Article
Chemistry, Physical
Dawei Wei, Xiaofeng Bai, Cuiping Guo, Changrong Li, Zhenmin Du
Summary: Isothermal sections at 1373 and 1473 K in the Co-Nb-Ti system were constructed using SEM/EDS, EPMA, and XRD techniques, revealing three three-phase regions and the formation of continuous solid solutions. The solubilities of Ti and Nb in the system vary at different temperatures, and no ternary compounds were observed.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Jiali Zhang, Jing Zhong, Qin Li, Lijun Zhang
Summary: Nb3Sn plays a crucial role in superconducting applications due to its stable performance under high magnetic field conditions. This study proposes a method to prepare Nb/Sn liquid-solid reactive diffusion couples and determine phase equilibria and interdiffusion coefficients, providing valuable insights for further thermodynamic and kinetic modeling. The results obtained are expected to have broad implications for other alloy systems with significant differences in melting points.
Article
Materials Science, Multidisciplinary
Xianjun Lei, Xiaopeng Wang, Fantao Kong, Haitao Zhou, Yuyong Chen
Summary: A model for studying the growth kinetics of intermetallic compounds was proposed based on binary phase diagrams, with the parabolic growth relationship of intermetallic compound being mathematically deduced. The solute diffusion coefficient was identified as the predominant parameter controlling the growth kinetics, with the smallest diffusion coefficient found in the Nb3Al phase. It was demonstrated that intermetallic layers formed at the interface can inhibit further corrosion of the Nb container by the TiAl melt, with the Nb3Al layer playing a dominant role.
Article
Materials Science, Multidisciplinary
Xianjue Ye, Biaobiao Yang, Ruilin Lai, Jiantao Liu, Yunping Li, Shu Yu
Summary: The influence of Nb addition on the internal oxidation of a novel powder metallurgy superalloy was investigated. The results showed that higher Nb concentration resulted in deeper internal oxidation but a narrower depletion region of the gamma' phase. Nb facilitated the partition of more Al into the gamma' phase, which restricted the outward diffusion of Al and promoted the nucleation of Al2O3, thereby reducing the hindrance to the inward diffusion of O. Therefore, Nb addition led to a deeper penetration of O into the alloy matrix or deeper internal oxidation.
Article
Chemistry, Physical
Shuai Xu, Junpin Lin, Yongfeng Liang, Jianping He, Yi Qiao, Limei Cha, Liang Yang, Xianquan Jiang
Summary: This paper continues our previous publication and systematically characterizes diffusion multiples using various techniques. The constructed isothermal sections include stable phases and phase regions at 980 degrees C. The experimental results provide missing thermodynamic data and enable accurate predictions of phase diagrams and reactions at intermediate temperatures.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Rohit Ojha, Kaustubh Kulkarni, Thomas Helander, K. C. Hari Kumar
Summary: The phase equilibria in the Fe-Cr-Ni-Al system were investigated at different temperatures using diffusion couple technique, showing formation of different phases at different temperatures. Thermodynamic calculations using different database combinations were compared to experimental results to predict phase formation under specific conditions.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Vidur Tuli, Antoine Claisse, Luca Messina, P. A. Burr
Summary: Through density functional theory calculations, it was found that in BCC-Cr and BCC-Nb, Nb and Zr diffuse faster than Cr, while Cr diffuses slower than Nb and Zr. The segregation of solutes towards vacancy sinks varies at different temperatures.
JOURNAL OF NUCLEAR MATERIALS
(2021)
Article
Chemistry, Physical
Shuai Xu, Junpin Lin, Yongfeng Liang, Jianping He, Xiaohua Chen, Limei Cha, Xianquan Jiang
Summary: Determining the phase diagrams at intermediate temperatures for Ti-Al-Nb alloys is challenging due to various factors, but through diffusion simulation guidance, this study successfully constructed and characterized the phase diagrams for the system. The findings provide valuable insights for the development of Ti-Al-Nb alloys at intermediate temperatures.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
G. Vazquez, S. Chakravarty, R. Gurrola, R. Arroyave
Summary: High Entropy Alloys (HEAs) are important in metals research and a thorough estimation of the phases in HEA is crucial for alloy design. Machine Learning offers a cost-effective method for predicting new HEAs. A deep neural network model is developed using a dataset generated by high-throughput computational thermodynamic calculations. The model successfully identifies the recurrent phases and can be used for real-time materials discovery/design tasks.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Morgan R. Jones, N. Scott Bobbitt, Frank W. DelRio, Mark A. Wilson, Hannah C. Howard, Melina A. Endsley, Jonathan W. Pegues, Ping Lu, Andrew B. Kustas, Irene J. Beyerlein, Michael Chandross, Nicolas Argibay
Summary: The temperature-dependent hardness of additively-manufactured near-eutectic Ni-Nb was studied. The alloy formed a two-phase nanoscale microstructure with peak hardness at temperatures up to 400 degrees C. Irreversible softening occurred above this temperature. Deformation mechanisms differed between single-phase nanocrystalline volumes and the two-phase regions, highlighting the potential of additive manufacturing and multi-phase intermetallic compounds for high-strength, printable superalloys.
JOURNAL OF MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Mengdi Cheng, Yangxi Yan, Zhimin Li, Pangpang Wang, Ri-ichi Murakami, Dongyan Zhang
Summary: This study investigates Pb(Ni, Nb)O-3-Pb(Lu, Nb)O-3-PbTiO3 piezoelectric ceramics, among which the 0.52PNN-0.16PLN-0.32PT ceramic exhibits the best performance (d(33) = 850 pC N-1, d(33)* = 1139 pm V-1). The excellent piezoelectricity can be attributed to multiphase coexistence and an enhanced local heterogeneous structure. Polar nanoregions that promote polarization rotation play a crucial role in achieving high piezoelectricity, as observed through SEM and PFM characterization. TEM analysis confirms the presence of a heterogeneous domain configuration with two coexisting phases. Additionally, the ceramic maintains a large signal piezoelectricity of 1000 pm V-1 in the temperature range of 20-90°C. This work showcases the achievement of both high piezoelectric properties and a good temperature range in relaxor ferroelectric ceramics.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Chemistry, Physical
Shuai Xu, Junpin Lin, Yongfeng Liang, Liang Yang, Jianping He, Xianquan Jiang
Summary: This paper continues the author's recent publications Xu et al. (2022, 2023). The diffusion multiples were characterized using various techniques and a composition range for the 1010 degrees C isothermal section was constructed. The phase diagram shows multiple stable phases, three-phase regions, and two-phase regions. Phase reactions occur between 1010 degrees C and 980 degrees C. The phase diagram and reaction works are essential for the design and application of TiAl-based alloys, providing important data for optimizing the Gibbs free energy descriptions of this ternary system.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Chang-Yu Hung, Stoichko Antonov, Paul D. Jablonski, Martin Detrois
Summary: Alloys based on Inconel 725 with elevated levels of Nb and Ta were studied for their phase stability and transformation after aging and long-term exposure at 700 degrees C for 10,000 hours. Scanning electron microscopy and transmission electron microscopy were used to characterize the microstructure changes. The results showed that the addition of Nb/Ta promoted the formation of gamma '/gamma'' co-precipitates in the low Ti/Al ratio alloy, while only gamma '' precipitates were present in the high Ti/Al ratio counterpart. After 10,000 hours exposure, complex geometrical closed-packed (GCP) phases formed from the gamma'/gamma'' co-precipitates in a layer-by-layer manner, with plate-like delta phase precipitates decorated by blocky alpha-Cr and enveloped by a wavy gamma ' film.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
G. H. Cao, Z. Zhang, X. Li, W. Skrotzki, E. Mueller, R. Schneider, D. Gerthsen
Summary: The study found that nickel plays an important role in stabilizing the high-temperature Pt3Al(h) phase, while phases such as Ni2PtAl and NiPt2Al have been observed and confirmed experimentally. The phase transition and formation mechanisms involved during cooling have also been analyzed.
Article
Chemistry, Physical
Yongkang Tan, Rongjie Zhuang, Guanlin Yang, Xiaoma Tao, Hongmei Chen, Yifang Ouyang, Yong Du
Summary: In this study, the solid-solid diffusion reaction and growth kinetics of the Ni-Zn system were investigated using diffusion couple technique. Three intermetallic compounds were observed in the diffusion zone, and the growth process was dominated by volume diffusion. The Young's modulus and hardness of the IMCs were evaluated from nanoindentation testing, showing that the properties varied with the Zn concentration. The calculated Young's modulus from first-principles calculations was consistent with experimental results.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Engineering, Biomedical
Samuel Rantataro, Ilmari Parkkinen, Ishan Pande, Andrii Domanskyi, Mikko Airavaara, Emilia Peltola, Tomi Laurila
Summary: Vertically aligned carbon nanofibers (VACNFs) have the potential to detect neurotransmitters, but their high rigidity may lead to mechanical mismatch with brain tissue. By adjusting fiber length and distance, the mechanical biocompatibility of VACNFs can be improved, reducing the formation of glial scars and impacting cell morphology.
ACTA BIOMATERIALIA
(2022)
Article
Engineering, Manufacturing
Nikhilendu Tiwary, Vesa Vuorinen, Glenn Ross, Mervi Paulasto-Krockel
Summary: This study provides a detailed investigation of the Cu-Sn SLID bonding process using finite element simulations, and explores the effects of different steps on stress formation during the bonding process. The results demonstrate that low-temperature SLID process can significantly reduce the stress levels in Cu-Sn bonds.
IEEE TRANSACTIONS ON COMPONENTS PACKAGING AND MANUFACTURING TECHNOLOGY
(2022)
Article
Chemistry, Physical
Dorothea Golze, Markus Hirvensalo, Patricia Hernandez-Leon, Anja Aarva, Jarkko Etula, Toma Susi, Patrick Rinke, Tomi Laurila, Miguel A. Caro
Summary: We present a quantitatively accurate machine-learning model that can predict core-electron binding energies and obtain X-ray photoelectron spectroscopy spectra. The model combines density functional theory with GW and utilizes kernel ridge regression for machine learning predictions. We applied this new approach to disordered materials and small molecules containing carbon, hydrogen, and oxygen, achieving qualitative and quantitative agreement with experimental results, resolving spectral features within 0.1 eV of reference experimental spectra. The method only requires users to provide a structural model for the material under study to obtain XPS predictions within seconds. Our new tool is freely available online through the XPS Prediction Server.
CHEMISTRY OF MATERIALS
(2022)
Article
Electrochemistry
Laura Ferrer Pascual, Ishan Pande, Ayesha Kousar, Samuel Rantataro, Tomi Laurila
Summary: The use of carbon nanofiber (CNF) electrodes allows for effective control of length and surface density. The formation of a thin liquid layer and the increased apparent surface area of the electrodes contribute to a decrease in peak potential difference and an increase in apparent heterogeneous electron transfer constant.
ELECTROCHEMISTRY COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Elli Leppanen, Maedeh Akhoundian, Sami Sainio, Jarkko Etula, Olli Pitkanen, Tomi Laurila
Summary: Carbonaceous nanomaterials have great potential in electroanalytical applications, but their structure-performance relationship is still not well understood. In this study, a systematic electrochemical characterization is conducted on a set of carbon nanomaterials to establish this relationship and highlight the sensitivity of electrochemical performance to structural properties.
Article
Materials Science, Paper & Wood
Vasuki Durairaj, Touko Liljestrom, Niklas Wester, Peter Engelhardt, Sami Sainio, Benjamin P. Wilson, Panpan Li, Katri S. Kontturi, Tekla Tammelin, Tomi Laurila, Jari Koskinen
Summary: This study comprehensively investigates the influence of nanocellulosic material properties on the electroanalytical performance of nanocellulose/CNT hybrid electrodes. By manipulating the functionalization and geometry of cellulose nanocrystals, cellulose nanofibers, and TEMPO-oxidized cellulose nanofibers, the optimal combination for hybrid electrode performance is determined. This research demonstrates for the first time the tunability of nanocellulose/CNT hybrid electrodes towards different biomolecules through the selection of nanocellulosic materials.
Article
Medicine, Research & Experimental
Mette Tengstrom, Bill Byrom, Sami Volotinen, Ulla Huopaniemi, Tomi Laurila
Summary: As the need for generating novel and informative clinical outcome measures using wearables and sensors for at-home assessment grows, there is an increasing interest in decentralizing aspects of clinical trials to simplify participation. This study explores the potential of using atmospheric pressure data from smartphone sensors to detect small height gains during a stair climb performance test, and the results suggest that the smartphone barometer can be suitable for future development of a stair-climbing performance outcome test using a mobile application.
CONTEMPORARY CLINICAL TRIALS
(2022)
Article
Chemistry, Analytical
Ayesha Kousar, Ishan Pande, Laura F. Pascual, Emilia Peltola, Jani Sainio, Tomi Laurila
Summary: One of the major challenges in measuring dopamine (DA) using electro-chemical methods in living organisms is to achieve selectivity in the presence of interfering substances like ascorbic acid (AA) and uric acid (UA). Researchers have used complicated multimaterial structures and ill-defined pretreatments to enhance selectivity. However, the lack of control over the electrode structures has made it difficult to establish a relationship between selectivity and structure. Carbon nanofiber (CNF) electrodes have shown promise in neurobiological applications due to their easily customizable structure. In this study, the sensitivity and selectivity of CNF electrodes towards DA were controlled by adjusting the lengths of the CNF during the fabrication process while maintaining similar surface chemistries. It was found that increasing the fiber length enhanced the sensitivity towards DA while also causing a shift in the oxidation peaks of AA and DA, leading to excellent selectivity.
ANALYTICAL CHEMISTRY
(2023)
Article
Materials Science, Multidisciplinary
Ishan Pande, Laura Ferrer Pascual, Ayesha Kousar, Emilia Peltola, Hua Jiang, Tomi Laurila
Summary: This study investigates the effect of catalyst materials and process parameters on the growth of carbon nanofibers (CNFs). Different adhesive layers are used to alter the macroscale geometric parameters of CNFs. The unstable Ti-Ni interface leads to diffusion of Ni towards the silicon wafer, decreasing the available Ni for CNF nucleation and reducing the fiber density. In contrast, the Cr-Ni interface results in higher fiber density but slower growth rate due to carbon diffusion into the thicker Cr layer.
DIAMOND AND RELATED MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Nikhilendu Tiwary, Glenn Ross, Vesa Vuorinen, Mervi Paulasto-Krockel
Summary: Continuous scaling of package architectures requires high-density microbumps, which often result in the formation of intermetallic compounds. In this study, test structures made of Cu3Sn IMC microbumps were manufactured, and electromigration tests were conducted to investigate failure spots in the interconnects. The formation of Cu3Sn in undesirable locations was found to aggravate current crowding and lead to thermal runaway.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Multidisciplinary Sciences
Samuel Rantataro, Laura Ferrer Pascual, Tomi Laurila
Summary: It is widely believed that ascorbic acid (AA) interferes with the detection of neurotransmitters using electrochemical methods. However, this study shows that AA concentration decreases rapidly in cell culture medium, eventually becoming undetectable by electrodes, allowing for effective monitoring of neurotransmitter concentrations.
SCIENTIFIC REPORTS
(2022)
Article
Pharmacology & Pharmacy
Johanna Kujala, Niklas Wester, Terhi J. Lohela, Mika Kurkela, Janne T. Backman, Bjorn Mikladal, Tomi Laurila, Jari Koskinen, Tuomas O. Lilius, Eija A. Kalso
Summary: This study aimed to validate a novel electrochemical point-of-care (POC) assay for rapid paracetamol concentration determinations. The results showed biases in POC compared with venous plasma and capillary blood HPLC-MS/MS at concentrations >30 μM. The novel POC method is considered a promising tool for paracetamol concentration analysis.
BRITISH JOURNAL OF CLINICAL PHARMACOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Ishan Pande, Sami Sainio, Jani Sainio, Ville Liljestrom, Hua Jiang, Tomi Laurila
Summary: This paper investigates the microstructure of carbon nanofibers (CNFs) grown on two different substrates and its correlation with surface chemistry. CNFs grown on Cr + Ni substrates show a slightly distorted herringbone-like structure, while those grown on Ti + Ni substrates have a relatively undefined structure. The latter possess a richer surface chemistry. These structure-chemistry correlations help tailor the features of CNFs for specific applications.
DIAMOND AND RELATED MATERIALS
(2023)
Article
Electrochemistry
Khadijeh Nekoueian, Maedeh Akhoundian, Niklas Wester, Tomi Laurila
Summary: In this study, an ultrasensitive sensing platform was designed to evaluate the physiologically relevant values of basal dopamine in a complex biological environment. The platform was fabricated using molecular imprinting technology and carbon hybrid nanomaterials. The three-dimensional molecularly imprinted polymer receptors on the carbon nanofiber sensing platform allowed for the determination of trace values of dopamine with high sensitivity and without interference from other biomolecules in various culture media.
ELECTROCHIMICA ACTA
(2023)
Article
Biochemistry & Molecular Biology
Touko Liljestrom, Katri S. S. Kontturi, Vasuki Durairaj, Niklas Wester, Tekla Tammelin, Tomi Laurila, Jari Koskinen
Summary: Protein fouling is a critical issue in electrochemical sensors for medical applications, the use of conductive nanomaterials, such as carbon nanotubes, can significantly improve fouling resistance and sensitivity. Nanocellulosic materials provide an efficient and sustainable approach to achieving functional nanoscale architectures. The NC/MWCNT composite electrodes offer advantages in measurement reliability, sensitivity, and selectivity over MWCNT-based electrodes, even in complex physiological environments.
