• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.252-253
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• 2014

This study is to XRD and image analysis of low carbon type recycled cement from waste concrete powder and cement raw materials. Waste concrete powder possible to low carbon type recycled cement in small part of additive materials. Also, low carbon type recycled cement using waste concrete powder is suitable for ordinary portland cement.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1061-1065
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• 1999

The effect of particle size of coating powder and coating temperature on the thickness of coating layer formed on metal surface was studied by using XRD, SEM and EDXS. Coating powder was separated according to particle size by 3 steps and coating temperatures were varied from $950^{\circ}C$ to $980^{\circ}C$. Calorizing carried out at air and Ar conditions for 5 hrs, respectively. XRD result show that $Al_2O_3$ and AlN were formed during calorizing at air condition. The thickness and Al content of coating layer increased as the particle size of coating powder decreased and coating temperature increased.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.511-512
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• 2006

Tungsten coatings with different interlayers onto the oxygen-free copper substrates were fabricated by atmosphere plasma spraying. The effects of different interlayers of NiCrAl, NiAl and W/Cu on bonding strength were studied. SEM, EDS and XRD were used to investigate the photographs and compositions of these coatings. The tungsten coatings with different initial particle sizes resulted in different microstructures. Oxidation was not detected in the tungsten coating, but in the interlayer, it was found by both XRD and EDS. The tungsten coating deposited directly onto the copper substrate presented higher bonding strength than those with different interlayers.

• Journal of Powder Materials
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• v.11 no.6 s.47
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• pp.493-502
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• 2004

In this study, nano-sized indium oxide powder with the average particle size below 100 nm is fab-ricated from the indium chloride solution by the spray pyrolysis process. The effects of the reaction temperature, the concentration of raw material solution and the inlet speed of solution on the properties of powder were studied. As the reaction temperature increased from 850 to $1000^{\circ}C$, the average particle size of produced powder increased from 30 to 100 nm, and microstructure became more solid, the particle size distribution was more irregular, the intensity of a XRD peak increased and specific surface area decreased. As the indium concentration of the raw material solution increased from 40 to 350 g/l, the average particle size of the powder gradually increased from 20 to 60 nm, yet the particle size distribution appeared more irregular, the intensity of a XRD peak increased and spe-cific surface area decreased. As the inlet speed of solution increased from 2 to 5 cc/min., the average particle size of the powder decreased and the particle size distribution became more homogeneous. In case of the inlet speed of 10 cc/min, the average particle size was larger and the particle size distribution was much irregular compared with the inlet speed of 5 cc/min. As the inlet speed of solution was 50 cc/min, the average particle size was smaller and microstructure of the powder was less solid compared with the inlet speed of 10 cc/min. The intensity of a XRD peak and the variation of specific area of the powder had the same tendency with the variation of the average par-ticle size.

• Resources Recycling
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• v.13 no.6
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• pp.16-25
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• 2004

In this study, nano-sized indium oxide powder with the average particle size below 100 nm is prepared from the indium chloride solution by the spray pyrolysis process. The effects of the concentration of raw material solution, the nozzle tip size and the air pressure on the properties of powder were studied. As the indium concentration of the raw material solution increased from 40 g/l to 350 g/l, the average particle size of the powder gradually increased from 20 nm to 60 nm, yet the particle size distribution appeared more irregular, the intensity of a XRD peak increased and specific surface area decreased. As the nozzle tip size increased from 1 nm to 5 nm, the average particle size of the powder increased from 40 nm to 100 nm, the particle size distribution was much more irregular, the intensity of a XRD peak increased and specific surface area decreased. As the air pressure increased from 0.1 kg/cm$^2$ to 0.5 kg/cm$^2$, the average particle size of the powder varies slightly upto 90~100 nm. As the air pressure increased from 1 kg/cm$^2$ to 3 kg/cm$^2$, the average particle size decreased upto 50~60 nm, the intensity of a XRD peak decreased and the specific surface area increased.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.1
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• pp.27-34
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• 2001

Refining of powder particles and their dissolution into the Al matrix during mechanical alloying(MA) were investigated by using X-ray diffraction(XRD) transmission electron microscopy (TEM) functions of alloy composition, milling time and ball to powder ratio(BPR). It is found that Ti particles less than 20nm are observed in a dark field image of mechanically alloyed Al-10wt%Ti whose XHD pattern exhibits no Ti peak. The observed change of lattice constant of AI indicates that about 1 wt%Ti can he solved in Al after MA for a long time, independent of alloy composition, milling time and BPR, suggesting that most of Ti particles arc retained in the Al matrix. It is concluded that the disappearance of XRD peaks in mechanically alloyed Al-10wt%Ti is not simply attributable to the dissolution of Ti into Al, but associated mainly with extreme refining and/or heavy straining of Ti Particles.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.39-40
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• 2011

This study is to analyse possibility cementitious powder from waste concrete as row material of recycled cement. From the results, we ascertained possibility as recycled cement through XRF & XRD of cementitious powder & recycled cement. As a result of the experiment, cementitious powder from waste concrete, which appeared to recovery hydration chemically at the calcining temperature of 700, suggested highly possibility as recycled cement.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.55-56
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• 2016

In the recent concrete industry, when producing recycled aggregates, waste concrete powder is by-produced in large quantities; however, since it is not used properly but buried or discarded. This study is to apply the waste concrete powder to a cement extruding panel as filler. Flexural strength and microstructure characteristics of panel is tested in order to improve the economics of the extruding panel. As a results of this study, it was found that extruding panel replacing silica(No.8) as the waste concrete powder totally showed little difference in the strength and satisfied the target flexural strength of 14MPa, comparing with controlled panel. In addition, we can understand that rich Portlandite and Calcite contributed to develop the strength in all curing conditions from XRD pattern.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.6
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• pp.244-251
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• 2005

The relationship between particle size of hydro-thermally synthesized barium titanate powders (BT01, BT02, BT03, BT04, BT05) and the powder properties was investigated by means of particle size, specific surface area, zeta potential, XPS, XRD and SEM. Particle size determined by laser light scattering is closely related with specific surface area and the tetragonality (c/a) obtained from XRD. The specific surface area of the samples inversely decreased with increasing particle size except BT03 powder. BT03 sample showed higher surface area than BT04 sample of equivalent particle size, which was attributed mostly to the agglomeration of particles in terms of SEM image and XRD analysis. Zeta potential increased with increasing particle size with the exception of BT02 and BT03 which showed larger minus value of zeta potential in comparison with other BT powders. Beta potential results of BT02 and BT03 are considered to be related with the dissolution of $Ba^{2+}$ ion in these powers which was examined by XPS.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.12
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• pp.1117-1123
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• 2005

In this study, our varistors based on M. Matsuoka's composition were fabricated with ZnO nano-powder whose sizes were 50 nm and 100 nm. Before fabrication of ZnO nano-powder varistors, structure and Phase were analyzed by FE-SEM and XRD with size of ZnO nano-powders to obtain manufacturing information to fabricate the first ZnO varistors using by nano-powders. As a results of these analyses, calcination and sintering temperatures were respectively designed at $600^{\circ}C\;and\;1050^{\circ}C$. ZnO nano-powder varistors were analyzed by SEM and XRD to measure the changes of microstructures and phase after sintered by out process conditions. Also, electrical properties of ZnO nano-powder varistors were obtained by capacitance-voltage, frequency-teal impedance, and current-voltage corves. Our ZnO nano-powder varistors had about 2.5 times of electric field at varistor voltage as compared with normal ZnO varistors fabricated with micro-powder. Also, leakage current and non-liner coefficient respectively had $2.0{\times}10^{-6}A/cm^{-2}$ and 41 for ZnO nano-powder varistors with 50 nm.