The physics of mechanical alloying: A first report

Organic synthesis by Twin Screw Extrusion (TSE): continuous, scalable and solvent-free

“…Furthermore, the Knoevenagel reaction between vanillin and malononitrile was also investigated to determine the effect of replacing the activated methylene reactant, barbituric acid, with a compound of substantially lower melting point. For comparison with the TSE results, all three reactions were initially carried out by ball milling as well as in anhydrous d 6 -DMSO, and were monitored by 1 H NMR spectroscopy, allowing any differences in the reactivities of the aldehydes in the solid state and in solution to be determined. Interestingly, it was found that a similar trend in reactivity was observed for both of these methods, with the reaction between vanillin and barbituric acid occurring most rapidly, whilst the reaction involving 5-bromovanillin was the slowest.…”

“…[1][2][3][4][5] Avoiding toxic solvents not only decreases potential hazards, but can also reduce the overall cost of a process. 5 A variety of materials and compounds have been prepared mechanochemically including metal alloys, 6 metal organic frameworks (MOFs), 7 and organic compounds from reactions such as the Knoevenagel condensation [8][9][10] and Wittig reaction, 11 amongst others. 12 However, two main drawbacks of mechanochemical synthesis are the general lack of both temperature control and scalability.…”

Fabrication of improved sige alloys for an 18-couple module test

“…Some small-scale samples prepared by this technique had figures-of-merit as high as 0.92x10-3 K"^, thus encouraging us to expect further improvements in the n-type figure-of-merit for production-scale compacts as this new technique is further optimized and refined. As shown in Figure 1, the n-type SiGe/GaP material was prepared by mechanically alloying (Maurice 1990) the elements to a fine powder, then consolidating the powder by hot isostatic pressing. A nominal composition of Sio.784Geo.197Gao.005Po.015 was selected based on previous results obtained on small-scale samples.…”

Microstructure and electrical resistivity features in Al-Al4C3 in-situ composite after attrition milling and double sequence of compaction and high temperature treatment

“…2). This in fact increases the potential to form a dense Al 4 C 3 precipitation and cluster formation on the substructure of Al during the cycle of secondary treatment [26,28,29,35]. Thus, more C dissolution means more potential and driving force for Al 4 C 3 formation in Al.…”

“…By elemental diffusion, atomic C penetrated in and located at interstitial sites of the convoluted crys- tal structure of Al. This was either due to very short milling time resulting inadequate synthesizing time for the formation of the Al 4 C 3 phase [19][20][21][22]26] or due to the amorphous phase of Al 4 C 3 that formed before crystallization [20,27,28]. Consequently, development of Al 4 C 3 was thermodynamically impractical during MA [28].…”