Статті в журналах: "Melting of oxygen-free copper"

1

S. Kazem, Murtadha, and Isam M. Abdulbaqi. "DESIGN OF INDUCTION COIL FOR OXYGEN FREE COPPER PRODUCTION." Journal of Engineering and Sustainable Development 25, no. 4 (July 1, 2021): 51–57. http://dx.doi.org/10.31272/jeasd.25.4.5.

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This paper deals with the design of an induction coil (IC) intended to be used for an oxygen free copper production. This coil differs in design because it should be placed in a vacuum or in a chamber filled with noble gas, such as Argon. The designed coil must be suitable for melting the copper in this environment. The coil design means, using the simulation of the melting process to determine the best, coil geometry, type of crucible, the required current, frequency, the consumed power, and time required for this process. These results will be used to determine the parameters of the induction furnace AC power source suitable for feeding such a melting process efficiently. The Finite Element Analysis (FEA) intended to simulate the heating process to determine the best coil dimensions, and choosing the crucible. It is found that the best crucible used for the melting of copper is the carbon crucible.

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2

Guo, Ming En, Yun Xu Shi, and Yu Chen Guo. "Research on Oxygen Content and Crack Control of Oxygen-Free Copper Billet in Horizontal Continuous Casting Process." Advanced Materials Research 569 (September 2012): 264–67. http://dx.doi.org/10.4028/www.scientific.net/amr.569.264.

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In this paper, research on reducing oxygen content and crack in oxygen-free copper strip during horizontal continuous casting process has been taken. First, reform the original copper alloy smelting-holding-casting three stages process. Through developing melting and holding integrative furnace, combine melting process and holding process for one, reforming smelting holding-casting two stages process. Second, pick up and realize on-off valve technics on controlling flow or stop of undercurrents copper liquid. Third, analyze the cracks in oxygen-free copper billet with flakinessratio 6500/20mm. And finally determine reasonable cooling process parameters through experiments. The results shows when oxygen content ≤0.0004% and density rise to 8.94-8.95 g/cm3, the crack has been completely eliminated.

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3

Lei, H. "Melting of free copper clusters." Journal of Physics: Condensed Matter 13, no. 13 (March 15, 2001): 3023–30. http://dx.doi.org/10.1088/0953-8984/13/13/315.

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4

Lee, Jung Il, Joo Ho Lee, Seung Hwan Park, Han Shin Choi, Hoon Cho, Hyung Ho Jo, Skae K. Kim, Hyuk Chon Kwon, and Jung Eui Hong. "Design of Manufacturing Process of Oxygen-Free High Conductivity Copper Using Mahalanobis-Distance Outlier Detection Method." Materials Science Forum 544-545 (May 2007): 965–68. http://dx.doi.org/10.4028/www.scientific.net/msf.544-545.965.

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The proper control of total impurities and oxygen contents of oxygen-free high conductivity (OFHC) copper prepared by vacuum high-frequency melting technique was studied using Mahalanobis-Distance (MD) outlier detection method as functions of raw material purities, vacuum pressure, melting temperature and holding time. The properties of vacuum-melted OFHC copper was examined by thermo-gravimetric analysis, differential scanning calorimetry, hardness test, macro and optical microstructure analyses and ultimate tensile test. In multivariate systems, the existence of outlier makes it difficult to analyze the system and oultier detection belongs to the most important tasks in experimental data analysis. Mahalanobis Distance is most commonly used as a diagnosis of existance of outlier in multivariate system. The relationship between experiment conditions and total impurities and oxygen contents can be defined with the regression analysis results. At this research, our desirable manufacturing conditions is to obtain the total impurities under 40 ppm and oxygen contents under 5 ppm. After this statistical approach, the suggested minimum maufacturing conditions are the purity of raw material was 4N, vacuum pressure was 10-1 torr, melting temperature was 1150°C and melt holding time was 20 minutes.

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5

Stefanova, V., K. Vutova, and V. Vassileva. "Thermodynamic analysis of the processes during electron beam melting and refining of copper." Journal of Physics: Conference Series 2240, no. 1 (March 1, 2022): 012034. http://dx.doi.org/10.1088/1742-6596/2240/1/012034.

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Abstract In the paper, results are presented and discussed obtained by thermodynamic analysis of the refining processes of copper aimed at removing metal impurities and oxygen via electron beam melting (EBM) in vacuum. Thermodynamic evaluations of the possible chemical interactions between the base metal (Cu) and the metal impurities present in Cu that can proceed during the refining of copper are made based on the calculated values of the Gibbs free energy and equilibrium constants taking into account the physical state of copper and of the metal impurities during EBM.

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6

Tsao, Lung-Chuan, Cheng-Kai Li, Yu-Kai Sun, Shih-Ying Chang, and Tung-Han Chuang. "Fluxless Direct Soldering of Transparent Conductive Oxides (TCOs) to Copper." Advances in Materials Science and Engineering 2021 (November 15, 2021): 1–7. http://dx.doi.org/10.1155/2021/8069719.

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Due to the combined advantages of low cost, good soldering properties, and appropriate melting temperature range, novel Sn8Zn3Bi1Mg active solder was developed for direct soldering of transparent conductive oxide (TCO) ceramic targets with oxygen-free copper at 200°C in air. The TCO specimens have aluminum-doped zinc oxide (AZO) and zinc oxide (ZnO) ceramics. The direct soldering process was performed without the need for flux or pre-metallization of the two transparent conductive oxides. The microstructure, phase constitution, melting characteristics, and soldering properties of the Sn8Zn3Bi1Mg active solder were investigated. The liquidus temperature of the Sn8Zn3Bi1Mg active solder was 198.6°C, which was very close to the binary Sn-Zn eutectic temperature of 198.5°C. The effect of temperature on the bonding strength of the solder joints was evaluated. The shear strengths of AZO/Cu and ZnO/Cu joints soldered with Sn8Zn3Bi1Mg active solder were 10.3 and 7.5 MPa at room temperature, respectively. Increasing the temperature from room temperature to 180°C reduced the bonding shear strengths of AZO/Cu and ZnO/Cu joints to 3.3 and 3.7 MPa, respectively.

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7

Li, Jianxing, Daniel Lau, Pingliang Tu, Andrew Delano, and Brian Knight. "High Melting Temperature Lead Free Solder for Die Attach Application." International Symposium on Microelectronics 2011, no. 1 (January 1, 2011): 000322–26. http://dx.doi.org/10.4071/isom-2011-tp4-paper1.

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Two lead free solders were developed for die attach application. The bismuth based solder has a melt temperature of 271C and thermal conductivity of 18W/mK. The zinc based solder has a melt temperature of 337C and thermal conductivity of 85W/mK. Both solders have acceptable wetting on bare copper and nickel plated copper substrate, could be processed using modified high lead solder process condition and survived 260C board level reflow simulation. This paper discusses the solder material properties, and presents the die attach process and reliability test results in a manufacturing environment.

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8

De Lucia, M. "Oxygen Enrichment in Combustion Processes: Comparative Experimental Results From Several Application Fields." Journal of Energy Resources Technology 113, no. 2 (June 1, 1991): 122–26. http://dx.doi.org/10.1115/1.2905785.

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The effects of using oxygen to partially or wholly replace fuel air in small-size melting furnaces were studied over a range of application fields. Following definition of the useful parameters, testing was conducted on furnaces for melting glass, ferrous metals (pigiron), nonferrous metals (copper alloys), and ceramic materials. In all cases, oxygen-enrichment was found to provide significant energy savings, as well as notable advantages in terms of both plant output and energy consumption.

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9

Ledford, Christopher, Christopher Rock, Paul Carriere, Pedro Frigola, Diana Gamzina, and Timothy Horn. "Characteristics and Processing of Hydrogen-Treated Copper Powders for EB-PBF Additive Manufacturing." Applied Sciences 9, no. 19 (September 24, 2019): 3993. http://dx.doi.org/10.3390/app9193993.

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The fabrication of high purity copper using additive manufacturing has proven difficult because of oxidation of the powder feedstock. Here, we present work on the hydrogen heat treatment of copper powders for electron beam powder bed fusion (EB-PBF), in order to enable the fabrication of high purity copper components for applications such as accelerator components and vacuum electronic devices. Copper powder with varying initial oxygen contents were hydrogen heat-treated and characterized for their chemistry, morphology, and microstructure. Higher initial oxygen content powders were found to not only reduce surface oxides, but also reduce oxides along the grain boundaries and form trapped H2O vapor inside the particles. The trapped H2O vapor was verified by thermogravimetric analysis (TGA) and residual gas analysis (RGA) while melting. The mechanism of the H2O vapor escaping the particles was determined by in-situ SEM heated stage experiments, where the particles were observed to crack along the grain boundaries. To determine the effect of the EB-PBF processing on the H2O vapor, the thermal simulation and the validation of single melt track width wafers were conducted along with melting single layer discs for chemistry analysis. A high speed video of the EB-PBF melting was performed in order to determine the effect of the trapped H2O vapor on the melt pool. Finally, solid samples were fabricated from hydrogen-treated copper powder, where the final oxygen content measured ~50 wt. ppm, with a minimal residue hydrogen content, indicating the complete removal of trapped H2O vapor from the solid parts.

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10

Song, Shu Xiang, Zhang Jian Zhou, Juan Du, and Chang Chun Ge. "Study on Interfacial Characterization and Mechanical Properties of Plasma-Sprayed Tungsten Coatings." Materials Science Forum 546-549 (May 2007): 1809–12. http://dx.doi.org/10.4028/www.scientific.net/msf.546-549.1809.

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Tungsten has the highest melting point among all metal, which makes it withstand thermal shock and erosion in high temperature environments. In this study, Tungsten coatings were sprayed onto the oxygen-free copper substrates by plasma spraying using inert gases protection. XRD, SEM and EDS were used to identify the phases, morphologies and compositions of the coatings. Vickers micro-hardness and bonding strength of the tungsten coatings were also measured. The results revealed that the hardness distribution of the tungsten coatings was different along the thickness direction. The tungsten coating without any interlayer showed higher bonding strength than that of the other two coatings with NiCrAl and W/Cu interlayers, respectively.

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11

Kang, Jeong-Won, and Ho-Jung Hwang. "Molecular Dynamics Simulations on Melting Properties of Free Icosahedral Copper Clusters." Transactions on Electrical and Electronic Materials 4, no. 1 (February 1, 2003): 1–6. http://dx.doi.org/10.4313/teem.2003.4.1.001.

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12

NING, HONGLONG, USHENG MA, FUXIANG HUANG, YONGGANG WANG, JIMAN ZHU, and ZHITING GENG. "INVESTIGATION OF THE INTERFACE OF THE DCB SUBSTRATE." Surface Review and Letters 10, no. 01 (February 2003): 95–99. http://dx.doi.org/10.1142/s0218625x03004640.

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DCB means direct copper bonding and denotes a process in which copper and a ceramic material are directly bonded. Between the temperature of the metal's melting point and the eutectic temperature of the metal-oxygen, DCB depends on the eutectic compound to join the copper and the ceramic. We do some research to investigate the interface between the copper foils and Al2O3 ceramics; it is the key factor in influencing the performance of the DCB substrate. We also discuss how to get good microstructure of the DCB interface.

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13

Araki, Noritoshi, Yasutomo Ichiyama, Ryo Oishi, Teruo Haibara, and Takashi Yamada. "Effect of Process Parameters on Free Air Ball Integrity in Copper and Palladium-Coated Copper Bonding Wires." Journal of Microelectronics and Electronic Packaging 12, no. 2 (August 1, 2015): 98–103. http://dx.doi.org/10.4071/imaps.460.

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The free air ball (FAB) formation processes of fine diameter Cu wires were observed, and the effects of process parameters were studied on the basis of high-speed camera observation. It was revealed that the FAB formation process is characterized by preheating before melting, melting that accompanies ball rising, and solidification periods. The relationships between the electronic flame-off (EFO) condition and the FAB formation were summarized for both bare Cu and palladium-coated Cu (PCC) wires. Further study was performed on the changes in FAB shape with different EFO conditions, wire types, and FAB sizes. Off-centered FABs were observed in the bare Cu wire whereas they were rarely observed in the PCC wire. The off-center tended to be affected by shielding gas condition, EFO torch gap, and FAB size. The mechanisms of the off-centered FAB formation were proposed through the high-speed camera observations. The optimization of process parameters to achieve defect-free, consistent FAB is discussed based on these findings, which is useful for the next generation high-density packaging.

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14

Araki, Noritoshi, Yasutomo Ichiyama, Ryo Oishi, Teruo Haibara, and Takashi Yamada. "Effect of Process Parameters on Free Air Ball Integrity in Copper and Palladium-coated Copper Bonding Wires." International Symposium on Microelectronics 2014, no. 1 (October 1, 2014): 000272–77. http://dx.doi.org/10.4071/isom-tp41.

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The Free Air Ball (FAB) formation processes of fine diameter Cu wires were observed, and the effects of process parameters were studied on the basis of high-speed camera observation. It was revealed that the FAB formation process is characterized by preheating before melting, melting that accompanies ball rising, and solidification periods. The relationships between the electronic flame-off (EFO) condition and the FAB formation were summarized for both bare Cu and palladium-coated Cu wires. Further study was performed on the changes in FAB shape with different EFO conditions, wire types, and FAB sizes. Off-centered FABs were observed in the bare Cu wire whereas they were rarely observed in the Pd-coated Cu wire. The off-center tended to be affected by shielding gas condition, EFO torch gap, and FAB size. The mechanisms of the off-centered FAB formation were proposed through the high speed camera observations. The optimization of process parameters to achieve defect-free, consistent FAB is discussed based on these findings, which is useful for the next generation high density packaging.

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15

Yao, Wei Zhi, Shu Xiang Song, Zhang Jian Zhou, Wei Wei Cong, and Chang Chun Ge. "Fabrication and Evaluation of Plasma-Sprayed Molybdenum for Plasma Facing Materials." Materials Science Forum 561-565 (October 2007): 1777–80. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.1777.

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Molybdenum has many prominent properties, such as high melting point, good thermal properties, and low erosion rate and so on, which make it promising candidate materials for plasma facing materials in the next fusion reactor. In this paper, Molybdenum coatings were deposited onto the oxygen-free copper substrates by atmospheric plasma spraying. The spraying parameters had been carefully selected. Different interlayers were induced between the substrate and the coating. SEM and XRD were used to investigate the photographs and compositions of these coatings. The micro-hardness and bonding strength were also tested. Thermal behaviors of the coatings were evaluated by thermal shock tests. The coatings with interlayers showed better resistance of thermal shock but lower bonding strength compared to coatings that without interlayers.

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16

Alekseev, A. V., T. N. Pahomkina, and Yu V. Lapshina. "DETERMINATION OF SULFUR, CARBON, NITROGEN AND OXYGEN IN COPPER BASED ALLOYS." Proceedings of VIAM, no. 11 (2021): 112–19. http://dx.doi.org/10.18577/2307-6046-2021-0-11-112-119.

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The determination of gas-forming impurities in samples of low-alloyed copper alloys of the Cu–Cr and Cu–Cr–Zr systems is carried out. The content of sulfur and carbon was determined by the method of combustion in an induction furnace of a gas analyzer with subsequent detection in the infrared cell of the spectrometer, and to determine oxygen and nitrogen, the method of reducing melting in a flow of an inert carrier gas was used, followed by the detection of oxygen in the infrared cell and nitrogen in the conductometric cell of the gas analyzer.

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17

Jadhav, Dadbakhsh, Vleugels, Hofkens, Puyvelde, Yang, Kruth, Humbeeck, and Vanmeensel. "Influence of Carbon Nanoparticle Addition (and Impurities) on Selective Laser Melting of Pure Copper." Materials 12, no. 15 (August 2, 2019): 2469. http://dx.doi.org/10.3390/ma12152469.

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The addition of 0.1 wt % carbon nanoparticles significantly improved the optical absorption and flowability of gas-atomized copper powder. This facilitated selective laser melting (SLM) by reducing the required laser energy density to obtain 98% dense parts. Moreover, the carbon addition led to an in situ de-oxidation of the copper parts during the SLM process. The properties of the as-built copper parts were limited to a tensile strength of 125 MPa, a ductility of 3%, and an electrical conductivity of 22.7 × 106 S/m, despite the advantageous effect of carbon on the powder characteristics and SLM behavior. The modest mechanical properties were associated with the segregation of carbon nanoparticles and other impurities, such as phosphorus and oxygen along grain boundaries of epitaxially grown grains. Whereas, the low electrical conductivity was mainly attributed to the phosphorus impurity in solid-solution with copper.

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18

Liu, Xuan, and Ping Feng. "Picosecond Pulsed Laser Induced Melting of Monocrystalline Copper: A Hybrid Simulation." Advanced Materials Research 97-101 (March 2010): 3807–10. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.3807.

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A hybrid method combing molecular dynamics and two-step radiation heating model is used to study the kinetics and microscopic mechanisms of picosecond laser melting of monocrystalline copper in stress confinement regime. The nonequilibrium processes of laser melting are simulated by classical MD method, and laser excitation as well as subsequent relaxation of the conduction band electrons are described continually by two-step radiation heating model. The mechanism responsible for melting of copper under picosecond laser pulse irradiation can be attributed to homogeneous nucleation of the liquid phase inside the solid region. The speed of stress wave is predicted to be 4400m/s equal to that of sound. The liquid and crystal regions are identified definitely in the atomic configurations by means of Local Order Parameter, in-plane structure and number density of atoms. Velocity-reducing technique is proved efficient in avoiding the influence of the reflected stress wave on melting process by comparing two models with velocity-reducing technique and free boundary condition at the bottom respectively.

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19

Prasad, V. V. Satya, V. Ramakrishna Rao, U. Prakash, P. Krishna Rao, and K. M. Gupt. "Electro Slag Crucible Melting for Recycling of Low Oxygen High Conductivity Copper Scrap." ISIJ International 36, no. 9 (1996): 1113–18. http://dx.doi.org/10.2355/isijinternational.36.1113.

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20

Camurri, Carlos, Claudia Carrasco, Antonio Pagliero, and Rodrigo Leite. "Influence of the Impurities on Cathodic Copper on the Ductility of Copper Wires." Materials Science Forum 706-709 (January 2012): 899–906. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.899.

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The main characteristic of cathodic copper is the concentration of impurities because it depends on mechanical characteristics, i.e. ductility, of the derived copper wires. The standard mechanical tests that evaluate their ductility, are quick elongation and spiral elongation tests. The results of these essais shown that there is not a clear correlation among the impurities content in cathodes and wire ductility. Also, the two mechanical tests actually used are not able to discriminate differences on the copper ductility associated to variations in impurities concentration, at ppm level. In this work, a design of new specimen for traction test, with a reduced gage length of 10 mm that clearly discriminate differences on copper ductility associated to variations in impurities concentration is exposed. In addition, from traction tests to copper wires and observation of their fracture surfaces by means of SEM and EDS it is concluded that the principal impurity affecting the ductility of the copper wires is the oxygen, mainly incorporated during the melting of the cathodes and casting of the rods. Also, the traditional annealing to the samples previous to the tensile tests must to be avoid since produces a dispersion on the matrix of the Cu2O oxides and so the deleterious effect of the oxygen on the copper ductility cannot be detected.

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21

Yastrebinsky, R. N., V. I. Pavlenko, A. I. Gorodov, A. A. Karnauhov, N. I. Cherkashina, and A. V. Yastrebinskay. "Effect of electrochemical modification of titanium hydride fraction on oxygen content in surface and deep layers." Materials Research Express 9, no. 1 (January 1, 2022): 016401. http://dx.doi.org/10.1088/2053-1591/ac45bd.

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Abstract The paper presents a study of the microstructure and oxygen concentration in the surface and deep layers of fractions of unmodified titanium hydride and titanium hydride modified by electrodeposited layers of Ti and Cu at temperatures of 300 °C–900 °C. The composition of the oxide layer and the concentration of titanium and oxygen atoms are estimated. It is shown that an increase in the thickness and compaction of the oxide layer with increasing temperature prevents the penetration of oxygen into the deep layers of the unmodified fraction of titanium hydride. Modification of titanium hydride by electrochemical deposition of metallic titanium at a temperature of 700 °C reduces the oxygen concentration in titanium hydride at a layer depth of 50 μm from 35 wt% to 12.5 wt%. Electrodeposition of coatings based on titanium and copper at 700 °C reduces the oxygen concentration to 9.2 wt%, which may be due to the protective mechanism of the formed copper titanate layer. At 900 °C, in the modification layer based on titanium and copper, due to the eutectoid transformation of the β-phase of titanium, the process of contact melting occurs and a multiphase zone is formed. The oxygen concentration at a layer depth of 50 μm is no more than 12.4 wt%.

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22

Shrestha, Sabita, and Sudha Maharjan. "Synthesis and Characterization of Copper Complex of Salicylaldehyde Benzoyl Hydrazone." Journal of Nepal Chemical Society 29 (December 3, 2013): 11–17. http://dx.doi.org/10.3126/jncs.v29i0.9231.

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Copper complex of type [Cu(SBH)2] was synthesized and characterized by different analytical procedure and spectral studies. The complex was insoluble in common organic solvents and it has melting point in between 254-258°C. Infrared spectrum showed the bonding through enolic oxygen and azomethine nitrogen. The electronic spectral studies showed that the Cu(II) is in tetrahedral coordination environment. DOI: http://dx.doi.org/10.3126/jncs.v29i0.9231Journal of Nepal Chemical SocietyVol. 29, 2012Page: 11-17Uploaded date : 12/3/2013

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23

Guschlbauer, Ralf, Alex K. Burkhardt, Zongwen Fu, and Carolin Körner. "Effect of the oxygen content of pure copper powder on selective electron beam melting." Materials Science and Engineering: A 779 (March 2020): 139106. http://dx.doi.org/10.1016/j.msea.2020.139106.

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24

Ilyushenko, V. M., T. B. Maidanchuk, A. N. Bondarenko, E. P. Lukianchenko, T. E. Udartseva, and D. I. Andreichuk. "Restoration Of End Part Of Copper Gas-oxygen Chambers Of Arc Steel-melting Furnaces." Sovremennaâ èlektrometallurgiâ 2019, no. 4 (December 28, 2019): 38–43. http://dx.doi.org/10.15407/sem2019.04.06.

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25

Kalyniuk, M. M., Ya P. Gritskiv, and L. M. Kahitanchuk. "Eloboration of Methods for Determination on Content of the Oxygen, Nitrogen, Hydrogen Admixtures in Titanium Aluminides." Metrology and instruments, no. 2 (May 21, 2020): 61–67. http://dx.doi.org/10.33955/2307-2180(2)2020.61-67.

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Titanium intermetalides (TiAl and Ti3 Al) and alloys on theirs bases applies in air — and spacetechnology and automobile industry. Physical and mechanical properties there alloys is better, then at classical Ti — or Ni — alloys, that are utilized in aeroplanes and rocets. Alloys, based on TiAl and Ti3Al, are made with utilization vacuum — arc, plasma — arc, induction- garnisage, magnetoperating electroslag melting, electron — beam melting with intermediate capacity, electroslag melting in inert atmosphere under «active» fluxes with metallic calcium, induction melting in muchsectional crystallizator and cold crucible, argon — arc melting with unexpended tungsten electrode in copper watercooling crucible. For connection of the details, that were made from these alloys, there were used welding by pressure, contact, electron — beam, diffusion welding. Alloys, based on titanium aluminide, have essential defects — high brittleness and low plasticity, viscosity and resistance thermal impact strength. Autors a lot of articles explaines these descriptions by structural special features of titanium aluminides and alloys on their bases, but does not consider possibilities of the influence by oxygen nitrogen, hydrogen admixtures. In literature information about methods of determination gaseous admixtures (O, N, H) contents in titanium aluminides and alloys on their bases are absented. Methods of determination oxygen, nitrogen, hydrogen contents in titanium aluminides on analysers TC436, RO316, TN114, RH402 are created. Parameters of these methods are described in this article (temperatures of heating on graphite crucibles, times, masses of analytical samples).

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26

Yao, Wei Zhi, Shu Xiang Song, Zhang Jian Zhou, Wei Wei Cong, Y. Ma, and C. C. Ge. "Study on the Plasma-Sprayed Molybdenum as Plasma Facing Materials in Fusion Reactor." Key Engineering Materials 373-374 (March 2008): 81–84. http://dx.doi.org/10.4028/www.scientific.net/kem.373-374.81.

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Molybdenum has many prominent properties, such as high melting point, good thermal properties, low erosion rate and so on, which make it promising candidate materials for plasma facing materials in the next fusion reactor. In the present work, molybdenum coatings were deposited onto the oxygen-free copper substrates by atmospheric plasma spraying. Different interlayers were introduced between the coatings and substrates. SEM, EDS and XRD were used to investigate the photographs and compositions of these coatings. The bonding strength of the coatings was tested to investigate the effect of interlayers on adhesion of the coatings at room temperature and it was found that the coating without interlayers showed the highest bonding strength. Water quenching method was used to evaluate the adhesion of the coatings under thermal cycling conditions and the results showed that the molybdenum coating with two interlayers possessed of the highest resistance of thermal cycling wrack.

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27

Vutova, Katia, Vladislava Stefanova, Vania Vassileva, and Milen Kadiyski. "Behaviour of Impurities during Electron Beam Melting of Copper Technogenic Material." Materials 15, no. 3 (January 26, 2022): 936. http://dx.doi.org/10.3390/ma15030936.

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The current study presents the electron beam melting (EBM) efficiency of copper technogenic material with high impurity content (Se, Te, Pb, Bi, Sn, As, Sb, Zn, Ni, Ag, etc.) by means of thermodynamic analysis and experimental tests. On the basis of the calculated values of Gibbs free energy and the physical state of the impurity (liquid and gaseous), a thermodynamic assessment of the possible chemical interactions occurring in the Cu-Cu2O-Mex system in vacuum in the temperature range 1460–1800 K was made. The impact of the kinetic parameters (temperature and refining time) on the behaviour and the degree of removal of impurities was evaluated. Chemical and metallographic analysis of the obtained ingots is also discussed.

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28

Wong, Wei Yee, Rabiatul Adawiyah Shamsudin, Muhammad Firdaus Mohd Nazeri, and Mohamad Najmi Masri. "The Preliminary Study of the Addition Zinc in Tin-Copper Lead Free Solder." Materials Science Forum 1010 (September 2020): 104–8. http://dx.doi.org/10.4028/www.scientific.net/msf.1010.104.

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Sn-0.7Cu lead free solder has become an alternative material to replace Sn-Pb solder. However, it has the weakness of high melting point and poor corrosion behavior. Through the study, Sn-0.7-xZn microstructure and phase changes were studied through scanning electron microscope (SEM) and X-ray diffraction (XRD). SEM result shows microstructure Cu6Sn5 is precipitated with rod like shape while CuZn is shown in bump oval shape whereas compounds that presented are Cu6Sn5 and Cu5Zn8 as shown in the XRD analysis result.

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29

Nassau, K., A. E. Miller, E. M. Gyorgy, and T. Siegrist. "Rapidly quenched Bi-containing high Tc superconducting oxide compositions." Journal of Materials Research 4, no. 6 (December 1989): 1330–38. http://dx.doi.org/10.1557/jmr.1989.1330.

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Twin roller quenching from the melt at cooling rates of ∼107 K s−1 was used on several Bi-containing high Tc compositions. Pure glass was obtained in most compositions and the route of crystallization was studied by differential thermal and thermogravimetric analysis, x-ray diffraction, and magnetic measurements. Heating of the glasses produced poorly crystallized short-range-order-only as determined by x-ray diffraction, despite passing through several exotherms, some of which were very strong. This anomalous behavior deserves further investigation. On heating to higher temperatures the expected double-copper-oxide-layer high Tc phase formed sluggishly via intermediate CuBi2O4 and/or single-copper-oxide-layer Bi2(Sr, Cu)2CuO4 phases. Considerable oxygen absorption of about 0.5 O per Cu occurs during these steps, peaking at about 680 °C; some of this oxygen is lost again by the time the high Tc phase forms just below the melting point.

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30

Netskina, Olga V., Svetlana A. Mukha, Kirill A. Dmitruk, Arkady V. Ishchenko, Olga A. Bulavchenko, Alena A. Pochtar, Alexey P. Suknev, and Oxana V. Komova. "Solvent-Free Method for Nanoparticles Synthesis by Solid-State Combustion Using Tetra(Imidazole)Copper(II) Nitrate." Inorganics 10, no. 2 (January 21, 2022): 15. http://dx.doi.org/10.3390/inorganics10020015.

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Анотація:

The development of solvent-free techniques for nanoparticles synthesis is one of the challenges of Green chemistry. In this work, the principled opportunity to obtain copper-containing nanosized particles without use of any solvents was shown. The copper complexes were prepared as precursors by the melting-assisted solvent-free synthesis. The formation of tetra(imidazole)copper(II) nitrate complex was confirmed by XRD, elemental analysis, FTIR spectroscopy, and thermal analysis. It was noted that their thermal decomposition occurs in two stages: (I) the low-temperature step may be related to redox interaction between organic ligands and nitrate-anions; (II) the high-temperature step may be related to the oxidation of the products of incomplete imidazole decomposition. TEM and XRD studies of solid products of complex combustion have shown that they are oxides with particle size less than 40 nm. Thus, the combustion of [Cu(Im)4](NO3)2 complex under air can be considered as a new approach to prepare nanosized particles of copper oxides without the use of solvents.

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31

Liu, J., and J. M. Cowley. "SREM imaging of copper (110) vicinal surfaces." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 542–43. http://dx.doi.org/10.1017/s0424820100154688.

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Анотація:

Scanning reflection electron imaging technique is sensitive to surface perturbations at nano-meter scale. Single atom high steps and defects on crystal surfaces can be observed with high contrast. Microanalysis of surface areas can be performed to study surface reaction problems. One advantage of SREM over conventional REM imaging is that by changing the objective lens current synchronously with the frame speed one can manage to keep more of the scanned areas in focus. This dynamic focusing is important for observing less flat surfaces such as the vicinal surface areas. We take this advantage to study the copper (110) vicinal surface structures by SREM technique. All the SREM images reported here are obtained with dynamic focusing conpensation. RHEED study of clean and oxygen adsorbed copper surfaces revealed that most of the vicinal surfaces will be faceted upon oxygen adsorption. Real space observations of these faceted surface areas by SREM imaging may yield some information about the vicinal surface structures with high resolution. The copper surfaces were obtained by melting copper wire in air with careful control to reduce high temperature oxidations on Ihe crystal surfaces. Reasonably flat copper crystal surfaces can be obtained by this preparation method and some of the surface areas are oxidized. The experiment was performed in a VG HB5 STEM instrument with a probe size of about 0.5 nm in diameter and a vacuum pressure of about 5×10-9 Torr.

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32

KANIGEL, AMIT, JOAN ADLER, and EMIL POLTURAK. "INFLUENCE OF POINT DEFECTS ON THE SHEAR ELASTIC COEFFICIENTS AND ON THE MELTING TEMPERATURE OF COPPER." International Journal of Modern Physics C 12, no. 05 (June 2001): 727–37. http://dx.doi.org/10.1142/s0129183101001900.

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Анотація:

We present molecular dynamics simulations of the influence of point defects on the shear elastic properties of copper. We find that vacancies do not influence these properties at all, while the introduction of interstitials causes a large reduction of the elastic coefficients. The simulations establish a phase diagram of the melting temperature as a function of the density of interstitials. A crystal having no free surface undergoes bulk mechanical melting as a result of the vanishing of C′ ≡ (C11 - C12)/2 once the specific volume reaches a critical value, equal to the experimental volume of liquid phase. This critical volume is history independent, in the sense that it does not depend on whether is it reached by heating the crystal or by adding defects at a constant temperature. These results generalize the Born model of melting for the case where point defects are present.

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33

Shen, Zhenzhen, Kun Fang, Mike Hamilton, R. Wayne Johnson, Erica Snipes, and Michael Bozack. "Lead-free Solder Attach for 200°C Applications." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2013, HITEN (January 1, 2013): 000260–67. http://dx.doi.org/10.4071/hiten-wa18.

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Анотація:

Conventional SAC lead-free solders have a melting point of 217°C to 227°C, limiting their suitability for applications at 200°C. AgBiXTM solder has potential for 200°C applications because of its ~260°C solidus temperature. BiAgX paste has been used to assemble SiC test die to ceramic substrates with direct bond copper (DBC), reactive brazed CuMo, thick film Au, thick film PtAu, thick film PdAg and thick film Ag. Surface mount chip resistors have also been attached to thick film metallized substrates. The assembly process and initial shear strength test results are presented. Assemblies have also been subjected to thermal testing: thermal cycling (−55°C to +195°C) and high temperature (200°C) storage. The shear strength of these assemblies after thermal testing are presented and compared to initial results.

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34

Ghosh, G., and M. E. Fine. "Interfacial Reaction Between Tin-Zinc Based Solders and Copper." Microscopy and Microanalysis 3, S2 (August 1997): 715–16. http://dx.doi.org/10.1017/s1431927600010461.

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Due to the interfacial reaction between the solder and substrate, either during manufacturing or in service, the solder joints may contain one or more intermetallic layers at the interface. While such intermetallic layers may provide strong bonding, they may also be responsible for problems associated with solderability and reliability of joints. Certain physical and mechanical properties of the intermetallic may determine the integrity and reliability of solder assembly. So far detailed analysis, modelling, and testing of simulated and actual joints have been performed with Pb-Sn solders. However, in view of the increasing environmental and legislative concerns, lead-free solders are currently being developed and designed for microelectronics applications. As the solder joints in high-performance electronic circuits are expected to carry increasing mechanical, electrical and thermal burdens, it is essential to address the technological and reliability issues for lead-free solders. Among the lead-free solders, tin-zinc based alloys can be designed to achieve melting and solidification behavior similar to those of lead-tin eutectic or near eutectic alloys.

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35

Aamir, Muhammad, Riaz Muhammad, Majid Tolouei-Rad, Khaled Giasin, and Vadim V. Silberschmidt. "A review: microstructure and properties of tin-silver-copper lead-free solder series for the applications of electronics." Soldering & Surface Mount Technology 32, no. 2 (October 14, 2019): 115–26. http://dx.doi.org/10.1108/ssmt-11-2018-0046.

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Анотація:

Purpose The research on lead-free solder alloys has increased in past decades due to awareness of the environmental impact of lead contents in soldering alloys. This has led to the introduction and development of different grades of lead-free solder alloys in the global market. Tin-silver-copper is a lead-free alloy which has been acknowledged by different consortia as a good alternative to conventional tin-lead alloy. The purpose of this paper is to provide comprehensive knowledge about the tin-silver-copper series. Design/methodology/approach The approach of this study reviews the microstructure and some other properties of tin-silver-copper series after the addition of indium, titanium, iron, zinc, zirconium, bismuth, nickel, antimony, gallium, aluminium, cerium, lanthanum, yttrium, erbium, praseodymium, neodymium, ytterbium, nanoparticles of nickel, cobalt, silicon carbide, aluminium oxide, zinc oxide, titanium dioxide, cerium oxide, zirconium oxide and titanium diboride, as well as carbon nanotubes, nickel-coated carbon nanotubes, single-walled carbon nanotubes and graphene-nano-sheets. Findings The current paper presents a comprehensive review of the tin-silver-copper solder series with possible solutions for improving their microstructure, melting point, mechanical properties and wettability through the addition of different elements/nanoparticles and other materials. Originality/value This paper summarises the useful findings of the tin-silver-copper series comprehensively. This information will assist in future work for the design and development of novel lead-free solder alloys.

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36

Ab Ghani, Noor Asikin, Iziana Yahya, Mohd Arif Anuar Mohd Salleh, Shamsuddin Saidatulakmar, Zainal Arifin Ahmad, and Ramani Mayappan. "Microstructure Evolution of Sn-3.5Ag-1.0Cu-0.5Ni/Cu System Lead Free Solder under Long Term Thermal Aging." Advanced Materials Research 620 (December 2012): 263–67. http://dx.doi.org/10.4028/www.scientific.net/amr.620.263.

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Due to environmental concerns, lead-free solders were introduced in replacing the lead-based solders in microelectronics devices technology. Although there are many lead-free solder available, the Sn-Ag-Cu solder was considered the best choice. But the solder has its draw backs in terms of melting temperature and intermetallic formations. In this study, the effect of 0.5wt% Ni addition on the microstructure of the Sn-3.5Ag-1.0Cu solder was investigated. The solder was synthesized via powder metallurgy route which includes blending, compacting and sintering. The solders were characterized for its densities and melting temperatures. SEM was used to observe the microstructure of intermetallic phases. The solders were melted on copper substrate at 250°C for one minute and aged at 150°C from 0 to 400 hours. The phases formed were studied under SEM. The SEM results showed the presence of Cu6Sn5, Cu3Sn, Ag3Sn and (Cu,Ni)6Sn5 intermetallics.

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37

Haruna, A., Rumah, M.M., Sani, U., and Ibrahim, A.K. "Synthesis, Characterization and corrosion Inhibition Studies on Mn (II) and Co (II) Complexes Derived from 1-{(Z)-[(2-hydroxyphenyl) imino]methyl}naphthalen-2-ol in 1M HCl Solution." International Journal of Biological, Physical and Chemical Studies 3, no. 1 (May 25, 2021): 09–18. http://dx.doi.org/10.32996/ijbpcs.2021.3.1.2.

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Schiff base derived from the reaction of 2-amino phenol and 2-hydroxy-1-naphthaldehyde and its Co (II), and Mn (II) complexes have been synthesized and characterized by solubility test, melting point/ decomposition temperatures, molar conductance, IR and magnetic susceptibility. The number of ligands coordinated to the metal ion was determined using Job’s method of continuous variation. Their molar conductance values indicate that all the complexes are non-electrolytes. Magnetic moment values of the complexes showed that both Mn (II) and Co (II) are paramagnetic. The spectroscopic data of metal complexes indicated that the metal ions are complexed with azomethine nitrogen and deprotonated oxygen atom. Corrosion inhibition of the schiff base and Mn (II) and Co (II) complexes were evaluated using the weight loss method in a 0.1MHCl solution for copper metal. The inhibition efficiency increased with increasing inhibitors concentration. The negative values of Gibb’s free energy of adsorption (ΔGads) confirmed the spontaneity and physical adsorption of the inhibition process which is inconsistent with Langmuir adsorption isotherm.

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38

Yao, Nan. "Surface studies of single copper crystals by REM." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 540–41. http://dx.doi.org/10.1017/s0424820100154676.

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Анотація:

In the last decade, the use of transmission electron microscopes for surface imaging in the reflection mode has been shown to have considerable potential as a means for studying surfaces. Many REM (Reflection Electron Microscopy) studies have been done as reviewed recently by Cowley and Yagi. However, due to the lack of success with clean and flat single-crystal surface preparation technique, the surface studies of less inert metals, such as copper single crystal, have not been reported. The normal method of forming spherical platinum or gold single crystal by simply melting the end of platinum or gold thin wire with an acetylene-oxygen flame in air for REM observation is difficult here. The formation of flat copper surfaces occurs during the well-controlled crystallization process and is sensitively influenced by its physical and chemical properties. This paper reports a new method of overcoming these difficulties in the copper single crystal preparation. Observations of the samples have been made by REM and RHEED (Reflection High Energy Elecrton Diffraction).

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39

Daswa, Pfarelo, Heinrich Möller, Madeleine du Toit, and Gonasagren Govender. "The Solution Heat Treatment of Rheo-High Pressure Die Cast Al-Mg-Si-(Cu) 6xxx Series Alloys." Solid State Phenomena 217-218 (September 2014): 259–64. http://dx.doi.org/10.4028/www.scientific.net/ssp.217-218.259.

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The 6xxx series alloys are well known for desirable combinations of high strength, weldability, corrosion resistance and formability. This paper investigates the influence of chemical composition on the solution heat treatment parameters of rheo-high pressure die cast (R-HPDC) 6xxx series aluminium alloys. The presence of copper in the 6xxx series aluminium alloys affects the solution heat treatment by promoting incipient melting. The incidence of incipient melting is investigated for the R-HPDC alloys using Differential Scanning Calorimetry (DSC) and optical microscopy. R-HPDC is known to produce surface liquid segregation and centre-line liquid segregation when processing the alloys and these areas are the most susceptible to incipient melting. The applicability of single and multiple step solution heat treatments are investigated. The alloys used for this study include the Cu-free alloy 6082, as well as the Cu-containing alloys 6013 and 6111.

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40

Kanlayasiri, Kannachai, and Nadee Meesathien. "Effects of Zinc Oxide Nanoparticles on Properties of SAC0307 Lead-Free Solder Paste." Advances in Materials Science and Engineering 2018 (June 26, 2018): 1–10. http://dx.doi.org/10.1155/2018/3750742.

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This research investigates the effects of zinc oxide (ZnO) nanoparticles of varying concentrations 0.0, 0.25, 0.50, 0.75, and 1.0 wt.% on the melting temperatures, wettability, printability, slump, and interfacial microstructure of the ZnO-doped Sn-0.3Ag-0.7Cu lead-free solder pastes on the copper substrate. The results revealed that the introduction of the ZnO particles had no effect on the solidus and liquidus temperatures of the solders. The maximum wettability was achieved with 0.25 wt.% ZnO nanoparticles, while the printability was inversely correlated with the nano-ZnO concentrations. The findings also indicated that, at room temperature, the slumping and the nano-ZnO concentrations were positively correlated and that, under the 150°C thermal condition, the maximum slumping was achieved with 0.25 wt.% ZnO. The slumping mechanism of the SAC0307-xZnO solder pastes is also provided herein. Moreover, the experiments showed that Cu6Sn5 was the single intermetallic compound present in the interfacial layer between the solders and the copper substrate, with the maximum intermetallic layer thickness realized at the 0.25 wt.% ZnO concentration.

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41

Godbole, Mukund J., Anthony J. Pedraza, Douglas H. Lowndes, and Edward A. Kenik. "Laser-induced interface reactions of copper thin films on sapphire substrates." Journal of Materials Research 4, no. 5 (October 1989): 1202–8. http://dx.doi.org/10.1557/jmr.1989.1202.

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The interface of a copper-sapphire couple that was irradiated with a nanosecond pulsed-exeimer laser was studied by transmission electron microscopy. Deposited layers of 30 or 100 nm thickness were laser treated with energy densities in the range of 0.5 to 0.75 J/cm2. Two different atmospheres were used during these treatments, viz., air or a mixture of argon-4 vol. % hydrogen. The copper film and a thin alumina layer were melted by the laser pulse. Two well differentiated regions could be observed in the modified layer. The region closer to the unmodified substrate consisted of epitaxially regrown alumina with crystallites misoriented up to 10° relative to the substrate sapphire orientation, while precipitate particles could be seen closer to the resolidified copper. The nature of the precipitates generated in the second region was dependent on the atmosphere present during the treatment. In air a trirutile-like compound was obtained which is either oxygen or copper deficient. In an argon atmosphere a compound having a hexagonal structure closely related to sapphire was observed, where copper substituted for some aluminum. These observations are in agreement with a previously developed mathematical model that predicts melting of a thin substrate layer.

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42

Bojarevics, Valdis, and Koulis Pericleous. "Cold crucible melting with bottom pouring nozzle." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 39, no. 1 (December 12, 2019): 36–42. http://dx.doi.org/10.1108/compel-05-2019-0208.

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Анотація:

Purpose The purpose of this paper is to investigate a new type of nozzle which is free from erosion and non-contaminating the outflow metal. Cold crucible melting technique with electromagnetic induction is used to obtain reactive metal castings and produce high-quality metal powders for aerospace, automotive and medical applications. An important part of this technology is the nozzle used to pour the molten alloy through the bottom opening. Design/methodology/approach The paper uses mathematical modeling technique, previously validated on multiple similar cases, to investigate a new type of nonconsumable nozzle made of copper segments. Findings The design of the nozzle requires to satisfy the narrow balance between the thin solidified protective layer on the wall while avoiding the blockage of the outflow if the nozzle is frozen completely. The sensitivity of the outflow to the nozzle diameter is investigated. The AC electromagnetic force leads to high mixing rates, transitional flow structures and turbulence of the melt, contributing to the melt shape dynamics and the heat loss to walls. Originality/value The beneficial features of the cold crucible melting to purify the melt from particulate contamination are explained using the full melting and pouring cycle.

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43

Mladenovic, Srba, Ljubica Ivanic, Mirjana Rajcic-Vujasinovic, Svetlana Ivanov, and Dragoslav Guskovic. "Electrochemical and wetting behavior of as-cast Sn-Zn-Sb lead free solders alloys." Chemical Industry 67, no. 3 (2013): 477–84. http://dx.doi.org/10.2298/hemind120608084m.

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Ternary alloys SnZn12Sb8, SnZn10Sb10, SnZn8Sb12, SnZn6Sb14, and SnZn2Sb18 were prepared by induction melting. Electrochemical behavior and wetting (contact angle) of prepared as-cast samples were investigated using open circuit potential measurement and sessile drop technique. The results of electrochemical investigation show that open-circuit potential, few seconds after immersing of electrodes, shifts toward more negative values, indicating a relatively smaller rate of dissolution during the spontaneous dissolution process under the curentless conditions. After that period, the values of potential tend to be constant with time. It was found that all investigated alloys have poor wettability on copper substrate and the contact angle values decrease with increasing superheat temperature.

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44

Terdthaichairat, Weerawat, Payoon Senthongkaew, and Ratchatee Techapiesancharoenkij. "Effect of Copper and Zinc on Microstructures, Melting Points and Corrosion Resistance of Sn-Zn-Cu-Bi Soldering Alloys." Key Engineering Materials 658 (July 2015): 59–63. http://dx.doi.org/10.4028/www.scientific.net/kem.658.59.

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Sn-Zn alloy is one of the Pb-free systems that are promising because of its relatively low melting temperature and low cost. However, Zn exhibits poor corrosion and oxidation resistance that hinders its soldering applications. The objective of this research is to study the effect of Zn and Cu alloying contents on the Sn-Zn performance. Four compositions of Sn-Zn alloys were studied in this research including: Sn-7Zn, Sn-9Zn, Sn-9Zn-2Cu-Bi, and Sn-9Zn-4Cu-Bi. The microstructures were studied using Optical Microscope (OM) and Scanning Electron Microscope (SEM). The melting temperatures and corrosion resistance of the alloys were evaluated by Differential Scanning Calorimeter (DSC) and Potentiodynamic Polarization technique, respectively. The results showed that an increase in the Cu-to-Zn ratio led to better corrosion resistance. The selective corrosion of the Zn-rich phase could be visibly observed, with OM, on the post-corrosion samples. With the Cu alloying, the Cu and Zn formed an intermetallic compound resulting in a higher value of Ecorr. However, the higher Cu content caused a significant increase in the liquidus temperature due to the Cu-Zn intermetallic compound, of which the melting temperature is higher than 400 °C, resulting in an incomplete melting at low temperature.

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45

Muriungi, Beatrice, Lijun Wang, and Abolghasem Shahbazi. "Comparison of Bimetallic Fe-Cu and Fe-Ca Oxygen Carriers for Biomass Gasification." Energies 13, no. 8 (April 18, 2020): 2019. http://dx.doi.org/10.3390/en13082019.

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Two bimetallic Fe-Cu and Fe-Ca oxygen carriers were studied for chemical looping gasification (CLG) of biomass. The SEM results indicated that there was no obvious agglomeration on the bimetallic Fe-Cu oxygen carrier supported on Al2O3 and Fe-Ca oxygen carrier after five redox cycles while agglomeration occurred on CuO supported on Al2O3 due to the low melting point of CuO. The XRD results indicated the presence of copper-ferrite and calcium-ferrite phases in the bimetallic materials. The two bimetallic oxygen carriers can be re-oxidized with air to form a crystalline that is similar to the fresh materials. The Fe-Ca oxide became active at 360 °C which was lower than 380 °C for the Fe-Cu oxygen carrier. The high thermal stability and redox reactivity of bimetallic Fe-Cu and Fe-Ca oxygen carriers make the bimetallic oxygen carriers more suitable for recycling during CLG. The method for preparing Fe-Cu oxygen carriers had no significant impact on biomass conversion efficiency but had significant effect on the quality of syngas. Proper control of the biomass/oxygen carrier mass ratio is critical to achieve high selectivity towards gasification instead of combustion. The Fe-Ca oxygen carrier could achieve higher selectivity towards gasification than the Fe-Cu oxygen carrier.

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46

Celik, F. A., and A. K. Yildiz. "A study to investigate phase transitions and nucleation kinetics of nickel and copper." Modern Physics Letters B 30, no. 11 (April 29, 2016): 1650129. http://dx.doi.org/10.1142/s0217984916501293.

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Анотація:

In this study, we investigate the homogeneous nucleation kinetics of copper and nickel system during cooling process using molecular dynamics simulation (MDS). The calculation is carried out for a different number of atoms consisting of 500, 2048, 8788 and 13,500 based on embedded atom method (EAM). It is observed that the melting points for the both model increases with increasing the size of systems (i.e. the number of atoms) as expected from Parrinello and Rahman MD method. The interfacial free energies and critical nucleus radius of nickel and copper are also determined by molecular dynamics, and the results are consistent with the classical nucleation theory. The structural development and phase transformation are also determined from the radial distribution function (RDF) and local bond orientational order parameters (LBOO).

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47

Kim, Minsuk, Seongbin An, Chaeeul Huh, and Chungseok Kim. "Development of Zirconium-Based Alloys with Low Elastic Modulus for Dental Implant Materials." Applied Sciences 9, no. 24 (December 4, 2019): 5281. http://dx.doi.org/10.3390/app9245281.

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The stress-shielding effect is a phenomenon in which the mutual coupling between bones and bio-materials of the human body is loosened due to the difference in elastic modulus, and bone absorption occurs due to the difference in density, which causes a shortening of the life of the material. The purpose of this study is to develop a zirconium-based alloy with low modulus and to prevent the stress-shielding effect. Zr–7Cu–xSn (x = 1, 5, 10, 15 mass%) alloys were prepared by an arc-melting process of pure zirconium, oxygen-free copper, and tin, respectively. The Zr–7Cu–xSn alloy has two phase α-Zr and Zr2Cu intermetallic compounds. Microstructure characterization was analyzed by microscopy and X-ray diffraction. Corrosion tests of zirconium-based alloys were conducted through polarization tests, and zirconium-based alloys had better corrosion characteristics than other metal bio-materials. In general, the elastic modulus value (14–25 GPa) of the zirconium-based alloy is very similar to the elastic modulus value (15–30 GPa) of the human bone. Consequently, the zirconium-based alloy is likely to be used as a bio-material that negates the effect of stress shielding on human bones.

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48

Renn, Michael J., Matthew Schrandt, Jaxon Renn, and James Q. Feng. "Localized Laser Sintering of Metal Nanoparticle Inks Printed with Aerosol Jet® Technology for Flexible Electronics." Journal of Microelectronics and Electronic Packaging 14, no. 4 (October 1, 2017): 132–39. http://dx.doi.org/10.4071/imaps.521797.

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Анотація:

Direct-write methods, such as the Aerosol Jet® technology, have enabled fabrication of flexible multifunctional 3-D devices by printing electronic circuits on thermoplastic and thermoset polymer materials. Conductive traces printed by additive manufacturing typically start in the form of liquid metal nanoparticle inks. To produce functional circuits, the printed metal nanoparticle ink material must be postprocessed to form conductive metal by sintering at elevated temperature. Metal nanoparticles are widely used in conductive inks because they can be sintered at relatively low temperatures compared with the melting temperature of bulk metal. This is desirable for fabricating circuits on low-cost plastic substrates. To minimize thermal damage to the plastics, while effectively sintering the metal nanoparticle inks, we describe a laser sintering process that generates a localized heat-affected zone (HAZ) when scanning over a printed feature. For sintering metal nanoparticles that are reactive to oxygen, an inert or reducing gas shroud is applied around the laser spot to shield the HAZ from ambient oxygen. With the shroud gas-shielded laser, oxygen-sensitive nanoparticles, such as those made of copper and nickel, can be successfully sintered in open air. With very short heating time and small HAZ, the localized peak sintering temperature can be substantially higher than that of damage threshold for the underlying substrate, for effective metallization of nanoparticle inks. Here, we demonstrate capabilities for producing conductive tracks of silver, copper, and copper–nickel alloys on flexible films as well as fabricating functional thermocouples and strain gauge sensors, with printed metal nanoparticle inks sintered by shroud-gas-shielded laser.

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49

Wu, Jie, Songbai Xue, Zhen Yao, and Weimin Long. "Study on Microstructure and Properties of 12Ag–Cu–Zn–Sn Cadmium-Free Filler Metals with Trace In Addition." Crystals 11, no. 5 (May 16, 2021): 557. http://dx.doi.org/10.3390/cryst11050557.

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Анотація:

The effect of different In contents on the melting characteristics, mechanical properties, and microstructure of 12Ag–Cu–Zn–Sn filler metal was investigated in this paper, and flame brazing of 304 stainless steel and copper plates was done using the 12Ag–Cu–Zn–Sn–xIn filler metal. The results indicate that adding appropriate amount of In can evidently decrease the solidus and liquidus temperatures and improve the wettability of the low silver based filler metals. In addition, the shear strength of 304 stainless steel and copper plates joint brazed by 12Ag–Cu–Zn–Sn–1In are satisfactory due to the solution strength effect, and scanning electron microscopy examination of the braze-zone revealed that more relatively sound joints were obtained when brazing was done with 12Ag–Cu–Zn–Sn–xIn filler metal than with Indium free one; its performance is comparable to that of the joint brazed with the 20Ag–Cu–Zn–Sn filler metal, having a remarkable silver-saving effect.

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50

Klyushnikov, Alexander M., and Evgeny N. Selivanov. "Simulation of the joint processing of pyrrhotite concentrate and nickeliferous oxidized ore." Butlerov Communications 58, no. 5 (May 31, 2019): 110–17. http://dx.doi.org/10.37952/roi-jbc-01/19-58-5-110.

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In this paper the issues of improving the efficiency of processing of pyrrhotite concentrates and magnesia-silicate nickeliferous ores are reviewed. An original technology is proposed, its basic stages are partial oxidative roasting of the concentrate and joint contractile melting the calcine with nickel ores to gain matte. Roasting of the pyrrhotite concentrate allows to extract 70-80% of sulfur from the concentrate into gases riched with SO2, reduce desulfurization during melting and extract nickel, copper, cobalt and precious metals from both raw materials into the matte. The implementation of fluxing potential of nickel ore completely eliminates the use of fluxes during smelting and increases the specific productivity of metallurgical units in concern of raw materials. On the laboratory scale, the modeling of the main technological operations is performed to justify the technology. The possibility of separation of slag and matte with joint reagent-free melting (1400 ºC) of the product of partial oxidative roasting and oxidized nickel ore, taken in equal quantities, is theoretically justified and experimentally confirmed. Parameters of the roasting of the pyrrhotite concentrate: temperature 800 ºС, desulfurization degree 71.7%. Pyrrhotite concentrate contained (% wt.) 1.9 Ni, 0.2 Cu, and 0.06 Co. Oxidized nickel ore contained (%wt.) 1.2 Ni, and 0.06 Co. The slag basicity module (about 1) provides relatively low content of non-ferrous metals in the slag (% wt.): 0.24 Ni, 0.08 Co, and 0.04 Cu. Matte contained (%wt.) 8.9 Ni, 0.22 Co, 0.5 Cu, 58.7 Fe, 25.0 S, and 6.6 O. Extraction level in the matte was 87.8% nickel, 48.0% cobalt, and 73.3% copper from their content in the initial mixture. High levels of matte enrichment degree with respect to the charge were achieved; their values were 5.5 for nickel, 5.7 for cobalt, and 4.5 for copper. Desulfurization degree during melting and metallization degree of matte were close to zero. The matte was suitable for processing with known routes. The results are expected to be used in the development of technologies aimed to resumption of processing of oxidized nickeliferous ores from the Ural deposits.

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