• 한국재료학회지
• /
• 제12권9호
• /
• pp.696-700
• /
• 2002

The Ti-aluminide intermetallic compound was formed from high purity elemental Ti and Al foils by self-propagating, high-temperature synthesis(SHS) in hot press. formation of $TiAl_3$ at the interface between Ti and Al foils was controlled by temperature, pressure, heating rate, and so on. According to the thermal analysis, it is known in this study that the heating rate is the most important factor to form the intermetallic compound by this SHS reaction. The V layer addition between Al and Ti foils increased SHS reaction temperatures. The fully dense, well-boned inter-metallic composite($TiA1/Ti_3$Al) sheets of 700 m thickness were formed by heat treatment at $1000^{\circ}C$ for 10 hours after the SHS reaction of alternatively layered 10 Ti and 9 Al foils with the V coating layer. The phases and microstructures of intermetallic composite sheets were confirmed by EPMA and XRD.

• 한국세라믹학회지
• /
• 제49권6호
• /
• pp.614-619
• /
• 2012

We investigated color and graphite layer formation on the surface of Type I tinted brown diamonds exposed for 5 minutes under a high-pressure high-temperature (HPHT) condition in a stable graphite regime. We executed the HPHT processes of Process I, varying the temperature from $1600^{\circ}C$ to $2300^{\circ}C$ under 5.2 GPa pressure for 5 minutes, and Process II, varying the pressure from 4.2 to 5.7 GPa at $2150^{\circ}C$ for 5 minutes. Optical microscopy and micro-Raman spectroscopy were used to check the microstructure and surface layer phase evolution. For Process I, we observed a color change to vivid yellow and greenish yellow and the growth of a graphite layer as the temperature increased. For Process II, the graphite layer thickness increased as the pressure decreased. We also confirmed by 531 nm micro-Raman spectroscopy that all diamonds showed a $1440cm^{-1}$ characteristic peak, which remained even after HPHT annealing. The results implied that HPHT-treated colored diamonds can be distinguished from natural stones by checking for the existence of the $1440cm^{-1}$ peak with 531 nm micro-Raman spectroscopy.

• 한국전기전자재료학회논문지
• /
• 제30권10호
• /
• pp.631-636
• /
• 2017

The degradation mechanism of $Mo_xW_{1-x}Si_2$ ultrahigh-temperature heating elements fabricated by self-propagating high-temperature synthesiswas investigated. The $Mo_xW_{1-x}Si_2$ specimens (with and without post-annealing) were subjected to ADTs (accelerated degradation tests) at temperatures up to $1,700^{\circ}C$ at heating rates of 3, 4, 5, 7, and $14^{\circ}C/min$. The surface loads of all the specimen heaters were increased with the increase in the target temperature. For the $Mo_xW_{1-x}Si_2$ specimens without annealing, many pores and secondary-phase particles were observed in the microstructure; the surface load increased to $23.9W/cm^2$ at $1,700^{\circ}C$, while the bending strength drastically reduced to 242 MPa. In contrast, the $Mo_xW_{1-x}Si_2$ specimens after post-annealing retained $single-Mo_xW_{1-x}Si_2$ phases and showed superior durability after the ADT. Consequently, it is thought that the formation of microcracks and coarse secondary phases during the ADT are the main causes for the degraded performance of the $Mo_xW_{1-x}Si_2$ heating elements without post-annealing.

• 한국전기전자재료학회논문지
• /
• 제18권6호
• /
• pp.554-559
• /
• 2005

Ni/Cr thin film is very interesting material as thin film resistors, filaments, and humidity sensors because their relatively large resistivity, more resistant to oxidation and a low temperature coefficient of resistance (TCR). These interesting properties of Ni/Cr thin films are dependent upon the preparation conditions including the deposition environment and subsequent annealing treatments. Ni/Cr thin films of 250 nm were deposited by DC magnetron sputtering on $Al_2O_3/Si$ substrate with 2-inch Ni/Cr (80/20) alloy target at room temperature for 45 minutes. Annealing treatments were performed at $400^{\circ}C,\;500^{\circ}C,\;and\;600^{\circ}C$ for 6 hours in air or $H_2$ ambient, respectively. The clear crystal boundaries without crystal growth and the densification were accomplished when the pores were disappeared in air ambient. Most of surface was oxidic including NiO, $Ni_2O_3$ and $Cr_xO_y$(x=1,2, y=2,3) after annealing in air ambient. The crystal growth in $H_2$ ambient was formed and stabilized by combination with each other due to the suppression of oxidized substance on film surface. Most oxidic Ni was restored when the oxidic Cr was present due to its stability in high-temperature $H_2$ ambient.

• 한국섬유공학회:학술대회논문집
• /
• 한국섬유공학회 2001년도 학술발표회 논문집(Proceedings of the Korean Textile Conference) 상
• /
• pp.123-126
• /
• 2001

• 한국자기학회:학술대회 개요집
• /
• 한국자기학회 2001년도 추계연구발표회 논문개요집
• /
• pp.68-69
• /
• 2001

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1998년도 추계학술대회 논문집
• /
• pp.151-154
• /
• 1998

We have investigated a correlation of the electrical properties of the Pd/Ge/Pd/Ti/Au ohmic contact on n-InGaAs with its microstructures for the high temperature application of compound semiconductor devices. The samples were heat-treated by the rapid thermal annealing at various temperatures. In the contact system, moderately good specific contact resistance was obtained even before annealing because of the low metals-InGaAs barrier height, and better ohmic performances were observed by annealing up to 400˚C. But the ohmic performance was degraded after annealing at 450˚C due to the increment of Pd$_2$Ga$\sub$5/ phases.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2010년도 춘계학술대회 논문집
• /
• pp.14-14
• /
• 2010

Recently, low temperature co-fired ceramic (LTCC) technology has gained a remarkable application potential in sensors, actuators and micro systems fields because of its very good electrical and mechanical properties, high reliability and stability as well as possibility of making 3D micro structures. In this study, we investigated the effects of annealing treatment on the electrical properties of $Pb(ZrTi)O_3$ (PZT) thin films deposited on LTCC substrate. PZT thin films were deposited on Au / LTCC substrates by RF magnetron sputtering method. Then, the change of the crystallization of the films were investigated under various annealing temperatures and times. The results showed that the crystallization of the films were enhanced as increasing annealing temperatures. The film, annealed at $700^{\circ}C$, 3min, was well crystallized in the perovskite structure.

• 전자공학회논문지A
• /
• 제29A권8호
• /
• pp.89-98
• /
• 1992

IIM(Implantation Into Metal) process usning Co silicides has been investigated to obtain ultra-shallow junctions less than 0.1$\mu$m. Rapid Thermal Annealing using halogen lamps was employed to form CoSi$_2$ and junctions simultaneously.. Resistivities of CoSi$_2$ were 13-17$\mu$ $\Omega$-cm. CoSi$_2$/p$^{+}$/Si and CoSi$_2$/n$^{+}$/Si junction were formed by diffusion of B and As, respectively, from Co film. It was found out that B and As were severely lost by the evaporation during high temperature annealing Therefore SiO$_2$ capping layers were introduced to prevent the evaporation of the implanted dopants from the films. Investigation of the behavior of dopants with respect to annealing time revealed that increasing the annealing time enhanced the diffusion of dopants into Si from CoSi$_2$.

• Journal of Korean Vacuum Science & Technology
• /
• 제4권2호
• /
• pp.50-54
• /
• 2000

We studied the synthesis of S $i_{1-x}$ Cx (x=0.016) epitaxial layer using ion implantation and solid phase epitaxy (SPE). The activation energy Ea was obtained for the loss of substitutional carbon using fourier transform-infrared spectroscopy (FTIR) and high-resolution x-ray diffraction (HR-XRD). In FTIR analysis, the integrated peak intensity was used to quantify the loss of carbon atoms from substitutional to interstitial sites during annealing. The substitutional carbon contents in S $i_{0.984}$ $C_{0.016}$ were also measured using HR-XRD. By dynamic simulations of x-ray rocking curves, the fraction of substitutional carbon was obtained. The effects of annealing temperature and time were also studied by comparing vacuum furnace annealing with rapid thermal annealing (RTA))))))