ISSN:0232-1300    

DOI:10.1002/crat.2170251223

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170251224

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170251225

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170251226

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170251227

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe growth of calcite crystals from an aqueous supersaturated solution of initial concentration 0.15 mol m−3containing 10 mol m−3of (NH4)2CO3has been studied at 298 K. The progress of growth has been followed through determining the composition of the solution by chemical analysis. The crystal growth is controlled by the surface reaction mechanism and satisfies a kinetic equation of the second order with the rate constant 3.7 × 10−6m4mol−1s−1that is independent on the surface area of the present solid. NH4+ions do not change the crystal growth mechanism but decrease the growth rate of calcit

ISSN:0232-1300    

DOI:10.1002/crat.2170251202

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170251203

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractGrowth and equilibrium forms of ammonium (A2/a) and potassium dichromate (P1) have been calculated by means of the Fourier transform method of crystal morphology. Twin laws of potassium dichromate and heteroepitaxial intergrowth of both substances can be explained by partitions of space. According to Shubnikov the (001) planes of potassium dichromate crystals grown in aqueous solutions are always smooth, the parallel opposite planes, however, roughened. Wagner observed that this effect only occurs at temperatures shortly above or below 25 °C. The present investigation has shown that roughening of (001) appears at 25 °C after addition of potassium chromate to the potassium dichromate solutions. This means that the one‐sided intergrowth can be explained by a stereospecific adsorption of polychromates. Solution additions like potassium permanganate and Chromotrope 2B generate roughenings on both {001} faces. X‐Ray diffraction investigations can be interpreted in such a way that the intergrown plates are mirror symmetric oriented to two planes being normal to thea‐ andb‐axes. This is in accordance with repeated formation of intergro

ISSN:0232-1300    

DOI:10.1002/crat.2170251204

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractGrowth of the habit of a single seed and the special growth of splicing “parallel” seeds were investigated and compared with. Chemical etching and X‐ray topography were used to characterize spliced KDP crystals. The kinetic data in different growth stages were measured. It is concluded that secondary capping is the most important stage in the splicing parallel‐seed growth, and that the subgrain boundaries emitted from the secondary cap are parallel to or overlap with the splicing boundary and stretch to the prismatic surface about 45° to thez‐axis, and that above the twin‐crystal regions with subgrain boundaries the real monocrystalline region appears. The growth kinetics of the subgrain boundary approximately corresponds to the growth mechanism of single‐spir

ISSN:0232-1300    

DOI:10.1002/crat.2170251205

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170251206

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY