Materials Synthesis

Synthesis of poly-, nano-, and single-crystalline metal alloys and composites is a major area of expertise at Ames.

Ames Laboratory is the leading authority in the discovery and synthesis of high-quality materials for magneto-, electro- and elastocaloric applications. The Laboratory has a full set of capabilities that are ideally suited for materials synthesis. Making quality samples in a variety of forms and shapes including ingots, ribbons and powders is paramount to control the caloric properties. We provide facile routes for microstructural refinement, nano-sizing and structuring of intermetallic alloys, ceramics and polymers. The typical sample size varies between 0.5 and 500 g. Scale-up and technology transfer is realized using capabilities of the Ames Laboratory Materials Preparation Center. A few examples of synthesis techniques include:

Arc melting allows rapid preparation of high-purity samples of stoichiometries ranging from the simplest to the most complex. Constituent elements and master alloys can be arc melted together in a high-purity argon atmosphere on a water-cooled copper hearth to produce alloys for caloric applications. Molds are used to shape materials upon solidification into buttons, rods, plates and other simple shapes. Samples can also be drop-cast as thin cylinders for better homogeneity.

Melt Spinning is a rapid solidification technique used to produce chemically homogenous thin metallic ribbons in an inert gas atmosphere by pouring liquid material onto a cold, rapidly spinning copper wheel. Amorphous and nanocrystalline materials are readily obtained from melt spinning. This technique is best suited for materials that require extremely high cooling rates in order to avoid phase segregation that may occur during slow cooling.

Induction melting utilizes high-frequency induction furnaces to synthesize materials in crucibles, open or sealed (for highly volatile components). The technique is suitable for near-equilibrium solidification and high temperature heat treatments.

High energy ball milling supports fast solvent-free synthesis of a variety of materials and enables solid-solid, solid-liquid and solid-gas reactions under a broad range of reaction parameters. A wide choice of materials, such as agate, tungsten carbide, stainless steel, and silicon nitride, are employed as the grinding media. Milling can be performed at room temperature at atmospheric or elevated pressures, or at liquid nitrogen temperature (−195.79 C; 77 K; −320 F).