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Yamaoka found that a certain amount of MnO additives plays a role in the promotion of grain growth [2].
The reason is that the substitutions of the Ti4+ (0.068nm) ions by Mn2+ (0.080nm) ions promote the grain growth, and reduce the number of grain boundaries within the unit volume.
Grain growth has also lead to the apparent dielectric constant ε of samples increasing.
Because the decrease of grain boundary acceptor states density leads to the grain boundary barrier height decreasing and the nonlinear coefficient relates to the grain boundary barrier height, the nonlinear coefficient α of the sample decreases when the grain boundary barrier height decreases.
In addition, the thin insulating layer of the grain boundary leads to the drain conductance of grain boundary increasing, so that the dielectric loss tanδ increases.

However, steel COST FB2 contains a relatively large number of particles of BN with a size of several micrometres, which suppress positive effect of the boron.
The average grain sizes of both the HAZs and of the weld metal are comparable with the grain sizes of steel COST F (about 20 μm).
The grain sizes of the coarse-grained parts of the HAZs are only slightly larger than the fine-grained parts of the HAZs; from 28 to 17 μm and from 38 to 14 μm for HAZ of COST FB2 and HAZ of COST F respectively.
The base metal COST F is fine-grained.
Similar average grain size was also observed in its HAZ with only slightly larger average size in the coarse-grained region.

As for the small cold rolling rate, the processing strain for the {100} columnar grains is small, remaining the texture in growing and re-crystallization grains.
Strip casting for grain-oriented silicon steel.
Then, the small grain size of less than 100μ m and large number of (110) [001] grains guarantee high B8 for the final products processed by normalization, cold rolling and annealing.
The above cooling rate can be controlled by adjusting water flow rate, nozzle number and shape, jet angle and length of cooling zone.
In this case, if soft rolling is conducted by cooling roller, there will be less interior defects and smaller grain size, result in improved toughness (i.e. bent number).

Elemental Quantitative Analysis Data of Pure Calcium Fluoride NPs Sample number ICP analysis data.
The grain size of Eu2+: CaF2 NPs (nm).
Because the Eu-doping results in a large number of F ions in the lattice gap, lattice defects increase as the reaction concentration increasing.
This indicated that the grain size decreased and the crystallinity of the crystal grains also decreased.
The trend graph of grain size and cell parameters.

From the photos after erosion, we can see the obvious grain boundary and grain distribution.
The black particles of sample 4# are distributed in the grain interior and grain boundaries, and the black particles in grain boundaries are slightly larger.
The grains of these two kinds of samples are equiaxed grains generally.
The grain of 5# is smaller than the grain of 4#, indicating that it can significantly refined alloys grains when the content of Pb increase from 1% to 2%.
And Fig.5 shows that the radius of capacitive reactance arc of 5# in high-frequency region is bigger than 4#, indicating that with the decreasing grain size and the increasing of the capacitive reactance arc radius, it is to say that the interfacial charge transfer resistance of the alloy increases, the corrosion rate slows down, the reason is that the refine of the grains may increase the grain boundary surface area, then the number of segregative phase in the grain boundary is reduced relatively, so that the properties of the alloy are improved[14].

Introduction Structural ceramics have a number of excellent properties, however, their wider application is still limited by their brittleness, low flaw tolerance and low reliability.
Their low flaw tolerance - high brittleness - is strongly connected with the presence of ionic or covalent atomic bonds and with the limited number of independent slip systems, which are cooperative when compared with the number of those necessary for plastic deformation commonly observed in metals and alloys [1,2].
Thermal shock resistance and creep behavior of layered ceramics There exist only a limited number of papers dealing with thermal shock resistance and creep behavior of layered ceramics, [54-60].
The higher high temperature properties of the layered composite in bending were caused by the improved properties of outer layer, where the intergranularly located SiC nanoparticles hinder the grain growth of the Si3N4, changing their shape and the shape and chemistry of the grain boundaries and grain boundary phases.
Moreover, the intergranularly located SiC nanoparticles interlock two neighbouring Si3N4 grains with a "puzzle" character and therefore prevents the grain boundary sliding.

Experimental results indicate that it produced the alloying coatings, exhibiting compact grain and be of amorphous state.
Nano-sized RE would preferentially occupy and pad the defective area between the cracked gap and micropores to limit the growth of the original Ni grain, and far from coarse grain.
Original RE particles (CeO2 or Ce4+) adsorbed on the actived surface acted as the direction for grain growth would co-deposit with Ni to promote higher crystal nucleus and obtain compact grain with less micropores, as seen from Fig.3(b).
During annealed at 400°C for 2 h, Ni grain in pure nickel coatings does grow up quickly, even more than 150 nm, appearing large boundary and cracks initiation, as shown in Fig. 6(a). when annealed at 400°C for 2 h with 1.5 g/L RE addition, Nano-sized RE preferentially pad and even occupy the defective zones between the glided cracks gap and micropores to limit the location of the original Ni grain, less than 120 nm, and far from coarse grain, as observed in Fig. 6(b).
Ni-CeO2 composite coatings prepared by PC+U can obtain compact grain and be of amorphous

However, finer grains were observed in the water-cooled specimens.
Theoretically, the microstructure composed of a finer grain size caused a higher tensile strength and a lower elongation [4].
The grey areas are Sn-rich phase and the dark grey areas composed of a needle-like or an elongated grain are the Cu6Sn5 intermetallic compound phase (Fig. 5(b)).
The Sn-rich and the Cu6Sn5 intermetallic compound were formed in all cooling systems, whilst the finer grain sizes formed when using the water-cooled system. 3.
Acknowledgements This work has been supported by Faculty of Science Research Fund, Prince of Songkla University (Fiscal Year 2014) under the contract number 257009.

Introduction In polycrystals with micrometer size grains, the surface contains an insignificant fraction of the total number of atoms and its effect on the overall properties of the material can be ignored.
In a number of publications detailing changes in the physical properties of nanocrystals related to their size [1 - 9] the dependencies reported are often related to the lattice parameters which, for very small crystals, appear to be a size dependent property of the material.
The deviation from ao increases with a decrease in the grain size.
In general, a number of different arrangements of atoms corresponding to a given lattice parameter exist.
Averback, Sintering and Deformation of Nano-grained Materials.

The results show that MWNTs were preserved in the composites after sintering and present good adherence to matrix grains.
The large amount of lower viscosity liquid phase provided by 30wt%BAS during sintering facilitated the α to β-Si3N4 phase transformation and grain growth of β-Si3N4.
As can be seen in figure 2a and b, β-Si3N4 grains are connected by separated MWNTs, through which load can transfer from matrix grains to MWNTs.
Consequently, the decreased number of rod-like β-Si3N4 grains led the toughness to reduce.
After sintering, MWNTs are still present in the composites and present good adherence to matrix grains.