Browsing by Author "Gavgali, M."

Now showing 1 - 7 of 7

Corrosion Characteristics of Al-cu/B4c (T6) Mmcs and Their Microstructure Evaluation
(Redakcia Kovove Materialy, 2009) Dikici, B.; Bedir, F.; Gavgali, M.; Kiyak, T.
In this study, the pitting susceptibilities of Al-Cu alloy based metal matrix composites (MMCs) reinforced with boron carbide (B4C) particles have been investigated using cyclic polarization (CP) technique in aerated and deaerated 3.5 wt.% NaCl solution. The effects of reinforcement particle volume fraction and artificially aged (T6) process on corrosion behaviour of the composites have been also examined. It has been found that the 30 % B4C MMC is more susceptible to pitting attack compared with 10 % B4C MMC.
Detrimental Effect of Particle Sol-Gel Coating on the Corrosion Behavior of A380-Sic Composite
(Pergamon-elsevier Science Ltd, 2009) Dikici, B.; Tekmen, C.; Yigit, O.; Gavgali, M.; Cocen, U.
In this study, the corrosion susceptibility of aluminum matrix composites reinforced with artificially oxidized SiO(2) and sol-gel Fe/TiO(2) coated silicon carbide particles (SiC(p)) has been investigated. Corrosion behavior of the composites, fabricated by the liquid metal infiltration technique, was established in chloride containing alkaline environments by cyclic polarization (CP) and electrochemical impedance spectroscopy (EIS) techniques. It has been found that, sol-gel coating of SiC particles with Fe/TiO(2) has a detrimental effect on the corrosion characteristics of A380-SiC metal matrix composite. (C) 2009 Elsevier Ltd. All rights reserved.
The Effect of Arc Current on the Corrosion Behaviour of Coated Niti Alloy on Aisi304 by Plasma Transferred Arc Process
(Maik Nauka/interperiodica/springer, 2012) Dikici, B.; Ozel, S.; Gavgali, M.; Somunkiran, I.
In this study, the effect of arc current on the corrosion behaviour of NiTi coating on stainless steel has been investigated. NiTi powder mixture was alloyed on surface austenitic AISI304 by using plasma transferred arc (PTA) method. Surface alloying process is turned out using 80, 90, 100 A current densities and Ar atmosphere which is plasma and protective. The corrosion resistance of the coatings was analyzed by measuring the potentiodynamic polarization scanning (PDS) technique. Results indicate that corrosion resistances of the coatings decrease with increasing the arc current. In addition, the localized corrosion on the surface of produced coating at 100A is more activated than other coatings and the most passive coating in view of corrosion was obtained at produced coating at 80A.
The Effect of Coating Thickness on Corrosion Resistance of Hydroxyapatite Coated Ti6al4v and 316l Ss Implants
(Springer, 2010) Aksakal, B.; Gavgali, M.; Dikici, B.
Hydroxyapatite (HAP) has been coated onto Ti6Al4V and 316L SS substrates by sol-gel method. The coating thicknesses for the analysis were about 40 and 72 mu m. Adhesion and corrosion tests have been conducted on uncoated and HAP-coated substrates. The coatings were characterized by XRD, SEM, and adhesion analysis. The corrosion resistance was examined in vitro by potentiodynamic polarization technique in Ringer's solution at room temperature. Electrochemical analysis indicated that the highest corrosion susceptibility was found on 72-mu m-coated 316L SS, and the 40-mu m HAP-coated Ti6Al4V showed the highest corrosion resistance. It was observed that the coating thickness was an effective parameter on both adhesion and corrosion resistance. It was shown that adhesion and corrosion resistance decreased with increasing coating thickness on both substrates.
The Effect of Cold-Worked Ratio on Corrosion Behavior of T8 Tempered Al-si-mg/Sicp Metal Matrix Composites
(International Committee on Composite Materials, 2007) Dikici, B.; Tekmen, C.; Gavgali, M.; Tsunekawa, Y.
The corrosion behaviors of T8 tempered Al-Si-Mg/SiCp metal matrix composites (MMCs) were investigated in aerated and deaerated 3.5wt% NaCl solutions by potentiodynamic polarization technique in this study. In order to determine the effect of cold work on the electrochemical behavior, the composites were cold-worked to a plastic strain of 4, 6, 10, 25 and 50%. A major change in the corrosion morphologies were observed cold working ratio increased from 4 to 50%. For example, electrochemical analysis indicated that the corrosion current densities (icor) of 20% vol. SiC composite increased from 0.8 to 5.9 with increasing cold-worked ratio after T8 temper. In addition, we find that there is a significant coloration between corrosion susceptibility and level of cold work.
Synthesis of in Situ Tic Nanoparticles in Liquid Aluminum: the Effect of Sintering Temperature
(Sage Publications Ltd, 2011) Dikici, B.; Gavgali, M.; Bedir, F.
In this study, in situ TiC nanoparticles with a diameter range of 70-400 nm have been successfully synthesized in liquid aluminum by conventional hot-pressing method. The effect of production temperature on the formation of the TiC phase during sintering was investigated by differential thermal analysis, X-ray diffraction, and scanning and transmission electron microscopies. The results show that the synthesizing temperature has a great effect on the formation of the TiC. Also, increase of producing temperature accelerates the formation of in situ TiC nanoparticles and decreases the portion of Al3Ti intermetallic phase in the liquid aluminum.
Wear Behavior of Plasma Sprayed Composite Coatings With in Situ Formed Al2o3
(Elsevier Sci Ltd, 2009) Mindivan, H.; Tekmen, C.; Dikici, B.; Tsunekawa, Y.; Gavgali, M.
In the present study, the wear behavior of in situ formed Al2O3 reinforced hypereutectic Al-18Si matrix composite coatings have been investigated. These coatings were successfully fabricated with mechanically alloyed Al-12Si and SiO2 powder deposited on aluminum substrates by atmospheric plasma spraying (APS). The produced samples were characterized by means of microscopic examinations, hardness measurements and wear tests. The obtained results pointed out that the amount of in situ formed Al2O3 particles increased with increasing spray distance and decreasing in-flight particle velocity and temperature, which was accompanied by an improvement in hardness and wear resistance. (C) 2009 Elsevier Ltd. All rights reserved.