonra ağırlıkça %0 ve %10 mullit (M) takviyeli magnezya katkılı zirkonya (MgZ) karışımları toz metalurjisi yöntemiyle hazırlanmıştır. Hazırlanan karışımlar zirkonya bilyalı değirmende 24 saat yaş öğütülmüş ve elenmiştir. Kurutulduktan sonra, tozlar 200 MPa'da tek eksenli presleme ile 56x12x10 mm'lik preformlara sıkıştırılmıştır. Devamında, yüksek sıcaklıklı bir fırında 5 oC/dak ısıtma hızı kullanılarak hava koşullarında 1500-1600 oC'de 1-5 saat sinterlenmiştir. Daha sonra mullit takviyeli magnezya katkılı zirkonya seramik kompozitler üzerinde mikroyapı (SEM), faz analizi (XRD), mekanik (sertlik, 3 nokta eğme ve aşınma) ve fiziksel özellikler (% küçülme, su emme, gözeneklilik ve yoğunluk) testleri yapılmıştır. Bu çalışmada, yüksek sinterleme sıcaklıklarında ZrO2 - MgO karışımında faz değişimi olup olmadığı ve mullit katkı maddesinin bu karışımın özelliklerine etkisi araştırılmıştır. Elde edilen veriler grafik ve tablolar halinde sunulmuş ve yorumları yapılmıştır.Öğe Mullit Takviyeli Y2O3 Katkılı ZrO2 Seramiklerinin İmalatı ve Karakterizasyonu(Mustafa CAN, 2021) Hafızoğlu, Mehmet Akif; Boyraz, Tahsin; Akkuş, AhmetBu çalışmada, mullit (3Al2O3.2SiO2) ve %3 mol itriya katkılı zirkonya (%3 mol Y2O3 - %97 mol ZrO2) seramik tozları geleneksel seramik üretim yöntemi ile sentezlenmiştir. Tüm karışımlar, zirkonya bilyalı değirmende aseton ortamında mekanik alaşımlama yöntemiyle hazırlanmıştır. Mullit ve itriya katkılı zirkonya seramik tozları sırasıyla 1600 oC'de 3 saat ve 1300 oC'de 2 saat sentezlenmiştir. Seramik fazlar kırma, öğütme ve eleme işlemleri ile seramik - seramik kompozitleri oluşturmaya hazır hale getirilmiştir. Daha sonra ağırlıkça %0 ve %10 mullit takviyeli itriya katkılı zirkonya karışımları toz metalurjisi yöntemiyle hazırlanmıştır. Kurutulduktan sonra, tozlar tek eksenli presleme ile sıkıştırılmıştır. Devamında, yüksek sıcaklıklı bir fırında hava koşullarında 1500-1600 oC'de 1-5 saat sinterlenmiştir. Daha sonra kompozitler üzerinde mikroyapı (SEM), faz analizi (XRD), mekanik (sertlik, 3 nokta eğme ve aşınma) ve fiziksel özellikler (% küçülme, su emme, gözeneklilik ve yoğunluk) testleri yapılmıştır. Bu çalışmada, yüksek sinterleme sıcaklıklarında ZrO2 - Y2O3 karışımında faz değişimi olup olmadığı ve mullit katkı maddesinin bu karışımın özelliklerine etkisi araştırılmıştır. Elde edilen veriler grafik ve tablolar halinde sunulmuş ve yorumları yapılmıştır.Öğe Prediction of Wear Properties of CaO and MgO Doped Stabilized Zirconia Ceramics with Artificial Neural Networks(Taylor & Francis Ltd, 2024) Yuksek, Ahmet Gurkan; Boyraz, Tahsin; Akkus, AhmetIn this research, the production and wear behavior of CaO and MgO doped stabilized zirconia ceramics prepared by powder metallurgy method were investigated and artificial neural network (ANN) models were established and predicted with the data produced as a result of real experiments. CaO/MgO doped stabilized zirconia ceramics were produced using a combination of ball milling, cold pressing - cold isostatic pressing and sintering methods. CaO and MgO were mixed with zirconia in different amounts (0-8 mol%). These mixtures were prepared by mechanical alloying. Green compacts were sintered at 1600 degrees C. The wear experimental results produced from the trials were converted into data suitable for modelling with ANN. Wear load, wear time of the load, MgO and CaO were given as input to the ANN model. The amount of wear according to the pressing method was set as the output variable value of the ANN. An ANN approach model was established to predict the wear behavior characteristics of zirconia ceramic composites. In order to emphasize the success of the model, the test data set was presented to the ANN model and the results produced were compared with the results produced experimentally, and as a result of these tests, high R-2 values of 0.99409 for 65N and 0.97512 for 80N were produced.Öğe Prediction of Wear Properties of Experimental Produced Porcelain Ceramics Using Artificial Neural Networks (ANN)(Sivas Cumhuriyet Üniversitesi, 2023) Yüksek, Ahmet Gürkan; Boyraz, Tahsin; Akkuş, AhmetIn this study, the production and wear properties of porcelain ceramics produced by powder metallurgy method were examined and modelling with artificial neural networks was studied using the experimental data obtained. Porcelain ceramics were prepared by the powder metallurgy route. Mixtures prepared by mechanical alloying method in alumina ball mills were produced by sintering under normal atmospheric conditions after being shaped in a dry press. After drying, the powders were compressed by uniaxial pressing at 200 MPa. The green compacts were sintered at 1100-1200 oC for 1-5 h in air. Then, characterization studies of the sintered samples were carried out and the wear experimental results obtained were converted into data suitable for modelling with artificial neural networks. In the continuation of the study, experimental wear results using artificial neural networks were analysed and modelled. Wear load, wear time, sintering temperature and sintering time were used as artificial neural networks input variables. Wear values were taken as output variables of artificial neural networks. An artificial neural network was established for the prediction of wear properties of porcelain ceramic composites. As a result, the training results and test results were compared with the actual values to control the network performance. A good agreement was observed between the experimental and artificial neural networks model results. After the artificial neural networks estimation, confirmation tests were performed to confirm the experimental results.Öğe Regression Modelling to Study Wear Properties of Experimental Produced Porcelain Ceramics(Sivas Cumhuriyet Üniversitesi, 2023) Yüksek, Ahmet Gürkan; Boyraz, Tahsin; Akkuş, AhmetIn this study, the production and wear properties of porcelain ceramics produced by powder metallurgy method were examined and modelling with regression were studied using the experimental data obtained. Porcelain ceramics were prepared by the powder metallurgy route. Mixtures prepared by mechanical alloying method in alumina ball mills were produced by sintering under normal atmospheric conditions after being shaped in a dry press. After drying, the powders were compressed by uniaxial pressing at 200 MPa. The green compacts were sintered at 1100-1200 oC for 1-5 h in air. Then, characterization studies of the sintered samples were carried out and the wear experimental results obtained were converted into data suitable for modelling with regression. In the continuation of the study, experimental wear results using regression was analysed and modelled. Wear load, wear time, sintering temperature and sintering time were used as regression input variables. Wear values were taken as output variables of regression. An regression was established for the prediction of wear properties of porcelain ceramic composites. As a result, the training results and test results were compared with the actual values to control the network performance. A good agreement was observed between the experimental and regression model results. After the regression estimation, confirmation tests were performed to confirm the experimental results.Öğe Structural and mechanical characterization of mullite and aluminium titanate reinforced yttria stabilized zirconia ceramic composites(KOREAN ASSOC CRYSTAL GROWTH, INC, 2019) Kucuk, Israfil; Boyraz, Tahsin3 mole % yttria stabilized zirconia (YSZ) ceramic and 20 wt. % mullite (M), and 20 wt. % aluminium titanate (AT) reinforced YSZ ceramic composites were produced using a conventional ceramic production process. After a combined method of wet ball milling and dry pressing, these samples were sintered at 1500 degrees C and 1600 degrees C for 1hr and 5hrs, respectively. Physical properties, microstructural and phase characterizations of the sintered samples were analyzed using Archimedes method, a scanning electron microscope with energy dispersive spectroscopy and X-ray diffraction technique, respectively. Thereafter, micro Vickers and three-point bending tests were performed. The density, relative density and firing shrinkage of the sintered samples increased with addition of M and AT and the increased sintering temperature at each time. However, both porosity and loss of water properties determined were inversely proportional to M and AT addition and sintering temperature and time increase. An increase in M and AT content influenced the grain morphology as is presented in the microstructures of the composites produced thus bringing about a rise in grain size, as well as homogeneity and density in YSZ samples. Promising results were observed with the Vickers and bending strength in the mullite reinforced YSZ samples sintered at 1600 degrees C for 5hrs due to mullite addition, which provides excellent mechanical features to the YSZ ceramic composites.Öğe The Effect of Mullite Addition on Wear Properties of SiO2 Doped ZrO2 Ceramics(2022) Hafızoğlu, Mehmet Akif; Boyraz, Tahsin; Akkuş, AhmetMullite (3Al2O3.2SiO2) and 10 mol% silica added zirconia (10 mol% SiO2 - 90 mol% ZrO2) ceramic powders were synthesized by conventional ceramic processing route. The mixtures were prepared by mechanical alloying method using zirconia ball mill in acetone environment. To synthesize mullite, Al2O3 and SiO2 powders mixture was prepared with stoichiometric proportions and fired it in the air at 1600 oC for 3 h. And the silica added zirconia composites were fired at 1300 oC for 2 h. Thus, silica - zirconia and mullite composite phases were obtained and milling and sieving processes were carried out. Then, mullite-free and 10% by weight mullite reinforced silicon oxide added zirconia mixtures were prepared by powder metallurgy method. The powders were compacted by uniaxial pressing. The formed samples were sintered in a high temperature furnace in air conditions for 1 and 5 h at 1500 and 1600 oC sintering temperatures. Finally, microstructure examinations of the composites with SEM, phase analysis with XRD, hardness, three-point bending and wear tests were performed. In addition, the results of water absorption, porosity and density from physical properties and the effect of mullite additive on the mechanical and especially wear properties of this mixture were investigated.Öğe The effect of mullite addition on wear properties of titania doped zirconia ceramics(2022) Hafızoğlu, Mehmet Akif; Boyraz, Tahsin; Akkuş, AhmetIn this study, whether there is a phase change in the zirconia-titania mixture at high sintering temperatures and the effect of mullite additive on the mechanical and especially wear properties of this mixture was investigated. We synthesized mullite and 8 mol % titania added zirconium dioxide (8 mol % titania - 92 mol % zirconia) powders by conventional ceramic production route. We prepared the mixtures in acetone environment by mechanical alloying technique. To synthesize mullite, we prepared Al2O3 and SiO2 powders mixture with stoichiometric proportions and fired in air at 1600 oC for 3 h. Then, we fired titania added zirconia composites at 1300 oC for 2 h. Thus, titania - zirconia and mullite composite phases were obtained and grinding and sieving processes were carried out. Then, we prepared mullite-free and 10% by weight mullite reinforced titanium oxide added zirconia mixtures. The powders were pressed by uniaxial pressing after drying. The formed samples were sintered in a high temperature furnace in air conditions for 1 and 5 h at 1500 and 1600 oC sintering temperatures. Finally, microstructure investigations, phase analysis, 3-point bending, hardness, wear tests, absorption of water, porosity, shrinkage and density results were examined on the composites. It was founded that with titania and mullite adding to zirconia matrix, there was not define a new phase in the composite microstructure. But mullite additive increased the wear resistance, hardness and three-point bending strength of the titania-zirconia composites.Öğe Thermomechanical properties of aluminium titanate (Al2TiO5)-reinforced forsterite (Mg2SiO4) ceramic composites(ELSEVIER SCI LTD, 2018) Kucuk, Israfil; Boyraz, Tahsin; Gokce, Hasan; Ovecoglu, Mustafa LutfiAluminium titanate (Al2TiO5)-reinforced forsterite (Mg2SiO4) ceramics were prepared by the powder metallurgy route including sintering the Al2TiO5-reinforced Mg2SiO4 green compacts at 1600 degrees C. Sivas talc (3MgO center dot 4SiO(2)center dot H2O) was used as a precursor for the Mg2SiO4 ceramics due to its excellent mechanical properties like thermal shock and abrasion resistance. In order to investigate thermal shock resistance behaviour, the as prepared samples were quenched in water and assessed. Investigations were carried out to study the effect of Al2TiO5 addition on microstructural, physical, thermal and mechanical properties of Al2TO5-reinforced Mg2SiO4 ceramic composites. The thermal and mechanical properties were examined before and after thermal shock tests. The results showed that the best thermal expansion coefficient (0.76 x 10(-6) (K-1)) and thermal shock resistance (6.82 GPa) of the Al2TiO5-reinforced forsterite (Mg2SiO4) ceramic composites were obtained after thermal shock test, which were better than those of the other concentrations of the Al2TiO5-reinforced forsterite (Mg2SiO4) ceramic composites. These findings suggest that 20 wt% Al2TiO5-reinforced forsterite (Mg2SiO4) ceramic composites possess good thermomechanical properties and thus might be suitable for potential applications such as filter material, pharmaceuticals, cosmetic manufacturing, optical, and chemical devices.
