Phase change materials salt hydrate

Table 2.40 Hydrated inorganic salts used for phase change materials... 

Gunther E, Mehling H, Werner M (2007) Melting and nucleation temperatures of three salt hydrate phase change materials under static pressures up to 800 MPa. J Phys D Appl Phys 40 4636 641... 

Reactant characterization also includes determination of any changes, such as loss of water of crystallization and/or phase transformations, prior to decomposition. Such processes may cause changes in composition (e.g. water loss) and/or surface textures, and in the numbers and distributions of imperfections. Some dehydrations yield an anhydrous salt, or lower hydrate, that is amorphous to X-rays, and a single crystal reactant is converted to an assemblage of fine crystalhtes. The consequences of annealing on defect concentrations and the decomposition of surface material of low stability may also require consideration. 

Both the Structure of the layered silicate hydrates and the product sequences are influenced primarily by the composition of the reaction mixture and the synthesis temperature [70-74]. The presence of neutral salts [73,76] and impurities of the raw materials, especially aluminum ions, must also be taken into consideration [25] when the varying phase compositions or impurities shift the synthesis fields or induce changes in the X-ray diffraction patterns of the crystallized products. 

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