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Pinning sites are attributed to various physical parameters such as grain boundaries, voids, inclusions and dislocations.
The number of measured points in a magnetizing cycle was 1000.
In this range, the dislocation density of the specimens is relatively low and additionally large carbide grains appear within the ferromagnetic grains (Fig. 6-a).

However, some advanced ceramics exist in a number of different polytypic forms, sharing nearly the same lattice spacing but with different crystal symmetries.
The XRD results for samples showed that α and β-SiAlONs are the predominant phases and no other crystalline phases appeared at the grain boundaries.
Y is much more adsorbed in the α-SiAlON and Nd is preferentially solved in the glassy grain boundary phase.
By incorporation of most cations (except Nd +3 sample) into α-SiAlON structure, reduced glass free grain boundaries are obtained.

A number of methodologies of treatment and recycling have been developed to minimize the harmful effects in the environment caused by the landfill disposal of solid wastes [1-4].
DTA tests were performed on powdered samples with average grain size < 74 μm in a TA Instrument Universal Analysis 2000 equipment.
Following this procedure, 5g of grained samples were treated at 95°C for 1h in 60cm3 of leaching solutions(0.01mol/L H2SO4 and 0.01 mol/L NaOH).
After washing and drying, the grained samples were weighed and the percentages of weight losses were calculated. 3.

Hence, numbers of conventional investigations have been mainly focusing on the fluid delivery methods that make large flux into the grinding zone in order to overcome boundary layer of air.
However, due to the wedge effect between wheel and workpiece surface, hydrodynamic pressure is generated considerably in the actual grain cutting process, which affects actual depth of cut as well as grinding resistance increase [1].
Theoretical models of hydrodynamic pressure It is well known that in the grinding process, shown in Fig.1, the delivered fluid makes hydrodynamic pressure generation due to the wedge effect between wheel peripheral surface and work surface, and that particularly the large magnitude of pressure is created in the case of resin bonded grain protrusion of the wheel surface.
The MQL technique leads to lower roughness values, probably because of the more effective lubrication and cooling of the abrasive grains at the work-tool interface.

The earliest changes in the appearance of the AlN ceramic were observed in the samples oxidized at 1173K: grain boundaries, invisible earlier on the polished surface of the ceramic, appeared.
After heating at a temperature of 1373K, the ceramic surface was covered with a new homogeneous phase, and some mass losses could be seen in the grain boundaries.
Probably, its unequivocal identification is impossible since the amount of TiN dispersed on the ceramic grain surfaces is small and the number of defects of the crystal lattice is large.

As shown in Fig. 2, these particles had formed preferentially at quasicrystalline phase boundaries as well as along matrix grain boundaries.
In the present case, no phase identification was attempted for these particles, but their preferential location at phase and grain boundaries as well as their "clean" diffraction contrast suggested that they were crystalline particles, which had formed due to compositional gradients established at solid-liquid interfaces during final freezing [9].
Individual particles are identified by numbers 1 through 8 in Fig. 3(a).
� It is suggested that the new multiphase particles formed by the simple growth of small, pre-existing and presumably crystalline particles that were found at quasicrystalline phase boundaries as well as at aluminum matrix grain boundaries in the as-quenched microstructure

The results show that enhanced solution treatment leads to a higher strength and fracture toughness than that of the single-stage solution treated samples by improving dissolution of the residual phase and restraining recrystallized grains.
Table1 Solution treatment schedules of the Al-Zn-Mg-Cu-Er-Zr aluminum alloy Sample number Solution condition Aged condition SHT1 430°C/2h 120°C/24h SHT2 450°C/2h SHT3 470°C/2h SHT4 490°C/2h SHT5 450°C/1h+480°C/0.5h SHT6 (30°C-450°C)/4h+450°C/1h+480°C/0.5h SHT7 450°C/1h+480°C/0.5h+420°C/0.5h SHT8 (30°C-450°C)/4h+450°C/1h+480°C/0.5h+420°C/0.5h Results and discussion Fig.1 shows the hardness of Al-Zn-Mg-Cu-Er-Zr alloy, it can be observed that hardness increase with increasing solution temperature, however, hardness decrease when solution temperature exceed 470°C in single-stage solution treatment.
SHT8 sample is similar to high-temperature pre-precipitation solution treatment which can enhance the distribution discontinuity of grain boundary precipitates lead to the increase resistance corrosion [13].
Subgrain is observed, and Al3(Er,Zr) particles pinning subgrain boundary to obstacle the grain boundary migration, inhibiting recrystallization from Fig.6 c, d.

Moreover, the bulk BiFeO3 is characterized by serious current leakage problems due to the existence of a large number of charge centres caused by oxygen ion vacancies.
It is clear from Fig. 2 that the average grain sizes of both ceramics are reduced with increasing the Ti doping.
The reduction of the average grain size in the co-doped BiFeO3 samples could be interpreted by the suppression of the formation of oxygen vacancies because substitution of T4+ for Fe3+ requires charge compensation which can be achieved by suppression of oxygen vacancies.
The decreased oxygen vacancies lead to a lower grain growth rate which is actually a consequence of slower oxygen ion motion.

Spinel structure Li-Mn-O is the most promising lithium ion insertion electrode materials for rechargeable lithium ion batteries because of a number of advantages over their alternatives [2].
It is obvious that the Bragg reflection peaks of the dynamically synthesized Lithium manganese oxides are broadened, which may result form small grain size and/or presence of microstrain.
The average grain size (D) was measured from the XRD peak using the Scherrer formula [11].
The calculated mean grain sizes were 21.64 nm.

On the other hand, in the diffusion process, since the diffusion speed of the aluminium towards the matrix is far larger than the diffusion speed of the iron towards the external surface, a large number of vacancies are formed for Kirkendall effect on the aluminums position of the biggest concentration gradient.
In accordance with the diffusion theory of metal atoms, because the diffusion speed along the grain boundary is greater, the growth of the intermetallic compound crystal grain at the earlier stage mainly generates along interfaces between alloy layer and matrix.
After the mutual converging of the precipitated intermetallic compound crystal grain, the continuous intermetallic compound layer shall be formed.