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ScienceDirect - Acta Materialia : On the effect of environment on spontaneous growth of lead whiskers from commercial brasses at room temperature .nojs { display: none; } 350? '350px':'auto'); max-height:60; height:expression(this.scrollHeight > 60? '60px':'auto');overflow:hidden;"> Athens/Institution Login Not Registered? User Name: Password: Remember me on this computer Forgotten password? Home Browse My Settings Alerts Help Quick Search Title, abstract, keywords Author Journal/book title Volume Issue Page Acta Materialia Volume 55, Issue 10, June 2007, Pages 3387-3396 Font Size: Abstract Abstract - selected Article Figures/Tables Figures/Tables - selected References References - selected Purchase PDF (1118 K) E-mail Article Add to my Quick Links Cited By in Scopus (0) Related Articles in ScienceDirectSpontaneous growth of whiskers from electrodeposited co...Journal of Crystal Growth Spontaneous growth of whiskers from electrodeposited coatingsJournal of Crystal Growth, Volume 10, Issue 1, June 1971, Pages 85-90V. K. Glazunova, K. M. GorbunovaAbstractThe whisker growth from electrodeposited tin was investigated. The inclusion of foreign metal atoms and the existence of internal stresses in the coating were shown to be the factors which lead to the growth of whiskers. The thermal treatment of the deposits and the action of ultrasonic waves prevent whisker growth. The mechanism of internal stress relaxation in connection with growth is discussed. Purchase PDF (745 K) The growth of whiskers in gold films due to high curren...Journal of Crystal Growth The growth of whiskers in gold films due to high current densitiesJournal of Crystal Growth, Volume 38, Issue 2, May 1977, Pages 149-154Y. Smooha, Y. KomemAbstractWhiskers and hillock growth as well as void formation were initiated in gold conductor films that were subjected to high current densities (0.8–1.15) × 106 A/cm2. The whisker distribution along the films that failed is dependent both on the negative temperature gradient and the structurdal inhomogeneities that exist in the film. The rate of whisker growth was measured by means of in situ scanning electron microscopy. The whisker growth rate was found to be about 3 microm/h at a current density of 1.05 × 106 A/cm2 and specimen temperature of 420°C. Purchase PDF (804 K) Growth of whiskers in the solid phaseActa Metallurgica Growth of whiskers in the solid phaseActa Metallurgica, Volume 6, Issue 2, February 1958, Pages 103-109J. FranksAbstractThe growth of whiskers from clamped tin plate has been studied. It has been shown that general extrusion must be inhibited for whisker growth to occur. If whiskers are removed after they have reached their terminal length, whiskers may grow subsequently on the same sites. Whiskers grown at temperatures up to 190°C in vacuum are similar to those grown at room temperature. Near this temperature existing whiskers collapse on to the surface from which they grew and further growth does not occur. In the presence of oxygen, whiskers grow thicker and longer at 215°C than at room temperature.A dislocation model has been developed which explains the known features of whisker growth. Its chief features are that the whisker generating dislocations move by glide, while the material of the whisker is supplied by diffusion. Dislocations may be produced in the whisker by the mechanism but they are not an essential part of it.RésuméL'auteur étudie la croissance des barbes sur des feuilles d'étain comprimées. On a montré précédemment que l'enlèvement généralisé des barbes doit être évité pour permettre le phénomène de croissance. Si les barbes sont détachées dès qu'elles ont atteint leur longueur finale, la croissance peut reprendre aux mêmes endroits. Les barbes obtenues jusqu'à des températures de 190°C sous vide sont identiques à celles préparées à la température ambiante. Au voisinage de cette température, les barbes existantes s'affaissent sur la surface d'où elles émergeaient et une croissance ultérieure ne se produit plus. En présence d'oxygène, les barbes sont plus grosses et plus longues à 215°C qu'à la température ambiante. L'auteur développe un modèle de dislocations expliquant les connaissances acquises dans la croissance des barbes. Les principales d'entre elles sont d'ailleurs que les dislocations initiant les barbes se déplacent par glissement tandis que la matière des barbes s'assemble par diffusion. Des dislocations peuvent apparaître dans la barbe au cours de ce mécanisme mais elles n'en constituent pas une part essentielle.ZusammenfassungDas Herauswachsen von Fadenkristallen (whiskers) aus eingespannten Zinnschichten wurde untersucht. Dabei ergab sich, dass Fadenkristalle nur entstehen, wenn verhindert wird, dass das Zinn einfach herausgequetscht wird. Werden Fadenkristalle nach Erreichen ihrer Endlänge beseitigt, so wachsen an dergleichen Stelle neue nach. Bei Temperaturen bis zu 190° im Vakuum gewachsene Kristalle sind ähnlich wie die bei Raumtemperatur entstandenen. In der Nähe von 190° stürzen schon vorhandene Fadenkristalle auf die Oberfläche, von der aus sie gewachsen sind, und ein weiteres Wachstum unterbleibt. In Anwesenheit von Sauerstoff wachsen bei 215° dickere und längere Fadenkristalle als bei Raumtemperatur.Es wurde ein Versetzungsmodell entwickelt, das die bekannten Erscheinungen des Fadenkristall-Wachstums zu erklären vermag. Die charakteristischen Züge des Modells sind, dass sich die die Fadenkristalle erzeugenden Versetzungen durch Gleiten bewegen, während die Materialanlieferung durch Diffusion erfolgt. Versetzungen in den Fadenkristallen können zwar durch den vorgeschlagenen Mechanismus erzeugt werden, doch stellt dies nicht einen wesentlichen Bestandteil des Mechanismus dar. Purchase PDF (1106 K) View More Related Articles View Record in Scopus doi:10.1016/j.actamat.2007.01.035 Copyright © 2007 Acta Materialia Inc. Published by Elsevier Ltd. On the effect of environment on spontaneous growth of lead whiskers from commercial brasses at room temperature ZhengMing Suna, , , Hitoshi Hashimotoa and Michel W. Barsoumb aMaterials Research Institute for Sustainable Development, National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560, JapanbDepartment of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, USA Received 7 November 2006; revised 22 January 2007; accepted 24 January 2007. Available online 12 March 2007. References and further reading may be available for this article. To view references and further reading you must purchase this article. AbstractIn this paper we report on a detailed statistics-based study of the effect of various environments – air, argon, vacuum, oil and water – on the room temperature spontaneous nucleation and growth of lead whiskers from hacksaw-cut surfaces of three leaded commercial brasses. The samples were initially held in the various environments for 166 h, before being stored in ambient air for a total of 1126 h. The environment was found to have a strong effect. The highest whisker density, 30,000 cm−2, was observed for the sample initially kept under a mechanical (1 Pa) vacuum; the lowest, 3000 cm−2, was observed for the sample initially immersed in water; the densities of the others were in between. The samples held in water only grew whiskers when removed from the water. Once exposed to air, a few whiskers grew at an average rate that, at 0.9 nm s−1, was the highest measured. When the samples were exposed to air, after the initial storage in the different environments, both nucleation and growth of the whiskers were accelerated, before ultimately ceasing to grow roughly 400 h after creating the surfaces from which the whiskers grew. These results are consistent with a scenario in which oxygen and/or moisture diffusion down the Pb/brass interfaces results in a volume expansion that provides the driving force for whisker growth. The results also indicate that the oxygen levels needed for whisker growth can be as low as a few parts per million. Keywords: Brass; Lead; Whisker; Spontaneous growth; Environment Article Outline1. Introduction2. Experimental3. Results3.1. Pb whiskers growing on three commercial brasses3.2. Whisker characteristics3.3. Effect of the environment on the statistics of Pb whiskers3.4. Growth rates3.5. Residual stress effect4. Discussion5. ConclusionsReferences Fig. 1. Backscattered SEM micrograph of a C3604 surface showing the distribution of Pb (bright areas) in the microstructure. View Within ArticleFig. 2. (a) Schematic illustration showing the statistical study of Pb whiskers on the surface of C3604: observed at ×1000 with an SEM and moved one frame each step to cross the entire 10 mm diameter. (b) Typical SEM micrograph of a 125 × 93 μm2 area. The entire area observed was 93 × 10,000 μm2, which corresponds to 80 individual frames. View Within ArticleFig. 3. Pb nanowhiskers observed on the hacksaw-cut surfaces of the three leaded brasses and their growth. (a, b) Free cutting brass C3604; (c, d) wrought brass C3771; (e) wrought brass C3712. View Within ArticleFig. 4. Pb whiskers (indicated with arrows) observed on the hacksaw-cut surface of C3604 alloy, showing their population and distribution. View Within ArticleFig. 5. A 500 μm long whisker with a diameter of 150 nm, for an aspect ratio of 3000, sprouting from the hacksaw-cut surface of the C3604 alloy. Insets show a whisker that when transferred from the brass surface to a conductive carbon tape, broke into smaller pieces (lower left). The upper right inset shows EDS results indicating the presence of only Pb in the whiskers. View Within ArticleFig. 6. Whisker length distributions for samples G, V, A, O and W, after a cumulative exposure time of (a) 166 h and (b) 1126 h. Note that the samples were all stored in air after being stored for the initial 166 h in the different environments listed in Table 2. View Within ArticleFig. 7. Statistical data of the whiskers observed on a C3604 brass surface showing (a) the number density, (b) the linear density and (c) the average lengths for samples G, V, A, O and W, and their variation with exposure time. View Within ArticleFig. 8. Variation of growth and nucleation rates of the whiskers with exposure time or exposure time interval for samples G, V, A, O and W. (a) Average growth rates (average length increment per unit time), (b) total length extension rates (total length increment per unit time), (c) growth rates of the longest whiskers at each observation (length/time) and (d) nucleation rates (number density increment per unit time). View Within ArticleFig. 9. Backscattered SEM micrograph of C3604 alloy surface, polished and then indented with a Vickers microhardness indenter at a force of 500 N. The bright areas are Pb, mostly in the form of hillocks. The inset shows the morphology of a small hillock at higher magnification. View Within ArticleFig. 10. Surface morphology of sample W, after being kept in water for 166 h, showing hydrocerussite crystals. View Within Article Table 1. Designation and compositions (in wt.%) of the three commercial leaded brasses used in this study following Japanese Industrial Standard JIS-H3250:2000 View Within ArticleTable 2. Sample designation for environmental effect investigation (C3604) as well as the cumulative exposure time and storage conditions after cutting a Ar atmosphere: O2 < 3 ppm, dew point: <−60 °C (H2O < 10 ppm).View Within Article Acta Materialia Volume 55, Issue 10, June 2007, Pages 3387-3396 Home Browse My Settings Alerts Help About ScienceDirect | Contact Us | Terms & Conditions | Privacy Policy Copyright © 2008 Elsevier B.V. All rights reserved. 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