• Title/Summary/Keyword: acid etching

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Dissolution Phenomenon in BaO-B2O3-ZnO Glass System by Acid Etching (산 에칭에 의한 BaO-B2O3-ZnO계 유리조성물의 용출 현상)

  • Kim, Jae-Myung;Hong, Kyung-Jun;Kim, Nam-Suk;Kim, Hyung-Sun
    • Journal of the Korean Ceramic Society
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    • v.43 no.1 s.284
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    • pp.33-37
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    • 2006
  • For producing the fine ribs structure of plasma display panel, the metal ions of barrier materials during the etching process should be understood on the etching mechanism with etching conditions. Etching was done on bulk glasses of the $BaO_B_2O_3-ZnO$ system with $HNO_3$ solution at $40^{\circ}C$. The surface structure of glasses and ion dissolution were analyzed by ICP (Inductive Coupled Plasma measurement). The structure and surface of the etched bulk glass were investigated by using scanning electron microscopy and nanoindenter. As a result, Ba (3-35 ppm/min) and Zn (2-27 ppm/min) ions as major components were leached in the solution and the leached layers were found to be phosphor-rich surface layers. A decrease of the bridge oxygen and relative increase of non bridge oxygen in the etched glass were found by X-ray photoelectron spectroscopy.

Shear bond strength of brackets bonded with different self etching primers (Self etching primer를 사용하여 부착된 교정용 브라켓의 전단결합강도의 비교)

  • Yang, Jin-Young;Kim, Min-Ji;Lim, Yong-Kyu;Lee, Dong-Yul
    • The korean journal of orthodontics
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    • v.37 no.4
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    • pp.283-292
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    • 2007
  • The purpose of this study was to evaluate the clinical usefulness of 4 self etching primers by measuring the shear bond strength of orthodontic brackets and examining the failure pattern of bracket-tooth interfaces. Methods: Seventy-five, defect-free, premolars were randomly assigned into five groups: control group (37% phosphoric acid + Transbond XT primer) and self etching primer treated groups (Transbond Plus self etching primer, Unifil bond, Clearfil SE bond, and Adhese). The shear bond strength was measured with a universal testing machine and the amount of residual adhesive remaining on the brackets after debonding was assessed by the adhesive remnant index (ARI). Results: The results showed that the groups conditioned with self etching primer had significantly lower shear bond strength than the control group (p < 0.05), although clinically acceptable. However, there were no significant differences in shear bond strength among the self etching primer groups (p > 0.05). Evaluation of the ARI scores indicated there was less resin remnant on the teeth in the groups conditioned with self etching primers, although not statistically significant. Conclusion: The results of this study suggest that all four of the self etching primers have shown acceptable bond strength for clinical use.

Preparation and Characterization of Porous Silicon and Carbon Composite as an Anode Material for Lithium Rechargeable Batteries

  • Park, Junsoo;Lee, Jae-Won
    • Journal of Powder Materials
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    • v.22 no.1
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    • pp.15-20
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    • 2015
  • The composite of porous silicon (Si) and amorphous carbon (C) is prepared by pyrolysis of a nano-porous Si + pitch mixture. The nano-porous Si is prepared by mechanical milling of magnesium powder with silicon monoxide (SiO) followed by removal of MgO with hydrochloric acid (etching process). The Brunauer-Emmett-Teller (BET) surface area of porous Si ($64.52m^2g^{-1}$) is much higher than that before etching Si/MgO ($4.28m^2g^{-1}$) which indicates pores are formed in Si after the etching process. Cycling stability is examined for the nano-porous Si + C composite and the result is compared with the composite of nonporous Si + C. The capacity retention of the former composite is 59.6% after 50 charge/discharge cycles while the latter shows only 28.0%. The pores of Si formed after the etching process is believed to accommodate large volumetric change of Si during charging and discharging process.

Laser-induced Thermochemical Wet Etching of Titanium for Fabrication of Microstructures (레이저 유도 열화학 습식에칭을 이용한 티타늄 미세구조물 제조)

  • 신용산;손승우;정성호
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.4
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    • pp.32-38
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    • 2004
  • Laser-induced thermochemical wet etching of titanium in phosphoric acid has been investigated to examine the feasibility of this method fur fabrication of microstructures. Cutting, drilling, and milling of titanium foil were carried out while examining the influence of process parameters on etch width, etch depth, and edge straightness. Laser power, scanning speed of workpiece, and etchant concentration were chosen as major process parameters influencing on temperature distribution and reaction rate. Etch width increased almost linearly with laser power showing little dependence on scanning speed while etch depth showed wide variation with both laser power and scanning speed. A well-defined etch profile with good surface quality was obtained at high concentration condition. Fabrication of a hole, micro cantilever beam, and rectangular slot with dimension of tess than 100${\mu}{\textrm}{m}$ has been demonstrated.

The Influence of Electrolytic Condition on Tunnel Etching and Capacitance Gain of High purity Aluminium Foil on capacitor (전해조건이 고순도 알루미늄 박 콘덴서의 터널에칭과 정전용량에 미치는 영향)

  • 이재운;이병우;김용현;이광학;김흥식
    • Journal of Surface Science and Engineering
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    • v.30 no.1
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    • pp.44-56
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    • 1997
  • Influence of electrochemical etching conditions on capacitance gain of aluminium electrolytic on capacitor foil has been investigated by etching cubic textured high purity aluminum foil in dilute hydrochloric acid. Uniformly distributed etch pit tunnels on aluminum surface have been obtained by pretreatment aluminium foil in 10% NaOH solution for 5 minutes followed by electrochemical etching. Electrostatic capacitance of etched aluminium foil anodized to high voltage increased with the increase of current density, total charge, temperature and concentration of electrolyte up to maximum CV-value and then deceased. Election optical observation of the etched foil revealed that the density of etch of etch pits increased with the increase of current density and concentration of electrolyte. this increase of etch pit density enlarged of the increase of capacitance. However, abnormal high current density and high electrolyte concentration induced the local dissolution of the foil surface which resulted the decrease of foil capacitance.

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Recycling of Acidic Etching Waste Solution Containing Heavy Metals by Nanofiltration (I): Evaluation of Acid Stability of Commercial Nanofiltration Membranes (나노여과에 의한 중금속 함유 산성 폐에칭액의 재생(I): 상용 나노여과 막의 산 안정성 평가)

  • Youm, Kyung-Ho;Shin, Hwa-Sup;Jin, Cheon-Deok
    • Membrane Journal
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    • v.19 no.4
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    • pp.317-323
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    • 2009
  • In this study the nanofiltration (NF) membrane treatment of a nitric acid waste solutions containing $Pb^{+2}$ heavy metal ion discharging from the etching processes of an electronics and semiconductors industry has been studied for the purpose of recycling of nitric acid etching solutions. Three kinds of NF membranes (General Electric Co. Duraslick NF-4040 membrane, Dow Co. Filmtec LP-4040 membrane and Koch Co. SelRO MPS-34 4040 membrane) were tested for their separation efficiency (total rejection) of $Pb^{+2}$ ion and membrane stability in nitric acid solution. NF experiments were carried out with a dead-end membrane filtration laboratory system. The membrane permeate flux was increased with the increasing storage time in nitric acid solution and lowering pH of acid solution because of the enhancing of NF membrane damage by nitric acid. The membrane stability in nitric acid solution was more superior in the order of Filmtec LP-4040 < Duraslick NF-4040 < SelRO MPS-34 4040 membrane. The total rejection of Pb+2 ion was decreased with the increasing storage time in nitric acid solution and lowering the pH of acid solution. The total rejection of $Pb^{+2}$ ion after 4 months NF treatment was decreased from 95% initial value to 20% in the case of Duraslick NF-4040 membrane, from 85% initial value to 65% in the case of SelRO MPS-34 4040 membrane and from 90% initial value to 10% in the case of Filmtec LP-4040 membrane. These results showed that SelRO MPS-34 4040 NF membrane was more suitable for the treatment of an acidic etching waste solutions containing heavy metal ions.

EFFECT OF SURFACE MODIFICATION ON BOND STRENGTH IN TITANIUM-PORCELAIN SYSTEM (티타늄의 표면처리 방법에 따른 저온소성도재와의 결합강도)

  • Roh, Sung-Wook;Vang, Mong-Sook;Yang, Hong-So;Park, Sang-Won;Park, Ha-Ok;Lim, Hyun-Pil
    • The Journal of Korean Academy of Prosthodontics
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    • v.45 no.5
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    • pp.589-600
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    • 2007
  • Statement of Problem: Titanium has many advantages of high biocompatibility, physical porperties, low-weight, low price and radiolucency, but it is incompatible with conventional dental porcelain due to titanium's oxidative nature. Many previous studies have shown that they used the method of sandblast surface treatment prior to porcelain application, the researchs are processing about the method of acid etching or surface coating. Purpose: The purpose of this research is to study the effect on bond strength between titanium and porcelain when using macro-surface treatment and micro-surface treatment and macro and micro surface treatment. Material and method: In this study, we evaluated the bond strength by using 3-point bending test based on ISO 9693 after classified 7 groups-group P : polished with #1200 grit SiC paper, group SS : sandblasted with $50{\mu}m$ aluminum oxides, group LS : sandblasted with $250{\mu}m$ alumium oxides, group HC : treated with 10% hydrochloric acid, group NF : treated with 17% solution of fluoric acid and nitric acid, group SHC : treated with 10% hydrochloric aicd after sandblsting with $50{\mu}m$ alumium oxides, group SNF treated with 17% solution of fluoric acid and nitric acid. Results : Within the confines of our research, the following results can be deduced. 1. Group SS which was sandblasted with $50{\mu}m$ aluminum oxides showed the highest bond strength of 61.74 MPa and significant differences(P<0.05). The bond strengths with porcelain in groups treated acid etching after sandblasting decreased more preferable than the group treated with sandblasting only. It gives significant differences(P<0.05). 2. After surface treatments, the group treated with sandblasting showed irregular aspect formed many undercuts, in the SEM photographs. The group treated with hydrochloric acid had the sharp serrated surfaces, the group treated with the solution of fluoric acid and nitric acid had the smooth surfaces, the group with sandblasting and hydrochloric acid had irrigular and porous structure, the group with sandblasting and the solution of fluoric acid and nitric acid had crater-like surfaces. But all of the groups treated with acid etching was not found and undercut. Conclusion: In above results, average surface roughness increase, bond strength also increase, but surface topographs influences more greatly on bond strengths.

A study on the Separation of Acetic Acid, Nitric Acid and Hydrofluoric Acid from Waste Etching Solution of Si Wafer Manufacturing Process (Silicon wafer 에칭공정시 발생(發生)되는 폐(廢)에칭액 으로부터 초산(醋酸), 질산(窒酸) 및 불산(弗酸)의 분리.회수(分離.回收)에 관한 연구(硏究))

  • Kim, Jun-Young;Lee, Hyang-Sook;Shin, Chang-Hoon;Kim, Ju-Yup;Kim, Hyun-Sang;Ahn, Jae-Woo
    • Resources Recycling
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    • v.16 no.1 s.75
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    • pp.59-67
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    • 2007
  • Recovery of acids from the waste etching solution of containing acetic, nitric and hydrofluoric acid discharged from silicon wafer manufacturing process has been attempted by using solvent extraction method. EHA(2-Ethylhexlalcohol) for acetic acid and TBP(Tri-butly Phosphate) for nitric and hydrofluoric acid as a extraction agent was used to the experiment to obtain the process design data in separation procedure. From the experimental data and McCabe-Thiele diagram analysis, we obtained the optimum conditions of phase ratio(O/A) and stages to separate each acid sequently from the mixed acids. The recovery yield was obtained above 90% for acetic acid from the acid mixtures, 90% for nitric acid from acetic acid extraction raffinate and then above 67% for hydrofluoric acid from final extraction raffinate.

Analysis of the bonding strength according to surface treatments of dental Co-Cr alloy for porcelain fused to metal (치과용 Co-Cr 금속도재관의 표면처리에 의한 도재와의 결합 강도 분석)

  • Park, Hee-Geun;Park, Won-UK;Zhao, Jinming;Hwang, Kyu-Hong
    • Journal of Technologic Dentistry
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    • v.38 no.3
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    • pp.175-183
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    • 2016
  • Purpose: Observation of Oxide Film Formation and Bonding Strength according to surface treatment of Co-Cr Alloy for porcelain fused to Metal. Methods: metal specimens $0.5mm{\times}25mm{\times}4mm$ in size were made using Co-Cr alloys for porcelain fused to metal crown (Heraenium P, Tae jung Medis). Dental porcelain $0.5mm{\times}25mm{\times}4mm$ in size was sintered on the metal specimens after changing the etching time, sandblasting condition, and heat treatment temperature. Subsequently, the bonding strength was compared by the three-point flexural strength test using a universal testing machine (UTM) to observe the fracture surface and oxidized layers. Results: With regard to the experimental group treated with acid-etching, Specimen 1 treated for 25 minutes (B-3) showed the highest bonding strength, and Specimen 2 treated only with sandblasting showed the most excellent bonding force at 3.5 bar (C-3). With regard to the experimental group treated with sandblasting at 3.5 bar after acid-etching for 25 minutes, Specimen 3 with heat treatment at $980^{\circ}C$ (D-3) showed the highest bonding strength. Conclusion: The specimen which went through both sandblasting and etching, showed an excellent ceramicmetal bond strength.

A Study on the Ohmic Contacts and Etching Processes for the Fabrication of GaSb-based p-channel HEMT on Si Substrate (Si 기판 GaSb 기반 p-채널 HEMT 제작을 위한 오믹 접촉 및 식각 공정에 관한 연구)

  • Yoon, Dae-Keun;Yun, Jong-Won;Ko, Kwang-Man;Oh, Jae-Eung;Rieh, Jae-Sung
    • Journal of IKEEE
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    • v.13 no.4
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    • pp.23-27
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    • 2009
  • Ohmic contact formation and etching processes for the fabrication of MBE (molecular beam epitaxy) grown GaSb-based p-channel HEMT devices on Si substrate have been studied. Firstly, mesa etching process was established for device isolation, based on both HF-based wet etching and ICP-based dry etching. Ohmic contact process for the source and drain formation was also studied based on Ge/Au/Ni/Au metal stack, which resulted in a contact resistance as low as $0.683\;{\Omega}mm$ with RTA at $320^{\circ}C$ for 60s. Finally, for gate formation of HEMT device, gate recess process was studied based on AZ300 developer and citric acid-based wet etching, in which the latter turned out to have high etching selectivity between GaSb and AlGaSb layers that were used as the cap and the barrier of the device, respectively.

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