• Journal of the Korean institute of surface engineering
• /
• v.32 no.1
• /
• pp.67-77
• /
• 1999

The Ni base superalloy Mar-M247 substrate was aluminized or aluminized after boronizing by the pack cementation under Ar atmosphere. The hot corrosion resistance and after-heat-treatment effect of aluminized specimens were studied by the cyclic hot corrosion test in $Na_2SO_4$-NaCl molten salt. XRD analysis showed that the $Ni_2Al_3$ phase was formed between the coated layer and substrate below 1273K but the NiAl phase above 1273K. The peak of the NiAl phase was developed after heat treatment. Corrosion test showed that corrosion resistance of the specimen with the NiAl phase was better than that with the $Ni_2Al_3$ phase. Corrosion resistance could be improved by heat treatment to form ductile NiAl phase, where cracks were not formed by thermal shock on coating layer. Moreover, it appeared that heat treatment played a role to improve corrosion resistance of Al diffusion coating above 1273K. The existence of boron in the Al diffusion coating layer obstructed outwared diffusion of Cr from the substrate, and it influenced on corrosion resistance of the coating layer by weakening adherence of the oxide scale.

• Journal of the Korean Applied Science and Technology
• /
• v.30 no.3
• /
• pp.423-430
• /
• 2013

Carbon coils could be synthesized using $C_2H_2/H_2$ as source gases and $SF_6$ as an incorporated additive gas under thermal chemical vapor deposition (CVD) system. Prior to the carbon coils deposition reaction, two kinds of samples having different combination of Ni catalyst and substrate were employed, namely, a commercially-made $Al_2O_3$ ceramic boat with Ni powders and a commercially-made $Al_2O_3$ substrate with Ni layer. By using a commercially-made $Al_2O_3$ ceramic boat, the synthesis of carbon coils could be enhanced as much as 10 times higher than that of $Al_2O_3$ substrate. Furthermore, the dominant formation of the microsized carbon coils could be obtained by using $Al_2O_3$ ceramic boat. The surface roughness of the supporting substrate of $Al_2O_3$ ceramic boat was understood to be associated with the large scale synthesis of carbon coils as well as the dominant formation of the larger-sized, namely the microsized carbon coils.

• Korean Journal of Materials Research
• /
• v.11 no.9
• /
• pp.776-780
• /
• 2001

$SiO_2$ and polycrystalline Si layers were sequentially grown on (100) Si. NiSi was formed on this substrate from a 20nm Ni layer or a 20nm Ni/5nm Ti bilayer by rapid thermal annealing (RTA) at $300~500^{\circ}C$ to compare thermal stability. In addition, MOS capacitors were fabricated by depositing a 20nm Ni layer on the Poly-Si/$SiO_2$substrate, RTA at $400^{\circ}C$ to form NiSi, $BF_2$ or As implantation and finally drive- in annealing at $500~800^{\circ}C$ to evaluate electrical characteristics. When annealed at $400^{\circ}C$, NiSi made from both a Ni monolayer and a Ni/Ti bilayer showed excellent thermal stability. But NiSi made from a Ni/Ti bilayer was thermally unstable at $500^{\circ}C$. This was attributed to the formation of insignificantly small amount of NiSi due to suppressed Ni diffusion through the Ti layer. PMOS and NMOS capacitors made by using a Ni monolayer and the SADS(silicide as a dopant source) method showed good C-V characteristics, when drive-in annealed at $500^{\circ}C$ for 20sec., and$ 600^{\circ}C$ for 80sec. respectively.

• Korean Journal of Metals and Materials
• /
• v.46 no.2
• /
• pp.69-79
• /
• 2008

A composition consisting of 10 nm-Ni/1 nm-Pd/(30 nm or 70 nm-poly)Si was thermally annealed using rapid thermal for 40 seconds at $300{\sim}1100^{\circ}C$ to improve the thermal stability of conventional nickel monosilicide. The annealed bilayer structure developed into $Ni(Pd)Si_x$, and the resulting changes in sheet resistance, microstructure, phase, chemical composition, and surface roughness were investigated. The silicide, which formed on single crystal silicon, could defer the transformation of $NiSi_2$, and was stable at temperatures up to $1100^{\circ}C$. It remained unchanged on polysilicon substrate compared with the sheet resistance of conventional nickel silicide. The silicides annealed at $700^{\circ}C$, formed on single crystal silicon and 30 nm polysilicon substrates exhibited 30 nm-thick uniform silicide layers. However, silicide annealed at $1,000^{\circ}C$ showed preferred and agglomerated phase. The high resistance was due to the agglomerated and mixed microstructures. Through X-ray diffraction analysis, the silicide formed on single crystal silicon and 30 nm polysilicon substrate, showed NiSi phase on the entire temperature range and mixed phases of NiSi and $NiSi_2$ on 70 nm polysilicon substrate. Through scanning probe microscope (SPM) analysis, we confirmed that the surface roughness increased abruptly until 36 nm on 30 nm polysilicon substrate while not changed on single crystal and 70 nm polysilicon substrates. The Pd-inserted nickel monosilicide could maintain low resistance in a wide temperature range and is considered suitable for nano-thick silicide processing.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2003.05a
• /
• pp.74-75
• /
• 2003

• Analytical Science and Technology
• /
• v.6 no.2
• /
• pp.217-223
• /
• 1993

Thin films of the Au/Cr, Au/Ni/Cr and Au/Pd/Cr systems were deposited on alumina substrates at ambient temperature and $250^{\circ}C$ in a high-vacuum resistance heating evaporator and annealed at $300^{\circ}C$, $450^{\circ}C$ and $600^{\circ}C$ for 1 hour in air, respectively. The film thicknesses of Au, Ni(or pd), and Cr were $1000{\AA}$, $300{\AA}$, and $50{\AA}$, respectively. The substrate temperature during deposition and the post-deposition annealing temperature affected the sheet resistance of thin-films due to the inter-diffusion of each layer. As a result of Auger depth profile analysis, in the Au/Cr system Cr already diffused out to Au surface during deposition at the substrate temperature of $250^{\circ}C$ and Au distribution changed after heat treatment. In the Au/Ni/Cr and Au/Pd/Cr systems, diffusion phenomena of Ni and Pd were found and especially Ni (approximately 45 at.%) diffused out to Au surface and oxidized.

• Korean Journal of Materials Research
• /
• v.32 no.9
• /
• pp.361-368
• /
• 2022

The overall process, from the pre-treatment of aluminum substrates to the eco-friendly neutral electroless Ni-P plating process, was observed, compared, and analysed. To remove the surface oxide layer on the aluminum substrate and aid Ni-P plating, a zincation process was carried out. After the second zincation treatment, it was confirmed that a mostly uniform Zn layer was formed and the surface oxide of aluminum was also removed. The Ni-P electroless plating films were formed on the secondary zincated aluminum substrate using electroless plating solutions of pH 4.5 and neutral pH 7.0, respectively, while changing the plating bath temperature. When a neutral pH7.0 electroless solution was used, the Ni-P plating layer was uniformly formed even at the plating bath temperature of 50 ℃, and the plating speed was remarkably increased as the bath temperature was increased. On the other hand, when a pH 4.5 Ni-P electroless solution was used, a Ni-P plating film was not formed at a plating bath temperature of 50 ℃, and the plating speed was very slow compared to pH 7.0, although plating speed increased with increasing bath temperature. In the P contents, the P concentration of the neutral pH 7.0 Ni-P electroless plating layer was reduced by ~ 42.3 % compared to pH 4.5. Structurally, all of the Ni-P electroless plating layers formed in the pH 4.5 solution and the neutral (pH 7.0) solution had an amorphous crystal structure, as a Ni-P compound, regardless of the plating bath temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.07a
• /
• pp.328-331
• /
• 2000

Carbon nanotube(CNT) was successfully grown on Ni-W alloyed substrate by applying PECVD technique(Plasma Enhanced Chemical Vapor Deposition). As a catalyst, Ni-W alloyed substrate was prepared by mechanical alloying method. In order to find the optimum growth condition, initially two different types of gas mixtures such ac $C_2$H$_2$-H$_2$and $C_2$H$_2$-MH$_3$were systematically investigated by adjusting results on the mixing ratio in temperature range of 500 to 80$0^{\circ}C$. In this work, we will report the preliminary results on the CNT processed by PECVD, which were characterized by XRD, SEM and TEM. Finally we will evalute the effect on CNT growth by changing many processing parameters, such as typical gas, mixing ratio between 2 mixture, plasma power and etc.

• Journal of the Korean Vacuum Society
• /
• v.9 no.1
• /
• pp.48-59
• /
• 2000

Electrochromic NiO films were prepared by using an electron-beam deposition method. The influence of the preparation conditions, especially the substrate temperature, on the electrochemical stability of film was investigated. The optical properties and stability of as-deposited films strongly depended on the substrate temperature during deposition. The NiO film prepared at a substrate temperature of 150~$200^{\circ}C$ was found to be the stabel when subjected to 5000cycles in a 0.5M solution of KOH between -6.0 and +0.8V. The best electrochromic parameters after 5000cycles were obtained for samples with substrate temperature of $150^{\circ}C$. The obtained electrochromic parameters are CE=-0.049($\lambda$=550nm), $\Delta$OD=0.88($\lambda$=550nm)$\textrm{cm}^2$/mC, Qin=-18.11mC/$\textrm{cm}^2$ and Qleft= 14.8mC/$\textrm{cm}^2$.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2012.05a
• /
• pp.218-219
• /
• 2012

Carbon coils could be synthesized using $C_2H_2/H_2$ as source gases and $SF_6$ as an incorporated additive gas under thermal chemical vapor deposition system. Prior to the carbon coils deposition reaction, two kinds of samples having different combination of Ni catalyst and substrate were employed, namely a commercially-made $Al_2O_3$ ceramic boat with Ni powders and a commercially-made $Al_2O_3$ substrate with Ni layer. By using a commercially-made $Al_2O_3$ ceramic boat, the production yield of carbon coils could be enhanced as much as 10 times higher than that of $Al_2O_3$ substrate. Furthermore, the dominant formation of the microsized carbon coils could be obtained by using $Al_2O_3$ ceramic boat.