The effect of alcohol on the passivation of Al alloys in 1 N H 2 SO 4 solution

In this study, the influence of different alcohol on the passivation of aluminium alloys have been investigated by using current potential curves. Experimental results show that the addition of alcohol in H2SO4 solution have been changed passivation potential distance of the alloys. Elemental compositions of alloys have also directly affected passivation of alloys. This influence is more effective especially in alloys con tent higher Si also and less Cu

Electrochemical polymerization of aniline on aluminum electrode from an oxalic acid and H2SO4 solutions

In this study, the polymerization of aniline on Al and Pt electrode was examined by cyclic voltammetry There had been reversible reaction on AI electrode. But on the other hand there had been irreversible reaction on Pt electrode. The addition of aniline into the solution led the decrease of current values. The current decreased by adsorption of anodic products on polymer surface. The fact that the anodic peak potential shifted to positive value shows that polyaniline (PANI) catalyzed the formation of polymer. This case shows that the aniline shifted the electrode potential to positive side by the adsorption on the surface. When Al electrode covered with polymer (in 50 mV s –1 potential scanning rate after 20 cycles) was immersed into 1 N HCl solution, the inorganic layer decomposed on the metal surface. This led to decrease the polarization resistance of the metal. SEM microphotographs and EDX fingerprints also confirmed these results

Elektrokimyasal Biriktirme Yöntemi ile Hidroksiapatit (HAP) Kaplanmış Ti6Al4V İmplantlarının Korozyon Davranışlarının İncelenmesi

Bu araştırmada, hidroksiapatit (HAP) elektroforez yöntemi ile Ti6A14V alaşımı yüzeyine kaplanmıştır. Elektroforez yönteminde HAP kaplama elde etmek için, NH4H2PO4, P öncüsü olarak ve Ca(NO3)2.4H2O, Ca öncüsü olarak alınmıştır. Ek olarak, Ti6A14V'ye 5 N NaOH ön-muamele yüzey işlemi (PTSO) uygulanmıştır. PTSO, HAP kaplamanın yüzeye yapışmasında etkilidir. Kaplanmamış ve HAP kaplanmış numunelerin korozyon davranışları simüle vücut sıvısında (SBF) 7, 14, 21 ve 35 gün bekletildikten sonra incelenmiştir. Elektroforez yöntemiyle elde edilen HAP kaplamalar korozyonun önlenmesi için inhibisyon göstermemiştir. Numunelerin yüzey görüntüleri taramalı elektron mikroskobu (SEM), enerji saçınımlı X ışınları (EDX) ve X ışınları difraksiyonu (XRD) yöntemleri ile tanımlanmıştır. SEM görüntülerinden, açık gözenekler ve kaplamada gözenekler arasındaki bağlantılar gözlenmiştir ve bu da osteointegrasyonu arttırmaktadır. HAP kaplamalı numunelerin yüzeylerinin EDX analizlerinde yüzeyde Ca, O ve P olduğu not edilmiştir. HAP kaplamalı numunelerin XRD analizinde yüzeylerde TiO2, HAP ve kalsiyum fosfat yapılarının olduğu görülmektedir.In this research, hydroxyapatite (HAP) has been coated on the Ti6A14V alloy surface by electrophoresis method. In this electrophoresis method, NH4H2PO4 is taken as P precursor and Ca (NO3)2.4H2O is taken as Ca precursor to obtain HAP coating. Additionally, 5 N NaOH pre-treatment surface operation (PTSO) has been applied to Ti6A14V. PTSO are effective on clinging of HAP coating to the surface. The corrosion behaviours of uncoated and HAP coated samples are examined in simulated body fluid (SBF) after for holded 7, 14, 21 and 35 days in SBF. HAP coatings have obtained by electrophoresis method was not showed inhibition for preventing corrosion. The surface images of the samples were described by scanning electron microscope (SEM), energy dispersive X-ray analysis (EDX), and X-ray diffraction (XRD). From SEM images have been observed open pores and connections among pores in the coating, which increases osteointegration. It is noted in EDX analyses of the surfaces of the HAP coated samples that there is Ca, O and P on the surface. It is seen in XRD analysis of HAP coated samples that there are TiO2, HAP and calcium phosphate structures on the surfaces

The examination of Afyonkarahisar's geothermal system corrosion

Corrosion and scaling of metal surfaces are the major problems caused by geothermal fluids when metallic structures are used. This article describes a study of corrosion and scaling problems in the Afyonkarahisar Geothermal Heating System (AFJET) in Afyonkarahisar, Turkey. Water analysis, XRD, SEM, EDX, IC, ICP-OES analyses, and electrochemical methods were used in this study. Pentasodium triphosphate (Na5P3O10), maleic anhydride (C4H2O3), and 1,3-benzendisulfonic acid disodium salt (C6H4Na2O6S2) were used as corrosion inhibitors. Tests were carried out using geothermal water from AF11 well. The experimental temperatures were chosen as 298, 333, and 358 K. Inhibitor concentrations were chosen as 131021, 131022, 131023, and 131024 mol/dm3. Moreover, mixed inhibitor solutions were prepared using the inhibitor concentrations that showed the best inhibition. The first mixed inhibitor solution showed 96% inhibition. The second mixed inhibitor solution showed 90% inhibition. The tested inhibitors act as anodic inhibitors. XRD analysis shows that there is CaCO3 aragonite scaling in the system. Increasing TDS, alkalinity, and hardness all promote scale formation. The photomicrographs from SEM-EDX and the metallographic microscope show that the tested inhibitors form a protective film on the surface. IC and ICP-OES analyses show that the concentration of Ca2+ is very high, which supports scale formation

Hydroxyapatite (HAP) coating with biomimetic method abstract

Biomimetik yöntemle hidroksiapatit (HAP) kaplama en gelecek vaat eden tekniklerden birisidir. Bu çalışmada, üç farklı ön yüzey işlemi (HNO3, anodik polarizasyon, 5 N NaOH-1 N HCl (BA)) altlıkların (Ti ve Ti6Al4V) yüzey pürüzlülüğünü arttırmak için kullanılmıştır. Biomimetik apatit katmanlarının morfoloji, bileşim ve yapısı SEM, EDX ve FT-IR teknikleri ile incelenmiştir. 3xSBF’de 35 günlük daldırma sonrası yüzeyin tamamı apatit kaplama ile kaplanmıştır. SEM-EDX sonuçları kemikte bulunan tercihli yönlenme ve benzer bileşimin iyon bileşimi ve çözeltinin derişimine bağlı olarak biomimetik olarak sentezlendiğini göstermiştir. Kemik benzeri apatit katmanı sentezi, implantların biyoaktif yüzeylerini geliştirmek için bu biomimetik yöntemin etkin bir yol olduğunu göstermiştir. FT-IR analizi karakteristik HA absorpsiyon bantlarının sinterlenmiş yüzeyde oluştuğunu göstermiştir.One of the most promising techniques to deposit hydroxyapatite (HAP) coating is the biomimetic method. In this paper, different pretreatments (HNO3, anodic polarization, 5 N NaOH-1 N HCl (BA)) were used to increase surface roughness of the substrates (Ti ve Ti6Al4V). The morphology, composition and structure of the biomimetic apatite layers were investigated with SEM,EDX and FT-IR techniques. The entire surface after immersed for 35 days in 3xSBF was covered by an apatite coating. The SEM-EDX results show that apatite layers with preferred orientation and composition similar to that found in bone can be biomimetically synthesized depending on the ion composition and concentration of the solution. It was shown that this biomimetic synthesis of a bone-like apatite layer may be an effective way to produce bioactive surfaces of implants. FT-IR analysis shows that characteristic HA absorption bands have occurred the sintered surface

The coating of hydroxyapatite ( HAP ) on 316L stainless steel and Ti6Al4V alloy use by Sol-Gel method

In this research, hydroxyapatite (HAP) coatings have been coated on Ti6Al4V alloy and 316 L stainless steel substrates by sol-jel method. (NH4)H2PO4 is taken as P precursor and Ca(NO3)2.4H2O is taken as Ca precursor to obtain HAP coating. Additionally HNO3 pretreatment process has been applied to Ti6Al4V alloy and 316L stainless steel substrates. It is seen in SEM images that open pores and attachments among pores have been observed in the coating, which increases osteointegration. It is noted in EDX analyses of the surfaces of the HAP coated samples that there is only Ca, O and P on the surface. Ca\P ratio for 316L stainless steel was founded 1,58 and Ca\P ratio for Ti6Al4V alloy was founded 1,42. XRD analysis show that coatings have hydroxyapatite structure

Effect of alcohol on the corrosion of al alloys in 1 N H2SO 4 solution Part i

The aim of this paper is to examine the effects of alcohol (1-buten–3-ol-l, 2-methyl–3-butyn–2-ol, 3-methyl–2-buten–1-ol, 3-methyl–3-buten–1-ol, 3-methyl–1-pentyn–3-ol, 5-hexen–1-ol) on the corrosion of Al alloys. The inhibiting effect of alcohol was investigated by electrochemical current-potential curves, atomic absorption spectrometry (AAS), metal microscopy,SEM and EDS. The results showed that alcohol (1-buten– 3-ol, 2-methyl–3-butyn–2-ol, 3-methyl–2-buten–1-ol, 3-methyl–3-buten–1-ol, 3-methyl–1-pentyn–3-ol, 5-hexen–1-ol) had an inhibiting effect on the corrosion of aluminium alloys. Experimental results show that corrosion of alloys in H 2 SO 4 solution have been effected by elements in alloys such as Cu, Zn, Mg and adsorption of alcohol on the surface of alloys in H 2 SO 4 solution obeys Temkin adsorption isotherm. The use of alcohol in H 2 SO 4 solution were shifted corrosion potentials (E cor ) to more negative values and acted as cathodic inhibitors on the aluminum alloys. EDS analysis of alloys displayed different intermetallic compounds on the surface of alloys, which might have changed the activity of alcohols depending on the surface morphology of alloys. This paper has showed that these alcohol inhibited corrosion of aluminium alloys in H 2 SO 4 solution. The concentration of 20 mM alcohol was shown that above 90% inhibition was achieved, which is a rather high value

Corrosion and wear behaviors of boronized AISI 316L stainless steel

In this study, the effects of a boronizing treatment on the corrosion and wear behaviors of AISI 316L austenitic stainless steel (AISI 316L) were examined. The corrosion behavior of the boronized samples was studied via electrochemical methods in a simulation body fluid (SBF) and the wear behavior was examined using the ball-on-disk wear method. It was observed that the boride layer that formed on the AISI 316L surface had a flat and smooth morphology. Furthermore, X-ray diffraction analyses show that the boride layer contained FeB, Fe2B, CrB, Cr2B, NiB, and Ni2B phases. Boride layer thickness increased with an increasing boronizing temperature and time. The boronizing treatment also increased the surface hardness of the AISI 316L. Although there was no positive effect of the coating on the corrosion resistance in the SBF medium. Furthermore, a decrease in the friction coefficient was recorded for the boronized AISI 316L. As the boronizing temperature increased, the wear rate decreased in both dry and wet mediums. As a result, the boronizing treatment contributed positively to the wear resistance by increasing the surface hardness and by decreasing the friction coefficient of the AISI 316L

Tertiary amine methacrylate based polymers as Corrosion Inhibitors in double distilled water. Part I

In the current study, the inhibitive performances of tertiary amine methacrlate based water soluble diblock copolymers on the corrosion behaviour of AISI 304 stainless steel were investigated in double distilled water (DDW, at pH = 7.6) using potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM) and inductively coupled plasma optical emmision spectrometry (ICP OES) methods. Related diblock copolymers were poly[2-(dimethylamino)ethylmethacrylate] (PDMA), poly[2-(diethylamino)ethylmethacrylate] (PDEA), poly[2-(diisopropylamino)ethylmethacrylate] (PDPA) homopolymers and poly[2-(dimethylamino)ethylmethacrylate]- b-poly[methylmethacrylate] (PDMA-b-PMMA), poly[2-(diethylamino)ethylmethacrylate]-bpoly[ methylmethacrylate] (PDEA-b-PDMA) and poly[2-(diisopropylamino)ethylmethacrylate]-b-poly[2-(dimethylamino) ethylmethacrylate] (PDPA-b-PDMA). Diblock copolymers having different molecular weight and different comonomer ratios. Polarisation curves indicated that all the studied polymers were acting as a mixed type inhibitors. All electrochemical measurements showed that inhibition efficiencies increased with an increase in the inhibitor concentration. It was determined that the increase of inhibitor efficiency by concentration resulted from the adsorption of polymers to metal surface, and the adsorption fitted to Langmuir adsorption equation. Adsorption equilibrium constant (Kads) and free energy of adsorption(ΔGads), which were thermodynamic parameters of adsorption were calculated by benefiting from the drawn adsorption isotherms. The variation in inhibitive efficiency mainly depended on the type and the nature of the substituents present in the inhibitor molecule and also depended on the molecular weight of the inhibitors. The best inhibition in DDW showed VB207 diblock copolymer. Surface images obtained with SEM, EDX and AFM methods, determined by verifying these results that inhibitors decreased the dissolution of metal, and prevented the corrosion

Corrosion inhibition of st37 steel in geothermal fluid by quercus robur and pomegranate peels extracts

Plant extracts have become important as an environmentally acceptable, readily available and renewable source of wide range of inhibitors. Tannins, a class of natural, non toxic and biodegradable polyphenolic compounds, extracted from plant sources are already used as corrosion inhibitors in aqueous media. This study investigates the inhibiting effect of Quercus robur and pomegranate peels extracts on st37 steel corrosion in geothermal fluid using the Tafel polarization method. It was found that the extracts act as good corrosion inhibitors for geothermal fluid. 250 ppm of Quercus robur oak extract was seen to have 90% corrosion inhibition efficiency. The values of pH, potential, conductivity, total hardness and Ca2+ hardness, dissolved solid substance (TDS) and salinity of geothermal fluid were analyzed before and after the addition of extract into it. According to these analyses, increasing pH level more than 5 indicates that corrosion con structive aggressive ions (H+) decrease. Furthermore the decrease of conductivity values as a result of the decrease of inhibitor concentration shows that corrosion slows down. Ryznar and Langelier Indexes are cal culated for AF11 well, reinjection and collected pools. The values of indexes show that geothermal fluid is corrosive and scale properties