Evidence for spiral growth on the pyramidal faces of KDP and ADP single crystals

Enckevort, W.J.P. van; Rosmalen, R. Janssen–van; Linden, W. H. van der

doi:10.1016/0022-0248(80)90124-4

Cited by 71 publications

(18 citation statements)

References 18 publications

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“…The latter will emerge at face intersections and will probably contribute to the growth of all adjacent faces. Consequently, one could anticipate that these could lead to the generation of spiral-growth features, centred both on the faces and at the face edges as have been observed by Van Enckevort et al (1980). In summary, we confirm that the growth of the prismatic growth sectors of ADP is most likely to occur by a spiral-growth mechanism.…”

Section: Discussionsupporting

confidence: 69%

“…In contrast, a number of publications speculate that screw dislocations play no part in the growth of the {101} faces and suggest alternative mechanisms (Torgesen & Jackson, 1965;Lutsau, Fishman & Res, 1970;Belouet & Stacy, 1978). The observation of spiral-growth patterns on these faces (Van Enckevort, Janssen van Rosmalen & Van der Linden, 1980), however, contradicts this speculation. This difference of opinion requires resolution.…”

Section: Introductionmentioning

confidence: 66%

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The growth and perfection of crystals of ammonium dihydrogen orthophosphate, NH4H2PO4. I. Dislocation characterization in self-nucleated crystals

Bhat¹,

Sherwood²

1983

J Appl Cryst

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A combined theoretical analysis and experimental study has been made of the nature of dislocations which propagate in the prismatic and pyramidal growth sectors of ammonium dihydrogen phosphate (ADP). In general the line energies of the dislocations formed in both the sectors are less than 45 eV nm-~. A few higher-energy dislocations (123 eV nm-1) were characterized in the prismatic sectors. The line directions of dislocations which are formed in the pyramidal sectors are such that they propagate towards the growth-sector boundaries and cross into the prismatic sectors. Alternatively, they follow the growth-sector boundaries and emerge at the intersection of adjacent faces. Few, if any, dislocations propagate within these sectors. Consequently, although dislocation-controlled mechanisms of growth may contribute to the growth of the { 101 } faces of ADP in the early stages of growth, other mechanisms will dominate at longer times. In contrast, the prismatic sectors are more imperfect, containing both screw and mixed dislocations. For these sectors spiral-growth mechanisms are more likely to dominate at all stages of growth.

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Section: Discussionsupporting

confidence: 69%

Section: Introductionmentioning

confidence: 66%

The growth and perfection of crystals of ammonium dihydrogen orthophosphate, NH4H2PO4. I. Dislocation characterization in self-nucleated crystals

Bhat¹,

Sherwood²

1983

J Appl Cryst

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“…The effect of growth modifiers on the shape is closely linked to the molecular arrangement in the crystal lattice. Often different crystal faces exhibit different charges hence impurities with positive or negative charges will adsorb preferentially on different faces of the crystal 16,24,27,[54][55][56][57][75][76][77][78] . In the case of the current work, divalent and trivalent metal ions preferably adsorb on the {100} face of KDP crystal, which leads to decreased growth rate of the corresponding characteristic length.…”

Section: Materials and Experimental Setupmentioning

confidence: 99%

“…Population balance modeling is widely used in order to describe the evolution of crystal properties such as size and shape distribution 43,44 . Multidimensional population balance models are suitable for investigation and simulation of crystal morphology when the shape of the particles is described by the sizes of the characteristic crystal faces 9,[45][46][47][48][49][50][51][52][53]78 .…”

Section: Introductionmentioning

confidence: 99%

Multi-Impurity Adsorption Model for Modeling Crystal Purity and Shape Evolution during Crystallization Processes in Impure Media

Borsos

Majumder

Nagy

2015

Crystal Growth & Design

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“…The crystal surface is on top of the KAP solution. This procedure with observed from beneath the growth cell through an n-hexane is needed to reduce surface artefacts due optical window (on which the crystal is fixed to a sudden increase in growth rate [24]. mechanically) and the crystal itself.…”

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confidence: 99%

Size distribution of embryos produced by crystal-rod contacts

Heijden

Elwenspoek

Eerden

1989

Journal of Crystal Growth

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We performed contact nucleation experiments on the (010) face of potassium hydrogen phthalate (KAP) crystals growing in a stagnant supersaturated aqueous solution and determined -after a given growth time t -(cx situ) the crystal size distribution (CSD) of the secondary nuclei (which at t = 0 are called "embryos") by using a scanning electron microscope (SEM). The origin of the secondary nuclei could clearly be revealed (damage to the crystal surface). The CSD can be fitted with a log-normal distribution which is typical for many powders obtained by grinding. Minimum size and mean size can be quantitatively understood by elementary fracture mechanics. I. Infroductionwhich describes how the number density n (i.e. the distribution of the total number of particles Knowledge of the crystal size distribution over the crystal size L) varies in time taking into (CSD) is of major importance in industrial crysaccount the interactions and process-controlling tallization in order to control the production of parameters mentioned above. To solve this innew crystals. In a CMSMPR crystallizer a number tegro-differential equation analytically, some apof interactions between crystals or crystal-crystalproximations have to be made. Firstly, one conlizer parts are active which, each in its own way, siders a clear liquid feed, i.e. the slurry which influences the CSD: secondary nucleation, attrienters the crystallizer contains no crystals. Section, breakage and agglomeration. Further, often ondly, the rate processes secondary nucleation, the smallest crystals (the fines) are removed from attrition, breakage, agglomeration, fines removal the crystallizer. In order to run a crystallizer at and product classification can be ignored if these high supersaturations and to produce large crystals processes can be suppressed or if they are operat high production rates, nuclei should be selecative at such a minor level, that the influence on tively removed from the process, so these excessive the CSD is negligible. Thirdly, one assumes that nuclei do not compete for supersaturation.all the crystals grow with the same rate G (this is Withdrawal of crystals in the larger size range is generally referred to as the LL law of McCabe). carried out to obtain a product classification. A And, finally, one assumes that the number density general population equation can be derived [1] does not change in time, so a steady state has been 0022-0248/89/$03.50

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Evidence for spiral growth on the pyramidal faces of KDP and ADP single crystals

Cited by 71 publications

References 18 publications

The growth and perfection of crystals of ammonium dihydrogen orthophosphate, NH4H2PO4. I. Dislocation characterization in self-nucleated crystals

The growth and perfection of crystals of ammonium dihydrogen orthophosphate, NH4H2PO4. I. Dislocation characterization in self-nucleated crystals

Multi-Impurity Adsorption Model for Modeling Crystal Purity and Shape Evolution during Crystallization Processes in Impure Media

Size distribution of embryos produced by crystal-rod contacts

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