Phase-Transformation Analyzer: Monitoring Principles and Materials Applications

A phase-transformation analyzer measures thermodynamic parameters and kinetic behavior during melting, solidification, crystallization, and other heat-absorbing or heat-releasing transformations. It monitors heat flow or temperature difference between a specimen and a reference under programmed temperature control.

Most such analyzers use differential scanning calorimetry (DSC). A furnace provides programmed heating, cooling, or isothermal conditions from approximately −150 to 600 °C for conventional models, with higher-temperature models also available. A thermopile or platinum-resistance sensor monitors the specimen and reference crucibles, and the data system plots heat-flow–temperature or heat-flow–time curves.

Place a small specimen, normally several milligrams to several tens of milligrams, in an aluminium or ceramic crucible with an empty reference crucible. Under nitrogen, argon, or vacuum, heat or cool at the selected rate. Melting produces an endothermic peak, while crystallization produces an exothermic peak; onset, peak temperature, and peak area are used to determine transformation temperature and enthalpy.

Applications described include austenitization, martensitic transformation, and precipitation-related transformations in metals; glass transition, melting, and crystallinity in polymers; polymorph and excipient compatibility studies in pharmaceuticals; phase-change energy-storage materials; and rock and mineral analysis. Control specimen mass, keep crucibles clean, choose the heating rate for the method or study; 10 °C/min is an example rate for the described procedure, and seal crucibles or use pressure-resistant containers for volatile or reactive specimens.