• 제목/요약/키워드: post-heat treatment

검색결과 449건 처리시간 0.026초

Thermal Stability of TiN/Ti Barrier Metals with Al Overlayers and Si Substrates Modified under Different Annealing Histories (형성조건에 따른 TiN/Ti Barrier Metal의 Al 및 Si 과의 열적 안정성)

  • 신두식;오재응;유성룡;최진석;백수현;이상인;이정규;이종길
    • Journal of the Korean Institute of Telematics and Electronics A
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    • 제30A권7호
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    • pp.47-59
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    • 1993
  • The thermal stability of "stuffed" TiN/Ti barrier matals with different annealing history has been studied to improve the contact reliability of Al/Si contacts in 16M DRAM. The annealing conditions before the Al deposition such as film thickness, the annealing temperature and the annealing ambient have been varied. For TiN(900A)/Ti(300A) annealed at 450 in nitrogen ambient to form a "stuffed barrier" by inducing oxygen atoms into grain boundaries, there is no observation of Al penetrations into Si substrates after the post heat treatment of up to 700 even though there are massive amounts of Al found in TiN film after the post heat treatment of 600 indicating that TiN has a "sponge-like" function due to its ability to absorb several amounts of aluminum at elevated temperature. The TiN/Ti diffusion barrier annealed at 550 has, however, failed after the post heat treatment at 600. The thinner diffusion barriers with TiN(300A)/Ti(100A) failed after the post heat treatment at 600.he post heat treatment at 600.

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Effect of Laser Welding Variables on the Formability of Si Added Steel Welds (3wt% Si 첨가강의 레이저용접부 성형성에 미치는 용접변수의 영향)

  • Park, Joon-Sik;Woo, In-Su;Lee, Jong-Bong
    • Journal of Welding and Joining
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    • 제24권4호
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    • pp.15-21
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    • 2006
  • The aim of present study is to investigate the effect of welding parameters and heat treatment conditions on the formability of the $CO_2$ laser welded silicon steel sheet. It was found that there is optimum range of the heat input ($0.6{\sim}0.7kJ/cm$) and gap distance ($0.125{\sim}0.150mm$) for the high tensile strength and the avoidance of the fracture in weld metal. Also, it was essential fur the improvement of formability to perform pre- and post-welding heat treatment which cause the uniform mixture of base metal and welding consumable.

Preparation of SnO2 Film via Electrodeposition and Influence of Post Heat Treatment on the Battery Performances (전해도금법을 이용한 SnO2 제조 및 후 열처리가 전지 특성에 미치는 영향)

  • Kim, Ryoung-Hee;Kwon, Hyuk-Sang
    • Journal of the Korean Society for Heat Treatment
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    • 제30권2호
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    • pp.61-66
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    • 2017
  • $SnO_2$ was electrodeposited on nodule-type Cu foil at varing current density and electrodeposition time. Unlike the previous research results, when the anodic current is applied, the $SnO_2$ layer was not electrodeposited and the substrate is corroded. When the cathodic current was applied, the $SnO_2$ layer could be successfully deposited. At this time, the surface microstructure of the powdery type was observed, which showed similar crystallinity to amorphous and had a very large surface area. Crystallinity increased after low-temperature heat treatment at $250^{\circ}C$ or lower. As a result of evaluating the charge/discharge performances as an anode material for lithium ion battery, it was confirmed that the capacity of the heat treated $SnO_2$ was increased more than 2 times, but it still showed a limit point showing initial low coulombic efficiency and low cyclability. However, it was confirmed that the battery performances may be enhanced through optimizing the electrodeposition process and introducing post heat treatment.

Corrosion Characteristics of Welding Zone by Types of Repair Welding Filler Metals and Post Weld Heat Treatment

  • Lee, Sung-Yul;Moon, Kyung-Man;Lee, Yeon-Chang;Kim, Yun-Hae;Jeong, Jae-Hyun
    • International Journal of Ocean System Engineering
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    • 제2권4호
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    • pp.209-213
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    • 2012
  • Recently, the fuel using in the diesel engines of marine ships has been changed to a low quality of heavy oil because of the steady increase in the price of oil. Therefore, the wear and corrosion in all parts of the engine such as the cylinder liner, piston crown, and spindle and seat ring of exhaust valves has correspondingly increased. The repair welding of a piston crown is a unique method for prolonging its lifetime from an economic point of view. In this case, filler metals with a high corrosion and wear resistance are mainly being used for repair welding. However, often at a job site on a ship, a piston crown is actually welded with mild filler metals. Therefore, in this study, mild filler metals such as CSF350H, E8000B2, and 435 were welded to SS401 steel as the base metal, and the corrosion properties of the weld metals with and without post weld heat treatment were investigated using some electrochemical methods in a 0.1% $H_2SO_4$ solution. The weld metal welded with CSF350H filler metal exhibited the best corrosion resistance among these filler metals, irrespective of the heat treatment. However, the weld metal zones of the E8000B2 and 435 filler metals exhibited better and worse corrosion resistance with the heat treatment, respectively. As a result, it is suggested that in the case of repair welding with CSF350H and 435 filler metals, no heat treatment is advisable, while heat treatment is desirable if E8000B2filler metal is used with repair welding.

Effects of post weld heat treatment conditions on localized corrosion resistance of super duplex stainless steel tube used for thermal power plant applications (화력발전용 슈퍼 듀플렉스 스테인리스 강 조관재의 용접 후 열처리 조건이 국부부식 저항성에 미치는 영향)

  • Lee, Jun Ho;Park, Jin sung;Cho, Dong Min;Hong, Seung Gab;Kim, Sung Jin
    • Journal of the Korean institute of surface engineering
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    • 제54권5호
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    • pp.248-259
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    • 2021
  • This study examined the influence of post weld heat treatment (PWHT) conditions on corrosion behaviors of laser-welded super duplex stainless steel tube. Due to the high cooling rate of laser welding, the phase fraction of ferrite and austenite in the weld metal became unbalanced significantly. In addition, the Cr2N particles were precipitated adjacent to the fusion line, which can be susceptible to the localized corrosion. On the other hand, the phase fraction in the weld metal was restored at a ratio of 5:5 when exposed to temperatures above 1060 ℃ during the post weld heat treatment. Nevertheless, the high beltline speed during the PWHT, leading to the insufficient cooling rate, caused a precipitation of σ phase at the interface between ferrite/austenite in both weld metal and base metal. This resulted in the severe corrosion damages and significant decrease in critical pitting temperature (CPT), which was even lower than that measured in as-welded condition. Moreover, the fraction of σ phase in the center region of post weld heat treated steel tube was obtained to be higher than in the surface region. These results suggest that the PWHT conditions for the steel tube should be optimized to ensure the high corrosion resistance by excluding the precipitation of σ phase even in center region.

EFFECT OF POST-WELD HEAT TREATMENT OF MARINE STRUCTURE STEEL DURING CATHODIC PROTECTION

  • Kim, Seong-Jong;Masazumi Okido;Kim, Jin-Gyeong;Moon, Kyung-Man
    • Proceedings of the KWS Conference
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    • 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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    • pp.273-275
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    • 2002
  • The effect of post-weld heat treatment (PWHT) of marine structures steel was investigated at electrochemical viewpoint. In addition, slow strain rate test (SSRT) was carried out to investigate both electrochemical and mechanical properties by PWHT effect during impressed current cathodic protection. The optimum cathodic protection potential by SSRT was -770 mV(SCE). At the applied cathodic protection potential of -770 mV -850 mV(SCE), the fracture morphology was dimple pattern with ductile fracture, while it was transgranular pattern (Q.C: quasi cleavage) under -875 mV(SCE).

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Effect of post-annealing on single-walled carbon nanotubes synthesized by arc-discharge

  • Park, Suyoung;Choi, Sun-Woo;Jin, Changhyun
    • Journal of Ceramic Processing Research
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    • 제20권4호
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    • pp.388-394
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    • 2019
  • In this study, high-purity single-walled carbon nanotubes (SWCNTs) were prepared by removing the unreacted metal constituents and amorphous carbon impurities using a post-annealing process. Unlike conventional thermal processing techniques, this technique involved different gas atmospheres for efficient removal of impurities. A heat treatment was conducted in the presence of chlorine, oxygen, and chlorine + oxygen gases. The nanotubes demonstrated the best characteristics, when the heat treatment was conducted in the presence of a mixture of chlorine and oxygen gases. The scanning electron microscopy, transmission electron microscopy, ultraviolet absorbance, and sheet resistance measurements showed that the heat treatment process efficiently removed the unreacted metal and amorphous carbon impurities from the as-synthesized SWCNTs. The high-purity SWCNTs exhibited improved electrical conductivities. Such high-purity SWCNTs can be used in various carbon composites for improving the sensitivity of gas sensors.

Numerical analysis of post welding heat treatment base on the thermal creep elastic-plastic theory (점열탄소성 이론에 의한 용접후열처리에 대한 수치해석)

  • 방한서;차용훈;오율권;노찬승;김종명
    • Journal of Ocean Engineering and Technology
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    • 제11권1호
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    • pp.113-123
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    • 1997
  • The welding residual stresses produced by welding frequently cause a crack and promote stress corrosion etc. in heat affected zone contained with external load and weakness of material. For the purpose pof relaxation of welding residual stress, post welding heat teratment(PWHT) is widely used. In this paper, the computer program which is based on Thermal-Elasto-plastic-creep theory for plane deformation on developed by finite element method (F.E.M) and verified its propriety by experimental measurement and also by using the developed computer program. The mechanical behavior of butt welding joint is clairfied during PWHT.

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Optimal Post Heat-treatment Conditions for Improving Bonding Strength of Roll-bonded 3-ply Ti/Al/Ti Sheets (롤 본딩된 Ti/Al/Ti 3-ply 다층금속 판재의 접합강도 향상을 위한 최적 후열처리 조건 도출)

  • Kim, M.H.;Bong, H.J.;Kim, J.H.;Lee, K.S.
    • Transactions of Materials Processing
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    • 제31권4호
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    • pp.179-185
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    • 2022
  • The influence of post-roll bonding heat treatment conditions such as temperature and time on the variation in the diffusion layer, generated at the bonding interface and the subsequent mechanical properties of the roll-bonded Ti grade 1/Al1050/Ti grade 1 sheets, was systematically investigated. The intermetallic compound (IMC) phase generated by post heat treatment conditions adopted in this study was obviously indexed as monolithic TiAl3. Whereas the thickness of IMC layer generated by annealing at 500 ℃ was approximately 100 nm scale, it drastically increased above 1.5 ㎛ when annealed at 600 ℃. Uniaxial tensile and peel tests were then performed to compare mechanical properties. As a result, the bonding strength drastically increased above 7.9 N/mm by annealing at 600 ℃, which implies that proper annealing condition was a prerequisite, to improving interface bonding strength as well as global elongation properties for Ti/Al/Ti 3-ply sheet.