Search results for "CORROSION"
showing 10 items of 456 documents
Metodyka doboru stopu konstrukcyjnego uwzględniająca wpływ wodoru na właściwości korozyjno-mechaniczne stopów
2016
Stopy metali są najczęściej wykorzystywanym materiałem konstrukcyjnym. Ponadto metale absorbują wodór, który osłabia ich własności mechaniczne i korozyjne. Ze tego względu konieczne jest opracowanie metodyki pozwalającej na dobór stopu zapewniający wydłużenie czasu niezawodności eksploatacyjnej konstrukcji. Zaproponowana metodyka obejmuje zarówno dobór materiału pod względem wytrzymałości mechanicznej, jak i odporności korozyjnej. Pomiary wytrzymałości mechanicznej obejmują próby udarności metodą Charpy’ego oraz odporności na rozciąganie. W obu przypadkach próbie poddawane są próbki nienawodorowane, jak i nawodorowane. Pomiary odporności korozyjnej przewidziano jako pomiar SEM korozyjnego o…
Deposition and characterization of coatings of Hydroxyapatite, Chitosan, and Hydroxyapatite-Chitosan on 316L for biomedical devices
2018
In the last decades, the scientific community has turned on great interest towards the development of increasingly performing biomedical systems. In the orthopedic field, biomedical devices are made up by metallic materials (mainly steel and titanium alloys), which have low/medium resistance to corrosion and a low osteointegration capacity when implanted inside the human body. This can lead to infection or inflammation that can damage the tissues surrounding the implant. The use of biocompatible coatings allows cancelling or mitigating these phenomena. The coating interposing between aggressive environment and biomedical device inhibits corrosion so limiting the metal ions release into the …
Error analysis and calibration for a novel pipe profiling tool
2020
Integrity of industrial pipework is ensured through routine inspection. Internal visual inspection tools are capable of characterising degradation in the form of corrosion, pitting, erosion and cracking. The accuracy of such inspection systems has a direct impact on decisions regarding the remaining lifetime of the asset. By minimising error margins, the asset may be operated with confidence for longer, with less uncertainty. This paper considers a probe system consisting of a laser profiler and camera that produces a textured 3D model of the internals of 2 – 6 inch pipework. The accuracy of the system is defined by the ability to extract laser projections from an image as it travels down t…
Shear and flexural strength of corroded R.C. beams
2016
Simplified equations aimed at evaluating the flexural and shear capacity of corroded R.C. beams are presented and discussed in this paper, with reference to ordinary beams reinforced both longitudinally (with same-size bars) and transversely (with stirrups). A model is developed to take care of diffused and localised corrosion (pitting corrosion), concrete decay in compression and bond-strength decay at concrete-reinforcement interface. A fairly innovative contribution of this study is the introduction into the proposed equations of the main parameters governing the corrosion processes. The proposed approach is simple and effective, and may be adopted in the assessment of many damaged struc…
Incorporation mechanism of colloidal TiO2 nanoparticles and their effect on properties of coatings grown on 7075 Al alloy from silicate-based solutio…
2021
Plasma electrolytic oxidation (PEO) was applied using a pulsed unipolar waveform to produce Al2O3-TiO2 composite coatings from sol electrolytic solutions containing colloidal TiO2 nanoparticles. The sol solutions were produced by dissolving 1, 3, and 5 g/L of potassium titanyl oxalate (PTO) in a silicate solution. Scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, and Raman spectroscopy were applied to characterizing the coatings. Corrosion behavior of the coatings was investigated using polarization and impedance techniques. The results indicated that TiO2 enters the coating through all types of micro-discharging and is doped into the alumina phase. The higher…
Effect of Molybdate on Corrosion Performance of Oxide Coating Produced on 7075 Al Alloy Using PEO
2022
In this research, plasma electrolytic oxidation (PEO) coatings were prepared on 7075 Al alloy in a silicate-based solution with Na2MoO4 additive using a unipolar waveform at constant current density. The coatings displayed micro-pores, micro-cracks, pancake-like and crater-like features, and also solidified molten oxide particles on the surface. The coatings were majorly composed of Al2O3 (γ, δ, and α), SiO2 (amorphous), and MoO3 phases, which confirms the incorporation of molybdenum in the case of additive-containing coatings. Molybdenum species were transported through cracks, channels, and micropores, as the ready access pathways into the coating and partly sealed the c…
Effect of Hot Dip Galvanized Steel Surface Chemistry and Morphology on Titanium Hexafluoride Pretreatment
2017
Titanium hexafluoride pretreatments are known to improve paint adhesion and function as a barrier between the coating and the hot dip galvanized (HDG) steel surface. Interactions at the zinc/pretreatment interface are of utmost importance for the formation of pretreatment layers and the corrosion resistance of color coated hot dip galvanized steels. Removal rate of inert aluminum oxide from HDG steel samples by chemical dissolution was studied. XPS measurements showed that the surface Al2O3 layer thickness decreased rapidly already at mild alkaline cleaning, while complete removal of Al required severe etching. Low reactivity of an Al2O3-rich surface was confirmed by impaired formation of a…
Wpływ dodatku bioaktywnych mikrocząstek srebra na właściwości użytkowe tynków mineralnych
2013
Aktywność mikroorganizmów, a przede wszystkim bakterii i grzybów w istotny sposób wpływa na swoiste cechy i wartość użytkową materiałów budowlanych. Jest to rodzaj korozji biologicznej, stanowiącej szczególny przypadek korozji chemicznej, która powoduje obniżenie lub utratę właściwości użytkowych materiału. Oprócz korozji biologicznej, grzyby mogą również stwarzać zagrożenie dla zdrowia użytkowników zasiedlonych obiektów. Ich toksyczne oddziaływanie na zdrowie ludzi i zwierząt uważa się za znacznie groźniejsze w skutkach od biokorozji materiałów. Stosowane obecnie środki biobójcze w postaci biocydów i nanocząstek srebra również mogą stanowić zagrożenie. W prezentowanej pracy przedstawiono w…
Experimental Investigation on Stiffness and Strength of Single-Lap Z-Pinned Joints in a Laminated CFRP Stress-Ribbon Strip
2016
Carbon fiber-reinforced polymer (carbon-polymer) is an advanced lightweight composite material with high strength and excellent resistance to corrosion and fatigue. Over the past decades, application of fiber-reinforced polymers has been spread from the aerospace to other branches of industry such as automobile and civil engineering. Unidirectional carbon-polymers have a high potential for replacing steel in tensile members. Recently, the first carbonpolymer stress-ribbon bridge has been constructed in Germany. The non-laminated strip-loop carbon-polymer thin strips were used as the load bearing components in this bridge. In comparison with the laminated components, the applied cables are c…
Predictive Model for Cut-Edge Corrosion of Galvanized Steels
2006
A numerical model for the electrochemical behavior of cut-edge of galvanized steels is proposed. Some experimental data of current densities above cut-edge immersed in a 0.03M NaCl solution have been measured, using a scanning vibrating electrode technique, and compared with some simulated ones. A good fit has been obtained. The model geometry has been modified by decreasing the electrolyte thickness in order to tend towards an atmospheric corrosion case; such situation that is not easily accessible by electrochemical studies. Three regions can be distinguished according to the efficiency of the galvanic coupling to protect steel.