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Introduction Silicon oxynitride glasses were first discovered as grain boundary phases in silicon nitride based ceramics in the 20th century 60 years.
This liquid would fill around the Si3N4 grains, thereby promoting sintering.
In order to understand the nature of these glass phases, a number of investigations on the formation and properties of oxynitride-glass have been undertaken over the last two decades [3-9].

The low energy required the most environmentally friendly process compare to other grain refinement methods.
However, the literature review reveals that the application of mechanical, sonic and ultrasonic vibration has a number of notable effects such as grain refinement, increased density, degassing, shrinkage, and the shape, size and distribution of the second phase.

Metal grains (0.04 - 0.2 μm in size) Oxide layer Oxide particles (2.5 - 50 nm in size) Voids Inclusions Bulk metal grains Boundary between the subsurface layer and the bulk Worn rolls Newly ground rolls Surface damage and coating Grinding defects Heat balance at the surface layer The DE formulation for the heat transfer problem has been simplified by the following assumptions: the temperature difference within a DE is small; heat transfer between the DE is restricted to the contact surfaces and is due to convection.
 (1) where nc is the number of elements in contact with element i.

There exsist a large number of fish-bone-shaped dendrites in the cladded coating of sample 1, and the microstructure is continuous, smooth and homogeneous, but coarse.
The microstructure of sample 2 is consisted of many fine cellular dendrites, but some crystal grains in some local areas are coarser, this is because the cooling velocity in different parts of the cladded coating was different during the laser cladding process, with an increase of the cooling velocity, the degree of subcooling increased, so the crystal grains would be more fine.

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It is evident that an increase in CO2 content in the shielding gas increases the grain size.
The highest hardness numbers found on the weld metals with shielding gas Argon.
An increase in CO2 content in the shielding gas increases the grain size of microstructure. 2.

The mean grain size of the PCD was 5 μm.
Table1 Specifications of the PCD tool Number of cutting edges 4 Tool diameter [mm] 12.4 PCD grain size [μm] 5 Rake angle [°] 0 Clearance angle [°] 11 Shank diameter [mm] 10 100μm   Uni-directional prepregs Woven fabric prepregs Fig.2 Structure of the CFRP workpiece Fig.1 Photographs of the PCD cutting tool Workpiece Material.

Initially, the grain size of the VC powder was approximately about 0,5-10mm (Fig. 1a).
Aluminium samples before surface treatment were mechanically ground on laboratory Tegramin 30 Struers grinding machine with sandpaper of 60, 40 and finally 15mm grain size.
In order to obtain the remelting width of about 6 mm two scans of the laser beam was used, as shown in figure 2 (number 1-2 - first scan and 3-4 second laser scan).
Taking these facts into account, the surface material can be qualified as ultra-fine grained material (UFG).
Analysing the TEM investigation results, also the occurrence of both strengthening mechanisms can be stated: the grain refinement as well as the precipitation strengthening, with a grain refinement up to 20µm in size and Al8V5 phase size of ca 250µm.

After 20h all materials exhibited additional inward oxide grain growth.
Inwardly oriented oxide areas have been detected as comparatively large single grains of pure Cr2O3.
This existence of such grains indicates fast inward transport of oxygen.
In Crofer these grains grow up to the end of the oxidation test, whereas in ITM and ITM14 they re-dissolve.
(a) (b) (c) (a) (b) Cr2O3 EDX-analysis Large Cr2O3- grains Fig. 7.

The coatings proposed by Veprek and Reiprich consist of a nanocrystalline nitride (nc) nanocomposite enveloped by a super-tough and amorphous (a) phase, forming a thin tissue only a few monolayers thick around the nanocrystalline grains [3].
The high hardness value was explained as a combination of grain refinement of the nc-TiN phase and the blocking of slip at the grain boundary due to the strong interface that develops between the TiN grains and the amorphous Si3N4 tissue [3,9,11].
The cold plasma can enhance adhesion between the substrate and the coating, as it provides a controlled environment capable of preventing the diffusion of elements from the environment to the substrate, as well as reducing the number of pores and cracks during film growth [12].
The authors believed that the C series was mostly built by TiN-matrix and with homogeneously distributed Ti2Cu and Ti3CuN grains reducing slipping of the material under mechanical stress, thus increasing the wear strength of the material.
Influence of Ti–Si cathode grain size on the cathodic arc process and resulting Ti–Si–N coatings.