Reactive milling

At this frequency of impacts the energy transferred to the powder would be comparable with that achieved in a planetary ball mill. The milling cylinder suitable for reactive milling is shown in Fig. 1.8. 

Mechanochemical synthesis (MCS) by reactive milling of metal powders or intermetaUics in hydrogen gas... 

Mechanochemical activation synthesis (MCAS) by reactive milling of componnds... 

In DSC measurements, the weight percent of a phase was calculated using the peak area of the DSC curve and its reported heat of formation. For example, weight percent of the p-MgHj in a reactively milled powder can be estimated using the peak area of the DSC curves and the reported P-MgHj heat of formation (-74 kJ mol [175], which equals to -2,811 J g ). The DSC curve was analyzed by the NETZSCH thermal analysis software. First, the onset and end temperature of the peak were determined. Then, the peak area was calculated using the linear approach from the onset temperature to tlie end temperature (Fig. 1.37) by the DSC software. 

Typical evolution of particle size (BCD) as a function of reactive milling time of selected synthesized powders from Table 2.15 is shown in Fig. 2.34. SEM miaograph... 

It is also clearly seen in Fig. 2.34 that the relative frequency distribution of powder particles remains log-normal starting from Mg through any powder regardless of the duration of reactive milling time. This is exactly the same behavior as already described for mechanically milled commercial MgH powders (Fig. 2.20). The experimental coefficient of variation, CV(ECD) = 5D(ECD)/M(ECD) (where SD is the standard deviation... 

Table 2.17 Selected results of XRD analysis and DSC analysis of the reactively milled powders in the Mg-H system [63]... 

Fig. 2.34 Particle size distributions and morphology of (a) initial Mg and selected synthesized MgH powders from Table 2.15 reactively milled for (b) 20 h under HES (MglH20), (c) 50 h under HES (MglHSO), and (d)150 h under IMP2 (MgSH) [62]...

Fig. 2.35 A general example of the evolution of the XRD patterns as a function of reactive milling time [63]...

Fig. 2.36 Nanograin (crystalline) size of P-MgH phase synthesized in the Mg-H powders under different reactive milling modes (Table 2.16). S sequential milling C continuous milling [63]...

Fig. 2.41 Representative DSC curves of MgHj powders synthesized by reactive milling for more than 20 h showing (a) peak with a shoulder (hidden peak) and a well-developed peak or (b) double peaks (doublet) (heating rate 4°C/min) [63]...

The addition of carbon nanotubes that were either reactively milled under hydrogen mixed with Mg powder [142] or simply mixed with MgH and subsequently milled [143, 144] was investigated. In vacuum, desorption at 200°C gave 3.6 wt.% within 1,800 s [142]. Another reference reports 5 wt.%Hj desorbed at 300°C within... 

Fig. 3.2 (a) Evolution of the XRD patterns of 2Mg-Fe mixture reactively milled sequentially for various times under 1MP2 mode in 880 kPa of hydrogen. For comparison the XRD pattern of the mixture milled continuously for 270 h is also shown, (b) Morphology of 2Mg-Fe mixture reactively milled for 270 h in a continuous manner... 

Table 2.16 Nanograin size and strain of [VMgl I2 synthesized by reactive milling of Mg-H powders (calculated as shown in Sect. 1.4.3) [63]...

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