• 한국세라믹학회지
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• 제34권5호
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• pp.453-460
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• 1997

Sr-ferrite having magnetoplumbite structure is similar to Ba-ferrite in magnetic characteristics, but better magnetic characteristics for using motor application. To improve remanence magnetic flux density(Br) and coercive force(iHc), it is necessary that sintered ferrites must have high density and grain size less than 1 $\mu$m. By varying n values in SrO.nFe2O3 basic composition, calcination temperature, and BaO addition, Sr-ferrite powder and sintered specimen was prepared. The n values, calcination temperature, and BaO addition affected secondary phase formation, particle size, and particle shape. BaO addition enhanced Fe2O3 secondary phase and hexagonal shape particle. Fe2O3 phase reduced sintered density which greatly decreased Br.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.759-760
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• 2006

Ti-6Al-4V has low specific gravity, high corrosion resistance and superior mechanical properties but it is very difficult to control oxygen content in MIM process. It is necessary to use powders with coarse particle size to decrease oxygen content of powders, so feedstocks with poor fluidity and sintered bodies with lower density are obtained in such cases. Fine titanium hydride-dehydride powders were blended with atomized powders to accomplish higher fluidity and sintered density. Sintered bodies had higher sintered density and mechanical properties equivalent to those of wrought materials by controlling oxygen content less than 0.35mass%.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1988년도 추계학술대회 논문집
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• pp.36-40
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• 1988

High TC Y-Ba-Cu-O Superconductors were fabricated by sintering, sinter+HIP encapsulation. Specimens were sintered at 920$^{\circ}C$∼960$^{\circ}C$. A part of sintered specimens were treated by HIP, and HIP conditions were 150 MPa, 880$^{\circ}C$, 30min under the Ar atmosphere. The relative density of HIP specimens was increased 5∼8% in comparison with sintered one(90∼93% relative density). X-ray analysis represented the orthorhobic-tetragonal phase transition with annealing condition. Tc measurements showed a sharp drp within 3$^{\circ}C$, 91K onset and 89K offset. Transport current density(Jc) of sintered specimens showed typically∼159A/㎤ but that of sinter+HIP encapsulation was decreased to∼89A/㎤ because of insufficient oxygen diffusion, Hardness(H) and Toughness(Kc) were increased to 38GPa; and 2.9 MPam$\^$$\frac{1}{2}$/, respectively.

• 한국분말재료학회지
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• 제8권4호
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• pp.239-244
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• 2001

To investigate the effect of process parameters on selective laser sintering of Cu/polyamide mixed powder, Cu/polyamide mixed powder was sintered by selective laser with changing laser power and scanning speed. The properties of sintered body were evaluated by measuring the density and tensile strength, and analysis of XRD, FT-Raman and microstructure. With an increase in the laser power, the density and ultimate tensile strength of sintered Cu/polyamide body increase and then decrease. The maximum values of the density and ultimate tensile strength were decreased with increasing laser scanning speed. These changes were concerned with the difference of irradiation energy of laser into the powder layer. It was considered that the change of the mechanical property of the sintered body with irradiation energy of laser is due to the changes of amount of copper particle and property of polyamide.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.605-609
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• 2001

Low density ceramic supporter was prepared by using fly ash as a starting material for the application to the biological aerated filter (BAF) system, and the effect of additives and sintering atmosphere on the apparent and bulk density of the carrier was examined. Borax, Na$_2$O and glass powders were added to produce liquid phase. The density of the supporter decreased as the amount of borax increased. The bulk density of 0.79 g/㎤ and the apparent density of 1.10 g/㎤ were obtained when the fly ash with 15% of borax was sintered at 116$0^{\circ}C$ for 15 minutes. The density also decreased as the plate glass powders past through 22${\mu}{\textrm}{m}$ size were mixed. When the fly ash with 12% of grass powder was sintered at 128$0^{\circ}C$ for 10 minutes, the bulk and apparent density were 0.90g/㎤ and 1.00 g/㎤, respectively. Apparent density of 1.6~1.8g/㎤ was obtained when the fly ash was sintered at 120$0^{\circ}C$ in a weak reducing atmosphere. By maintaining the reducing atmosphere and sintering at a high heating rate, the liquid phase was farmed from the reduced composition of fly ash. This resulted in the formation of closed pores that enabled the low apparent density.

• 한국분말재료학회지
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• 제16권4호
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• pp.268-274
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• 2009

For the purpose of obtaining basic information on the development of lead-free materials, a high density composites (a) W-Cu, (b) W-Sn (c)W-Cu-Sn and (d) W-Cu-Ni were fabricated by the P/M method. The particle size of used metal powders were under 325 mesh, inner size of compaction mould was $\phi8$ mm, and compaction pressure was 400 MPa. A High density composite samples were sintered at a temperature between $140^{\circ}C$ and $1050^{\circ}C$ for 1 hour under Ar atmosphere. The microstructure, phase transformation and physical properties of the sintered samples were investigated. As the results, the highest relative density of 95.86% (10.87 g/$cm^3$) was obtained particularly in the sintered W-Cu-Sn ternary system sample sintered at 450 for 1hr. And, Rockwell hardness (HRB) of 70.0 was obtained in this system.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2008년도 춘계학술발표대회 개요집
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• pp.40-40
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• 2008

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1995년도 추계학술강연 및 발표대회 강연 및 발표논문 초록집
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• pp.9-9
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• 1995

MATERIAL AND PROCESS VARIABLES THAT STRONGLY AFFECT THE CORROSION RESISTANCE OF PA4 STAINLESS STEELS, INCLUDE : ALLOY COMPOSITION, POWDER CLEANLINESS, NITROGEN, OXYGEN AND GARBON CONTENTS, CHROMIUM DEPLETION DUE TO SURFACE EVAPORATION AND SINTERED DENSITY. THE OPTIMUM PROCESS PARAMETERS FOR DELUBRICATION AND SINTERING THAT RESULT IN LOWEST LEVELS OF NITROGEN, OXYGEN AND CARBON AND MINIMUM LEVELS OF CHROMIUM DEPLETION WILL BE PRESENTED, FOR A NUMBER OF AUSTENTIC AND FERRITIC STAINLESS STEELS. THE EFFECT OF SINTERED DENSITY ON THE CORROSION RESISTANCE OF BOTH AUSTENITIC AND FERRITIC GRADES OF STAINLESS STEEL WILL ALSO BE COVERED.

• 한국세라믹학회지
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• 제32권10호
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• pp.1162-1168
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• 1995

Systematic studies of the effects of additives and processing variables on the sintered density and the effect of crystalline forms of starting powders on the microstructure of pressureless sintered silicon carbide are described. Oxide additives were effective for the densification of SiC up to 96% of theoretical density at temperature as low as 185$0^{\circ}C$. Use of embedding powder increased the sintered density, up to 98% of theoretical density, by decreasing the weight loss during sintering. Composite type duplex microstructure has been developed due to the $\beta$longrightarrow$\alpha$ phase transformation of SiC by sintering at 185$0^{\circ}C$ and heat treatment at 195$0^{\circ}C$ for 1h.

• 공업화학
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• 제28권3호
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• pp.345-350
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• 2017

원자력연료 제조공정에서 생산되는 우라늄산화물(uranium oxide, UOX) 소결체의 밀도 분석은 일반적으로 소결공정을 거친 후, 소결체의 표본을 가지고 측정한다. 본 연구에서는 우라늄산화물의 중간물질인 중우라늄산암모늄(ammonium diuranate)의 색도를 분광기(spectrophotometer)로 측정함으로써 소결공정 이전에 우라늄산화물 소결체의 밀도를 분석해 보았다. 중우라늄산암모늄 표준 샘플 5개를 통해 얻은 명도 및 색의 좌푯(L, a, b)값과 통상적인 방법으로 얻은 소결체 밀도의 상관관계 추세선을 바탕으로 표적 샘플의 밀도를 분석한 결과, L 값에 대한 소결체의 밀도 분석이 결정계수 $R^2$ 값 0.9967로 가장 신뢰성이 높게 나왔음을 확인하였다. a 값에 대한 결정계수 $R^2$ 값은 0.9534로 상관관계가 높은 편이나 L 값보다는 낮았다. 이에 반해 b 값에 대한 결정계수 $R^2$ 값은 0.4349로 상관관계가 거의 없었다.