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Introduction Mercuric iodide (HgI2) is one of the most suitable semiconductor materials for γ- and X-ray detectors operating at room temperature because of its favorable characteristics such as high atomic number of its constituent elements and large band gap (2.13 eV), resulting in a high photopeak efficiency [1-3].
High-quality polycrystalline mercuric iodide thick film must have an uniform grain size, grain columnar and orientation, which are prepared for nuclear radiation detectors to high energy resolution and spatial resolution [9].In Fig.1(a) there are many square facets on the film surface indicating that the α-HgI2 film is highly (001) orientated.
Sizes of the α-HgI2 grains are about100～150μm.
Achievement of columnar grain structure is one of the most important prerequirements to produce high-quality thick films.
When the applied frequency is less than 10K HZ, the capacitance fluctuates which can be attributed to the low-frequency discrete caused by the grain boundary at low frequencies.

These research works have described that the void initiation takes place around or inside martensite grains.
Calcagnotto et al. [7] investigated failure behavior of DP steels with different grain sizes using mini tensile test with DIC technique and showed that while in classical DP steels (of coarse grain and high impurity) the cleavage fracture and grain split cause failure, in modern DP steels (of fine grain and low impurity) grain boundaries play the significant role.
Metallography shows ferrite grain size of 3.21 µm and martensite fraction of 46% [11].
Acknowledgments This research was carried out under Project number MC2.07293 in the framework of the Research Program of the Materials Innovation Institute M2i (www.m2i.nl).

From figure 2a),because of equidistribution for HA and ZrO2 crystals on coating surface,which is representative when was tested.It is not only compact related to fracture toughness with phases composing for ceramic material,but also crystalline grain.So the toughness reinforce ways include second phase toughening, phase transformation toughening and microcrack toughening, microstructure toughening and so on.But for the last one,crystalline grain must be processed by nano technolygy which will be difficult to produce the material.
a) b) Fig.2 Surface morphology after SBF soaked a-crystalline grain，b-whisker Secondly,in different temperatures,there are three kinds of polymorphism for ZrO2 crystalloids,and there is transformation between them following[7]: (1) (1)There is square crystal ZrO2 as shown in figure 1a).Because microarc dischange moment temperature is higher than 2000oC which could produce t-ZrO2 on coating surface,as well as room temperature of the electrolyte who can be instantaneous cooling for t-ZrO2,and then parts of t-ZrO2 who are not transformed into m-ZrO2 in time are covered around HA;(2) Because desity of t-ZrO2 (6.10g/cm3) is bigger than m-ZrO2 one,when phase transformation ZrO2 grain will disperse in coating with increasing the volume 3%~5%,which will restain the change.At the same time phase transition temperature is decreased,and the change is stopped when it arrices at room temperature;(3)Because of additional
Lastly，in complex ceramic coating if t-ZrO2 crystalline grain’s size is bigger than critical value,and in MAO latter period because of phase transition volume effect and volume effect, a large number microcracks are produced,(1) when the crack lies by front of primitive host-crack,it will absorb parts of energy of the host-crack expasion,and decreases stress concentration of it;(2) The interactions between microcrack and host one,which make the host one itself be bifurcated and close crystal boundart broken or extended,so energy is absorb.
Microcrack toughening effect is in inverse proportion to the crystalline grain size for the main reason.Inside of coating ZrO2 crystalline grain size is less compared to HA one and uniform distribution,so plays a part in microcrack toughening.

Experimental procedure α-alumina powder (mean grain size 0.4 µm, purity of 99.8%, Showa Denko Co., Ltd., Japan), zirco- nium oxychloride (ZrOCl2.8H2O, purity of 99.0%, Kishida Chemical Co.
As expected, the grain size of Al2O3 increases with the sintering temperature.
This should be mainly attributed to the coarser grains of such alumina ceramics (see Fig. 5).
Fine dispersion of ZrO2 can inhibit grain growth of Al2O3 and increases the wear resistance of the Al2O3−−−−15 wt% ZrO2 composites.
Acknowledgements One of the authors (PR) acknowledges the financial support of Japan Science and Technology (JST) and Guangdong Natural Science Foundation (Grant number 031446).

We developed a precursor, type 48%Cu–47%Sn–4%P–1%Si, powder, grain size 0.05mm.
Table 1 Mineral Composition [mass %] · Powder addition from silver ecological materials, grain size max. 0,1 mm as well as a mass participation up to 5 % sort B-Ag40CuZnSn – 670/710 according to EN ISO 3677:1995, · Boric frit (boric glass)..................................................................................... 35 %; · Mechanical homogenized mixture- potassium hydroxide.............................. 26 %; · Fluoride frit (fluoride glass)............................................................................ 20 %; · Plasticizer (CMC) carboxyl-methylcellulose................................................... 1 %; · Binder (distilled water)................................................................................... 13 %.
In order to achieve the new product we used as a rod, extruded alloy, diameter Φ 2x500 mm, Ag125, according to SR EN ISO 17672:2010, with restrictions on residual, hazardous and embrittling elements: Ø The content of residual elements is limited, according to ROHS, at : Cd < 0.1%; Hg < 0.1%; Cr < 0.1%; Pb < 0.1% Ø The content of embrittling elements : Sb, Fe, Bi < 0.3% To activate the coat we developed a new precursor [3] with its chemical composition presented in table 2, it was accomplished through casting and powder grinding, grain size maximum 0.05 mm.
Acknowledgements: „This work was supported by a grant of the Romanian National Authority for Scientific Research, CNDI– UEFISCDI, and project number PN-II-PT-PCCA-2011-3.2 - 0918” Bibliography [1]A.

The ice is hammered into ice grains which’s maximum diameter is about 3mm.
Then the ice grains are put into the frozen mould, and then the frozen mould included ice grains is placed into the refrigerator, after 10 minutes, the water which temperature is 0℃ is poured into the frozen mould included ice grains along the opening edges, then the frozen mould is placed into the refrigerator, kept 24 hours
With the increasing of loading speed, many stable cracks of cracking are taken shape in ice inside, and the number of cracks gradually increases as stress increases, at the same time, slippage phenomenon still exists.
It is further research on choosing precisely loading speed at different frozen temperature (3) When loading speed is very small, the ice grains have a lot of time to produce dislocation slippage along the boundary of the ice grains, at the same time, the boundary of the ice grains generate enough tiny cracks.

Fracture secondary cracks can be seen, and covered with a large number of corrosion products, the local crystal surface can be observed in the morphology of corrosion pits(Figure 3III).
Principle of intergranular corrosion is that S penetrates along the grain boundaries of stainless steel, and chemical reaction with the metal to produce a brittle or loose S compounds.
The surface is relatively smooth with small grain and obvious signs of gully.
The grain of corrosion gully area is very coarse, corrosion gully is evident.
Between grain and grain is a serious erosion-corrosion, intergranular gap is relatively large.

Despite the extremely high interest of industries in this technology and the number of parts already produced as prototypes or for final applications, there are few alloy powders suitable to AM processing available on the market.
Keller’s reagent and a solution of HF in water were used as chemical etchants for the 2618 and A360 alloy, respectively, to reveal grain size and other microstructural features.
Fig. 6a depicts a representative micrograph of an Al cast alloy, showing coarse grain size (size is around 100 mm) and a fairly large amount of Si phase (as part of the eutectic constituent) located at grain boundaries.
Specifically, a sub-micrometer size cellular structure is generated owing to rapid solidification conditions in SLM alloys, as opposed to coarse grain structure with grain boundary eutectic segregation in cast alloy.
Grain refining of aluminium and its alloys using inoculants.

Compared with the steel specimen without adding Ce, the inclusions at the grain boundaries of the specimen No. 4 are smaller and smoother.
Because harmful elements such as S and P segregate along the grain boundaries, the grain boundary strength is reduced.
The fracture surface shows a number of spherical inclusions with diameter less than 5μm and with composition of Ce-S oxides, indicating Ce reduces the sizes of the inclusions in matrix.
Cracks grow relatively slow in the precipitates, inclusion and matrix interfaces, the grain boundaries, and the weakness points prior to expansion.
After adding Ce in the steel, Ce segregations at the grain boundaries purify the grain boundaries and reduce the sizes of the inclusions, transmitting fracture mode from intergranular to transgranular type, and thus effectively improving the impact toughness of the steel.

Because of both the very small geometrical　interference angle　of the grain ig in approach to the area (1), and the interference region is larger, the grinding forces might be large.
This is related to the fact that the geometrical interference angle of the grain ig is very small such as nearly equal to zero.
On the contrary, it is assumed that the wheel wear become small in the left right-side end of the wheel, because the load acting on each grain becomes small.
(4) In the central area of the wheel, large and sharp force distributions occurred, therefore the load of the actual cutting grain is larger than the left right-side end of the wheel
(5) In the left side of the wheel, as the interference angle is smaller, the grinding force becomes larger, however the interference region is broad, then the real cutting grain number becomes large, therefore the load acting actual cutting grain is reduced.