Nucleation in the system calciumsulphatesubhydrates / water

半水硫酸钙的水化过程受成核作用的控制。因为这是石膏结构形成的第一步，详细了解这个过程很重要。通过成核、晶种形成和晶种生长，决定了水泥的微观结构、强度发展和水化速度。因此，在最后阶段确定石膏粘合剂的性能。DFG项目框架内的这项工作有助于深入了解成核和晶种形成过程。结果表明，晶种的形成机制是由均质成核和非均质成核组成的，这是由于溶解达到饱和的速度不同以及非均质晶种的数量不同造成的。这些机制在真实的系统中并行运行，但基于不同的条件。因此，进行了不同的实验模型，以了解和检查这些参数对各个过程的影响。纯半水合物应制备成具有均匀成核和添加非常明确的晶体，以研究这些异质晶种在水合过程中对真实的体系的影响。在第二步中，可以添加通常存在于真实的系统中的其它表面以研究其影响。此外，异质种子的影响，这种系统的方法将导致更好的理解。第二和第三个工作包取得的成果已用于执行第四个工作包。这一办法将确保最佳地执行工作包，并最大限度地利用所获得的知识。在该项目的框架内，（LM和ESEM），相组成（QXRD，STA），形成的反应产物的生长速率（LM），溶液相的组成（[Ca 2 +]-SE和LE），动力学（DCA，超声法确定和检查过程的结构和机械性能。研究了非均匀形核过程中的影响。半水硫酸钙的水化过程提供了更多的信息，水化的历史，微观结构的形成，晶体形态，力学性能和石膏基与石头结合的微观结构。在预期结果的基础上，应该有可能研究上述各个过程的影响，并从纳米级结构形成的异质成核开始，在微观和宏观层面上更好地理解晶体生长的微观层面。这使得直接控制成核和晶体生长的技术性能。本研究的主要目的是积极影响硫酸钙系统的成核，其最终用途的性能和硫酸钙基粘合剂的强度。

The nucleation controls the hydrations process of calcium sulphate hemihydrates. Because this is the first step of formation of the plaster structure and it is important to understand this process in detail. The microstructure, strength development and hydration speed are determined through the nucleation, seed formation and seed growth. Thus, determine the properties of gypsum binders at the final stages. This works within the framework of the DFG-Project contributed to the deep understanding of the nucleation and seed formation process. The results were verified that the mechanism of seeds formation is consisting of both homogeneous and heterogeneous nucleation, due to the different speeds of the dissolution, reaching the saturation level and different amounts of heterogeneous seeds. These mechanisms in the real system run parallel, but based on varying conditions. Therefore, different experimental models were carried out to understand and examine the influence of these parameters on the individual processes. A pure hemihydrate should be prepared to have homogeneous nucleation and addition of a very well-defined crystals to study the influence of these heterogeneous seeds on the real system during the hydration process. In the second step other surfaces, which are normally exist in the real system, can be added to study its influences. Furthermore the influence of heterogeneous seeds this systematic approach will lead to better understanding. The results, which were obtained from the second and third work package were applied in the implementation of the fourth work package. This approach will ensure the optimal implementation of the working packages and maximize the gained knowledge. Within the framework of the project will the morphology (LM and ESEM), the phase composition (QXRD, STA), the growth rate of the formed reaction products (LM), the composition of the solution phase ([Ca2 +]-SE and LE), the kinetics (DCA, ultrasonic method (US)) determines and examines the structure of processes and the mechanical properties.Investigations of the effect of the heterogeneous nucleation during the hydration process of calcium sulphate hemihydrate gives more information about the history of hydration, microstructure formation, crystal morphology, mechanical properties and microstructure of gypsum-based binding with stone. On the basis of the expected results, it should be possible to investigate the influences of the above individual processes and starting with the heterogeneous nucleation at the nano level structure formation on micro - and macro-level better understanding of crystal growth on the micro level. This enables to a direct control of nucleation and crystal growth in terms of technical properties.The main aim of this investigations is positively influencing the nucleation of calcium sulfate system, its end-use properties and the strength of calcium sulfate-based binders.