• 한국생산제조학회지
• /
• 제9권1호
• /
• pp.96-101
• /
• 2000

Ceramic, PCD and CBN tools are available for the difficult-to-cut-materials such as hardened carbon tool steel, stainless steel, Inconel 718 and etc.. Ceramic toolsare likely to be chipped and abruptly broken before the appearance of normal wear in turning. Ther2efore ceramic tools are suitable for continuous cut in turning not for intermittent in milling. In this study, TiN/TiCN multi-layer coated ceramic tools were found to restrain the chipping, breaking and early fracture and to increase the critical cutting speed owing to TiN/TiCN multi-layer coating in Arc Ion Plating of PVD method.

• 한국재료학회지
• /
• 제13권7호
• /
• pp.420-423
• /
• 2003

Coatings of TiCrN ion-plated on a steel substrate was oxidized at $800^{\circ}C$ in air, and their oxidation mechanism was presented. During oxidation, substrate elements and Ti and Cr in the coating always diffused outwardly to form the oxide scale. Simultaneously, oxygen from the atmosphere diffused inward1y to react with Ti and Cr to form $TiO_2$and $Cr_2$$O_3$, respectively. Also, the counter-diffusion of cations and oxygen resulted in some oxygen dissolution in the unoxidized TiCrN coating, and Fe dissolution in the oxide scale. When the Ti content in the coating was high, the $TiO_2$-forming tendency was strong, while when the Cr content was high, the $Cr_2$$O_3$-forming tendency was strong.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
• /
• pp.281-285
• /
• 2001

This technology Provides an economical Production of high value added goods applicable to electro chemicals by recycling of waste products in EGL(Electro Galvanizing Line). The waste products produced in EGL contain potassium chloride (KCI), nickel and zinc. Highly pure KCI and Zinc Chloride which are raw material of electro plating, can be produced by the development of the recycling process. The scope of this study ranges from laboratory experiments to pilot test in plant. We have developed the whole process of recycling technology such as purification method of waste products, fabrication methods of electro chemicals, basic design of plant, pilot scale production and evaluation of pilot goods, Developed electro chemicals were pure enough to satisfy the specification of steel company.

• 한국표면공학회지
• /
• 제28권4호
• /
• pp.199-206
• /
• 1995

A kinetic study on the electrodeposition of Ni-Zn-P ternary alloys onto a steel in chloride solutions was carried out using a rotating disc electrode. The coatings were characterized using SEM/EPMA and A. A. analysis. The results showed that the plating rates of three components were increased with applied potential, disc rotating speed and temperature. The activation energies of Ni, Zn and P of the coatings were 6.1, 5.1 and 8.0 kcal/mole respectively. Therefore, the deposition rates were controlled partly by surface electrochemical reaction and partly by mass transport. As the potential, temperature of bath and rotating speed of cathode disc were raised, the vol. % ratios of Ni and P of coating layer were increased but that of Zn decreased. The effect of coating parameters on the surface morphology was also examined.

• 한국표면공학회지
• /
• 제35권1호
• /
• pp.53-63
• /
• 2002

Ni coating was carried out by pulse plating at room temperature. So, experimental conditions for Ni-coating were based on Watt's bath, and new additives(propionic acid) were introduced in the Watt's bath electrolyte as $H_3$$BO_3$ alternatives. By adding propionic acid, coating layer demonstrated a good adhesion and uniformity without special pre-treatment of the 316L stainless steel at room temperature. With a decrease of amount of propionic acid and applied average current density, cathode current efficiency increased. Also, edge effect was decreased with decreasing a peak current and increasing a pulse frequency in the same bath condition. It was found that the optimum condition for Ni coating was a current density of 10~20mA/$\textrm{cm}^2$ at below 500 mA peak current in the $5m\ell/\ell$ propionic acid solution.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2001년도 추계학술발표회 초록집
• /
• pp.63-63
• /
• 2001

As a new approach to substitute for a hard alloy of stellite 6B containing Co which is radioactive in nuclear system, a hard-phase coating of CrN will be applicable to protect 12Cr steel from erosion at leading edge on steam turbine blade. The CrN coating was prepared by arc ion plating on 12 Cr steel and was undertaken in liquid impact test at the velocity of 35Om/sec, which simulate the environment in the last stage of blade. The erosion resistance of coating was evaluated by optical observation on damaged surface. The threshold number of impact was closely related with surface hardness. And thus, it was confirmed that surface hardening improves the life time of steam turbine blade.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2003년도 추계학술발표회초록집
• /
• pp.136-137
• /
• 2003

In this study, in order to fabricate sintered dental implant, the effects of HA, Ti and TiN on corrosion and biocompatibility, cell toxicity, osseointegration of electroless Cu-plated and sintered stainless steel implant were investigated using various characteristics. The effects of Ti/TiN/HA coating on the interface activation and surface characteristics of sintered stainless steels(SSS) by electron-beam physical vapor deposition(EB-PVD) method have been studied. Stainless steel compacts containing 2, 4, and 10 wt%Cu were prepared by electroless Cu-plating method which results in the increased homogenization in alloying powder. The specimens were coated with HA, Ti and TiN with few $\mu\textrm{m}$ thickness respectively by EB-PVD method. The microstructures and phase analysis were conducted by using SEM. Biocompatibility were investigated in experimental dog. The corrosion behaviors were investigated using potentiosat in 0.9% NaCl solution and corrosion surface was observed using SEM and XPS.

• 한국표면공학회지
• /
• 제38권3호
• /
• pp.95-99
• /
• 2005

Quaternary Ti-Cr-Si-N coatings were synthesized onto steel substrates (SKD 11) using a hybrid method of arc ion plating (AIP) and sputtering techniques. For the Syntheses of Ti-Cr-Si-N coatings, the Ti-Cr-N coating process was performed substantially by a multi-cathodic AIP technique rising Cr and Ti targets, and Si was added by sputtering Si target during Ti-Cr-N deposition. In this work, comparative studies on microstructure and evaluation of mechanical properties between Ti-Cr-N and Ti-Cr-Si-N coatings were conducted. As the Si was incorporated into Ti-Cr-N coatings, the Ti-Cr-Si-N coatings showed largely increased hardness value of approximately 42 GPa than one of 28 GPa for Ti-Cr-N coatings. The average friction coefficient of Ti-Cr-N coatings largely decreased from 0.7 to 0.35 with increasing Si content up to 20 at. $\%$. In addition, wear behavior of Ti-Cr-N coatings against steel ball was much improved with Si addition due to the surface smoothening effect and tribe-chemical reaction.

• Corrosion Science and Technology
• /
• 제22권1호
• /
• pp.21-29
• /
• 2023

In this paper, a SiC nano electroless nickel plating layer with excellent corrosion resistance was fabricated using the Taguchi method. The electroless plated low carbon steel was subjected to tests to examine the influence of corrosive media, microhardness, and corrosion rate on the corrosion resistance of this alloy. Three different corrosive media (HCl, Na₂SO₄, and NaCl) at various temperatures (80, 90, and 100 ℃) were used, and at three different times (40, 80, and 120 min.) with a speed of stirring equal to 500 rpm. The results of microhardness were found from 134.276 HV to 278.578 HV at various conditions, while the corrosion rate results were obtained from 0.89643 mpy to 7.12571 mpy at different circumstances. Corrosion, and mechanical characteristics were explained using Taguchi design. Taguchi technique was used to account for all possible combinations of elements in order to conduct a complete study. Models that link the response and procedure parameters were developed using the results of these tests, and the analysis of variance was utilized to validate these models (ANOVA). For maximum efficiency, a function called "desirability" was applied to all responses at once.

• 한국재료학회지
• /
• 제17권5호
• /
• pp.256-262
• /
• 2007

Effects of interlayer and the combination of different coating methods on the mechanical and corrosion behaviors of TiN and CrN coated on 420 stainless steel have been studied. STS 420 specimen were tempered at $300^{\circ}C$ for 1 hr in vacuum furnace. The TiN and CrN thin film with 2 ${\mu}m$ thickness were coated by arc ion plating and DC magnetron sputtering following the formation of interlayer for pure titanium and chromium with 0.2 ${\mu}m$ thickness. The microstructure and surface analysis of the specimen were conducted by using SEM, XRD and roughness tester. Mechanical properties such as hardness and adhesion also were examined. XRD patterns of TiN thin films showed that preferred TiN (111) orientation was observed. The peaks of CrN (111) and $Cr_2N$ (300) were only observed in CrN thin films deposited by arc ion plating. Both TiN and CrN deposited by arc ion plating had the higher adhesion and hardness compared to those formed by magnetron sputtering. The specimen of TiN and CrN on which interlayer deposited by magnetron sputtering and thin film deposited by arc ion plating had the highest adhesion with 22.2 N and 19.2 N. respectively. TiN and CrN samples shown the most noble corrosion potentials when the interlayers were deposited by using magnetron sputtering and the metal nitrides were deposited by using arc ion plating. The most noble corrosion potentials of TiN and CrN were found to be approximately -170 and -70 mV， respectively.