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Yang D, Phillips NW, Song K, Barker C, Harder RJ, Cha W, Liu W, Hofmann F. In situ Bragg coherent X-ray diffraction imaging of corrosion in a Co-Fe alloy microcrystal. CrystEngComm 2022; 24:1334-1343. [PMID: 35634094 PMCID: PMC9074767 DOI: 10.1039/d1ce01586a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 01/18/2022] [Indexed: 11/21/2022]
Abstract
Corrosion is a major concern for many industries, as corrosive environments can induce structural and morphological changes that lead to material dissolution and accelerate material failure. The progression of corrosion depends on nanoscale morphology, stress, and defects present. Experimentally monitoring this complex interplay is challenging. Here we implement in situ Bragg coherent X-ray diffraction imaging (BCDI) to probe the dissolution of a Co–Fe alloy microcrystal exposed to hydrochloric acid (HCl). By measuring five Bragg reflections from a single isolated microcrystal at ambient conditions, we compare the full three-dimensional (3D) strain state before corrosion and the strain along the [111] direction throughout the corrosion process. We find that the strained surface layer of the crystal dissolves to leave a progressively less strained surface. Interestingly, the average strain closer to the centre of the crystal increases during the corrosion process. We determine the localised corrosion rate from BCDI data, revealing the preferential dissolution of facets more exposed to the acid stream, highlighting an experimental geometry effect. These results bring new perspectives to understanding the interplay between crystal strain, morphology, and corrosion; a prerequisite for the design of more corrosion-resistant materials. Morphology, 3D lattice strain, and dissolution of a Co–Fe microcrystal was monitored using in situ Bragg coherent X-ray diffraction imaging.![]()
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Affiliation(s)
- David Yang
- Department of Engineering Science, University of Oxford Oxford OX1 3PJ UK
| | | | - Kay Song
- Department of Engineering Science, University of Oxford Oxford OX1 3PJ UK
| | - Clara Barker
- Department of Materials, University of Oxford Oxford OX1 3PH UK
| | - Ross J Harder
- Advanced Photon Source, Argonne National Laboratory Argonne IL 60439 USA
| | - Wonsuk Cha
- Advanced Photon Source, Argonne National Laboratory Argonne IL 60439 USA
| | - Wenjun Liu
- Advanced Photon Source, Argonne National Laboratory Argonne IL 60439 USA
| | - Felix Hofmann
- Department of Engineering Science, University of Oxford Oxford OX1 3PJ UK
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Hadjittofis E, Isbell MA, Karde V, Varghese S, Ghoroi C, Heng JYY. Influences of Crystal Anisotropy in Pharmaceutical Process Development. Pharm Res 2018; 35:100. [PMID: 29556822 PMCID: PMC5859710 DOI: 10.1007/s11095-018-2374-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 02/19/2018] [Indexed: 01/27/2023]
Abstract
Crystalline materials are of crucial importance to the pharmaceutical industry, as a large number of APIs are formulated in crystalline form, occasionally in the presence of crystalline excipients. Owing to their multifaceted character, crystals were found to have strongly anisotropic properties. In fact, anisotropic properties were found to be quite important for a number of processes including milling, granulation and tableting. An understanding of crystal anisotropy and an ability to control and predict crystal anisotropy are mostly subjects of interest for researchers. A number of studies dealing with the aforementioned phenomena are grounded on over-simplistic assumptions, neglecting key attributes of crystalline materials, most importantly the anisotropic nature of a number of their properties. Moreover, concepts such as the influence of interfacial phenomena in the behaviour of crystalline materials during their growth and in vivo, are still poorly understood. The review aims to address concepts from a molecular perspective, focusing on crystal growth and dissolution. It begins with a brief outline of fundamental concepts of intermolecular and interfacial phenomena. The second part discusses their relevance to the field of pharmaceutical crystal growth and dissolution. Particular emphasis is given to works dealing with mechanistic understandings of the influence of solvents and additives on crystal habit. Furthermore, comments and perspectives, highlighting future directions for the implementation of fundamental concepts of interfacial phenomena in the rational understanding of crystal growth and dissolution processes, have been provided.
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Affiliation(s)
- Eftychios Hadjittofis
- Surfaces and Particle Engineering Laboratory (SPEL), Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Mark Antonin Isbell
- Surfaces and Particle Engineering Laboratory (SPEL), Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Vikram Karde
- Surfaces and Particle Engineering Laboratory (SPEL), Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Sophia Varghese
- DryProTech Laboratory, Chemical Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, Gujarat, 382355, India
| | - Chinmay Ghoroi
- DryProTech Laboratory, Chemical Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, Gujarat, 382355, India
| | - Jerry Y Y Heng
- Surfaces and Particle Engineering Laboratory (SPEL), Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
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Rusin M, Ewan BCR, Ristic RI. The glycine-stimulated nucleation and solution-mediated polymorphic transformation ofl-glutamic acid. CrystEngComm 2013. [DOI: 10.1039/c2ce26344k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Giocondi J, Rohrer GS, Skowronski M, Balakrishna V, Augustine G, Hobgood HM, Hopkins RH. The Relationship Between Micropipes and Screw Dislocations in Pvt Grown 6H-Sic. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-423-539] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractThe growth surface of a 6H-SiC boule, grown by physical vapor transport, was examined using scanning force microscopy. The dimensions of surface/micropipe intersections and screw dislocation Burgers vectors have been determined from topographic data. All micropipes are positioned along the lines of super screw dislocations with a Burgers vectors of at least 4 times the c-axis repeat distance (15.2 Å). Perfect c-axis screw dislocations with Burgers vectors of only 15.2 Å are stable and do not have open cores. Measurements show that micropipe core radii, determined indirectly from the width of the craters formed at the surface/micropipe intersections, increase with the square of the dislocation Burgers vector.
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Abstract
In order to understand the fundamental processes leading to biomineralization, this chapter focuses on the earliest events of homo/heterogeneous nucleation from an initial supersaturated solution phase and subsequent growth involving various possible precursor phases (amorphous or crystalline) to the final mineral phase by specific template and other influences. We also discuss how the combination of macroscopic constant composition and microscopic atomic force microscopy provides insights into the physical mechanisms of crystal growth and phase stability and the influences of proteins, peptides or other small molecules.Biodemineralization reactions of tooth enamel and bone may be inhibited or even suppressed when particle sizes fall into certain critical nanoscale levels. This phenomenon actually involves particle-size-dependent critical conditions of energetic control at the molecular level. Clearly, this dissolution termination is a kinetic phenomenon and cannot be attributed to reaction retardation as a result of surface modification by additives. Almost all biomineralized structures are highly hierarchical at many different length scales. At the lowest level they often consist of tiny crystals, typically tens to hundreds of nanometers. This size is not arbitrary; rather, it seems to give biominerals such as bone and tooth remarkable physical characteristics.
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Meakin P, Rosso KM. Simple kinetic Monte Carlo models for dissolution pitting induced by crystal defects. J Chem Phys 2008; 129:204106. [DOI: 10.1063/1.3021478] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Wang L, Tang R, Bonstein T, Orme CA, Bush PJ, Nancollas GH. A new model for nanoscale enamel dissolution. J Phys Chem B 2007; 109:999-1005. [PMID: 16866472 DOI: 10.1021/jp046451d] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The dissolution kinetics of human tooth enamel surfaces was investigated using nanomolar-sensitive constant composition (CC) and in situ atomic force microscopy (AFM) under simulated caries formation conditions (relative undersaturation with respect to hydroxyapatite = 0.902, pH = 4.5). Scanning electron microscopic (SEM) examination of the resulting etched enamel surfaces showed that deminerzalization, initiated at core/wall interfaces of rods, developed anisotropically along the c-axes. After an initial rapid removal of surface polishing artifacts, the dissolution rate decreased as the reaction proceeded in accordance with our recently proposed crystal dissolution model, resulting in hollow enamel cores and nanosized remaining crystallites, resistant to further dissolution. Generally, dissolution of minerals is regarded as a spontaneous reaction in which all the solid phase can be dissolved in undersaturated solutions. However, the dissolution of some biominerals may be suppressed when the crystallites approach nanometer size. This study shows that CC demineralization of enamel in acidic medium follows this new model that can be used to mimic carious lesion formation. In dissolution studies, nanosized enamel crystallites exhibit a remarkable degree of self-preservation in the fluctuating physiological milieu.
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Affiliation(s)
- Lijun Wang
- Department of Chemistry, School of Dental Medicine, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
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Affiliation(s)
- John W Morse
- Department of Oceanography, MS-3146, Texas A&M University, College Station, Texas 77843, USA.
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Herschke L, Lieberwirth I, Wegner G. Zinc phosphate as versatile material for potential biomedical applications Part II. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2006; 17:95-104. [PMID: 16389476 DOI: 10.1007/s10856-006-6333-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2004] [Accepted: 05/09/2005] [Indexed: 05/06/2023]
Abstract
Surface chemical reactivity of two modifications of synthetic zinc phosphate tetrahydrate (alpha - and beta -form of Hopeite, alpha -,beta -ZPT) has been studied by selective chemical and e-beam etching in presence of diluted phosphoric acid and ammonia by Scanning Electron Microscopy (SEM) and microelectrophoresis (zeta potential measurements) in correlation with the corresponding bulk properties and crystal size distributions. The subtitle crystallographic differences between alpha -and beta -ZPT originating from a unique hydrogen bonding pattern, induce drastic variations of both surface potential and surface charge. Biogenic Hydroxyapatite (HAP) and one of its metastable precursors, a calcium dihydrogen phosphate dihydrate (DCPD) or Brushite were used to underline this resulting variation of chemical reactivity in zinc phosphates. In-situ monitoring of the transformation of Brushite in Hydroxyapatite is also reported.
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Affiliation(s)
- L Herschke
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128, Mainz, Germany. lieberw@mpip
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Lasaga AC, Luttge A. Variation of crystal dissolution rate based on a dissolution stepwave model. Science 2001; 291:2400-4. [PMID: 11264534 DOI: 10.1126/science.1058173] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A formulation based on defect-generated dissolution stepwaves of the variation of dissolution rate with the degree of undersaturation is validated by near-atomic-scale observations of surfaces, Monte Carlo simulations, and experimental bulk dissolution rates. The dissolution stepwaves emanating from etch pits provide a train of steps similar to those of a spiral but with different behavior. Their role in accounting for the bulk dissolution rate of crystals provides a conceptual framework for mineral dissolution far from equilibrium. Furthermore, the law extends research to conditions closer to equilibrium and predicts a nonlinear decrease in the rate of dissolution as equilibrium is approached, which has implications for understanding artificial and natural processes involving solid-fluid reactions.
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Affiliation(s)
- A C Lasaga
- Department of Geology and Geophysics, Yale University, New Haven, CT 06520, USA
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11
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Chiril?? R, Iliescu B. Dislocations in synthetic quartz. CRYSTAL RESEARCH AND TECHNOLOGY 1994. [DOI: 10.1002/crat.2170290202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Ballato A, Gualtieri JG. Advances in high-Q piezoelectric resonator materials and devices. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 1994; 41:834-844. [PMID: 18263273 DOI: 10.1109/58.330264] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In order to compare piezoelectric materials and devices, an intrinsic parameter, the motional time constant tau(1)/sup (m/)=(omega/sub m/Q/sub m/)(-1) for a particular mode m is employed. The use of tau(1)/sup (m/) follows from the accommodation of acoustic loss in the elastic compliance/stiffness and the establishment of material coefficients that are elements of viscosity matrices. Alternative and fully equivalent definitions of tau(1) are given based on the RC time constant derived from the equivalent circuit representation of a crystal resonator, acoustic attenuation, logarithmic decrement, and viscosity or damping. For quartz devices, the variation of tau(1): for any simple thickness mode, for the Y'X shear mode for rotated Y-cuts, and with diameter-thickness ratio for AT-cuts is discussed. Other factors such as mounting loss and loss caused by crystal inhomogeneities (dislocations, defect positions in the resonator, and impurity migration under vibrational stress) are briefly considered with quartz devices as the model. Some new piezoelectric materials/material constants/devices are reviewed and their motional time constants are compared. A physical parameter, composed of acoustic velocity, piezoelectric coupling, and tau(1) is identified which aids in understanding the maximum frequency limitations of plate resonators.
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Affiliation(s)
- A Ballato
- US Army Res. Lab. Electron. and Power Sources Directorate, Fort Monmouth, NJ
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van Enckevort WJP, Bennema P, van der Linden WH. On the Observation of Growth Spirals with very Low Step Heights on Potash Alum Single Crystals. ACTA ACUST UNITED AC 1981. [DOI: 10.1524/zpch.1981.124.2.171] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Enhanced Reactivity at Dislocations in Solids. ADVANCES IN CATALYSIS 1969. [DOI: 10.1016/s0360-0564(08)60032-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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