Wyniki wyszukiwania - BazTech

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Characterization of Al 6061/Al2O3/SiC composites with cerium oxide: corrosion analysis and microstructural insights

Sharma Vipin Kumar, Kumar Pardeep, Kumar Dinesh, Chalisgaonkar Rupesh, Akhai Shalom

Composites Theory and Practice

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2024

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R. 24, nr 1

49--56

EN

CeO2) is incorporated, employing electrochemical analysis and scanning electron microscopy (SEM) techniques. This study investigated the impact of cerium oxide on the corrosion behavior and assessed the hydrophobic properties of the composite surface in corrosive environments using contact angle measurements. The experimental methodology comprised several key components, like the selection of specific materials, the production of hybrid composites by the stir casting technique, the analysis of corrosion using the potentiodynamic polarization method, and the characterization of surface wettability. The metallographic analysis of the composites provided insights into the impact of various reinforcements on the microstructural properties. The incorporation of cerium oxide served to mitigate agglomeration and augment grain refinement within the composites. The utilization of potentiodynamic polarization analysis revealed enhanced corrosion resistance in hybrid composites containing cerium oxide in comparison to the Al 6061 alloy. The corrosion current density exhibited a decrease as the content of CeO2 increased. The findings indicate that cerium oxide can effectively prevent corrosion in aluminum hybrid, composites. These composites show potential for use in corrosion-prone applications.

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Investigating the steel–cement interface in high-temperature, high-pressure carbon dioxide environments

Zhu Ge

Materials Science Poland

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2023

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Vol. 41, No. 4

57--67

EN

This study investigates the impact of high-temperature, high-pressure carbon dioxide on the steel-cement interface, crucial in engineering structures and carbon capture storage systems. Experiments conducted on N80 steel and ordinary portland cement in synthetic aquifer brine revealed that CO2 exposure significantly exacerbates steel corrosion and cement degradation. The corrosion current density of steel increased to 1.2 μA/cm2 after six months in CO2, compared to 0.3 μA/cm2 in unexposed samples. Cement samples showed a marked decline in mechanical properties, with hardness reducing from 1.25 GPa (giga-Pascal) in control samples to 0.65 GPa after six months. The steel—cement interface integrity also diminished, as evidenced by a decrease in acoustic impedance from 45.0 M-Rayl to 34.0 M-Rayl over six months. These results emphasize the need for advanced materials and strategies to enhance the durability and safety of structures in CO2 -rich environments.

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Using a segmented voltage sweep mode and a Gaussien curve fitting method to improve heavy metal measurement system performance

Dias Pereira J. M., Postolache O., Silva Girao P.

Metrology and Measurement Systems

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2012

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Vol. 19, nr 2

381-394

EN

This paper presents a voltammetric segmented voltage sweep mode that can be used to identify and measure heavy metals' concentrations. The proposed sweep mode covers a set of voltage ranges that are centered around the redox potentials of the metals that are under analysis. The heavy metal measurement system can take advantage of the historical database of measurements to identify the metals with higher concentrations in a given geographical area, and perform a segmented sweep around predefined voltage ranges or, alternatively, the system can perform a fast linear voltage sweep to identify the voltammetric current peaks and then perform a segmented voltage sweep around the set of voltages that are associated with the voltammetric current peaks. The paper also includes the presentation of two auto-calibration modes that can be used to improve system's reliability and proposes the usage of a Gaussian curve fitting of voltammetric data to identify heavy metals and to evaluate their concentrations. Several simulation and experimental results, that validate the theoretical expectations, are also presented in the paper.