표면처리가 장석도재의 굴곡강도에 미치는 영향

정성화,임범순,김철위 서울대학교 치과대학 치과생체재료학교실 1995 치과생체재료학 논문집 Vol.3 No.1

Dental ceramics exhibits excellent esthetic, compressive strength and chemical durability, good tissue compatibility and transulcency comparable to natural teeth. Dental ceramics, however, have brittleness as ell as low tensile and shear strength and are extremely sensitive to brittle fracture initiated at surface defects. Glazing and polishing treatments can reduce the influence surface flaws, which lead to an increase in strength of the porcelain. And the other method of strengthening the porcelain is to generate a state of residual compression in the surface, which can be accomplished either by ion exchange treatment or thermal tempering. The object of this study was to compare the effect of various surface treatments on the flexural strength of feldspathic porcelain. Bars of feldspathic porcelain specimen (3×3×30㎜) were prepared from Vintage (Shofu) body procelain by condensing slurries into a platinum foil mould , then sintered in a furnace (Master Splint 120) according to the manufacturer's recommendations under vacuum. The bars were divided into the seven groups : self-glazing (control), over glazing subsequent to ion exchange, and ion exchange subsequent to over-galzing. The ion exchange treatment consisted of applying Ceramicoat past (GC) as evenly as possible to the porcelain using a paintbursh. The coating material was dried for 20 minutes at 150℃, followed by firing at 450℃ for 30 minutes. To evaluate the effect of ion exchange temperature, the same drying cycle was followed by 30-minute heat treatments at 350℃, 400℃, 500℃, and 550℃. Each specimen was loaded to failure on a universal testing machine with a crosshead speed of 0.02 ㎝/min. 7∼10 specimens in each groups were test and the mean value for flexural strength was calculated. The fracture surfaces were examined by a scanning electron microscope. For qualitative analysis of the relative changes in potassium and sodium concentrations after ion exchange treatment, energy dispersive x-ray analysis was performed on the surface and bulk section of the fractured surface. Quatitative chemical analyses were performed on the cross section of the specimen after ion exchange treatment by a scanning elecron microscope equipped with a wavelength dispersive x-ray analyzer. Analyses were made in 10∼20 ㎛ below the treated surface. From the experiment, the following results were obtained: 1. The flexural strength was increased by 37% using over-laze treatment, but polishing or heat treatments of feldspathic did not show significant difference (p>0.05) relative to the self-glaze control group. 2. Relative to the control group (self-glaze), the mean flexural strengths of specimen were increased by ion exchanged treatment : 20% at 350℃, 28% at 400℃, and 56% at 450℃ and 500℃. 3. The effect of ion exchange treatment was lost if the porcelain was subsequently treated by self-glaze. The group with ion exchange treatment subsequent to over-glaze treatment showed the highest flexural strength among the experimental groups. 4. The fracture surface of the specimen with ion exchange treatment showed the hackle region, which could imply the degree of fracture resistance in the ion exchanged layer. 5. The chemical analysis (EDX and WDX) results showed that the effect of ion exchange was extended to 50 ㎛ below the ion treated surface.

Effects of surface treatment of ITO anode layer patterned with shadow mask technology on characteristics of organic light-emitting diodes

Park, C.Y.,Lee, J.H.,Choi, B.H. Elsevier Science 2013 Organic electronics Vol.14 No.12

We investigated the effects of various surface treatments of indium tin oxide (ITO) on the electrical and optical characteristics of organic light-emitting diodes (OLEDs). A 150-nm-thick ITO anode layer was patterned directly with a shadow mask during the sputtering process without the use of a conventional photolithography patterning method. The sputtered ITO layer was subjected to thermal and oxygen plasma treatments to reduce the sheet resistance and improve surface roughness. The thermal treatment was performed for 1h at temperatures of 250 and 380<SUP>o</SUP>C, which were chosen so that the glass substrates would not deform from thermal damage. The measured sheet resistance decreased from 30.86Ω/sq for the as-sputtered samples to 8.76Ω/sq for the samples thermally treated at 380<SUP>o</SUP>C for 1h followed by oxygen plasma treatment. The root-mean-square surface roughness measured by atomic force microscopy considerably decreased to 3.88nm with oxygen plasma treatment. The thermal treatment considerably decreased the sheet resistance of the ITO anode layer patterned with the shadow mask. The spike-like structures that are often formed and observed in shadow mask-patterned ITO anode layers were almost all removed by the oxygen plasma treatment. Therefore, a smooth surface for shadow mask-patterned ITO layers with low sheet resistance can be obtained by combining thermal and oxygen plasma treatments. A smooth surface and low sheet resistance improves the electrical and optical characteristics of OLEDs. The surface-treated ITO layer was used to fabricate and characterize green phosphorescent OLED devices. The typical characteristics of OLED devices based on surface-treated shadow mask-patterned ITO layers were compared with those fabricated on untreated and photolithography-patterned ITO layers to investigate the surface treatment effects. The OLED devices fabricated by thermal treatment at 380<SUP>o</SUP>C for 1h followed by oxygen plasma treatment for 180s showed the highest luminance and current density. Furthermore, the leakage current that might be induced by the rough ITO surface was dramatically reduced to 0.112mA/cm<SUP>2</SUP>. Our study showed that the shadow mask-patterned ITO anode layer treated by heat and plasma and having a low sheet resistance and surface roughness yielded excellent electrical and optical properties for OLEDs compared to those based on an untreated ITO layer. The fabricated OLED devices using the surface-treated shadow mask-patterned ITO layer exhibited comparable characteristics to those obtained from a conventional photolithography-patterned ITO anode.

Control of Optical Properties by the Stepwise Chemical and Plasma Spray Treatment of Polycarbonate

전법주 한국진공학회 2018 Applied Science and Convergence Technology Vol.27 No.6

Using the Polycarbonate (PC) polymer sheet, the change in optical properties was compared by changing the surface shape with the primary chemical surface treatment and plasma spray treatment. Plasma treatment affects surface composition changes and has a small effect on surface structure changes. Changes in surface structure are important to control the optical characteristics of the PC polymer sheet. Thus, it was possible to control changes in surface composition and changes in surface structure through secondary plasma treatment after primary chemical treatment. The primary chemical treatment had a small effect on changes in the chemical composition of the surface, but the surface roughness was influenced by swelling. The secondary plasma spray treatment affected optical properties changes, which allowed control of changes in surface structure after primary chemical treatment. At the same time after the first chemical treatment, the secondary plasma treatment was easy to control of optical properties by changing the surface structure as well as the surface properties due to changes in chemical composition by surface cross-linking reaction.

Control of Optical Properties by the Stepwise Chemical and Plasma Spray Treatment of Polycarbonate

Bup Ju Jeon 한국진공학회(ASCT) 2018 Applied Science and Convergence Technology Vol.27 No.6

Using the Polycarbonate (PC) polymer sheet, the change in optical properties was compared by changing the surface shape with the primary chemical surface treatment and plasma spray treatment. Plasma treatment affects surface composition changes and has a small effect on surface structure changes. Changes in surface structure are important to control the optical characteristics of the PC polymer sheet. Thus, it was possible to control changes in surface composition and changes in surface structure through secondary plasma treatment after primary chemical treatment. The primary chemical treatment had a small effect on changes in the chemical composition of the surface, but the surface roughness was influenced by swelling. The secondary plasma spray treatment affected optical properties changes, which allowed control of changes in surface structure after primary chemical treatment. At the same time after the first chemical treatment, the secondary plasma treatment was easy to control of optical properties by changing the surface structure as well as the surface properties due to changes in chemical composition by surface cross-linking reaction.

Effect of surface treatments on shear bond strength of resin composite bonded to CAD/CAM resin-ceramic hybrid materials

Gungor, Merve Bankoglu,Nemli, Secil Karakoca,Bal, Bilge Turhan,Unver, Senem,Dogan, Aylin The Korean Academy of Prosthodonitics 2016 The Journal of Advanced Prosthodontics Vol.8 No.4

PURPOSE. The purpose of this study was to assess the effect of surface treatments on shear bond strength of resin composite bonded to thermocycled and non-thermocycled CAD/CAM resin-ceramic hybrid materials. MATERIALS AND METHODS. 120 specimens ($10{\times}10{\times}2mm$) from each material were divided into 12 groups according to different surface treatments in combination with thermal aging procedures. Surface treatment methods were airborne-particle abrasion (abraded with 50 micron alumina particles), dry grinding (grinded with $125{\mu}m$ grain size bur), and hydrofluoric acid (9%) and silane application. According to the thermocycling procedure, the groups were assigned as non-thermocycled, thermocycled after packing composites, and thermocycled before packing composites. The average surface roughness of the non-thermocycled specimens were measured after surface treatments. After packing composites and thermocycling procedures, shear bond strength (SBS) of the specimens were tested. The results of surface roughness were statistically analyzed by 2-way Analysis of Variance (ANOVA), and SBS results were statistically analyzed by 3-way ANOVA. RESULTS. Surface roughness of GC were significantly lower than that of LU and VE (P<.05). The highest surface roughness was observed for dry grinding group, followed by airborne particle abraded group (P<.05). Comparing the materials within the same surface treatment method revealed that untreated surfaces generally showed lower SBS values. The values of untreated LU specimens showed significantly different SBS values compared to those of other surface treatment groups (P<.05). CONCLUSION. SBS was affected by surface treatments. Thermocycling did not have any effect on the SBS of the materials except acid and silane applied GC specimens, which were subjected to thermocycling before packing of the composite resin.

Bioactive effect of alkali-heat treated TiO₂ nanotubes by water or acid treatment

Kim, S.Y.,Kim, Y.K.,Jang, Y.S.,Park, I.S.,Lee, S.J.,Jeon, J.G.,Lee, M.H. Elsevier Sequoia 2016 Surface & coatings technology Vol.303 No.1

Various surface treatments are used to enhance the biological activity of titanium. Alkali and heat treatments promote the formation of hydroxyl apatite (HAp), which increases the bone-bonding ability in simulated body fluid (SBF). The sodium titanate layer is converted to the more bioactive layer, with sodium-ion removal from alkali- and heat-treated surfaces, via a water treatment. The anatase phase resulting by water treatment is effective in generating apatite nuclei in SBF. In this study, two types of surface treatment were performed to improve the bioactivity of alkali and heat-treated TiO<SUB>2</SUB> nanotubes: One is the only water treatment for 48h. Another is the combination of the acid-solution (10 and 50mM of HCl or HNO<SUB>3</SUB>) treatment for 24h and the water treatment for 24h. Each treatment was conducted after the fabrication of alkali-treated TiO<SUB>2</SUB> nanotubes via anodization and an alkali treatment in 5M NaOH. Finally, all of the treated groups were all heated at 550<SUP>o</SUP>C. The properties, bioactivity, and cytotoxicity of the alkali-heat treated TiO<SUB>2</SUB> nanotubes were determined after the water or acid treatment. In addition, histological samples were evaluated by inserting implants into bilateral rat tibia for 3 and 6weeks. The concentration of O ions and the amount of anatase phase increased after the HCl treatment. Furthermore, the apatite-forming ability was greatly enhanced with an increase in the amount of anatase phase, especially in the 50mM HCl-treated group. The surface of the water- or 50mM HCl-treated group promoted osteoblastic proliferation and differentiation, thereby allowing effective osteointegration. In the 6-week implant, the uniform new bone layer grew in the case of the HC50 group only. Therefore, we conclude that the HCl treatment constitutes the most favorable surface-modification method for improving the bioactivity of alkali- and heat-treated TiO<SUB>2</SUB> nanotubes.

Effect of surface treatments on shear bond strength of resin composite bonded to CAD/CAM resin-ceramic hybrid materials

Merve Bankoğlu Güngör,Seçil Karakoca Nemli,Bilge Turhan Bal,Senem Ünver,Aylin Doğan 대한치과보철학회 2016 The Journal of Advanced Prosthodontics Vol.8 No.4

PURPOSE The purpose of this study was to assess the effect of surface treatments on shear bond strength of resin composite bonded to thermocycled and non-thermocycled CAD/CAM resin-ceramic hybrid materials. MATERIALS AND METHODS 120 specimens (10×10×2 mm) from each material were divided into 12 groups according to different surface treatments in combination with thermal aging procedures. Surface treatment methods were airborne-particle abrasion (abraded with 50 micron alumina particles), dry grinding (grinded with 125 µm grain size bur), and hydrofluoric acid (9%) and silane application. According to the thermocycling procedure, the groups were assigned as non-thermocycled, thermocycled after packing composites, and thermocycled before packing composites. The average surface roughness of the non-thermocycled specimens were measured after surface treatments. After packing composites and thermocycling procedures, shear bond strength (SBS) of the specimens were tested. The results of surface roughness were statistically analyzed by 2-way Analysis of Variance (ANOVA), and SBS results were statistically analyzed by 3-way ANOVA. RESULTS Surface roughness of GC were significantly lower than that of LU and VE (P<.05). The highest surface roughness was observed for dry grinding group, followed by airborne particle abraded group (P<.05). Comparing the materials within the same surface treatment method revealed that untreated surfaces generally showed lower SBS values. The values of untreated LU specimens showed significantly different SBS values compared to those of other surface treatment groups (P<.05). CONCLUSION SBS was affected by surface treatments. Thermocycling did not have any effect on the SBS of the materials except acid and silane applied GC specimens, which were subjected to thermocycling before packing of the composite resin.

Surface characteristics of indium tin oxide deposited by facing target sputtering and its effect on the performance of organic light emitting diode

Chul Yoon,Sang-Ho Kim 한국물리학회 2009 Current Applied Physics Vol.9 No.3

A new facing target sputtering (FTS) method that has two facing targets and substrate locates vertically to the targets was used for ITO anode deposition in OLED. The ITO different from it by a conventional DC or RF magnetron sputtering was optimized in crystallinity, grain morphology, surface roughness and oxygen content by plasma treatment, and the effect on the OLED I–V characteristic was identified. Crystallinity of ITO was improved with a short plasma treatment time less than 15 min. The grains were an equi-axed as deposited state and changed to columnar grains when the plasma treatment time was exceeded above 20 min. The surface roughness was maintained within the targeted 1.8–2.0 nm range with plasma treatment from 5 to 20 min. Oxygen content measured using XPS analysis was increased with 15 min plasma treatment during the ITO grains maintained an equi-axed, but it was decreased again with 25 min plasma treatment. The I–V characteristic of OLED was relatively good with 15 min plasma treatment. It was considered because the ITO anode can contain higher oxygen in equi-axed grains, and can have better crystallinity and relevant surface roughness by 15 min plasma treatment. A new facing target sputtering (FTS) method that has two facing targets and substrate locates vertically to the targets was used for ITO anode deposition in OLED. The ITO different from it by a conventional DC or RF magnetron sputtering was optimized in crystallinity, grain morphology, surface roughness and oxygen content by plasma treatment, and the effect on the OLED I–V characteristic was identified. Crystallinity of ITO was improved with a short plasma treatment time less than 15 min. The grains were an equi-axed as deposited state and changed to columnar grains when the plasma treatment time was exceeded above 20 min. The surface roughness was maintained within the targeted 1.8–2.0 nm range with plasma treatment from 5 to 20 min. Oxygen content measured using XPS analysis was increased with 15 min plasma treatment during the ITO grains maintained an equi-axed, but it was decreased again with 25 min plasma treatment. The I–V characteristic of OLED was relatively good with 15 min plasma treatment. It was considered because the ITO anode can contain higher oxygen in equi-axed grains, and can have better crystallinity and relevant surface roughness by 15 min plasma treatment.

금속 표면처리에 따른 레진과의 결합에 관한 연구

김철위,임범순 대한치과기재학회 1997 대한치과재료학회지 Vol.24 No.1

Bonding of resin to dental alloys has been improved significantly over the last decade and various commercial bonding agents have been introduced. These approaches include macromecha- nical retention, micromechanical retention, and chemical adhesion. Sandblasting was often used to clean the surface of materials and to achieve both microretentive topography and increased surface area. Adhesive systems have relied on the chemical bond of adhesive luting agents to oxidized air-abraded base metal alloys, silicon-coated alloys, or tin-plated alloys. The purpose of this study was to evaluate the effect of surface treatment of dental alloys on shear bond strength and compare characteristic surface patterns by having various surface treatments. Six dental casting alloys and three resin cements were tested ; alloy surfaces were treated differently. The surface treatments included electrolytic etching, chemical solution immersion etching, sandblasting, tin plating, and combinations of sandblasting with other treatments. The shear bond strength of resin to alloy was determined by loading the samples to an Instron Universal Testing Machine using a crosshead speed of 0.02 cm/min. Specimen surface after various treatments and the fractured surface after bonding test were evaluated by optical microscope and observed with the scanning electron microscope. From the experiment, the following results were obtained : 1. In control(CTL) and the etched groups (EE, CE), the shear bond strength of alloys was ranked accordingly : base metal alloys > Ag-Pd based alloys > Au based alloys. The etching treatments created a less effect on the Au based alloys. 2. SB groups showed an enhanced boned strength in all kinds of alloys. TP groups was more effective for the noble metal alloys than the base metal alloys. 3. Double treatment groups such as SB+EE, SB+CE and SB+TP, did not yield the additive effect on each treatment on the final bond strength of those groups. It was observed that some alloys etched with either electrochemical process or immersion process was less effective than the other treatment. 4. It was found that tin electroplating was less effective for base metal alloys because of the low bond strength between the tin layer and the base metal surface.

미세역학적 실험법에 의한 금속섬유의 플라즈마 처리효과에 관한 연구

권미연,이승구 한국접착및계면학회 2022 접착 및 계면 Vol.23 No.4

In this study, the hydrophilicity of the metal fiber is improved by introducing an oxygen-containing functional group to the fiber surface after treatment of the metal fiber using the oxygen plasma treatment time as an experimental variable. For the surface modification of metal fibers, changes in surface properties before and after plasma treatment were observed using SEM and x-ray photoelectron spectroscopy (XPS). In order to observe the effect of the plasma treatment time on the surface of the metal fiber, the change in contact angle of the metal fiber with respect to a polar solvent and a non-polar solvent was measured. After calculating the change in surface free energy using the measured contact angle, the contact angle and the surface free energy for metal fibers before and after oxygen plasma treatment were compared, and the correlation with the adhesion work was also considered. The microdroplet specimens were prepared to investigate the effect of surface changes of these metal fibers on the improvement of shear strength at the interface when combined with other materials and the interfacial shear strength was measured, and the correlation with the adhesion work was also identified. Therefore, the oxygen plasma treatment of the metal fiber results in an increase in the physical surface area on the fiber surface and a change in contact angle and surface energy according to the introduction of the oxygen-containing functional group on the surface. This surface hydrophilization resulted in improving the interfacial shear strength with the polymer resin.