Investigation of Peritectic Solidification Morphologies by Using the Binary Organic Model System TRIS-NPG

Abstract

Under pure diffusive growth conditions, layered peritectic solidification is possible. In reality, the competitive growth of the primary α-phase and the peritectic β-phase revealed some complex peritectic solidification morphologies due to thermo-solutal convection. The binary organic components Tris-(hydroxylmenthyl) aminomethane-(Neopentylglycol) were used as a model system for metal-like solidification. The transparency of the high-temperature non-faceted phases allows for the studying of the dynamic of the solid/liquid interface that lead to peritectic solidification morphologies. Investigations were carried out by using the Bridgman technic for process conditions where one or both phases solidify in a non-planar manner. Different growth conditions were observed, leeding to competitive peritectic growth morphologies. Additionally, the competitive growth was solved numerically to interpret the observed transparent solidification patterns.

NPG–TRIS Thermal Storage System. Quantification of the Limiting Processes: Sublimation and Water’s Adsorption

“…In order to verify the reported special handling environmental conditions when manipulating NPG and TRIS and their mixtures [35,[44][45][46], the water content present in the pure compounds and in a peritectic sample was reanalyzed and quantified using the method described in Section 2.3.1. As mentioned above, DSC measurements of the samples (S Lab , NPG and TRIS) were acquired in temperature ranges that include the temperature of water solidification (melting).…”

“…) is one of the typical plastic crystals studied as a candidate for thermal energy storage. Although previous studies concerning neopentane derived compounds strongly recommended very controlled humidity conditions to avoid deviations from the desired composition, no quantitative data on the absorbed water content were reported, and only qualitative claims can be found [33][34][35]. With the aim of clarifying the reasons behind the claimed demanding conditions, the influence of environmental moisture in NPG, TRIS, and in a NPG-TRIS mixture were carefully investigated in a quantitative manner.…”