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The substrate on which the metal powder was placed was carbon steel (AISI 1049), and its surface was sandblasted by WA abrasive grains with an average grain diameter of 300 μm to improve the wettability of the melted powder.
The number of pores was increased with the decrease of volume specific energy density.
(1) The number of pores was influenced by the volume specific energy density.

For a transformation of a bcc structure (α') with coordination number 8 to a fcc structure (austenite), which is more dense with coordination number 12, a isotropic contraction is expected.
Fig. 4b, shows the same alloy after reheating to 800°C and cooling down to room temperature where the � phase is light grey and the possible oxidation product, which is situated at the grain boundaries, is dark grey.
Nevertheless, making the correlation between the strained microstructure (Fig. 4a) and the one after reheating (Fig. 4b) allows linking the nucleation places of the dark phase to the �-� high angle grain boundaries, twin boundaries or former �-� phase boundaries.

In addition to the low volume fraction of CFe3, its orthorhombic structure spreads the scattering intensity into a large number of Bragg reflections.
The pearlitic microstructure is so fine (see Fig. 1c), that despite the small gauge volumes employed the number of diffracting grains is large enough to give adequate grain statistics.

Using lasers to clean and dress grinding wheels has been investigated by a number of groups around the world over the past three decades.
The dressing process has also to remove bond material and either remove blunt cutting grains or fracture them to create new cutting faces.
A new class of high brightness laser systems has been developed by a number of laser companies that hold the promise of laser micromachining structures at higher speeds, and thus could be viable for the laser cleaning operation.
Figure 2 Optical micrographs of laser cleaned aluminium oxide ball wheel The work-piece material can be seen as dark filaments winding round the aluminium oxide grains.

The thermal shock properties of materials depend on large number of parameters, e.g. tensile strength, fracture toughness, Young’s modulus and thermal expansion coefficients.
Compared to the Hasselman quench-strength method [12], the evaluation procedure is simple, the sample preparation is easy and only a small number of samples are needed for a series of measurements at different temperatures.
The microstructure of the sintered composites consisted mainly of elongated b-Si3N4 grains (several micrometers in length), equaixed b-Si3N4 grains, hBN particles and intergranular phase.

Laser cladding is an important statement and modification techniques, has been a large number of applications[4] in the industrial field.
Smaller laser bath containing a small amount of high-melting nanoparticles convection and heat and mass transfer effects on melt compared to higher levels, organizations are more conducive to the formation of alloy solidification compounds, while nanoparticles solidification crystallization front impede dendrites grow fine grain and raise as heterogeneous nucleation resulting enhanced nucleation rate is also conducive to improved wear resistance[5].
Figure 1 Metallographs of laser cladding different nano-Al2O3 content The nano-Al2O3 powder by 0%, 1%, 2% and 3% (by mass) of the added amount of Ni-base alloy powder in an agate mortar were thoroughly mixed, and the sample powder mixed in turn mark number: Ni-base, Ni1, Ni2 and Ni3.
Improve coating hardness and dry sliding wear resistance performance improvement is believed to be a small compound with a more dispersed in the coating formed on; Laser bath containing a small amount of high-melting nanoparticles melt convection smaller and heat and mass transfer effects compared to higher levels of the organization are more conducive to the formation of alloy solidification compounds; while solidifying crystalline nanoparticles hinder the forefront of dendrite growth and improved as heterogeneous nucleation nucleation produce fine grain rate enhancement also help to improve the wear resistance.

The number of it is very large in Heilongjiang Province coal cities, in Jixi City, for example, the storing up of coal gangue are nearly one hundred million tons, and increased at the rate of about 8.5 million tons every year.
Third, efforts are made to improve the legal system and regulatory mechanisms based on the existing conditions of the Heilongjiang Province and achieve the sustainable development strategy of coal urban living environment fundamentally. 4.2 Control the direction of coal urban industrial development In Heilongjiang coal cities, not only the presence of a large state-owned coal mines, there are a large number of coal enterprises as well.
First, the slope collapse area formed renovation, puddles turned into the aquarium, sloping tree-planting or planting crops to establish breeding industry, feed mills, to form a complete food chain engineering systems; Second, restoring Green ecological restoration planting, forest complex grass, in a certain range of living, strengthen the construction of plant habitats; Finally, make the use of coal gangue the generation or grain mill brickmaking it turning waste into treasure, not only can make the use of waste and energy savings, but also can greatly reduce the area of cultivated land occupied and effectively alleviate the air pollution. 5 Conclusion The three main themes of the 21st century is the population, resources and environment.
Heilongjiang as a province rich in resource, is not only in terms of coal resources, but also in timber, grain, oil and other national development necessary resources.

As shown in Figure 3 (a), the grains of the raw materials are unevenly distributed, and the micro structure is continuous.
The results show that horizontal wedge rolling can significantly improve the grains, but the risk of central Damage should be considered.
Figure 6 (C) shows that macro -Damage has obvious cross -shaped characteristics, and there are a large number of shear cracks in the field of pore aggregates.
With the growth and convergence of micropores, such as enlarged images, a large number of crack distribution at the tip of the tip is damaged, which further illustrates the cracking of the metal matrix before the microphone gathering.

Test samples of RCA have always different source, grain composition and other physical and mechanical properties, which are variously described in each different paper.
Type of MSC is closely related to amount of fine particles, water absorption and shape index of grains.
The smaller number of gained points for crucial factors is, the more suitable RCA is.

A number of oxides, carbides and nitrides were used as second phase particles to produce electroplated or electroless composite coatings.
Improvement of the properties of the coating can be achieved by refining the grain size of the deposit.
Each experiment was carried out using a plating bath that contains nickel sulphate hexahydrate as the source of nickel, ferrous sulphate heptahydrate as the source of iron, nickel chloride hexahydrate as complexing agent, boric acid as buffer, and sodium saccharine as grain refinement agent.
The presence of the Si3N4 particles in the nickel-iron nanocomposite coating increases the number of boundaries between particles in the matrix.