• 제목/요약/키워드: molten alloy

검색결과 202건 처리시간 0.022초

정적법을 이용한 Mg-Al계 합금과 순수 Ti의 고온 젖음현상 및 Al계면에서의 정합성에 미치는 영향 (Effects of Mg-Al Alloy and Pure Ti on High Temperature Wetting and Coherency on Al Interface Using the Sessile Drop Method)

  • 한창석;김우석
    • 한국재료학회지
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    • 제31권1호
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    • pp.38-42
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    • 2021
  • In this study, high temperature wetting analysis and AZ80/Ti interfacial structure observation are performed for the mixture of AZ80 and Ti, and the effect of Al on wetting in Mg alloy is examined. Both molten AZ80 and pure Mg have excellent wettability because the wet angle between molten droplets and the Ti substrate is about 10° from initial contact. Wetting angle decreases with time, and wetting phenomenon continues between droplets and substrate; the change in wetting angle does not show a significant difference when comparing AZ80-Ti and Mg-Ti. As a result of XRD of the lower surface of the AZ80-Ti sample, in addition to the Ti peak of the substrate, the peak of TiAl3, which is a Ti-Al intermetallic compound, is confirmed, and TiAl3 is generated in the Al enrichment region of the Ti substrate surface. EDS analysis is performed on the droplet tip portion of the sample section in which pure Mg droplets are dropped on the Ti substrate. Concentration of oxygen by the natural oxide film is not confirmed on the Ti surface, but oxygen is distributed at the tip of the droplet on the Mg side. Molten AZ80 and Ti-based compound phases are produced by thickening of Al in the vicinity of Ti after wetting is completed, and Al in the Mg alloy does not affect the wetting. The driving force of wetting progression is a thermite reaction that occurs between Mg and TiO2, and then Al in AZ80 thickens on the Ti substrate interface to form an intermetallic compound.

IF 고강도 합금화 용융아연도금강판의 표면품질에 미치는 합금원소의 영향 (Effect of Alloy Elements on Galvannealed Coating Quality in IF High Strength Steels)

  • 전선호;진광근;신광수;손호상;김대룡
    • 대한금속재료학회지
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    • 제46권5호
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    • pp.289-295
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    • 2008
  • The effect of the alloy elements(Si/Mn) ratio on the coating quality including wettabilty with molten zinc, galvannealing kinetics and crater has been investigated in interstitial-free high strength steel(IFHSS) containing Si and Mn. When the Si/Mn ratio was below 0.75, IF-HSS exhibited a good wettability leading to a good galvannealed coating quality after annealing at $800^{\circ}C$ for 40s in $15%H_2-N_2$ mixed gas with dew point $-60^{\circ}C$. In contrast, the wettability and galvannealed coating quality were deteriorated in the Si/ Mn ratio above 0.75. It is shown that they have relevance to oxides forms by selective oxidation on the steel surface. The oxide particles dispersed on the steel surface with a surface coverage of below 40% resulted in good wettability and galvannealed coating quality. The oxide particle is mainly consisted of $Mn_2SiO_4$ with low contact angle in molten zinc. On the other hand, the continuous oxide layer on the steel surface, such as network- and film-type,caused to poor wettability and galvannealed coating quality. The coverage of oxide layer was above 80%, and its chemical species was $SiO_2$ with high contact angle in molten zinc. Consequently, the Si/Mn alloy ratio played an importance role in galvannealed coating quality of IF-HSS.

알루미늄 용탕 보온용기의 단열재 적층구조 변경을 통한 보온성 향상 (Thermal Insulation Improvement by Laminated Adiabatic Structure Change in Holding Furnace with Molten Aluminum Alloy)

  • 황준선;강충길
    • 한국주조공학회지
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    • 제31권6호
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    • pp.336-341
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    • 2011
  • Recently, aluminium usage in the automobile industry has been increased cause of its lightweight. The aluminium has a melting-solidification process in producing line and another melting process was needed in manufacturing process. Two times of melting process for making ingot and casting not only makes the loss of time and money but contaminates the air with Sox, Nox. For this reason, the holding furnace with laminated adiabatic material was developed. This holding furnace can deliver the molten aluminium directly to the industry needing molten aluminium. Recent holding furnace has above $15^{\circ}C/h$ of cooling rate and that causes solidification of molten aluminium. The ANSYS software was used to analysis the heat transfer. The adiabatic materials were laminated with optimized arrangement and holding furnace shape was changed with optimized modelling by ANSYS analysis for reducing the cooling rate of molten aluminium in holding furnace.

800℃ 용융염 환경에서 부식된 재료의 마모 성능 평가 (Evaluation of Wear Performance of Corroded Materials in an 800℃ Molten Salt Environment)

  • 최용석;박경렬;강성민;김운성;정경은;이지하;하태웅;이경준
    • Tribology and Lubricants
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    • 제40권3호
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    • pp.97-102
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    • 2024
  • The next-generation Molten Salt Reactor is known for its high safety because it uses nuclear fuel dissolved in high-temperature molten salt, unlike traditional solid atomic fuel methods. However, the high-temperature molten salt causes severe corrosion in internal structural materials, threatening the reactor's safety. Therefore, it is crucial to investigate the high-temperature corrosion resistance and wear performance of materials used in reactors to ensure safety. In this study, the high-temperature corrosion resistances and wear performances of corrosion samples in a NaCl-MgCl2-KCl (20-40-40 [wt%]) molten salt are investigated to evaluate the applicability of economically viable stainless steels, 316SS and 304SS. Hastelloy C276 and a new alloy containing a small amount of Nb are used as reference samples for comparative analysis. The mass loss, mass loss rate per unit volume, and surface roughness of each sample are measured to understand the corrosion mechanisms. Scanning electron microscopy and energy-dispersive spectroscopy analyses are employed to analyze the corrosion mechanisms. Wear tests on the corroded samples are also conducted to assess the extent of corrosion. Based on the experimental results, we predict the lifespans of the materials and evaluate their suitability as candidate materials for molten salt reactors. The data obtained from the experiments provide a valuable database for structural materials that can enhance the stability of molten salt reactors and recommend high-temperature corrosion-resistant materials suitable for next-generation reactors.

치과용 고주파 주조기를 위한 비접촉 단일 온도센서 설계 (Design of a non-contacting single infrared sensor for high frequency dental casting machine)

  • 황인;원용관;이상훈;송성근
    • 한국정보통신학회논문지
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    • 제20권8호
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    • pp.1546-1552
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    • 2016
  • 일반적으로 치과용 주조기는 불때를 이용하여 합금을 용해하기 때문에 합금의 적절한 용융온도 및 주조시간을 조절하기 어렵고 이로 인해 가스공이나 핀홀과 같은 주조결함을 발생시키며 과열로 인한 보철물의 결함을 보이고 있다. 또한 합금이 용융된 후 주조 시 대부분 투시창이나 비접촉식 온도센서를 부착하여 적절한 주조온도가 되면 작업자가 원심력을 발생하는 버튼을 눌러 도가니에 용융된 합금을 주조링에 주입한다. 이러한 결과로 대부분 주조온도가 너무 높거나 낮아서 주조결함을 많이 발생하고 있으며 균일한 주조체를 얻지 못하고 있는 실정이다. 본 논문에서는 외부의 비접촉식 온도 센서를 이용한 온도계측이 아닌 실제 합금의 사용 온도를 계측할 수 있는 단일 온도센서를 이용한 치과용 고주파 주조기를 개발하였다.

BCuP계 합금의 쌍롤주조시 주조특성과 미세조직에 미치는 주입온도의 영향 (Effect of Pouring Temperature on the Casting Characteristics and Microstructure of Twin-roll Cast BCuP Alloy)

  • 주대헌;김명호
    • 한국주조공학회지
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    • 제21권4호
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    • pp.232-238
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    • 2001
  • Experimental study on the twin roll strip casting of BCuP-5(Cu-15wt%Ag-wt5%P) alloy was carried out using laboratory scale horizontal type twin roll caster. In this study, among the various operating parameters, such as tundish angle, contact angle, pouring temperature, roll speed, presetting gap of the rolls and kinds of roll and tundish materials, effect of pouring temperature for strip casting of BCuP-5 alloy which has long freezing range of about $170^{\circ}C$ was mainly investigated. BCuP-5 alloy strip was successfully produced when pouring molten metal at lower temperature than its liquidus temperature. Microstructure of the cast strip consists of primary Cu and eutectic. Especially the size of primary Cu phase increased with decreasing of pouring temperature.

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AlZnMg-합금의 용융산화에 의한 $Al_2O_3$-복합재료의 형성 (Formation of $Al_2O_3$-Composites by the Melt Oxidation of an AlZnMg-alloy)

  • 김일수;김상호;강정윤
    • 한국세라믹학회지
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    • 제33권9호
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    • pp.985-994
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    • 1996
  • The initiation and growth of $\alpha$-Al2O3/metal composites by the directed oxidation of molten commercial AlZnMg-alloy at 1223-1423K were investigated. Spontaneous bulk growth did not occur on the alloy alone. but the uniform initiation and growth of the composite were obtained by putting a thin layer of SiO2 particles on the surface of the alloy. Without SiO2 the external surface of the oxide layer was convered by MgO and MgAl2O4. But with the SiO2 reaction initiate the porous ZnO layers were found on the growth surface. The higher process temperature yielded a lower metal content. The oxidation product of $\alpha$-Al2O3 was found to be oriented with c-axis parallel to th growth direction. The growth rates increased with temperature and the apparent activation energy was 111.8 kJ/mol.

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알루미나의 Ag-33.5Cu-1.5Ti 브레이징 합금 계면에서 생성되는 반응층의 미세조직 관찰과 상 동정 (Identification and Microstructure Observation of Reaction Products formed at Alumina/Ag-33.5Cu-1.5Ti Brazing alloy Interface)

  • 최시경;권순용
    • 한국세라믹학회지
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    • 제33권9호
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    • pp.1045-1049
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    • 1996
  • Pressureless-sintered polycrystalline alumina and carbon steel were joined with Ag-33.5Cu-1.5Ti (wt%) brazing alloy. SEM observation revealed that two reaction layers with different thicknesses were continuously formed between the alumina and the brazing alloy. A thick layer formed on the brazing alloy side was identified as Ti3(Cu0.93Al0.07)3O phase with diamond cubic structure. Another thin layer adjacent to the alumina was revealed as $\delta$-TiO phase of which the crystal structure was HCP with a lattice parameter of a0=0.419 nm and c0=0.284 nm. It was confirmed using XPS analysis that $\delta$-TiO was formed directly by a redox reaction of alumina with titanium ir, molten brazing alloy.

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APPLICATION OF DISPROPORTIONATION REACTION TO SURFACE TREATMENT

  • Oki, Takeo
    • 한국표면공학회지
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    • 제29권5호
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    • pp.478-481
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    • 1996
  • Disproportionation reaction is very important and interesting reaction to be applied to such surface treatment as metal, alloy, compound coating, a surface etching and so on. In gaseous system, the reaction of Al chloride is applied to Al and Al alloy coating, and the similar reaction of Ti chloride is also used for Ti, Ti alloy and Ti compound coating. As for aqueous system, this reaction is utilized to such metal coat as Sn etc. and metal etching such as Cu, Fe and so on. Also in molten salts system, this reaction has many application for surface treatment like metal, alloy and compound coatings for corrosion, wear, heat resistance and so forth. For instance, carbide film, nitride film, boride film, alloy film, quite new different film from the components of substrate material are coated in single and multiple component film system by the disproportionation reaction.

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용융 Al-10wt.%Si 합금의 산화피 형성에 미치는 첨가원 (The Effect of Additive Elements on the Formation of Oxide Skins of AI-10wt.% Si Alloy Melts)

  • 최재영;양정식;백영남
    • 한국표면공학회지
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    • 제22권4호
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    • pp.179-184
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    • 1989
  • This study seeks to the morphological changes in the oxide skin of the Al-10wt.%si alloy melts. These changes depend on the oxidation time and the temperature of the molten alloy, as well as the effects of adding Mg, Cu and Ni. Thess affects observed by X-ray diffractometer(XRD) and scanning electron microscope(SEM)' Very litte oxide skins on Al-10wtwt.%Si alloy melts can be detected by XRD because it is less than the measuring capabillity of the XRD, or the formation of noncrystalline oxide skins oxide skins canbe deteced by SEM. The addition of 1%Mg and 1%Cu-1%Mg-2.5%Ni to this base alloy crystallized the structure of the oxide skins and increased the oxidation in proportion to the length of time, but adding 3% had hardiy anyaffect at all on the crystal structure of the oxide skins.

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