• Corrosion Science and Technology
• /
• 제10권6호
• /
• pp.199-204
• /
• 2011

Hot dip metallic coated steels like as galvanized (GI), zinc-aluminium (GL) and aluminium coated steels are mostly used where corrosion resistance is needed. There are two kinds (type 1 and type 2) of aluminium coated steel being commercially used among them. Type 1 aluminium coated steel is coated with an Al-5~11 wt%Si alloy and Type 2 aluminium coated steel consists of commercially pure aluminium. Type 1 Al coated steel is generally used in automotive components and electrical appliances while type 2 aluminium coated steel is mainly used in construction applications such as building cladding panels, air conditioning and ventilation system. In this study, Type 1 aluminium coated steels have tested by accelerated conditions (salt spray or corrosive gas) and outdoor exposure condition in order to understand their corrosion behaviour. Due to the distinct corrosion mechanism of Al which exposes to the severe chloric condition, Salt Spray Test cannot predict the ordinary atmospheric corrosion of Al based coated materials. In addition, the test results and their corrosion feature of Al coated steel sheets will be discussed comparing with other metallic coated steel sheets of GI and GL.

• 한국표면공학회지
• /
• 제37권5호
• /
• pp.249-252
• /
• 2004

Effects of HA and TiN coating on the electrochemical characteristics of Ti-6AI-4V alloys for bone plates were investigated using various test methods. Ti-6AI-4V alloys were fabricated by using a vacuum induction furnace and bone plates were made by laser cutting and polishing. HA was made of extracted tooth sintered and then tooth ash was used as HA coating target. The TiN and HA film coating on the surface were carried on using electron-beam physical vapor deposition (EB-PVD) method. The corrosion behaviors of the samples were examined through potentiodynamic method in 0.9% NaCI solutions at $36.5\pm$$1^{\circ}C$ and corrosion surface was observed using SEM and XPS. The surface roughness of TiN coated bone plates was lower than that of tooth ash coated plates. The structure of TiN coated layer showed the columnar structure and tooth ash coated layer showed equiaxed and anisotrophic structure. The corrosion potential of the TiN coated specimen is comparatively high. The active current density of TiN and tooth ash coated alloy showed the range of about $1.0xl0^{-5}$ $A\textrm{cm}^2$, whereas that of the non-coated alloy was$ 1.0xl0^{-4}$ $A\textrm{cm}^2$. The active current densities of HA and TiN coated bone plates were smaller than that of non-coated bone plates in 0.9% NaCl solution. The pitting potential of TiN and HA coated alloy is more drastically increased than that of the non-coated alloy. The pit number and pit size of TiN and HA coated alloy decreased in compared with those of non-coated alloy. For the coated samples, corrosion resistance increased in the order of TiN coated, tooth ash coated, and non-coated alloy.

• 한국표면공학회지
• /
• 제43권6호
• /
• pp.260-265
• /
• 2010

STD 61 steel has been widely used for tools, metallic mold and die for press working because of its favorable mechanical properties such as high toughness, and creep strength as well as excellent oxidation resistance. The STD 61 tool steel coated with TiN and ZrN by sputtering results in improvement of wear and corrosion resistance. In this study, surface characteristics of TiN and ZrN film coated STD 61 by sputtering were studied by using FE-SEM, EDS, XRD, and XRR and nanoindentation tests. From the results of surface characteristics of coated specimen, the ZrN coated surface showed finer granular than that of TiN coated surface. The coated layer structures of ZrN and TiN were grown to (111) and (200) preferred orientation. From the results of XRR test for surface roughness, density and growth rate of coating film, surface roughness and growth rate of ZrN coated film revealed lower values those of TiN coated film, whereas density of ZrN coated film showed higher values than that of TiN coated film. From the nanohardness and elastic modulus test, nanohardness value and elastic modulus of ZrN coated film became higher than those of TiN coated film.

• Journal of Pharmaceutical Investigation
• /
• 제2권1호
• /
• pp.40-51
• /
• 1972

Water vapor sorption of corn starch in various protective film coated capsules in 100% RH chamber for 14 days were as follows: The percent of water vapor sorption were 28.63% in uncoated capsule, 25.16% in hydroxy propylcellulose(HPC) coated capsule, 15.59% in 2-methyl-5-vinyl pyridine-methyl acrylated-methacrylic acid (MPM) coated capsule and 15.50% in polyvinyl acetal diethyl amino acetate(AEA) coated capsule. 2. Water vapor sorotion of magnesium trisilicate in various protective film coated capsules in 100% RH chamber for 14 days were as follows. The percent of water vapor sorption were 13.91% in uncoated capsule, 13.30% in HPC-coated capsule, 10.87% in MPM-caated capsule and 9.9% in AEA-coated capsule. 3. Water vapor sorption of magnesium carbonate in various protective film coated capsules in 100% RH chamber for 14 days were as follows: The percent of water vapor sorption were 12.48% in uncoated capsule, 10.72% in HPC-coated capsule, 8.10% in MPM coated capsule and 7.8% in AEA-coated capsule. 4. MPM-coated capsules and AEA-canted capsules were mere effective to protect water vapor sorption than HPC-coated capsules.

• 한국펄프종이공학회:학술대회논문집
• /
• 한국펄프종이공학회 2011년도 추계학술발표회 논문집
• /
• pp.443-453
• /
• 2011

This study was carried out in order to elucidate effects of types of binder used in pre-coated layer on optical properties and printability of top-coated layer. Coated papers with four different types of SB latex were prepared. Tg, particle size and gel contents of latices were of different. Optical properties and printability of coated paper including print mottle were evaluated. It was confirmed that properties of pre-coated layer distinctively affected final properties of top-coated layer. Tg was found to be the most influencing factor on the print mottle of coated paper: the SB latex with lower Tg and higher particle size resulted in a superior print mottle. These results indicate that final printability and properties of top-coated layer can be controlled by adjusting pre-coated layer.

• 대한치과기공학회지
• /
• 제35권4호
• /
• pp.343-352
• /
• 2013

Purpose: The purpose of this study was to investigate to effect of the ZrN coated on corrosion resistance and physical property of dental Co-Cr alloys using various instruments. Methods: The specimens were used, respectively, for experiment, Arc Ion plating was carried out for dental casting alloys using ZrN coated materials with nitrogen gas. ZrN coated surface of each specimen was observed with field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), vickers hardness tester, and electrochemical tester. Results: The current density of ZrN coated specimen was smaller than that of non-coated specimen in 0.9% NaCl solution. Pit nucleated at scratch of specimen. The pitting corrosion resistant |$E_{max}-E_{rep}$| increased in order of ZrN coated (110 mV), and non-coated wire (100 mV). Conclusion: The corrosion potential of the ZrN coated specimen was comparatively high. the surface of ZrN coated specimen was more smooth than that of other kinds of non-coated specimen. ZrN coated surface showed higher hardness than that of non-coated surface.

• 한국표면공학회지
• /
• 제35권6호
• /
• pp.391-400
• /
• 2002

Corrosion characteristics of Ti, Ti/Cr coated and plasma-nitrided surface for stainless steel containing Ti have been studied. Stainless steels containing 0.09-0.92wt% Ti were fabricated by using vacuum furnace and solutionized for 1hr at 105$0^{\circ}C$. Ti and Cr coatings were done on solutionized stainless steel surface by EB-PVD. The Ti coated specimen were coated by Cr and were nitrided by plasma at $450^{\circ}C$ for 5hr. Microstructure and phase analysis were performed using SEM, OM and EDX. Corrosion behavior of the coated specimen was investigated by electrochemical test. The coated surface was of fine columnar structure. The Ti/Cr coated surface was denser than the Ti coated and the Ti coated-nitrided surfaces. The corrosion and pitting potential increased in proportion to the Ti content, coating temperature, coating thickness and formation of stable oxide film. The current density in active and passive region decreased in the case of Ti/Cr coated sample and Ti coated-nitrided samples. Especially the plasma nitrided specimen after Ti coating have a good corrosion resistance compared with the Ti coated specimen. The number and size of pits decreased as Ti content of matrix increased.

• 한국표면공학회지
• /
• 제36권1호
• /
• pp.89-98
• /
• 2003

Corrosion characteristics of Ti, Ti/Cr coated and plasma-nitrided surface for stainless steel containing Ti have been studied. Stainless steels containing 0.09-0.92wt% Ti were fabricated by using vacuum furnace and solutionized for 1hr at $1050^{\circ}C$. Ti and Cr coatings were done on solutionized stainless steel surface by EB-PVD. The Ti coated specimen were coated by Cr and were nitrided by plasma at $450^{\circ}C$ for 5hr Microstructure and phase analysis were performed using SEM, OM and EDX. Corrosion behavior of the coated specimen was investigated by electrochemical test. The coated surface was of fine columnar structure. The Ti/Cr coated surface was denser than the Ti coated and the Ti coated-nitrided surfaces. The corrosion and pitting potential increased in proportion to the Ti content, coating temperature, coating thickness and formation of stable oxide film. The current density in active and passive region decreased in the case of Ti/Cr coated sample and Ti coated-nitrided samples. Especially the plasma nitrided specimen after Ti coating have a good corrosion resistance compared with the Ti coated specimen. The number and size of pits decreased as Ti content of matrix increased.

• 한국표면공학회지
• /
• 제32권1호
• /
• pp.49-60
• /
• 1999

The protective oxide scales and coatings formed on high temperature materials must be preserved in high temperature atmosphere. And the thermal stresses induced by thermal cycling and the growth stresses by the formation of oxide scales can cause the loss of adherence and spalling of the oxide scales and coated layers. Among the coating processes Al diffusion coating is favored due to thermochemical stability and superior adherence in an hostile atmosphere. In this study, protective oxide forming element, Al was coated on Ni, Inconel 600 and 690 by diffusion coating process varying coating temperature and time. And the surface stability and adherence of oxide scales formed on those Al diffusion coated materials were evaluated by thermal cycling test. Al diffusion coated specimens showed superior cyclic oxidation resistance compared to bare ones and specimens coated for longer period had better cyclic oxidation resistance, due to the abundant amount of Al in the coated layer. Meanwhile Al diffusion coated Inconel 600 and 690 showed improved cyclic oxidation resistance by the effect of Al in the coated layer and Cr in the substrate. Comparing both Al diffusion coated Inconel 600 and 690, Al diffusion coated Inconel 690 maintained better adhesion between coated layer and substrate by virtue of the bridging effect resulting from the segregation of Cr in the interdiffusion zone.

• 대한치과보철학회지
• /
• 제33권2호
• /
• pp.317-334
• /
• 1995

The purpose of this study was to compare the bone formation, maturation around HA-and titaniumcoated dental implants in dog. 5 hydroxyapatite coated IMZ implants and 5 titanium coated IMZ implants were placed into the previously extracted site in the mandible of 5 adults dogs. All dogs were injected intravenously Tetracycline, Alizalin red S, and Calcein for bone fluorescent labelling, After the experimental period of 16weeks, the dogs were sacrificed and tissue samples around the implants were obtained. Microscopic observations(ligth, polariged and fluorescence microscope), morphometric analysis, line profile with EPMA, and quantitative analysis for Ca,P, and Ti were performed. The results were as follows ; 1. Bone maturations around the implants were relatively lower than those of natural teeth. No significant differences in bone maturation and remodeling patterns were observed between the two implants groups. 2. Calcification of bone surrounding the implants was initiated in 8-11 weeks for HA-coated implants, while it took 11 weeks or more for Ti-coated implants. 3. Bone-to-implants contact ratio of 82.63% was recorded for HA-coated group and 72.25% for titanium coated group, with no significant difference between the two groups. 4. Bone around the implants exhibited reduced quantity of Ca and P in the $100{\mu}m$ region relative to natural teeth, while the rest of the regions showed no statistical differences. No significant differences were found between the two implant groups. 5. There was a separation of HA layer from the implant core and subsequent infiltration of inflammatory cells into the resulting space in the HA-coated implants, and evidences of phagocytosis of HA particles by macrophages. Bone calcification was more rapid around HA-coated implants compared to titanium-coated implants, but HA coated implants did not show any significant differences either in the degree of calcification or the bone-to-implant contact ratio over Ti coated implants. HA coated implants may have complications associated with HA absorption and separation of HA layer from the implant core.