A Study of the Possible Use of Materials With Shape Memory Effect in Shipbuilding

Ivošević, Špiro; Majerič, Peter; Vukičević, Miroslav; Rudolf, Rebeka

doi:10.18048/2020.00.20.

Cited by 10 publications

(12 citation statements)

References 7 publications

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“…Our study demonstrated a higher hardness of NiTi-2 in comparison to the NiTi-1 alloy. This can be explained by a higher nickel content, and/or iron content, as shown by EDX/XRF analysis, which is in agreement with previous reports [ 25 , 26 ]. An additional EBSD analysis revealed that there were two phases in the microstructure of NiTi-1 samples (NiTi-cubic and Ni 3 Ti hexagonal), while an additional NiTi 2 -cubic phase was detected in the NiTi-2 microstructure.…”

Section: Discussionsupporting

confidence: 92%

“…In the present study we compared the biofunctional properties of nickel–titanium alloys obtained by two different production processes. Contrary to conventional casting, continuous casting was previously reported to be a production process that was able to produce stands of relatively small diameter with an acceptable surface quality [ 17 , 25 , 26 ]. Even though the correlation between production processes and material properties has been proven in numerous studies [ 27 , 28 ], there is still no clearly defined consensus on the accepted model for the production of these alloys for application in dentistry.…”

Section: Discussionmentioning

confidence: 99%

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Experimental Investigation of the Biofunctional Properties of Nickel–Titanium Alloys Depending on the Type of Production

et al. 2022

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Nickel–titanium alloys used in dentistry have a variety of mechanical, chemical, and biofunctional properties that are dependent on the manufacturing process. The aim of this study was to compare the mechanical and biofunctional performances of a nickel–titanium alloy produced by the continuous casting method (NiTi-2) with commercial nitinol (NiTi-1) manufactured by the classical process, i.e., from remelting in a vacuum furnace with electro-resistive heating and final casting into ingots. The chemical composition of the tested samples was analyzed using an energy dispersive X-ray analysis (EDX) and X-ray fluorescence (XRF). Electron backscatter diffraction (EBSD) quantitative microstructural analysis was performed to determine phase distribution in the samples. As part of the mechanical properties, the hardness on the surface of samples was measured with the static Vickers method. The release of metal ions (Ni, Ti) in artificial saliva (pH 6.5) and lactic acid (pH 2.3) was measured using a static immersion test. Finally, the resulting corrosion layer was revealed by means of a scanning electron microscope (SEM), which allows the detection and direct measurement of the formatted oxide layer thickness. To assess the biocompatibility of the tested nickel–titanium alloy samples, an MTT test of fibroblast cellular proliferation on direct contact with the samples was performed. The obtained data were analyzed with the IBM SPSS Statistics v22 software. EDX and XRF analyses showed a higher presence of Ni in the NiTi-2 sample. The EBSD analysis detected an additional NiTi2-cubic phase in the NiTi-2 microstructure. Additionally, in the NiTi-2 higher hardness was measured. An immersion test performed in artificial saliva after 7 days did not induce significant ion release in either group of samples (NiTi-1 and NiTi-2). The acidic environment significantly increased the release of toxic ions in both types of samples. However, Ni ion release was two times lower, and Ti ion release was three times lower from NiTi-2 than from NiTi-1. Comparison of the cells’ mitochondrial activity between the NiTi-1 and NiTi-2 groups did not show a statistically significant difference. In conclusion, we obtained an alloy of small diameter with an appropriate microstructure and better response compared to classic NiTi material. Thus, it appears from the present study that the continuous cast technology offers new possibilities for the production of NiTi material for usage in dentistry.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Experimental Investigation of the Biofunctional Properties of Nickel–Titanium Alloys Depending on the Type of Production

et al. 2022

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“…Chemical analysis of the percentages of Ni and Ti of the initial test samples (before being exposed to the seawater environment) is shown in Table 1 [32]. The pitting depth measurements on the selected six-line topographical profiles on the pitting hole are shown in Figure 3.…”

Section: Resultsmentioning

confidence: 99%

“…Motivated by previous research [ 29 , 30 , 31 , 32 ], in this paper we analysed the pitting corrosion of a Ni–Ti alloy in the marine environment. Specifically, 3 test samples of Ni–Ti alloy were immersed in the sea, near the coast, at a depth of three metres, during the period from September 2018 to March 2020.…”

Section: Methodsmentioning

confidence: 99%

A Nonlinear Probabilistic Pitting Corrosion Model of Ni–Ti Alloy Immersed in Shallow Seawater

et al. 2022

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The degradation of metal materials in a marine environment represents the consequence of the electrochemical corrosion of metals under the influence of the environment. The application of new materials in the maritime industry requires experimental, real-world research on the form of corrosive damage and the intensity of the corrosion. This paper analyses the pitting corrosion of a rod-shaped nickel–titanium (Ni–Ti) alloy that was produced by means of the continuous casting method. In total, three samples were posted in a real seawater environment and analysed after 6, 12, and 18 months. Pits were detected on the Ni–Ti alloy after 18 months of exposure to the marine environment. The database on pitting corrosion was created by measuring depth in mm, which was performed by means of a nonlinear method, and by the generation of an artificial database of a total of 120, gauged in critical pit areas. The data were obtained by the application of a nonlinear model, and under the assumption that corrosion starts after 12 months of exposure in the corrosive marine environment. The EDX analysis of the Ni–Ti alloy composition inside the pits and on the edges of the pits indicated that the corrosion process in the hole of the pit occurs due to the degradation of the Ni.

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“…In the sea at a depth of 3 m, the minimum value of salinity was measured at 27.6 (‰) (December), the maximum value was 39.40 (‰) (August), while the average value was 36.68 (‰). Metallographic observations and microstructure observations of all NiTi1 [21] and NiTi2 samples were conducted in order to monitor the occurrence of the corrosion process and prepare the samples for testing [22] To determine the changes in the chemical composition of the surfaces that had been exposed to different environments, before the start of the experiment, preliminary analyses were performed using Inductively Coupled Plasma (ICP) and X-Ray Fluorescence (XRF). The measured elements (such as chemical composition) are shown in Table 1 [22].…”

Section: Methodsmentioning

confidence: 99%

Multivariate Regression Analysis of the NiTi Alloys’ Surface Corrosion Depending on the Measured Oxygen Value: Tests in Three Different Marine Environments

et al. 2022

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Actual corrosion experiments are based mainly on methodologies that measure the corrosion rate of alloys as a function of the parameters that characterise different external influences and the specific environment in which the alloys are placed. Corrosive processes are viewed as complex stochastic processes described by linear and nonlinear probabilistic models. In contrast to these common ways of analysing corrosive processes, this paper investigates the corrosion process in terms of chemical changes in the alloys’ surface compositions. For this purpose, two NiTi Shape Memory Alloys obtained by different technological production processes were tested, followed by an analysis of the empirical data obtained in a real experiment that included monitoring the corrosion behaviour. Both the analysed alloys were exposed to three different types of marine environment: air, tide, and sea. Data were collected continuously after 6, 12 and 18 months of samples’ exposure to the marine environmental influences. A total of six empirical databases were formed, one for each of the observed NiTi alloys in each of the three observed environments. The empirical databases systematised the data related to the measurements of the surface chemical composition obtained using Energy Dispersive X-Ray (EDX) and Focused Ion Beam (FIB) analyses. Statistical analysis was performed to determine the correlation between the corrosion depth and the percentage of oxygen in the sample surfaces as well as to determine the similarities and differences in the corrosive behaviour of the two observed alloys in different marine environments.

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A Study of the Possible Use of Materials With Shape Memory Effect in Shipbuilding

Cited by 10 publications

References 7 publications

Experimental Investigation of the Biofunctional Properties of Nickel–Titanium Alloys Depending on the Type of Production

Experimental Investigation of the Biofunctional Properties of Nickel–Titanium Alloys Depending on the Type of Production

A Nonlinear Probabilistic Pitting Corrosion Model of Ni–Ti Alloy Immersed in Shallow Seawater

Multivariate Regression Analysis of the NiTi Alloys’ Surface Corrosion Depending on the Measured Oxygen Value: Tests in Three Different Marine Environments

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