• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 추계 학술논문 발표대회
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• pp.49-50
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• 2011

This study tried to utilize basic data for developing the cement substitute material through ternary system inorganic composite properties of flowing and strength. W/B and addition ratio of Na2SiO3 have been changed in ternary system inorganic composite combined blast furnace slag, red mud and fly ash. As to the experimental result inorganic composite, the flowing and intensity improvement effect was showed to be bigger than W/B according to the addition ratio change of the Na2SiO3. When particularly the Na2SiO3 addition ratio was 6%, the rapid flowing and strength improvement effect was confirmed.

• 한국주조공학회지
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• 제24권3호
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• pp.138-144
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• 2004

Effects of alloying elements such as Si, Mn, Zn on the fluidity and mechanical properties of high ductility Al-Mg based alloys were investigated. The fluidity of alloys was evaluated using a vacuum suction fluidity test, and Si addition was observed to increase the fluidity of AI-Mg binary alloys substantially while Zn somewhat decreased the fluidity. However, both the strength and ductility were significantly deteriorated by the Si additions. It was observed that a small amount of Mn addition to Al-Mg alloy increased the tensile strength effectively without losing much ductility but the effect of Zn addition on the strength was relatively small.

• 대한금속재료학회지
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• 제48권3호
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• pp.248-255
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• 2010

The effect of various alloying elements and melt treatment on the microstructural control of Al-Sn metallic bearing alloy was investigated. The thickness of tin film crystallized around primary aluminum decreased with the addition of 5% Cu in Al-Sn alloy, with tin particles being reduced in size by intervening the Ostwald ripening. With the addition of Si in Al-10%Sn alloy, the tin particles were crystallized with eutectic silicon, resulting in uniform distribution of tin particles. With the addition of Cu and Si in Al-Sn alloy, both the tensile strength and yield strength increased, with the increasing rate of yield strength being less than that of tensile strength. Although the Al-10%Sn-7%Si alloy has similar tensile strength compared with Al-10%Sn-5%Cu, the former showed superior abrasion resistance, resulting from preventing the tin particles from movement to the abrasion surface.

• 공학논문집
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• 제3권1호
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• pp.215-222
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• 1998

촉매 연소용 촉매 담체인 $\gamma-Al_2O_3$ 분말의 열안정화에 미치는 La과 Si의 첨가 효과에 대하여 연구하였다. 첨가제의 첨가는 습식 impregnation방법으로 행하였고, 출발 물질은 $La(NO_3)_3{\cdot}6H_2O$와 $Si(OC_2H_5)_4$를 사용하였다. 열안정화 효과는 혼합분말을 고온에서 열처리 한 후 비표면적을 측정하여 고찰하였다. 첨가제로 첨가한 La과Si는 모두 순수한 $\gamma-Al_2O_3$분말에 비하여 소결을 억제함으로써 열 안정화 효과가 있음이 확인되었으며, 특히 Si 첨가한 경우에는 $\alpha-Al_2O_3$의 생성을 현저히 억제한다는 것을 확인하였다. 이들 첨가제에 의한 열안정화 효과는 첨가제에 의한 새로운 상의 생성과 표면 확산의 억제등이 주된 요인으로 판단되었다.

• 한국재료학회지
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• 제27권10호
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• pp.544-551
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• 2017

In order to develop a new commercial Al-12%Si casting alloy with improved physical properties, we investigated the effect of adding Sr and TiB to the alloy. Al-12%Si alloys were prepared by die casting at $660^{\circ}C$. The eutectic temperature of the Sr-modified Al-12%Si alloy decreased to $9^{\circ}C$ and the mushy zone region increased. The shape of the Si phase changed from coarse acicula to fine fiber with the addition of Sr. The addition of TiB in the Al-12%Si alloy reduced the size of the primary ${\alpha}$-Al and eutectic Si phases. When Sr and TiB were added together, it worked more effectively in refinement and modification. The density of twins in the Si phase-doped Sr increased and the width of the twins was refined to 5 nm. These results are related to the impurity induced twinning(IIT) growth.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.97.2-97.2
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• 2018

This study formed a hard TiAlSiWN coating layer using Ti, Al, Si and W raw powders that were mechanically alloyed and refined. The TiAlSi and TiAlSiW coating targets were fabricated using a single PCAS process in a short time with the optimal sintering conditions. The coating targets were deposited on the WC substrate by forming coating layers using TiAlSiN and TiAlSiWN nitride nano-composite structures with an AIP process. The properties of the nitride nano-composite coating layers were compared according to the addition of W. The microstructure of the nitride nano-composite coating layer was analyzed, focusing on the distribution of the crystalline phases, amorphous phases ($Si_3N_4$), and growth orientation of the columnar crystal depending on the addition of W. The mechanical properties of the coating layers were exhibited a hardness of approximately $3,000kg/mm^2$ and adhesion of about 117.77N in the TiAlSiN. In particular, the TiAlSiWN showed excellent properties with a hardness of more than $4,300kg/mm^2$ and an adhesion of about 181.47N.

• 한국세라믹학회지
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• 제46권5호
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• pp.488-492
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• 2009

Porous frit-bonded SiC ceramics were successfully prepared at a temperature as low as $800^{\circ}C$ from SiC, frit, and microbeads (glass or polymer). The effects of SiC starting particle size and microbead addition on microstructure, porosity, and flexural strength were investigated. The addition of hollow glass microbead improved the strength of frit-bonded SiC ceramics without the loss of porosity by acting additional binder phase between SiC grains. The 65 ${\mu}m$-sized SiC resulted in lower porosity and higher strength than 50 ${\mu}m$-sized SiC because of higher packing density. Typical flexural strengths of frit-bonded SiC were 23 MPa at 46% porosity and 19 MPa at 49% porosity.

• 한국세라믹학회지
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• 제50권6호
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• pp.402-409
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• 2013

The objective of this study was to develop a synthesis process for ${\beta}$-SiC powders to reduce the synthesis temperature and to control the particle size and to prevent particle agglomeration of the synthesized ${\beta}$-SiC powders. A phenol resin and TEOS were used as the starting materials for the carbon and Si sources, respectively. $SiO_2$-C hybrid precursors with various C/Si mole ratios were fabricated using a conventional sol-gel process. ${\beta}$-SiC powders were synthesized by a carbothermal reduction process using $SiO_2$-C hybrid precursors with various C/Si mole ratios (1.6 ~ 2.5) fabricated using a sol-gel process. In this study, the effects of excess carbon and the addition of Si powders to the $SiO_2$-C hybrid precursor on the synthesis temperature and particle size of ${\beta}$-SiC were examined. It was found that the addition of metallic Si powders to the $SiO_2$/C hybrid precursor with excess carbon reduced the synthesis temperature of the ${\beta}$-SiC powders to as low as $1300^{\circ}C$. The synthesis temperature for ${\beta}$-SiC appeared to be reduced with an increase of the C/Si mole ratio in the $SiO_2$-C hybrid precursor by a direct carburization reaction between Si and excess carbon.

• 한국주조공학회지
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• 제15권6호
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• pp.558-565
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• 1995

Effects of high Si-P addition on microstructure and mechanical properties of thin ductile cast iron have been investigated. The amount of silicon addition have fixed on 4.0wt% and the amounts of phosphorus addition and thickness of specimen have been varied from 0.05 to 0.8wt% and ${\phi}13mm$, ${\phi}10mm$ and ${\phi}6mm$, respectively. As the casting thickness decreased, the average diameter of spheroidal graphite was decreased and the hardness of the cast iron increased. By adding P, the average diameter of spheroidal graphite was increased and the count of the spheroidal graphite was decreased continuously. And the tensile strength and the elongation was decreased, and the hardness was increased. With the P added more than 0.2wt%, the abraded amount was decreased significantly. The addition of P improved the wear resistance and the hardness of thin ductile cast iron.

• 한국주조공학회지
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• 제24권1호
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• pp.45-51
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• 2004

Fe and Si are common impurity elements in the aluminum alloys. In this investigation, the effects of the addition of Fe and Si on the age-hardening behaviors of the Al-Cu-Mn-Ti-Zr-Cd casting alloys were examined through hardness measurements, calorimetric techniques and observation of the transmission electron microscopy. The addition of Fe depresses the formation of GPII and ${\theta}'$, and thus retards the peak aging time and reduces the peak hardness of the Al-Cu-Mn-Ti-Zr-Cd alloys. On the contrary, the addition of Si accelerates the formation of GPII and ${\theta}'$ and thus accelerates age-hardening behaviors of the Al-Cu-Mn-Ti-Zr-Cd alloys.