Effect of high pressure on the preparation of Pd–Si–Cu bulk nanocrystalline material

Abstract

A Pd-Si-Cu bulk nanocrystalline material was prepared by quenching the melted Pd 78 Si 16 Cu 6 alloy at a cooling rate of 200 K͞s under 2-6 GPa. It was found that the nanocrystalline material consists of Pd(Cu) disordered solid solution and a metastable phase-II, Pd 4 Si. The grain size was found to decrease with increasing pressure. The influence of high pressure on the grain size of bulk nanocrystalline material is discussed, and a possible formation mechanism is proposed.

Effect of Pb Filling and Synthesis Pressure Regulation on the Thermoelectric Properties of CoSb3

“…Figure a,b show the SEM micrographs of Pb 0.2 Co 4 Sb 11.5 Te 0.5 samples prepared at 1.5 and 3.5 GPa. The grain size of Pb 0.2 Co 4 Sb 11.5 Te 0.5 prepared at 1.5 GPa is smaller than that of Pb 0.2 Co 4 Sb 11.5 Te 0.5 prepared at 3.5 GPa, which is corresponding to the results of Yao et al This is mainly due to that the nucleation rate of crystals will increase with the increase of synthesis pressures significantly. , Under the same synthesis time and the same element content, the number of grains synthesized under 3.5 GPa is larger than that of Pb 0.2 Co 4 Sb 11.5 Te 0.5 synthesized under 1.5 GPa, while the size of grains is smaller than that of Pb 0.2 Co 4 Sb 11.5 Te 0.5 prepared under 1.5 GPa. In order to investigate the chemical homogeneity of Pb-filled sample, we mapped the elemental distributions of Pb 0.2 Co 4 Sb 11.5 Te 0.5 prepared at 3.5 GPa by EDS in Figure c–f.…”

“…As the particle size decreases, the Raman diffraction peaks move to low wavenumber and become wider and weaker, so the Raman diffraction peaks in Figure 1b decrease with increasing synthetic pressures. 17 This is mainly due to that the nucleation rate of crystals will increase with the increase of synthesis pressures significantly. 18,19 Under the same synthesis time and the same element content, the number of grains synthesized under 3.5 GPa is larger than that of Pb 0.2 Co 4 Sb 11.5 Te 0.5 synthesized under 1.5 GPa, while the size of grains is smaller than that of Pb 0.2 Co 4 Sb 11.5 Te 0.5 prepared under 1.5 GPa.…”

High Pressure and Chemical Bonding in Materials Chemistry

“…The effect of high pressures on the preparation of bulk nanocrystalline materials has also been, observed for the ternary system Pd-Si-Cu [38] and the binary system Ti-Cu [39].…”

Microstructural Control via Copious Nucleation Manipulated by In Situ Formed Nucleants: Large‐Sized and Ductile Metallic Glass Composites

“…Yao et al [ 33 ] deduced an equation for predicting the grain size during solidifi cation Virtually, nucleation and crystal growth are a mutual competing progress during solidifi cation.…”