Halim Kovacı

Halim Kovacı
Ataturk University · Department of Mechanical Engineering, Faculty of Engineering

PhD

About

41
Publications
13,922
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462
Citations
Additional affiliations
January 2011 - present
Ataturk University
Position
  • Research Assistant

Publications

Publications (41)
Article
Cp-Ti is frequently used in biomedical applications because of its good corrosion and high biocompatible properties. However, its poor wear resistance limits its use in some applications. Therefore, this study aims to improve its wear and corrosion resistance by producing Ni-doped Al2O3 nanocomposite coatings on Cp-Ti. In order to achieve this goal...
Article
In order to prevent failure as well as ensure comfort, patient-specific modelling for prostheses has been gaining interest. However, deterministic analyses have been widely used in the design process without considering any variation/uncertainties related to the design parameters of such prostheses. Therefore, this study aims to compare the perform...
Article
In order to increase the surface wettability and corrosion resistance of commercial pure titanium (Cp-Ti), TiO2 anodic films were produced by anodization method using H2SO4/H3PO4 solution mixtures. Boric acid, graphene oxide and hydroxyapatite were added to the H2SO4/H3PO4 solution and their electrochemical properties and surface wettability were i...
Article
In order to prevent failure as well as ensure comfort, patient-specific modelling for prostheses has been gaining interest. However, deterministic analyses have been widely used in the design process without considering any variation/uncertainties related to the design parameters of such prostheses. Therefore, this study aims to compare the perform...
Article
Many engineering (biomedical, automotive, aerospace etc.) structures suffer from wear and corrosion damage under service conditions and this situation shortens their useful life. In common cases, these damage mechanisms do not act on materials separately. On the contrary, their combined effect called as tribocorrosion cause more decrease in their l...
Article
DLC films are widely used in different engineering products. However, some problems such as inadequate toughness, insufficient adhesion and internal stresses affect their performance. Therefore, we aimed to enhance the mechanical and tribological features of Cp-Ti by metal-free and metal-doped DLC films in this study. Cp-Ti samples were coated with...
Article
Titanium and its alloys have many advantages such as acceptable biocompatibility and good corrosion resistance and these advantages make them a widely preferred biomaterial. However, it is also known that they have some disadvantages such as poor wear resistance and insufficient surface wettability. Therefore, to overcome this disadvantages, boric/...
Article
Boriding is a method used to increase the biocompatibility and strength of metallic materials. However, by this time, no study has been encountered in the literature regarding investigation of the effects of boriding on metal-ceramic bond strength of Co–Cr alloy fabricated by selective laser melting. Boriding of metallic surfaces may be an alternat...
Article
In this study, a comprehensive analysis was performed to investigate the corrosion and tribocorrosion behavior of untreated and duplex ceramic coated AISI 4140 steel. Therefore, samples were plasma nitrided in a glow discharge environment and then, they were coated with diamond-like carbon (DLC) film. Electrochemical impedance spectroscopy, potenti...
Article
Surface texturing, which depends on the formation of different patterns on materials, is used to improve the tribological performance of materials. Therefore, the effects of different surface textures fabricated by selective laser melting (SLM) and plasma nitriding on the friction and wear properties of AISI 316L stainless steel were investigated i...
Article
Selective laser melting (SLM) or laser powder bed fusion (L-PBF), which is one of the additive manufacturing methods, has gained much more importance in recent years. Commercially pure titanium (Cp-Ti) is commonly used for biomedical applications in this process but it exhibits poor wear and friction properties during its use. Therefore, this study...
Article
Shot peening treatment is a well-known and practical method to improve surface properties of materials. In this method, surfaces of materials are peened by small steel shots and thus, surface hardening is provided. Although it is used in a wide range of applications, this process could affect the electrochemical behavior of materials because of cha...
Article
Purpose This paper aims to investigate the effects of boriding on the structural, mechanical and tribological properties of CoCrW dental alloy manufactured by the method of selective laser melting. Design/methodology/approach In this study, CoCrW alloy samples that are used in dentistry were manufactured by the method of laser melting, and borid...
Article
In recent years, hybrid surface treatments which include plasma nitriding combined with pre-shot peening operations have been proposed for the improvement of nitriding efficiency. The main objective of this study is to characterize the effects of dual process on the friction and wear behavior of metallic materials. For this purpose, AISI 4140 steel...
Article
Commercially pure titanium (Cp-Ti) is commonly used in different applications due to its good structural properties but its low mechanical and tribological properties restrict its usage areas. Therefore, different surface modifications based on TiO2 formation on material surfaces are applied to enhance surface features of materials. In this study,...
Article
Spinal implants are commonly used in the treatment of spinal disorders or injuries. However, the biomechanical analyses of them are rarely investigated in terms of both biomechanical and clinical perspectives. Therefore, the main purpose of this study is to investigate the effects of rod diameter on the biomechanical behavior of spinal implants and...
Article
316L stainless steel is commonly used in biomedical applications. However, its use is limited because of its insufficient tribological properties. In this study, a duplex surface modification process of laser melting and plasma nitriding is proposed and wear characteristics of coated 316L stainless steel were investigated. Titanium layers were prod...
Article
CuO and CuS films were coated on AISI 4140 steel samples by Successive Ionic Layer Adsorption and Reaction (SILAR) to investigate their usability as solid lubricant. Wear tests were performed using pin-on-disk tribo-tester under dry and lubricated conditions. The structural, morphological and morphological features of untreated, CuO and CuS coated...
Article
Diamond-like carbon (DLC) films are effectively utilized to improve the tribological properties of materials due to their low friction coefficient, good wear resistance and high hardness. In recent years, different pre-treatments such as plasma assisted diffusional processes have been used to increase long-term durability of these coatings. In the...
Article
Forged low-carbon alloy Co – 27% Cr – 6% Mo – 0.06% C is studied after 2-h plasma nitrocarburizing in a gaseous mixture of 10% CO2 + 20% N2 + 70% H2 at 400, 500 and 600°C. The surface layer and the core are studied by diffractometric analysis and scanning electron microscopy. The microhardness and the tribological characteristics of the alloy are d...
Article
Duplex surface treatments composed of diamond like carbon (DLC) coating followed by plasma nitriding have drawn attention for a while. In this study, AISI 4140 steel substrates were plasma nitrided at different treatment temperatures and times. Then, DLC films were deposited on both untreated and plasma nitrided samples using PVD magnetron sputteri...
Article
The effect of the temperature and duration of plasma nitriding on the microstructure and friction and wear parameters of Inconel 718 nickel alloy is investigated. The process of plasma nitriding is conducted in a nitrogen-hydrogen gaseous mixture at a temperature of 400, 500 and 600°C for 1 and 4 h. The modulus of elasticity of the nitrided layer,...
Article
In this study, a novel pre-magnetization process, which enables easy diffusion of nitrogen, was used to enhance plasma nitriding efficiency. Firstly, magnetic fields with intensities of 1500(Formula presented.)G and 2500(Formula presented.)G were applied to the untreated samples before nitriding. After the pre-magnetization, the untreated and pre-m...
Article
Plasma nitriding is an effective surface treatment to improve unsatisfactory wear properties of machine elements. Such machine elements may also subject to magnetic fields in many industrial applications. Therefore, AISI 4140 ferromagnetic steel samples were plasma nitrided. Then, the samples were quenched in water and then post-aged at a temperatu...
Article
Root shaped screw type dental implants are damaged depending on their mechanical and electrochemical properties as a results of alternating force and excessive exposure time with living tissue in usage period. In these implant systems the possibility of failure is increased with synergistic effects of combined failure mechanisms like corrosion, wea...
Article
Full-text available
The plate-screw fixation is widely used in the treatment of tibia diaphysis fractures. Also the structural differences such as design variables and the connection type, locked and unlocked fixation, in plate-screw system affect biomechanical behavior of bone-implant structure. In this study, the mechanical effects of locked and unlocked plate-screw...
Article
Full-text available
This study investigated the fracture-healing effects of α-lipoic acid (α-LA), which was applied orally once daily in preventive treatment mode during 1 month after fracture induction. Rats were randomly divided into sham-operated group (group 1), femoral fracture control (group 2), femoral fracture + 25 mg/kg α-LA (group 3), and femoral fracture +...
Article
Full-text available
Fracture of the radius diaphysis is an unusual injury in adults. Open reduction and plate osteosynthesis has been recommended by most of the authors. However, this trend has started to change with the recent introduction of newly designed interlocking intramedullary (IM) nails. New generation of IM nails are developed in order to utilise the advant...
Article
Numerous machine components are constantly subject to different magnetic fields mainly due to the environments they are in, and they show some wear process throughout their life time. To understand this wear process better, the effect of magnetic field on the tribological properties of AISI 4140 steel has been investigated by applying different mag...
Article
Günümüzde çene kırıklarının tedavisi için farklı geometrilere sahip mini plaklar kullanılmaktadır. Çene kemiğinin karmaşık geometrisinden dolayı, çene kırıklarında kullanılan plaklarda hasar olasılıklarını tespit etmek için oluşacak maksimum gerilmenin doğru olarak hesaplanması gerekmektedir. Bu amaçla, çene geometrisinin ve farklı tipte plakların...
Article
Full-text available
ZET Önkol kırıklarında plak-vida osteosentezi sıklıkla tercih edilen tedavi yöntemi olmakla birlikte intramedüller çivileme uygulamaları son yıllarda önem kazanmıştır. Bu amaçla, sırasıyla önkol BT görüntülerinden radius kemik modeli elde edilmiş, modelde kırık hattı oluşturularak iyileşme sürecinde oluşan kallus yapısı modellenerek kırık kısma yer...
Article
In this study, cortical bone screws (Sistem Orthopedics and Medical Devices, Konya, Turkey) which were manufactured from Ti6Al4V, a widely used metallic biomaterial in medical and dental applications, were oxidized using four different surface treatment methods and their pull-out strengths were investigated. Cortical screws were divided into five g...

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Projects (2)
Archived project
This Project aims to design patient-specific prostheses using anatomical bone curves for Total Knee Prosthesis (TKP), which are very frequently observed to be used by people over 60 in a rapidly increasing number, and to theoretically and experimentally investigate the performance of prosthesis designed with artificial bones which are prepared according to anatomical bone geometry.