Oriented Nucleation of Diopside Crystals in Glass - Crystal Growth

Article pubs.acs.org/crystal

Oriented Nucleation of Diopside Crystals in Glass Wolfgang Wisniewski,* Katrin Otto, and Christian Rüssel Otto-Schott-Institut, Jena University, Fraunhoferstrasse 6, 07743 Jena, Germany ABSTRACT: Ceramic or glass-ceramic materials containing diopside attract a great deal of interest due to their potential use as bioactive materials. In this paper, the growth of diopside from the surface of a glass with the weight percent composition 54.96SiO2·18.4MgO·25.64CaO·1Al2O3 is described. EBSD-patterns were recorded from the surface and indexed as diopside. It was observed that the crystals were oriented with respect to the surface of the glass. The crystals grew in the form of asymmetrical pyramids which protrude from the surface by up to 0.3 μm. These pyramids contain at least four different orientations which share a common (100)-plane, indicating mechanical twinning. The crystal orientation of each twin changes during growth along the surface. Kinetic selection was observed during crystal growth into the bulk which does not occur in the form of solid crystal bodies. A glass skin covering the crystals was not detected.

■

piezoelectricity of fresnoite,23−25 without producing single crystals. The recent application of electron backscatter diffraction (EBSD) to the surface crystallization of glass26−31 provided a more detailed view of occurring crystal orientations and revised a number of conclusions drawn in the literature. The existence of a thin layer of glass covering crystals after surface crystallization was confirmed in some cases28−31 using the method of EBSD-pattern degradation.32 This thin layer had first been described in the cordierite system,33 which is the main model system for surface crystallization of glass.20−22,33 It led to a theory describing nucleation to occur some nanometers beneath the surface instead of at the immediate interface.33 The aim of this article is to clarify the mechanism of surface crystallization in diopside glass and contribute to the fundamentals of surface crystallization in glasses. For this purpose, the crystal orientations in the glass featured in ref 18 are analyzed with respect to oriented nucleation, crystal interaction during growth into the bulk, and finally, the question if nucleation occurs at the immediate surface or a few nanometers below it.

INTRODUCTION

Diopside ceramics have generated high interest, mainly due to their potential application as a biomaterial. This application has been reviewed in 2008 by Liu et al.1 The ceramics were reported to be bioactive2−4 and a promising material for artificial bones and dental roots.4,5 Porous diopside was suggested for applications in bone tissue engineering6 and drug delivery. 7 Diopside is also of interest for the immobilization of toxic and nuclear waste8,9 and as sealants for solid oxide fuel cells.10 Diopside is a pyroxene of the composition CaMgSi2O6. Structural changes of the monoclinic crystals due to temperature and pressure variations have been described11−14 as well as some physical properties15 and the thermodynamics of melting and glass transitions.16 According to ICSD-file no. 30522, the unit cell is given by the axes a = 9.741 Å, b = 8.919 Å, and c = 5.257 Å with β = 105.97°. The crystal structure has been described in detail in ref 11. Surface crystallization of diopside has been reported in some glass compositions,5,10,17 including an almost stoichiometric glass.18 Here 1 wt % of Al2O3 was added to the melt to inhibit spontaneous crystallization during cooling of the melt.18 While the crystal growth kinetics in such melts has been determined,19 the surface crystallization of diopside has also served as one of the model systems in research focused on the fundamentals of nucleation and crystal growth in glasses.20−22 However, information on the crystal orientations of surface crystallized diopside could not be found by the authors. Oriented surface crystallization phenomena in glasses are of interest for gaining a fundamental understanding of the process itself as well as controlling crystal growth in order to obtain oriented crystalline layers. The latter enables exploitation of macroscopic properties of a desired phase, for example, the © 2012 American Chemical Society

■

EXPERIMENTAL SECTION

The raw materials SiO2 (Quarz), Mg5(CO3)4(OH)2(H2O)4, CaCO3, and Al(OH)3 were melted in a platinum crucible at 1450 °C for 5 h in order to produce a glass of the composition 54.96 SiO2·18.4MgO·25.64CaO·1Al2O3 (wt %) in analogy to ref 18. The melt was cast onto a brass block and transferred into a cooling furnace preheated to 740 °C which was subsequently switched off, allowing the glass to cool. Received: July 17, 2012 Revised: August 15, 2012 Published: August 20, 2012 5035

dx.doi.org/10.1021/cg3009909 | Cryst. Growth Des. 2012, 12, 5035−5041

Crystal Growth & Design

Article

Samples were cut from the glass block and polished with abrasive slurries down to diamond paste of 1 μm grain size in order to remove scratches from the surface which would function as heterogeneous nucleation sites during crystallization. The samples were subsequently heated to 820 and 870 °C using a rate of 10 K/min and held for up to 2 h in order to grow diopside crystals. Some crystallized samples were cut perpendicular to the surface, embedded in Araldite, and subsequently polished using decreasing grain sizes of diamond paste. A final finish of colloidal silica was applied in order to achieve a surface quality appropriate for the acquisition of EBSD-patterns. All samples were contacted with Agpaste and coated with a thin layer of carbon at about 10−3 Pa to avoid surface charging in the scanning electron microscope (SEM). The solid glass was analyzed by dilatometry (Netzsch Dil 402 PC) using a heating rate of 5 K/min and differential thermal analysis (Shimadzu DTA 50) using a heating rate of 10 K/min. X-ray diffraction (XRD) was performed using Cu Kα radiation in a SIEMENS D5000 diffractometer. The surface topography was analyzed using laser scanning microscopy (LSM Axio Imager Z1M with a LSM5-Pascal). EBSD has been applied in materials science for only about 20 years. The method is based on calculating crystal orientations from diffraction patterns acquired in an SEM34 and allows local orientation measurements down to the nanometer-scale. Orientations may be visualized using the inverse pole figure (IPF)-map to provide an overview or an orientation map, where specific orientations and tolerances may be defined. Both color maps may be combined with a grayscale image quality (IQ)-map to gain an impression of the pattern quality. The Euler angles (φ1; Φ; φ2) are one way to describe a crystal orientation in space.34 In the case of the diopside crystals featured here, Φ describes the tilt of the c-axes from the surface normal; that is, for Φ = 0° and 180°, the c-axes are perpendicular to the surface while Φ = 90° indicates that the c-axes are oriented parallel to the surface. φ2 describes the rotation around the c-axis, while φ1 describes the rotation of the c-axes. The samples were analyzed using a Jeol JSM-7001F equipped with an EDAX Trident analyzing system containing a TSL Digiview 1913 EBSD-camera. EBSD-scans were captured and evaluated using the programs TSL OIM Data Collection 5.31 and TSL OIM Analysis 5. The scans were performed using a current of about 2.40 nA (measured with a Faraday cup) and a voltage of 20 kV. Only points with a minimum confidence index (CI)34 of 0.1 were considered in EBSDmaps, indicating the attributed orientation solutions are correct with a probability of at least 96%.35 The method of EBSD-pattern degradation was applied to the material using the same experimental conditions stated in ref 32 to ensure comparability: 20 kV; 4.55 nA; binning: 2 × 2; gain: 0; exposure: 0.45; 50 steps per row. As in all recent experiments on this topic, a digital filter composed of (1) background subtraction (avg 10), (2) a mean smoothing filter, (3) dynamic background subtraction (passes: 20; balance: 100), and (4) a normalized intensity histogram was applied during EBSD-pattern acquisition.

Figure 1. Optical micrograph of the crystallized surface after annealing for 1 h at 870 °C.

Figure 2. XRD-pattern obtained from the surface of a solid sample and the theoretical pattern of diopside for comparison.

1092). While all the peaks observed in the collected pattern may be attributed to diopside, the 020-, 002-, and 600-peaks are of significantly enhanced intensity, indicating a nonrandom orientation distribution of the crystals. The EBSD-patterns presented in Figure 3 were obtained from the surface featured in Figure 1 and indexed using a

■

Figure 3. EBSD-patterns obtained from the unpolished surface. The stated parameters indicate a reliable indexing procedure.

RESULTS AND DISCUSSION Solid Surface. The produced glass was transparent and colorless. The glass transition temperature Tg was determined to be 731 °C by DTA and 729 °C by dilatometry, which is in agreement with previous reports from the same glass composition.15 Annealing the transparent glass for 1 h at 820 °C in analogy to ref 18 did not result in any detectable crystals. After increasing the temperature to 870 °C and again annealing for 1 h, about 50% of the surface was covered with crystals of about 15 μm in diameter, as shown in Figure 1. Bulk nucleation was not observed in any performed experiment. The XRD-pattern recorded directly from the surface of a solid sample annealed for 1 h is presented in Figure 2 along with a theoretical pattern of diopside (JCPDS-file no. 01-075-

material file based on the data of ICSD-file no. 30522. The indexing parameters in Figure 3 indicate that the material file allows reliable pattern analysis, which was confirmed by its successful application in EBSD-scans containing crystals of various orientations. The IPF+IQ-map of such a scan is presented in Figure 4 next to the SEM-micrograph of the scanned area. While the IPFmap provides an overview of the orientations occurring in the scan (each orientation is attributed to a color), many crystals are colored turquoise, indicating a preferred [010]-orientation in the corresponding IPF-legend. This matches the XRD-results 5036



Article

pattern formation, e.g. through shadowing effects, the sides of the pyramid in Figure 5 rise from the glass with an angle of only about 3°, making it unlikely that the drastic difference of EBSDpattern quality indicated by the IPF+IQ-map in Figure 4 is caused by topography. The diopside pyramid in Figure 6a was analyzed in detail toward this problem of EBSD-pattern acquisition and indexing. The individual patterns obtained from the respective locations of the crystal show that indeed only two sides of the pyramid provide acceptable EBSD-patterns, meaning indexing is not the main problem in these regions. Additionally, each of these two sides is divided into two regions which provide individual EBSD-patterns, indicating the pyramid is possibly composed of at least eight different areas of crystal orientation, of which only four may be analyzed via EBSD. The respective wire frames of unit cells visualizing the orientations indicated by the respective patterns are also presented in Figure 6a. Lowering the voltage during EBSD-analysis in an attempt to improve the spacial resolution did not enable pattern acquisition from the top and bottom sides of the pyramid. No EBSD-patterns could be obtained at all below 10 kV. The crystal was scanned and then rescanned after rotating it by 90° in order to analyze the effect of surface topography. The respective IPF+IQ-maps are presented in Figure 6b and clearly show that the topography does not significantly influence the pattern quality, as the same sides of the pyramid provide indexable EBSD-patterns in both scans. An orientation+IQmap of the first scan is presented in Figure 6c in order to illustrate the four different crystal orientations measured in this crystal. It also shows that these orientations change for up to 11° during growth, beginning from the center, which is assumed to be the locus of nucleation. The 100-, 010-, and 001poles of the four orientations are also presented in Figure 6c. The colors correspond to the color code of the orientation+IQmap. The 100-pole figure (PF) shows that the a-axes of all four areas are parallel to the surface. Correspondingly, the b-axes are perpendicular to the surface: two pointing up and two pointing down (circles). As the 100-poles are all in the same area of the PF, the four regions basically share a common (100)-plane, which points toward twinning as the corresponding 001-poles are spread out. Diagonally opposite areas of the crystal also show poles in the respectively opposite quadrant of the PF. The mechanical twinning of diopside on the (100)- and (001)-planes has already been described in the literature.36,37 It was shown that pressure led to the formation of twin lamellae, glide bands with unit dislocations, and other lamellar features.36 As easier stress relaxation near the surface is seen as a reason for preferred surface nucleation38,39 in glasses; mechanical stresses during the surface crystallization of diopside would not be a surprise. Stresses during the crystallization of glasses have recently been proven40 and theoretically discussed,41−44 and they may even lead to the formation of high pressure phases.45 At this point it is noteworthy that the density increases from 2.8 g/cm3 to 3.2 g/cm3 during crystallization in this system.46−49 Hence, tensile stresses would occur at the surface of these samples instead of compressive stresses. Dislocations and twins would hence be introduced to stretch the crystal lattice in order to avoid fractures of the surface. A densification at the surface may also lead to the elevated pyramids if the crystal regions contract toward the locus of nucleation to relax tensile stresses. They may also explain why two quarters of the crystal do not provide EBSD-patterns: a high density of crystal defects such as

Figure 4. SEM-micrograph and IPF+IQ-map of an EBSD-scan performed on the surface. The white arrows highlight crystals of various orientations while the red arrows point toward [010]-oriented crystals which only provide EBSD-patterns from two opposite sides of the respective diopside pyramid.

presented in Figure 2. While most crystal bodies show only one color, the crystals marked by white arrows in Figure 4 clearly show a number of colors in the corresponding IPF+IQ-map. Another interesting feature is that only two opposite quarters of many crystals appear in the IPF+IQ-map (red arrows). The quarters themselves are often separated by a dark line, which may indicate a grain boundary, i.e. a region of reduced EBSDpattern quality. In order to ratify the impression of surface topography gained from the SEM-micrograph of Figure 4, the latter was measured using LSM and is presented in Figure 5. The crystals tend to form four-sided pyramids that rise from the surrounding glass matrix for about 0.3 μm, as indicated by profiles 1 and 2. While a local topography may inhibit EBSD-

Figure 5. LSM-micrograph and surface profiles of a surface crystallized diopside crystal. 5037



Article

Figure 6. Single diopside crystal analyzed in detail: (a) Crystal and individual EBSD-patterns obtained from the indicated locations. The wire frames illustrate the orientations calculated from the respective patterns. (b) IPF+IQ-maps of EBSD-scans performed on the crystal shown in part a and after a rotation of 90°. (c) Orientation+IQ-map of the first EBSD-scan illustrating four different orientations and how they change during crystal growth along the surface. The 100-, 010-, and 001-poles of the individual orientations are also presented. Circles indicate poles in the negative hemisphere.

dislocations, lattice distortions, or nanoscale twins inhibit the formation of EBSD-patterns as the diffraction condition cannot be fulfilled. The diopside pyramids in Figures 4 and 6 generally produce EBSD-patterns on their long sides but not on their short sides. As mechanical twinning is a mechanism leading to stress relaxation, high frequency twinning on the nanometerscale may explain the formation of the asymmetric pyramids as well as the prevention of EBSD-patterns if twins are introduced to the lattice instead of dislocations. The long sides of the pyramids clearly contain a continuous accumulation of dislocations which lead to the orientation changes outlined in Figure 6c. These dislocations would lead to a lower density of lattice planes, i.e. more space and a lower defect density, allowing the formation of EBSD-patterns. Further insight into these mechanisms may be gained by TEM-analysis but is beyond the scope of this article. As the EBSD-scan featured in Figure 4 does not cover enough crystals to be representative for the surface, a number of larger scans were performed for texture analysis. The 010-PF of a texture calculated from a scan covering an area of 230 μm × 390 μm is presented in Figure 7a. However, there are a number of thinkable orientation combinations which would lead to this pole figure. Evaluating the individual Euler angle histograms presented in Figure 7b provides clarification: the values of φ1 show a relatively homogeneous distribution in the entire 360° range. Φ was convoluted into a 90° range to simplify analysis and shows a pronounced maximum at 82 ± 8°. The histogram of Euler angle φ2 shows discrete peaks at 0, 90, 180, 270, and 360°. While φ2 = 90 and 270° point toward the a-axes oriented perpendicular to the surface, φ2 = 0, 180, and 360° indicate that the b-axes are oriented perpendicular to the surface. The peaks related to the latter are more intense. Convoluting the 360° range into a 90° range by first mirroring the values at 180° and then again at 90° confirms this impression and shows that the orientations with the b-axes perpendicular to the surface systematically occur more often than orientations with the a-axes perpendicular to the surface.

Figure 7. (a) 010-pole figure of a texture calculated from an EBSDscan of the surface. (b) Histograms illustrating the occurrence of the individual Euler angles (φ1; Φ; φ2). (c) Generally preferred orientations observed at the surface.

As the value of Φ is fixed, the central probability peak in the 010-PF is attributed to φ2 = 0, 180, and 360° with φ1 = statistical while the outer ring is attributed to φ2 = 90 and 270° with φ1 = statistical. The exaggerated XRD-peaks in Figure 2 and the predominant colors in the IPF+IQ-map of Figure 4 also match this description: the exaggerated 020-peak and the turquoise color, which stands for an oriented (010)-plane, indicate the b-axes perpendicular to the surface. The exaggerated 600-peak and the blue/green colors indicate oriented (100)-planes, i.e. the a-axes perpendicular to the surface. The preferred orientations are summarized in Figure 7c: (i) the a- or b-axes are oriented perpendicular to the surface (b is preferred against a); (ii) the c-axes are tilted by 8 ± 8° from being parallel to the surface; and (iii) the rotation around whichever crystallographic axis happens to be perpendicular to the surface is statistical. 5038



Article

If a hierarchy in orientation preferences is assumed, the (a,b)-orientation would dominate because an orientation of the (a,b)-axes in the described manner automatically causes the caxes to be oriented. The reverse argument cannot be made as orientations with the c-axis aligned but the (a,b)-axes random are quite possible but rarely occur in the presented data. The question if the c-axes orientation is just a result of the (a,b)-axes orientation or a necessary condition for the oriented nucleation observed in these samples cannot be answered at this point. Polished Cross Sections. After crystallizing for 2 h at 870 °C, the crystals grew about 20 μm into the bulk, as indicated by the SEM-micrograph in Figure 8. The IPF+IQ-

The claim of oriented nucleation in these systems is based on the very limited information volume of EBSD and the fact that none of the surface orientations described so far in the literature26−28 prevail during crystal growth into the bulk; that is, the orientation at the immediate surface is not kinetically preferred during crystal growth. The information depth of EBSD using an acceleration voltage of 20 kV has been reported to be in the range from 10 to 50 nm and has been discussed in greater detail in ref 32. If the nuclei were statistically oriented, they would have to form at a significant distance from the surface in order to achieve the detected degree of orientation during growth toward the surface. EBSD data shows that the crystal lattices are periodical enough in the topmost 10−50 nm or more of the sample to produce EBSD-patterns and that the detected orientations lead to clear textures in the EBSD-scans. If the orientation would change significantly within the topmost few nanometers at the surface, clear EBSD patterns would not be obtained. However, assuming the location of nucleation to be far enough from the surface to allow an orientation selection during growth toward the surface eliminates any cause for localized surface crystallization and contradicts all surface nucleation theories, whether they describe nucleation to occur at the immediate surface or a few nanometers beneath it. As the scan in Figure 8 only features a few crystals, an alternative approach was chosen to validate the orientational changes during crystal growth into the bulk. Figure 9 focuses on

Figure 8. SEM-micrograph of the cross section of a sample annealed at 870 °C for 2 h. The micrograph is superimposed by the IPF+IQ-map of an EBSD-scan. The orientation map quantifies the degree of orientation change while the wire frames 1−4 visualize crystal orientations at the locations 1−4. Differences in chemical compositions are illustrated by the results of an EDX-map performed on the area scanned by EBSD.

map of an EBSD-scan superimposed on the SEM-micrograph shows that the crystals are not solid but split into separate arms which change their orientation during growth, indicated by the continuous color gradients. The orientation map of the leftmost crystals shows that the change of the defined orientations reaches up to 35° within these first 20 μm of crystal growth. The wire frames 1−4 visualize the orientations at the locations 1−4; they show that the c-axes become increasingly perpendicular to the surface during growth. Additionally, Figure 8 presents the results of an EDX-mapping performed with 15 kV on the area scanned by EBSD: the crystallization front and grain boundaries show an enrichment of calcium while magnesium and oxygen are depleted. Silicon is apparently distributed homogeneously. These results indicate that crystal growth is hindered by an accumulation of calcium and a lack of magnesium and oxygen at the crystallization front. Hence, the crystals split into separated arms in order to surround residual glass which cannot crystallize. Also, the mechanism of kinetic selection is not via preferably oriented crystals outgrowing and blocking the rest, as, for example, observed during the surface crystallization of Ba-fresnoite,26 but rather fits the model of continuous orientation change also observed during the surface crystallization of Sr-fresnoite.27 Obviously, the crystal orientation preferred during nucleation is not preferred during growth into the bulk. Similar behavior was also observed in other surface crystallizing systems that show oriented nucleation.26−29

Figure 9. Surface crystallized sample polished under an angle of about 4° so as to expose diopside crystals at increasingly deeper cut planes below the surface. The pole figures from the respective areas of the EBSD-scan illustrate the preferred crystal axes orientations and how they change during growth. 5039



Article

to (a) total pattern degradation, (b) acceptable pattern degradation, and (c) no pattern degradation during comparable EBSD-scans of the surface. As the step sizes are comparable between the unpolished and polished surfaces, a glass skin covering the crystals was not detected. It must be noted that this does not prove that it is not there.

a SEM-micrograph of a surface crystallized sample polished under an angle of about 4° in order to expose the diopside crystals at increasingly deeper cut planes below the surface as illustrated in Figure 9a. The SEM-micrograph in Figure 9b hence shows, from left to right, polymer (black), then exposed but unpolished crystals, followed by polished crystals with their cut plane increasingly below the surface, and finally residual glass. The IPF+IQ-map of an EBSD-scan superimposed on the SEM-micrograph shows turquoise colors at the left but increasingly green colors as the cut plane shifts beneath the surface. The corresponding PFs from areas 1−3 of the EBSD-scan in Figure 9b are shown in Figure 9c and illustrate a clear change in the preferred crystal orientations. The first 100-PF shows a weak central peak (a-axis perpendicular to the surface) and a relatively strong outer ring (a-axis parallel to the surface). This outer ring is weaker in the 100-PF of area 2 while the central peak becomes stronger and broader. The 100-PF of sector 3 shows no outer ring, but a broad central pole; that is, the a-axes are now predominantly perpendicular to the surface but deviate more from the surface normal. As the a- and b-axes enclose an angle of 90°, it is no surprise that the opposite is observed in the 010-PF: the strong central peak and weak outer ring change to a strong outer ring and a weak central peak. However, comparing the central peak of the first 010-PF with the central peak of the third 100-PF clearly shows that the oriented axes deviate more from the surface normal beneath the surface than at the surface. This is also indicated by the 001-PFs, where an outer ring changes toward a central circle; that is, the preferred c-axes orientation changes from parallel to the surface towards perpendicular to the surface. This is in agreement with the orientation changes described in Figure 8. Hence, it may be concluded that crystals with the a-axis perpendicular to the surface outgrow those with their b-axes perpendicular to the surface while both orientations are subject to a kinetic selection which shifts the c-axes from being parallel to the surface to being perpendicular to the surface. This may be explained by the angle β = 105.97° between the a- and the caxes: if the a-axis is perpendicular to the surface, the c-axis is already tilted by 15.97° from the surface. If, however, the b-axis is perpendicular to the surface, the c-axis is parallel to the surface. Hence, a-axis oriented crystals are already about 16° closer to the kinetically preferred orientation and outgrow the b-oriented crystals. EBSD Pattern Degradation. In order to analyze if the surface crystals are covered by a thin layer of glass,33 the method of EBSD-pattern degradation32 was applied to this material. Figure 10 presents the different step sizes which lead

■

CONCLUSION Under the supplied conditions, surface crystallization of diopside was achieved while bulk nucleation did not occur. The oriented nucleation of diopside was described and a glass skin covering the crystals was not detected, meaning nucleation beneath the surface is not indicated. Diopside preferably nucleates with the a- or b-axes perpendicular to the surface; orientations with the b-axes perpendicular to the surface occur more often. The density increase during crystallization causes tensile stresses which are compensated by twinning, orientation changes, and probably topographical effects as the crystals form asymmetric pyramids that rise about 0.3 μm from the surface. During growth into the bulk, a diffusion barrier formed by excess calcium and a deficiency of magnesium is formed. The crystal orientations change so that the c-axes of the crystals become increasingly perpendicular to the surface while they were initially oriented parallel to the surface, i.e. the orientations of preferred nucleation and those preferred during crystal growth are different.

■

AUTHOR INFORMATION

Corresponding Author

*Tel: (0049) 03641 948515. Fax: (0049) 03641 948502. Email: [email protected]. Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS This work was supported by Deutsche Forschungsgemeinschaft (DFG) in Bonn Bad Godesberg (Germany) via project nr. RU 417/14-1.

■

REFERENCES

(1) Liu, X.; Morra, M.; Carpi, A.; Li, B. Biomed. Pharmacother. 2008, 62, 526−529. (2) Kobayashi, T.; Okada, K.; Kuroda, T.; Sato, K. J. Biomed. Mater. Res. 1997, 37, 100−107. (3) Salama, S. N.; Darwish, H.; Abo-Mosallam, H. A. Ceram. Interfaces 2006, 32, 357−364. (4) Nonami, T.; Tsutsumi, S. J. Mater. Sci. 1999, 10, 475−479. (5) Kansal, I.; Goel, A.; Tulyaganov, D. U.; Pascual, M. J.; Lee, H.-Y.; Kim, H.-W.; Ferreira, J. M. F. J. Mater. Chem. 2011, 21, 16247−16256. (6) Wu, C.; Ramaswamy, Y.; Zreiqat, H. Acta Biomater. 2010, 6, 2237−2245. (7) Wu, C.; Zreiqat, H. Acta Biomater. 2010, 6, 820−829. (8) Karnis, A.; Gautron, L. World Acad. Sci., Eng. Technol. 2009, 52, 44−47. (9) Donald, I. W.; Metcalfe, B. L.; Taylor, R. N. J. J. Mater. Sci. 1997, 32, 5851−5887. (10) Goel, A.; Tulyaganov, D. U.; Pascual, M. J.; Shaaban, E. R.; Muñoz, F.; Lü, Z.; Ferreira, J. M. F. J. Non-Cryst. Solids 2010, 356, 1070−1080. (11) Cameron, M.; Papike, J. J. Am. Mineral. 1981, 66, 1−50. (12) Levien, L.; Prewitt, C. T. Am. Mineral. 1981, 66, 315−323. (13) Thompson, R. M.; Downs, R. T. Am. Mineral. 2008, 93, 177− 186.

Figure 10. IQ- and IPF-maps of comparable EBSD-scans performed on unpolished and polished crystals leading to (a) total, (b) acceptable, and (c) no EBSD-pattern degradation. 5040



Article

(14) Oguri, K.; Funamori, N.; Sakai, F.; Kondo, T.; Uchida, T.; Yagi, T. Phys. Earth Planet. Inter. 1997, 104, 363−370. (15) Taniguchi, H.; Murase, T. J. Volcanol. Geotherm. Res. 1987, 34, 51−64. (16) Richet, P.; Bottinga, Y. Earth Planet. Sci. Lett. 1984, 67, 415− 432. (17) Goel, A.; Tulyaganov, D. U.; Goel, I. K.; Shaaban, E. R.; Ferreira, J. M. F. J. Non-Cryst. Solids 2009, 355, 193−202. (18) Zanotto, E. D. J. Non-Cryst. Solids 1991, 130, 217−219. (19) Reinsch, S.; Nascimento, M. L. F.; Müller, R.; Zanotto, E. D. J. Non-Cryst. Solids 2008, 354, 5386−5394. (20) Müller, R.; Zanotto, E. D.; Fokin, V. M. J. Non-Cryst. Solids 2000, 274, 208−231. (21) Zanotto, E. D.; Vokin, V. M. Philos. Trans. R. Soc. London A 2003, 361, 591−613. (22) Pannhorst, W., Ed. Surface Nucleation; International Commission on Glass: Charleroi, Belgium, 2000. (23) Halliyal, A.; Bhalla, A. S.; Newnham, R. E.; Cross, L. E. J. Mater. Sci. 1981, 16, 1023−1028. (24) Halliyal, A.; Safari, A.; Bhalla, A. S.; Newnham, R. E.; Cross, L. E. J. Am. Ceram. Soc. 1984, 67, 331−335. (25) Patschger, M.; Wisniewski, W.; Rüssel, C. CrystEngComm 2012, DOI: 10.1039/C2CE25933H. (26) Wisniewski, W.; Nagel, M.; Völksch, G.; Rüssel, C. Cryst. Growth Des. 2010, 10, 1414−1418. (27) Wisniewski, W.; Patschger, M.; Rüssel, C. CrystEngComm 2012, 14, 5425−5433. (28) Wisniewski, W.; Zscheckel, T.; Vö lksch, G.; Rüssel, C. CrystEngComm 2010, 12, 3105−3111. (29) Wisniewski, W.; Schröter, B.; Zscheckel, T.; Rüssel, C. Cryst. Growth Des. 2012, 12, 1586−1592. (30) Wisniewski, W.; Baptista, C. A.; Völksch, G.; Rüssel, C. Cryst. Growth Des. 2011, 11, 4660−4666. (31) Wisniewski, W.; Baptista, C. A.; Rüssel, C. CrystEngComm 2012, DOI: 10.1039/C2CE25293G. (32) Wisniewski, W.; Völksch, G.; Rüssel, C. Ultramicroscopy 2011, 111, 1712−1719. (33) Avramov, I.; Völksch, G. J. Non-Cryst. Solids 2002, 304, 25−30. (34) Schwartz, A. J.; Kumar, M.; Adams, B. L. Electron Backscatter Diffraction in Materials Science 2; Springer: New York, 2009. (35) Field, D. P. Ultramicroscopy 1997, 67, 1−9. (36) Kirby, S. H.; Christie, J. M. Phys. Chem. Miner. 1977, 1, 137− 163. (37) Avé Lallemant, H. G. Tectonophysics 1978, 48, 1−27. (38) Schmelzer, J.; Pascova, R.; Möller, J.; Gutzow, I. J. Non-Cryst. Solids 1993, 162, 26−39. (39) Schmelzer, J.; Möller, J.; Gutzow, I.; Pascova, R.; Müller, R.; Pannhorst, W. J. Non-Cryst. Solids 1995, 183, 215−233. (40) Tsakiris, N.; Argyrakis, P.; Avramov, I.; Bocker, C.; Rüssel, C. epl 2010, 89, 18004. (41) Möller, J.; Schmelzer, J.; Gutzow, I.; Pascova, R. Phys. Status Solidi B 1993, 180, 315−330. (42) Karamanov, A.; Georgieva, I.; Pascova, R.; Avramov, I. J. NonCryst. Solids 2010, 356, 117−119. (43) Avramov, I. J. Non-Cryst. Solids 2008, 354, 4959−4961. (44) Schmelzer, J. W. P.; Zanotto, E. D.; Avramov, I.; Fokin, V. M. J. Non-Cryst. Solids 2006, 352, 434−443. (45) Bocker, C.; Avramov, I.; Rüssel, C. Scr. Mater. 2010, 62, 814− 817. (46) Binsted, N.; Greaves, G. N.; Henderson, C. M. B. Contrib. Mineral. Petr. 1985, 89, 103−109. (47) Zanotto, E. D.; Müller, E. J. Non-Cryst. Solids 1991, 130, 220− 221. (48) Taniguchi, T.; Okuno, M.; Matsumoto, T. Mineral. J. 1995, 17, 231−244. (49) Karamanov, A.; Pelino, M. J. Eur. Ceram. Soc. 1999, 19, 649− 654.

5041


Oriented Nucleation of Diopside Crystals in Glass - Crystal Growth

Recommend Documents