• The Korean Journal of Ceramics
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• v.5 no.1
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• pp.78-81
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• 1999

Aluminium titanate is highly anisotropic in thermal expansion. As a result, thermal stresses build up in the material and intergranular cracks can develop. Both the outstanding thermal shock resistance and the low mechanical strength of aluminium titanate ceramics are a result of intergranular microcracking. The authors have previously identified a possibility of remarkably increasing fracture toughness of aluminium titanate without excessive penalty on strength. The paper shows that sintered density and porosity measurements can be used for optimizing the sintering and microstructure of aluminium titanate for an ideal balance between toughness and strength and, hence, the best thermal shock resistance.

• Journal of the Korean institute of surface engineering
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• v.49 no.6
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• pp.507-512
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• 2016

Expensive silver powder is used to form electrodes in most IT equipment, and recently, many attempts have been made to lower manufacturing costs by developing powders with Ag-Ni or Ag-Cu core-shell structures. This study examined the sintering behavior of Ag-Ni electrode powder with a core-shell structure for silicon solar cell with high energy efficiency. The electrode powder was found to have a surface similar to pure Ag powder, and cross-sectional analysis revealed that Ag was uniformly coated on Ni powder. Each electrode was formed by sintering in the range of $500^{\circ}C$ to $800^{\circ}C$, and the specimen sintered at $600^{\circ}C$ had the lowest sheet resistance of $5.5m{\Omega}/{\Box}$, which is about two times greater than that of pure Ag. The microstructures of electrodes formed at varying sintering temperatures were examined to determine why sheet resistance showed a minimum value at $600^{\circ}C$. The electrode formed at $600^{\circ}C$ had the best Ag connectivity, and thus provided a better path for the flow of electrons.

• Korean Journal of Metals and Materials
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• v.50 no.6
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• pp.469-475
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• 2012

A high-energy mechanical milling (HEMM) process was introduced to improve sinter-ability, and rapid sintering of spark plasma sintering (SPS) under pressure was used to make ultra fine grain (UFG) of Ti-Nb-Mo-CPP composites, which have bio-attractive elements, for increasing mechanical properties. Ti-Nb-Mo-CPP composites were successfully fabricated by SPS at $1000^{\circ}C$ within 5 minutes under 70 MPa using HEMMed powders. The Vickers hardness of the composites increased with increased milling time and addition of CPP contents. Biocompatibility and corrosion resistance of the Ti-Nb-Mo alloys were improved by addition of CPP, and the Ti-35%Nb-10%Mo-10%CPP alloy had better biocompatibility and corrosion resistance than the Ti-6Al-4V ELI alloy.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.2
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• pp.119-124
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• 2013

In this study, the two-dimensional transient temperature of printed Ag nanoparticle ink during continuous wave laser sintering was calculated. Ag nanoparticle ink was printed on a glass substrate by inkjet printing. Then, a 532-nm continuous wave laser with different laser intensities was irradiated on the printed Ag nanoparticle ink for 60 s. During laser irradiation, the in-situ specific resistance of the sintered ink was measured. To obtain the transient temperature of the sintered ink during the laser sintering process, a two-dimensional transient heat conduction equation was derived by applying the Wiedemann-Franz law. It was found that the specific resistance of the sintered ink decreased with an increase in the sintering temperature of the printed ink.

• Journal of the Korean institute of surface engineering
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• v.28 no.4
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• pp.207-218
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• 1995

Tungsten(W) metal has excellent properties in heat-resistance, corrison-resistance and impact-resistance but W-Metal is hard to sinter because higher than $2,000^{\circ}C$ is required to sinter W-powder. Con-sequently, a deposit technique of Nikel Phosphorus(NiP) on W-powber by the liquid reduction precipitation method was performed. Sintering temperature of the resulting W-NiP composite was lowered around to $1,000^{\circ}C$, and the mechanical properties of the sintered body was studied. The most suitable conditions for NiP thin film deposit on W-Powder by the liquid reduction precipitation method, which are composition, concentration, pH and temperature of the liquid reduction solution, were considered. The activated sintering was carried out in a reducing condition furnace. Components and properties of the sintered body were investigated by the density and the hardness measurements, X- ray diffraction analysis, and microscopic photographs of the surface. Quantity of NiP thin film on W-powder could be varied by the change of the liquid reduction solution composition. The sintering temperature of W-NiP composite powder is lowered to $950^{\circ}C$ from $2,000^{\circ}C$ and the hardness is increased (ca. 720 Hv). Large shrinkage could be observed since density was increased from 5.5 to 11.0 g/$cm^2$ which 86.2% of theoretical density. W metal and $Ni_3P$ crystal were detected through X-ray diffraction on the sintered body. Perfectly activated sintering was observed by microscopic photographs.

• Journal of Powder Materials
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• v.5 no.4
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• pp.286-292
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• 1998

Ni$_3$Al intermetallic compound has been tested as a binder phase, in order to improve the oxidation resistance and the mechanical properties of TiC-Ni cermet at a high temperature. The wettability of $Ni_3Al$ on TiC and the optimum sintering condition were investigated in TiC-(30, 40) vol% $Ni_3Al$ cermets with the sintering temperature (1380~$1430^{\circ}C$) and time (30~99 min). The results are summarized as follows: 1) Ni$_3$Al showed good wettability on TiC above 1400$^{\circ}C$ ; 2) The shrinkages of the specimens increased with the sintering temperature, the sintering time and the binder content, whereas the relative densities were decreased; 3) Any other phase did not appeared in the microstructures of all sintered cermets. The grain sizes of TiC became larger as the sintering temperature and the sintering time as well as the binder content increased; 4) The hardness of the cermets decreased with increase in the sintering temperature and the sintering time as well as the binder content; 5) The transverse-rupture strength of the cermets increased with the sintering temperature and the sintering time, whereas it decreased with the binder content.

• The Journal of Advanced Prosthodontics
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• v.16 no.1
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• pp.25-37
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• 2024

PURPOSE. To investigate the effect of sintering programs and surface treatments on surface properties, phase transformation and flexural strength of monolithic zirconia. MATERIALS AND METHODS. Zirconia specimens were sintered using three distinct sintering programs [classic (C), speed (S), and superspeed (SS)] (n = 56, each). One sample from each group underwent scanning electron microscopy (SEM) and grain size analysis following sintering. Remaining samples were divided into five subgroups (n = 11) based on the surface treatments: control (CL), polish (P), glaze (G), grind + polish (GP), and grind + glaze (GG). One sample from each subgroup underwent SEM analysis. Remaining samples were thermally aged. Monoclinic phase volume, surface roughness, and three-point flexural strength were measured. Monoclinic phase volume and surface roughness were analyzed by Kruskal-Wallis and Dunn tests. Flexural strength was analyzed by two-way ANOVA and Weibull analysis. The relationships among the groups were analyzed using Spearman's correlation analysis. RESULTS. Sintering program, surface treatment, and sintering × surface treatment (P ≤ .010) affected the monoclinic phase volume, whereas the type of surface treatment and sintering × surface treatment affected the surface roughness (P < .001). Type of sintering program or surface treatment did not affect the flexural strength. Weibull analysis revealed no significant differences between the m and σ_o values. Monoclinic phase volume was positively correlated with surface roughness in the SGG and SSP groups. CONCLUSION. After sintering monolithic zirconia in each of the three sintering programs, each of the surface treatments can be used. However, for surface quality and aging resistance, G or GG can be recommended as a surface finishing method.

• Journal of the Korean institute of surface engineering
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• v.27 no.3
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• pp.166-175
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• 1994

The effect of Co addition on the electrochemical performance and structural stability of porous Ni anode for molten carbonate fuel cell(MCFC) was evaluated by the anodic polarization and the sintering test in the simulated MCFC anode condition ($650^{\circ}C$, 80% $H_2$+20%$CO_2$). The anode current density ranged from 110mA/$cm^2$ to 144mA/$cm^2$ was obtained at +100mV overpotential by additions of Co up to 10 wt.%. The sintering resistance of Ni-Co anodes was higher than that of the pure Ni anode. The increase of sintering resistance seemed to be to the lower diffusion coefficient of Co than that of Ni.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.328-329
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• 2009

This paper presents the effect of organic Ag complex sintering temperature on the MEH-PPV photoluminescence (PL) properties. MEH-PPV and organic Ag complex was coated on the glass substrate by spin coating method. The coated Ag complex was sintered in an air atmosphere. The sintering temperature was varied from 100 to $200^{\circ}C$ and sintering time was 5 min. The Ag film sintered at temperature higher than $120^{\circ}C$ shows very low sheet resistance less than $0.5\;{\Omega}{/\square}$. The coated MEH-PPV measure photoluminescence (PL) intensity at 580 nm. The PL peak was shifted to the higher wavelength with increasing the sintering temperature.

• Journal of the Korean Ceramic Society
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• v.27 no.3
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• pp.337-344
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• 1990

As a function of sintering temperature and time, the electrical properties of ruthenium based thick film resistors were investigated with microstructure. The variatio of resistivity and TCR(temperature coefficient of resistance)trends of sintered speciman at various sintering temperature were different low resistivity paste(Du Pont 1721) from high one(Du Pont 1741). These phenomena are deeply relative to microstructure of sintered film. With increasing the sintering temperature for 1721 system, the electrical sheet resistivity decreased, but again gradually increased above 80$0^{\circ}C$. And TCR trends in 1721 system are all positive. On the other hand the electrical sheet resistivity of 1741 resistor system decreased with sintering temperature. And TCR trends variable according to sintering temperature. TCR of speciman sintered at $700^{\circ}C$ was negative value, and TCR of 80$0^{\circ}C$ sintered speciman coexisted negative and positive value. But in case of speciman sintered at 90$0^{\circ}C$, TCR was positive value. As results of this fact, it was well known that the charge carrier contributied to electrical conduction in 1741 resistor system varied with sintering temperature.