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"Early Access" The most common method of obtaining a superhydrophobic surface is to create a specific surface morphology and then coat it with a hydrophobic polymer. Numerous such morphological surfaces have been developed but are often fragile. Ceramic-based coatings show longer life with high wear resistance. In this study, surface micro-nano surface morphology was developed with β-Si3N4 powder and the influence of sintering regime on contact angle of ceramic surfaces was investigated. The contact angle, surface energy and surface roughness were determined from the developed surfaces and surface morphology analyzed by scanning electron microscopy, phase evolution was determined by X-Ray diffraction. Changes in sintering regimes lead to different phase evolutions, roughness, surface topography, surface free energies and contact angles. The superhydrophobicity resulted mainly due to the surface structure/topography in the micro-nano hybrid structures of β-Si3N4 crystals. The highest water contact angle achieved was 166º of the samples sintered at 980°C for 5 min. Bu yayın "UNESCO-TURKEY [2014]" tarafından desteklenmiştir. WOS:000640590900001 Q2

Su damlasının üzerinde 90o’den büyük açı yaptığı yüzeyler hidrofobik yüzeyler olarak adlandırılır. Hidrofobik yüzeyler özellikle hijyen gerektiren ortamlarda yaygın olarak kullanılmaktadır. Yapılan çalışmada endüstriyel porselen karo yüzeyinde hidrofobik yüzey özelliğinin alkol ve su bazlı iki farklı türde polimer kaplama yapılması ve kendinden hidrofobik özelliğe sahip çinko oksit tozu ile ticari porselen karo sırının modifiye edilmesiyle eldesi amaçlanmıştır. Yüzeylerin morfolojik gelişimi taramalı elektron mikroskobu ile incelenmiş ve faz gelişimi X-ışınları difraksiyon cihazı ile belirlenmiştir. Temas açısı gonyometresi kullanılarak polimer kaplanmamış ve alkol ve su bazlı polimer ile kaplanmış yüzeylerin temas açıları ölçülüp, kıyaslanmıştır. Sonuç olarak alkol bazlı polimer ile kaplanmış yüzeylerin su bazlı polimer ile kaplanmış yüzeylere göre daha iyi hidrofobik etki gösterdiği tespit edilmiştir. Mikron boyutunda çinko oksit ilavesi yapılan sır kompozisyonlarının endüstriyel fırında pişirim sonrasında willemit (Zn2SiO4) fazı gelişimi gözlenirken, nano boyutta çinko oksit kullanımı zinsit fazı (ZnO) gelişimini sağlamıştır. Nano çinko oksit modifiyeli sırlarda yüzeyde çatlak oluşumu yüzeyin su emmesini sağladığından kaplanmamış yüzeylerin temas açısı ölçümü gerçekleştirilememiştir. Polimer kaplama sonrası en yüksek temas açısı 139o olarak N2 kodlu sır kompozisyonunda elde edilmiştir.

In the present study, polymer-coated and Si3N4-modified glaze was developed to provide a synergetic effect of an antibacterial and superhydrophobic property on ceramic tile surface. The fact that the antibacterial activity of Si3N4 is not yet known in the tile industry and in many applications is unique aspect of the study. In addressing this issue, antibacterial effect was tested against gram-positive S. aureus and gram-negative P. aeruginosa. More significantly, the antibacterial and superhydrophobic surfaces were obtained firing at industrial kiln without changing the standard furnace regime for tile production. The superhydrophobic and antibacterial properties of the developed surfaces were determined by contact angle, surface energy, roughness, scanning electron microscopy, X-ray diffraction and antibacterial tests and the results compared with the commercial porcelain stoneware tiles. Superhydrophobic and antibacterial effect formation occurred due to micro-nano hybrid surface structure formed by Si3N4 crystals. The 155 ° water contact angle was reached on industrial tile surfaces. The Si3N4-modified surfaces resulted in a bacteria population reduction of over 99.97% and 99.11% for S. aureus and P. aeruginosa, respectively. It has found that the surface hydrophobicity is a clear determining factor for microbial growth and proliferation.

This study presents the tribological behavior of epoxy matrix composites containing two different fillers. The composites contain fillers with different particle sizes (

Turkey produces over 200,000 tons of walnut annually as the fourth largest producer in the world. Walnut shells amount to 40–60 % of the total weight, rendering over 100,000 tons of shells per year, mostly as waste. A limited quantity is utilized for fiberboard manufacturing, some as solid fuel or as scrubbing material in the chemical and metal industries. The purpose of this study is to develop low-cost polyester composites with enhanced physico-mechanical properties by using walnut cellulosic fibers as a reinforcement phase for polyester resin. The process not only makes production more economical but also reduces waste. The shells were ground and a detailed characterization of the waste fibers was carried out by scanning electron microscopy, X-ray diffraction, FTIR, laser diffraction and He gas picnometer techniques. The effects of the filler to matrix ratio as well as chemical treatment of walnut fibers on the physical and mechanical properties of the composite were determined. The composites were characterized by means of measurements for porosity, density, three point bending strength, impact resistance and hardness. The structure-property relationship of developed composites was discussed. Optimum physico-mechanical properties were obtained through a hydrophobic solution treatment of the powder since this provided better processability and enhanced interfacial adhesion.

Hydrophobic surfaces are also known to have antimicrobial effect by restricting the adherence of microorganisms. However, ceramic products are produced by high temperature processes resulting in a hydrophilic surface. In this study, an industrial ceramic wall tile glaze composition was modified by the inclusion of metallic zinc powder in the glaze suspension applied on the pre-sintered wall tile bodies by spraying. The glazed tiles were gloss fired at industrially applicable peak temperatures ranging from 980 °C to 1100 °C. The fired tile surfaces were coated with a commercial fluoropolymer avoiding water absorption. The surfaces were characterized with SEM, EDS, XRD techniques, roughness, sessile water drop contact angle, surface energy measurements, and standard antimicrobial tests. The surface hydrophobicity and the antimicrobial activity results were compared with that of unmodified, uncoated gloss fired wall tiles. A superhydrophobic contact angle of 150° was achieved at 1000 °C peak temperature due to the formation of micro-structured nanocrystalline zinc oxide granules providing a specific surface topography. At higher peak temperatures the hydrophobicity was lost as the specific granular surface topography deteriorated with the conversion of zinc oxide granules to the ubiquitous willemite crystals embedded in the glassy matrix. The antimicrobial efficacy also correlated with the hydrophobic character.

URL:http://sujest.selcuk.edu.tr/sumbtd/article/view/534 DOI: 10.15317/Scitech.2018.115, This study evaluates the effect of employment of vacuum application on the mechanical and tribological properties of porcelain waste added epoxy matrix composites. Tribological characterization was determined by friction, wear rate and mechanisms using ball-on-disk test by tungsten carbide counter-part without lubrication at room temperature. It is investigated the role of vacuum application on the wear mechanisms, tribo-chemical layer formation on the wear surfaces, frictional property and tribological performance. The microstructure, mechanical and physical properties and wear behavior correlation were discussed comprehensively. Vacuum application provided fully embedded and well wetted particles, and strong bonding strength between matrix and filler. It is demonstrated that well bonded particle reinforced composites have higher wear resistance, by resulting lower friction coefficient, and more smoother tribochemical layer than compared with the unvacuumed composites., Bu çalışma, vakum uygulamasının atık porselen katkılı epoksi matrisli kompozit malzemelerin mekanik ve tribolojik özelliklerine etkisini değerlendirmektedir. Tribolojik karakterizasyon; tungsten karbür aşındırıcı bilye kullanılarak oda sıcaklığında yağlayıcı olmadan bilye-disk (ball-on-disk) konfigürasyonunda triboloji testleri gerçekleştirilerek sürtünme, aşınma oranları ve aşınma davranışları belirlenmiştir. Vakum uygulamasının; aşınma mekanizmaları, aşınma yüzeylerinde tribo-kimyasal tabaka oluşumu, sürtünme özellikleri ve tribolojik performans üzerindeki rolü araştırılmıştır. Mikroyapı, mekanik ve fiziksel özellikler ile aşınma davranışı ilişkisi ayrıntılı incelenmiştir. Vakum uygulaması partiküllerin daha iyi ıslatılmasına, matris ve partikül arasında daha kuvvetli bağ mukavemeti oluşmasına sebebiyet vermiştir. Vakum uygulamasıyla üretilmiş kompozitler, vakumsuz üretilmiş kompozitlere göre daha düşük sürtünme katsayısı ve daha düzgün tribokimyasal tabakanın oluşmasına sebebiyet vererek daha iyi aşınma dayanımı sergilemişlerdir

In the literature, limited studies are available due to the challenges of the detailed microstructural characterization and determination of properties of diesel particulate filters (DPFs). For this reason, the characterization of a commercial DPF was carried out with different techniques with the aim to identify the manufacturing processes, the chemical composition, the microstructure and the mechanical, physical and thermal properties. Scanning electron microscopy (energy-dispersive X-ray spectroscopy, back-scattered electron, secondary electron detectors), X-ray diffraction, universal mechanical testing, Archimedes technique, dilatometer and C-therm thermal conductivity analysis tools were used for the characterization. During DPF regeneration, the tailoring of these properties has crucial effect on the reliability and durability of the filter. The value of the thermal shock resistance parameter group $$\sigma _{\mathrm{f}}/E\alpha $$ was calculated to be 426 K, while thermal conductivity (k) was determined as 1.95 W/mK. When compared to the literature values for dense SiC, the $$\sigma _{\mathrm{f}}/E\alpha $$ value indicated a better thermal shock resistance; however, thermal conductivity was on the limits of an order of magnitude worsening the thermal shock resistance. Therefore, to improve the thermal shock resistance of the filter material, the thermal conductivity value has to be increased to the maximum allowed by the required porosity. The study may lead to tailoring of an optimized SiC DPF material.

Seramik sağlık gereçleri alanında Türkiye, Avrupa'da en çok üretim yapan ülke konumundadır. Senelik 320.000 tonluk üretim miktarı, 21,3 milyonluk üretim adediyle ve üretiminin %60'ını ihraç etmesi nedeniyle ülke ekonomisinde önemli bir konuma sahiptir. Bu nedenle üretim esnasında oluşan atıkların miktarı ve çevreye olan etkisi düşünüldüğünde bu atıkların etkili bir şekilde değerlendirilmesi büyük bir önem arz etmektedir. Üretici firmalar oluşan yaş atığın büyük bir bölümünü değerlendirebilselerde sinterlenmiş ürünün değerlendirilmesinde üretim kısıtlamaları nedeniyle bu mümkün olamamaktadır. Bu durum atıkların farklı alanlarda fayda sağlayacak şekilde değerlendirilmesini zorunlu kılmaktadır. Bu çalışmada seramik sağlık gereçleri alanında üretim yapan bir firmanın atık vitreous china bünyeli sinterlenmiş ürünleri, belirli bir boyut aralığında olacak şekilde öğütülerek polyester matris içerisine farklı oranlarda katılarak kompozit sağlık gereci ürünler (lavabo vb.) elde edilmiştir. Elde edilen kompozit ürünün mekanik ve fiziksel özelliklerine atık sağlık gereci seramik ürün miktarının etkisi tartışılmıştır. Kompozit ürüne, üç nokta eğme, elastik modül, sertlik, % su emme, % toplam porozite, bulk yoğunluk, teorik yoğunluk, % açık porozite testleri yapılmıştır. Elde edilen ürünlerin mikro yapıları, kullanılan tozların tane şekilleri Taramalı Elektron Mikroskobu(SEM)-İkincil Electron(SE) dedektörü kullanılarak analiz edilmiştir. Artan atık seramik miktarı ile kompozit ürünlerde eğme mukavemetinde belirgin bir değişim görülmezken, sertlik ve elastik modul değerleri artmıştır. Artan seramik atık miktarı ile % su emme değerleri benzer iken % açık porozite, % toplam porozite, bulk yoğunluk değerleri artmıştır., The manufacturing of 320000 tons with 21.3 million pieces and exporting 60 % of them make Turkey as leading country at the production of sanitaryware field in the Europa. In the meantime, high amount of sanitaryware production and subsequent effect on the environment requires effective assessment of waste. Although manufacturer effectively utilize wet waste, sintered waste is difficult to regain due to some processing technical hitches. In this respect, the evaluation of waste materials in the various field needs to be investigated. In this study, polyester composite were obtained by adding certain size of vitreous china body waste from company produced sanitaryware products(sink etc.). The mechanical and physical properties of composites were determined in terms of effect of the amount of ceramic waste added into matrix. Elastic module, bending strength, hardness, water absorption, porosity and density were attained. Scanning Electron Microscopy (SEM) determined the grain size and morphology of samples. While the content of ceramic waste addition in the composites increased, bending strength did not change significantly but hardness and elastic modulus improved. Water absorption of composites did not changed whereas open and total porosity and bulk density were increased upon the addition of ceramic waste into polymer matrix.

The aim of this study was to develop low cost hybrid composites with enhanced mechanical properties by the addition of industrial wall tile and glass fiber wastes into epoxy resin. This process not only reduces the production cost, but also helps to eliminate solid wastes. The detailed characterization of waste particulate fillers was performed by scanning electron microscopy, X-ray diffraction, X-ray fluorescence, laser diffraction, and He gas picnometer techniques. The effects of the ceramic particulates to glass fiber ratio and the particle size of the waste materials on the physical and mechanical properties were determined with a fixed polymer to filler ratio of 40:60. The density, three point bending strength, impact resistance and hardness of the hybrid composites were measured. The results indicated that when the filler particle size increased, the bulk density almost remained unchanged, and the bending strength and impact resistance decreased, while the hardness and flexural modulus were almost constant. Because of the weak matrix-reinforcement interphase, mechanical properties deteriorated with the increasing amount of waste glass fiber and better mechanical properties were achieved with the use of finer particles. As a result of incorporation of industrial wastes such as ground ceramic wall tile and glass fiber instead of expensive fillers, low cost reinforcement of the hybrid epoxy matrix composites was achieved. POLYM. COMPOS., 2017. © 2017 Society of Plastics Engineers

Biocidal antimicrobial molecular barrier (BAMB) solutions are known to provide antimicrobial effect on the surfaces in industrial applications. However, there has been a lack of scientific reports about the subject in the literature. In this study, in order to impart an antimicrobial surface property on ceramic surfaces, a BAMB solution was applied on gloss fired ceramic wall tile substrates and the surface antimicrobial activity results were compared with that of plain wall tiles (without BAMB application). The ceramic surfaces were cleaned, and stove dried at120°C prior to spray coating with a BAMB solution. The coated substrates were dried in the ambient. The intactness of the coatings was checked with the bromophenol blue test. The microstructural and molecular characterization of the BAMB coated surfaces were carried out with SEM imaging and surface FTIR, respectively. The antimicrobial activity tests of the surfaces were conducted according to ASTM E2180-07 (Standard Test Method for Determining the Activity of Incorporated Antimicrobial Agent in Polymeric or Hydrophobic Materials). The microorganisms used were Staphylococcus aureus (ATCC 6538) and Pseudomonas aeruginosa (ATCC 15442) bacteria. The BAMB coated surfaces showed less flocculent bacterial growth in comparison to uncoated ceramic surfaces leading to the conclusion that the BAMB improved the antimicrobial property.

There is ongoing research interest in finding alternative sources of materials for composite manufacturing. Therefore, alternative non-wood based materials may play an important role in the forest product industry. Natural fibers have many advantages compared to synthetic fibers such as low density, lower cost, acceptable specific properties and being renewable and biodegradable. Natural fiber composites show high strength and stiffness, as well as good thermal and insulating properties. In this study, polymer matrix composites were manufactured using pine cone and marble waste and ATH powder as filler and polyester as matrix material with the casting method. Methyl ethyl ketone peroxide as hardener for cross-link network structure and cobalt naphthenate as accelerator were used to produce polyester matrix composites. Marble: ATH filler ratio was kept constant and polyester: filler (pine cone + marble + ATH) ratios were changed. Mechanical properties of composite materials were investigated and the final product tested to determine flexural strength, flexural modulus and hardness as well as some physical features such as bulk density, % total porosity and % open porosity. The experimental results showed that flexural strength and hardness of the composite materials decreased with the increase in pine cone: marble + ATH ratio.

SiAlON ceramics and their derivatives are potential materials for tribological applications where wear and friction are very crucial. TiN is a reinforcement phase and solid lubricant for SiAlON used to improve mechanical and tribological properties. In this study, alpha(1):beta(1)-SiAION composites incorporating nano- and micron-size TiN particles were produced by a gas pressure sintering method. Tribological behavior of the composites was investigated based on reinforcement particle size and physico-mechanical properties. Tribology tests were performed with a computer-controlled tribometer under dry unlubricated conditions with ball-on-disk configuration. It was found that the TiN particle size has an effect on surface roughness and hence the coefficient of friction. When the TiN particle size decreased to nano size, the wear mechanism was tribochemical, whereas, when the particle size increased to micron size, severe mechanical wear was observed besides tribochemical wear.

In the present study, industrial toilet seat wastes which contain 70 wt% urea formaldehyde and 30 wt% cellulose were used as a particulate reinforcement in epoxy matrix and their mechanical and physical properties were investigated. The usage of urea formaldehyde and cellulose mixture as filler of polymer composite materials is a novel study. Initially toilet seat wastes were ground and particles in the required size range were obtained. The characterization of waste particulate filler was carried out by scanning electron microscopy, X-ray diffraction techniques and He gas pycnometer. Optimum concentration of the filler was determined as a maximum of 40 wt% because of the increase in viscosity at higher waste concentration. The effect of particle size on mechanical properties such as hardness, bending strength and bending modulus was evaluated. These are the key properties most likely to be affected by incorporation of reinforcement phase. Experimental results showed that bending modulus and hardness increased and bending strength decreased with filler addition into epoxy resin. With the increase in filler content both porosity and bending strength decreased and bending modulus increased. On the other hand increase in particle size led to the enhancement of bending strength and bending modulus while accompanied with a decrease in porosity. As a result, incorporation of urea formaldehyde wastes basically resulted in the reinforcement of the epoxy matrix. This allows for the recycling of hardly recoverable thermosetting residues as well as improving some mechanical properties of the composites.

Yapilan calismada yaglayici ozelligi bulunan grafit dolgu elemaninin yuksek miktarlarda (hac.%25-52) epoksi matris icerisine ilave edilmesiyle epoksi matrisli kompozitin asinma direnci uzerine etkisi arastirilmistir. Epoksi matrisli kompozitler acik kaliplama teknigi ile uretilmistir. Grafit dolgulu kompozitlerin 3 noktali egme mukavemeti, egme modulu, sertlik, yogunluk olcumleri yapilmis ve mikroyapi gelisimleri incelenmistir. Asinma testleri 5N yuk altinda, 200m asinma mesafesine kadar ball-on-disk asinma cihazinda, oda sicakliginda gerceklestirilmistir. Fiziko-mekanik ozelliklerin ve mikroyapi gelisiminin asinma davranisi uzerine etkisi arastirilmistir. Sonuc olarak en iyi asinma direnci %30 grafit katkili kompozit malzemede elde edilmistir.

TiN particle size is an effective parameter on microstructure, mechanical and physical properties of SiAlON-TiN composites. In this study, the effect of TiN particle size (nano and micron level) on microstructural evolution, mechanical and physical properties were investigated. The phase and microstructural evolution, SEM and the XRD characterization methods were used to observe the effects of TiN particle size. Indentation fracture toughness and Vickers hardness of the samples were measured in order to evaluate the mechanical behavior. Archimedes principle was used in order to determine bulk density and porosity. Correlation between TiN particle size and hardness, fracture toughness, microstructure, phase evolution was discussed. It was observed that decrease in particle size led to little improvement in fracture toughness and hardness.

α:β-SiAlON and 10, 17, and 25 wt% TiN particle reinforced composites were produced by a gas pressure sintering method. The densification behavior, phase and microstructural evolution, mechanical and thermal shock behavior of materials were investigated. The TiN incorporation had significant influence on the matrix microstructure and improved fracture toughness of the material. The highest fracture toughness was obtained for the composite with 25 wt% TiN ( K 1c : 8.2±0.2 MPa m 1/2 ). SiAlON–TiN composites showed lower crack formation and propagation compared to the monolithic SiAlON. Above 700 °C passive oxidation took place and provided crack healing by filling the cracks with TiO 2 , and the thermal shock resistance behavior was improved.

WOS: 000415695900018, Polymer matrix composites (PMCs) play an increasingly important role in everyday life from energy conservation to national security. Recently, PMCs have been found to be used for sanitaryware due to their low density, giving a sense of warmth, which allows application for broad aesthetic features, high impact resistance, the ease of shaping and the possibility to produce thin sections. It is an alternative to ceramic sanitaryware products. While thin section PMC products range in the forefront with lightness and aesthetic features, thick section PMC products are aroused interest because of the impact resistance and ease of production. Little attention is devoted to the characterization of PMC sanitarywares up to date. Therefore, in order to identify manufacturing processes and determination of the chemical and mineralogical composition, optical microscopy, scanning electron microscopy (SEM) with SE, BSE and EDX detector, X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF) and thermogravimetric (TG/DTA) analysis of commercial PMC sanitarywares with two different structures (thick and thin sections) were carried out. Mechanical properties such as three-point flexural strength, flexural modulus and impact resistance were identified. As a result of these studies, matrix to filler ratio, filler shape, size and composition and manufacturing technique of PMC sanitarywares were determined. Such understanding is necessary in order to satisfy the market request and to improve the properties of the sanitarywares.