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Three different methods – melt quenching (MQ), twin rollers (TR) and mechanosynthesis (MS) – were used for the preparation of the 15Ag2O·70V2O5∙ 15P2O5 glass — a good amorphous semiconductor. It was demonstrated that physical properties of the final material depend to some extent on the preparation method. As-received samples were characterized by: X-ray diffractometry (XRD), differential scanning calorimetry (DSC), Raman scattering, X-PDF method and impedance spectroscopy (IS) in a wide temperature range from − 80 to 230 °C. Main conclusion of these studies is, that substantially different synthesis routes can be used to produce glasses of almost identical thermal and structural properties but different electronic conductivity. The explanation of the origin of that difference was proposed and discussed.

The 78AgI, 16.5Ag2O, and 5.5B2O3 mol% powder mixture, ultra-fast quenched 78AgI-16.5Ag2O-5.5B2O3 glass containing α-AgI crystalline precipitates and pristine AgI were ball-milled at a high rotation speed. For all the materials, the processing did not cause formation of α-AgI phase, in contrary, it prompted α to β phase transition of the α-AgI precipitates in the glass. Nanosize scale β/γ-AgI grains were detected both in the milled powder mixture and in the glass but not in the pristine AgI powder. The decrease of α to β phase transition temperature was observed for the milled materials during cooling from 170 °C, ca. 10 °C, 60 °C and 75 °C respectively for the AgI powder, the powder mixture and the glass. Stabilization of the α-AgI to low temperatures was related to the nanosize scale β/γ-AgI grains. The work demonstrates, that although it is not possible to stabilize α-AgI in pure silver iodide powder by ball-milling, nevertheless it is achievable for mixtures with high AgI contents.

Three different methods - melt quenching, twin rollers and mechanosynthesis - were used for preparation of the 50AgI·30Ag 2 O·20V 2 O 5 glass – a good amorphous superionic conductor. It was demonstrated that physical properties of the final amorphous material depend to some extent on the preparation method. As-received samples were characterized by: X-ray diffractometry (XRD), differential scanning calorimetry (DSC), infrared absorption (FTIR), Raman scattering and impedance spectroscopy (IS) in a wide temperature range from -150 to 20 °C. Main conclusion of the results of these studies is that substantially different synthetic routes can be used to produce amorphous materials of very similar but not identical properties.

The work studies the effect of selected milling variables on mechanosynthesis of the materials formed in the AgI–Ag 2 O–WO 3 system. These variables were: a rotation speed, a milling time, a ball-to-powder mass ratio, a process control agent and a level of preliminary grinding of the reactant powders. The mechanosynthesis was carried out using Fritsch Pulverisette 7 and Fritsch Pulverisette Premium Line planetary mills. The X-ray diffraction method was applied for phase identification in the final product and for determination of their relative contents. It has been found out that: the synthesis leads to amorphous products and its efficiency is enhanced when: i) rotation speed and milling time are increased, ii) ball-to-powder mass ratio decreased and iii) starting powders are pre-ground. When the substrates are milled too long or applied milling speed is too fast, exceeding 600 rpm, then the process of amorphisation is impeded. The limit values of rotation speed and milling time are interrelated. Additionally they depend on the type of mill and applied mode of work. Preliminary grinding of the starting compounds enhances the milling efficiency. Addition of acetone, a control agent, to the milling batch reduces efficiency of production of amorphous phase.

The room temperature mechanosynthesis of La 1 − x Sr x Ga 1 − y Mg y O 3 − δ was demonstrated for a broad compositional range ( x = 0.05, y = 0.10; x = 0.20, y = 0.20). This was achieved in atmospheric air with a planetary ball mill at 650 rpm in nylon containers rotating at 1300 rpm in the opposite direction. The maximum milling time was 360 min so that Zr contamination was kept below 0.25 mass%, as detected by ICP-AES. Powder X-ray diffraction revealed the formation of a perovskite phase since the early milling stages that becomes dominant in the patterns collected after milling for 360 min. The average crystallite diameter determined from XRD was ca. 30 nm, in good agreement with transmission electron microscopy observations. Ceramics with 93% of the theoretical density were obtained after sintering at 1300 °C.

Applicability of the mechanosynthesis for preparation of new amorphous silver superionic conductors is considered and its general features are discussed. Selected cases of successful applications of the method as well as negative ones are presented and analysed. The multi-stage model of the mechanosynthesis is suggested. The experimental evidences supporting the model are presented. New process, prompted by mechanosynthesis, in which concentration of silver iodide in a glass could be increased at room temperature is described.

The single-step synthesis of nanosized MgFe 2 O 4 via mechanochemical processing of binary oxide precursors is reported. The mechanochemical route is followed by X-ray diffraction and 57 Fe Mossbauer spectroscopy. The nanoscale nature of the mechanosynthesized material is evidenced by transmission electron microscopy. Quantitative information is provided on both ionic and spin configurations in nanosized MgFe 2 O 4 .

In this paper we show that mechanochemical approach allows fast synthesis of individual phases with fluorite and perovskite structures and preparation of dual-phase nanocomposites with mixed ionic–electronic conductivity. Binary oxides obtained by mechanosynthesis are frequently metastable compounds which decompose at moderate temperatures before sintering into the dense ceramics. Complex doping provides kinetic stabilization of perovskites and fluorites and allows their sintering into dense ceramics. Moreover, complex doping of structurally different phases makes possible a preparation of compatible compounds for nanocomposites. In all 10 nanocomposites considered here, the chemical interaction (interdiffusion) was found to occur in some degree. Rules are formulated for preparation of composites from compatible compounds. All perovskites and ceria-based composites are likely to be more promising as membrane materials.

In recent years, zinc ferrite has been used as an absorbent material for hot-gas desulphurization. This experimental work focuses on both the novel synthesis pathway (mechanosynthesis) to zinc ferrite and the study of the high-temperature reactivity of nanoscale mechanosynthesized zinc ferrite in coal gas desulphurization and in the subsequent regeneration process.

The mechanosynthesis method were used for preparation of the xAgI·0.25(100 − x)(3Ag2O·V2O5), 40 ≤ x ≤ 85 superionic materials. There was first time demonstrated, that by means of this method pure amorphous materials could be formed for 50 ≤ x ≤ 70 compositions. According to literature reports such materials are unobtainable by press or fast quench methods. Other synthesized materials were only partially amorphous and contained crystalline inclusions, which were identified as Ag2O for low doping with silver iodide or β/γ-AgI for highly doped materials. Complex impedance figures for partially crystalline samples demonstrated some departures from typical shapes characteristic for solid glasses. Electrical equivalent circuits were discussed and proposed to model ion properties of the studied materials in the range − 60 °C and + 40 °C and then they were employed for determination of ion conductivity and activation energy.