• 제목/요약/키워드: Zr-based alloys

검색결과 121건 처리시간 0.023초

Microstructure and Mechanical Properties of Mg-Li Powder by Hot Rolling Process

  • Choi, Jeong-Won;Kim, Yong-Ho;Kim, Jung-Han;Yoo, Hyo-Sang;Woo, Kee-Do;Kim, Ki-Beom;Son, Hyeon-Taek
    • 한국재료학회지
    • /
    • 제25권1호
    • /
    • pp.32-36
    • /
    • 2015
  • Hot rolling of Mg-6Zn-0.6Zr-0.4Ag-0.2Ca-(0, 8 wt%)Li powder was conducted at the temperature of $300^{\circ}C$ by putting the powder into the Cu pipe. The microstructure and mechanical properties of the samples were observed. Mg-6Zn-0.6Zr-0.4Ag-0.2Ca without Li element was consisted of ${\alpha}$ phase and precipitates. The microstructure of the 8 wt%Li containing alloy consisted of two phases (${\alpha}$-Mg phase and ${\beta}$-Li phase). In addition, $Mg_2Zn_3Li$ was formed in 8%Li added Mg-6Zn-0.6Zr-0.4Ag-0.2Ca alloy. By addition of the Li element, the non-basal planes were expanded to the rolling direction, which was different from the based Mg alloy without Li. The tensile strength was gradually decreased from 357.1 MPa to 264 MPa with increasing Li addition from 0% to 8%Li. However, the elongation of the alloys was remarkably increased from 10 % to 21% by addition of the Li element to 8%. It is clearly considered that the non-basal texture and ${\beta}$ phase contribute to the increase of elongation and formability.

소량의 첨가원소가 Strip-Cast Nd-Fe-B 향금의 미세 조직 형성에 미치는 영향 (Effect of Small Additives on the Microstructure of Strip-Cast Nd-Fe-B Alloys)

  • 이대훈;장태석;김동환;김승호
    • 한국자기학회지
    • /
    • 제14권5호
    • /
    • pp.196-200
    • /
    • 2004
  • 고에너지 Nd-Fe-B소결자석 제조용 strip-cast합금의 미세조직을 개선하기 위하여, Nd$_{14}$Fe$_{80}$B$_{6}$6의 기본 조성에 소량의 Cu (0.3 ~ 1.0 at%) Co (0.5 ~ 1.5 at%)를 각각 첨가하고 strip-casting법으로 합금을 제조한 후, 이들 Fe 치환원소의 첨가량 변화가 합금의 상형성, 상분포 및 조직 형성에 미치는 영향을 조사하였다. Cu첨가량이 증가함에 따라 용탕의 유동성이 증가하여 strip 두께가 감소함과 함께 strip표면에 수직한 방향으로의 수지상정 발달이 억제되었으나, Co첨가량이 증가한 경우에는 strip두께의 증가와 함께 strip표면에 수직한 방향으로 수지상정이 잘 발달하여 <001>방향으로의 preferred orientation이 증가하는 경향을 보였다. 이들 Cu와 Co의 첨가는 모두 수지상정을 미세화하는 효과가 있었으나, Cu는 Fe의 정출을 안정화시키는 경향이 있어서 Cu가 함유된 함금에서는 종종 Fe가 종종 정출한 반면, Co는 초정 Fe의 정출을 억제하는 효과가 있었다. 한편, 소량의 Zr (0.3, 0.5 at%)을 첨가하였을 때에는 전체적인 결정립의 조대화와 함께 수지상정의 붕괴를 초래하였다.

졸-겔 법에 의해 절연코팅된 철계 비정질 리본의 자기특성 (Magnetic properties of Fe-based amorphous ribbon insulated by sol-gel process)

  • 송재성;김병걸;정순종;김현식ㅂ;황시돌
    • E2M - 전기 전자와 첨단 소재
    • /
    • 제9권2호
    • /
    • pp.159-164
    • /
    • 1996
  • The development of an insulated coating which can be used for amorphous alloys is extremely important from the practical point of view. This importance may be enhanced by the influence of the coating on the magnetic properties. The purpose of this study is to show how new developed insulating coating materials and method influence the magnetic properties of amorphous Fe/sub 87/Zr/sub 7/B/sub 5/Ag/sub 1/(at%) ribbon.

  • PDF

Fe-계 비정질 합금의 절연 코팅이 자기적 성질에 미치는 영향 (Influence of Insulated Coatings on The Magnetic Properties of Fe-Based Amorphous Alloy)

  • 김현식;오영우;김병걸;전순종;김기욱;민복기;송재성
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1994년도 하계학술대회 논문집 C
    • /
    • pp.1311-1313
    • /
    • 1994
  • The development of an insulated coating which can be used for amorphous alloys is extremely important from the practical point of view. This importance may be enhanced by the influence of the coating on the magnetic properties. The aim of the study is to show how some coating influence the magnetic properties of $Fe_{87}Zr_7B_5Ag_1(at%)$ amorphous alloy.

  • PDF

Designing Materials for Hard Tissue Replacement

  • Nath, Shekhar;Basu, Bikramjit
    • 한국세라믹학회지
    • /
    • 제45권1호
    • /
    • pp.1-29
    • /
    • 2008
  • In last two decades, an impressive progress has been recorded in terms of developing new materials or refining existing material composition/microstructure in order to obtain better performance in biomedical applications. The success of such efforts clearly demands better understanding of various concepts, e.g. biocompatibility, host response, cell-biomaterial interaction. In this article, we review the fundamental understanding that is required with respect to biomaterials development, as well as various materials and their properties, which are relevant in applications, such as hard tissue replacement. A major emphasize has been placed to present various design aspects, in terms of materials processing, of ceramics and polymer based biocomposites, Among the bioceramic composites, the research results obtained with Hydroxyapatite (HAp)-based biomaterials with metallic (Ti) or ceramic (Mullite) reinforcements as well as $SiO_2-MgO-Al_2O_3-K_2O-B_2O_3-F$ glass ceramics and stabilized $ZrO_2$ based bioinert ceramics are summarized. The physical as well as tribological properties of Polyethylene (PE) based hybrid biocomposites are discussed to illustrate the concept on how can the physical/wear properties be enhanced along with biocompatibility due to combined addition of bioinert and bioactive ceramic to a bioinert polymeric matrix. The tribological and corrosion properties of some important orthopedic metallic alloys based on Ti or Co-Cr-Mo are also illustrated. At the close, the future perspective on orthopedic biomaterials development and some unresolved issues are presented.

Development and testing of multicomponent fuel cladding with enhanced accidental performance

  • Krejci, Jakub;Kabatova, Jitka;Manoch, Frantisek;Koci, Jan;Cvrcek, Ladislav;Malek, Jaroslav;Krum, Stanislav;Sutta, Pavel;Bublikova, Petra;Halodova, Patricie;Namburi, Hygreeva Kiran;Sevecek, Martin
    • Nuclear Engineering and Technology
    • /
    • 제52권3호
    • /
    • pp.597-609
    • /
    • 2020
  • Accident Tolerant Fuels have been widely studied since the Fukushima-Daiichi accident in 2011 as one of the options on how to further enhance the safety of nuclear power plants. Deposition of protective coatings on nuclear fuel claddings has been considered as a near-term concept that will reduce the high-temperature oxidation rate and enhance accidental tolerance of the cladding while providing additional benefits during normal operation and transients. This study focuses on experimental testing of Zr-based alloys coated with Cr-based coatings using Physical Vapour Deposition. The results of long-term corrosion tests, as well as tests simulating postulated accidents, are presented. Zr-1%Nb alloy used as nuclear fuel cladding serves as a substrate and Cr, CrN, CrxNy layers are deposited by unbalanced magnetron sputtering and reactive magnetron sputtering. The deposition procedures are optimized in order to improve coating properties. Coated as well as reference uncoated samples were experimentally tested. The presented results include standard long-term corrosion tests at 360℃ in WWER water chemistry, burst (creep) tests and mainly single and double-sided high-temperature steam oxidation tests between 1000 and 1400℃ related to postulated Loss-of-coolant accident and Design extension conditions. Coated and reference samples were characterized pre- and post-testing using mechanical testing (microhardness, ring compression test), Thermal Evolved Gas Analysis analysis (hydrogen, oxygen concentration), optical microscopy, scanning electron microscopy (EDS, WDS, EBSD) and X-ray diffraction.

Molten Salt-Based Carbon-Neutral Critical Metal Smelting Process From Oxide Feedstocks

  • Wan-Bae Kim;Woo-Seok Choi;Gyu-Seok Lim;Vladislav E. Ri;Soo-Haeng Cho;Suk-Cheol Kwon;Hayk Nersisyan;Jong-Hyeon Lee
    • 방사성폐기물학회지
    • /
    • 제21권1호
    • /
    • pp.9-22
    • /
    • 2023
  • Spin-off pyroprocessing technology and inert anode materials to replace the conventional carbon-based smelting process for critical materials were introduced. Efforts to select inert anode materials through numerical analysis and selected experimental results were devised for the high-throughput reduction of oxide feedstocks. The electrochemical properties of the inert anode material were evaluated, and stable electrolysis behavior and CaCu generation were observed during molten salt recycling. Thereafter, CuTi was prepared by reacting rutile (TiO2) with CaCu in a Ti crucible. The formation of CuTi was confirmed when the concentration of CaO in the molten salt was controlled at 7.5mol%. A laboratory-scale electrorefining study was conducted using CuTi(Zr, Hf) alloys as the anodes, with a Ti electrodeposit conforming to the ASTM B299 standard recovered using a pilot-scale electrorefining device.

수소와 불활성 가스 중 일산화탄소, 이산화탄소, 메탄 제거에 관한 연구 -연료전지에의 적용 가능성- (How to Eliminate CO, CO2 and CH4 in H2 & Inert Gas -Possibility of Fuel Cell Application-)

  • 이택홍;천영기
    • 한국수소및신에너지학회논문집
    • /
    • 제15권3호
    • /
    • pp.220-227
    • /
    • 2004
  • The purpose of this paper is, based on the theoretical background of the principle of gas purification and absorption, and the absorbing ability of metals, to syudy the efficiency of gas purification of inorganic gases using Zr alloys, so as to contribute to the IT industry. To produce and distribute gas with high purity and ultra-high purity, different types of gas purifier are currently being used: distillation type, getter type, catalyst type, absorption at low-temperature type, and membrane separation equipment. From the different purification methods mentioned above, the getter type gas purifier is capable of not only high performance and capacity but also P.O.U(Point Of Use) method. The key of the getter type gas purifier is its efficiency of gas purification, which is the subject chosen for this study.

Evaluations of Si based ternary anode materials by using RF/DC magnetron sputtering for lithium ion batteries

  • 황창묵;박종완
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2010년도 제39회 하계학술대회 초록집
    • /
    • pp.302-303
    • /
    • 2010
  • Generally, the high energy lithium ion batteries depend intimately on the high capacity of electrode materials. For anode materials, the capacity of commercial graphite is unlike to increase much further due to its lower theoretical capacity of 372 mAhg-1. To improve upon graphite-based negative electrode materials for Li-ion rechargeable batteries, alternative anode materials with higher capacity are needed. Therefore, some metal anodes with high theoretic capacity, such as Si, Sn, Ge, Al, and Sb have been studied extensively. This work focuses on ternary Si-M1-M2 composite system, where M1 is Ge that alloys with Li, which has good cyclability and high specific capacity and M2 is Mo that does not alloy with Li. The Si shows the highest gravimetric capacity (up to 4000mAhg-1 for Li21Si5). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. Si thin film is more resistant to fracture than bulk Si because the film is firmly attached to the substrate. Thus, Si film could achieve good cycleability as well as high capacity. To improve the cycle performance of Si, Suzuki et al. prepared two components active (Si)-active(Sn, like Ge) elements film by vacuum deposition, where Sn particles dispersed homogeneously in the Si matrix. This film showed excellent rate capability than pure Si thin film. In this work, second element, Ge shows also high capacity (about 2500mAhg-1 for Li21Ge5) and has good cyclability although it undergoes a large volume change likewise Si. But only Ge does not use the anode due to its costs. Therefore, the electrode should be consisted of moderately Ge contents. Third element, Mo is an element that does not alloys with Li such as Co, Cr, Fe, Mn, Ni, V, Zr. In our previous research work, we have fabricated Si-Mo (active-inactive elements) composite negative electrodes by using RF/DC magnetron sputtering method. The electrodes showed excellent cycle characteristics. The Mo-silicide (inert matrix) dispersed homogeneously in the Si matrix and prevents the active material from aggregating. However, the thicker film than $3\;{\mu}m$ with high Mo contents showed poor cycling performance, which was attributed to the internal stress related to thickness. In order to deal with the large volume expansion of Si anode, great efforts were paid on material design. One of the effective ways is to find suitably three-elements (Si-Ge-Mo) contents. In this study, the Si based composites of 45~65 Si at.% and 23~43 Ge at.%, and 12~32 Mo at.% are evaluated the electrochemical characteristics and cycle performances as an anode. Results from six different compositions of Si-Ge-Mo are presented compared to only the Si and Ge negative electrodes.

  • PDF

Application of Gamma Ray Densitometry in Powder Metallurgy

  • Schileper, Georg
    • 한국분말야금학회:학술대회논문집
    • /
    • 한국분말야금학회 2002년도 제3회 최신 분말제품 응용기술 Workshop
    • /
    • pp.25-37
    • /
    • 2002
  • The most important industrial application of gamma radiation in characterizing green compacts is the determination of the density. Examples are given where this method is applied in manufacturing technical components in powder metallurgy. The requirements imposed by modern quality management systems and operation by the workforce in industrial production are described. The accuracy of measurement achieved with this method is demonstrated and a comparison is given with other test methods to measure the density. The advantages and limitations of gamma ray densitometry are outlined. The gamma ray densitometer measures the attenuation of gamma radiation penetrating the test parts (Fig. 1). As the capability of compacts to absorb this type of radiation depends on their density, the attenuation of gamma radiation can serve as a measure of the density. The volume of the part being tested is defined by the size of the aperture screeniing out the radiation. It is a channel with the cross section of the aperture whose length is the height of the test part. The intensity of the radiation identified by the detector is the quantity used to determine the material density. Gamma ray densitometry can equally be performed on green compacts as well as on sintered components. Neither special preparation of test parts nor skilled personnel is required to perform the measurement; neither liquids nor other harmful substances are involved. When parts are exhibiting local density variations, which is normally the case in powder compaction, sectional densities can be determined in different parts of the sample without cutting it into pieces. The test is non-destructive, i.e. the parts can still be used after the measurement and do not have to be scrapped. The measurement is controlled by a special PC based software. All results are available for further processing by in-house quality documentation and supervision of measurements. Tool setting for multi-level components can be much improved by using this test method. When a densitometer is installed on the press shop floor, it can be operated by the tool setter himself. Then he can return to the press and immediately implement the corrections. Transfer of sample parts to the lab for density testing can be eliminated and results for the correction of tool settings are more readily available. This helps to reduce the time required for tool setting and clearly improves the productivity of powder presses. The range of materials where this method can be successfully applied covers almost the entire periodic system of the elements. It reaches from the light elements such as graphite via light metals (AI, Mg, Li, Ti) and their alloys, ceramics ($AI_20_3$, SiC, Si_3N_4, $Zr0_2$, ...), magnetic materials (hard and soft ferrites, AlNiCo, Nd-Fe-B, ...), metals including iron and alloy steels, Cu, Ni and Co based alloys to refractory and heavy metals (W, Mo, ...) as well as hardmetals. The gamma radiation required for the measurement is generated by radioactive sources which are produced by nuclear technology. These nuclear materials are safely encapsulated in stainless steel capsules so that no radioactive material can escape from the protective shielding container. The gamma ray densitometer is subject to the strict regulations for the use of radioactive materials. The radiation shield is so effective that there is no elevation of the natural radiation level outside the instrument. Personal dosimetry by the operating personnel is not required. Even in case of malfunction, loss of power and incorrect operation, the escape of gamma radiation from the instrument is positively prevented.

  • PDF