Welding of Fine Metal Particles by Using a Tungsten Needle and Measurement of the Strength of the Joints

2007 ◽  
Vol 561-565 ◽  
pp. 1027-1030
Author(s):  
Takeshi Konno ◽  
Mitsuru Egashira ◽  
Mikihiko Kobayashi
Keyword(s):  
Electric Discharge ◽  
Joint Strength ◽  
Gas Flow ◽  
Inert Gas ◽  
Metal Particles ◽  
Gold Substrate ◽  
Scanning Laser Microscopy ◽  
Fine Metal Particles ◽  
Tungsten Needle ◽  
Fractured Surface

Gold particles several tens of micrometers in size were welded onto a gold substrate. High voltages of 4 kV or more were applied to a tungsten needle in contact with the particle on the substrate at a very low contact pressure. The particle was welded to the substrate in an instant with sparks. The needle was then retracted to 20 !m above the particle and a high voltage of about 2kV was applied to the needle. An electric discharge between the needle and the substrate enveloped the particle, and the joint was strengthened. The joint strength was measured, and the fractured surface was examined by scanning electron microscopy and scanning laser microscopy. The mechanism of joint strengthening is discussed. It is clear that an inert gas flow during the electric discharge is necessary to strengthen the joints.

A Prototype of Electric Discharge Gas-Flow Oxygen–Iodine Laser: 2. Simulation of the Parameters of the Active Medium Formed in a Gas-Flow Slab RF Discharge in O2 : He : CF3I Mixtures

2020 ◽  
Vol 46 (11) ◽  
pp. 1114-1123
Author(s):  
N. P. Vagin ◽  
A. A. Ionin ◽  
A. Yu. Kozlov ◽  
I. V. Kochetov ◽  
A. P. Napartovich ◽  
...  
Keyword(s):  
Active Medium ◽  
Electric Discharge ◽  
Gas Flow ◽  
Rf Discharge ◽  
Iodine Laser ◽  
Discharge Gas

scholarly journals Tribofilms Produced by Supply of Fine Metal Particles in Vacuum

2011 ◽  
Vol 6 (1) ◽  
pp. 50-54
Author(s):  
Hirotaka Kato ◽  
Akihiro Takimi ◽  
Minoru Umemoto
Keyword(s):  
Metal Particles ◽  
Fine Metal Particles

Effect of Inert Gas Flow Nature on SiC Microtube Synthesis

2005 ◽  
pp. 220-225 ◽  
Author(s):  
Jae Won Kim ◽  
Seoung Soo Lee ◽  
Dong Ho Park ◽  
Yeon Gil Jung ◽  
Je Hyun Lee ◽  
...  
Keyword(s):  
Gas Flow ◽  
Inert Gas

Semi-Solid Slurry Casting Using Gas Induced Semi-Solid Technique to Enhance the Microstructural Characteristics of Al-4.3Cu Alloy

2019 ◽  
Vol 285 ◽  
pp. 253-258
Author(s):  
M. Abdi ◽  
S.G. Shabestari
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Temperature Drop ◽  
Inert Gas ◽  
Globular Structure ◽  
Cast Sample ◽  
A206 Alloy ◽  
Gas Purging ◽  
Semi Solid ◽  
Conventionally Cast

Semi-solid processing of Al-4.3%Cu (A206) alloy was performed by Gas Induced Semi-Solid (GISS) process in different condition. The flow rate of argon gas, starting temperature for gas purging (the temperature of superheated-melt) and the duration of gas purging were three key process variables which were changed during this investigation. It was found that inert gas purging near liquidus, significantly, led to the microstructural modification from fully dendritic to globular structure. Thermal analysis was successfully implemented through CA-CCTA technique to understand the cause of the microstructure change during GISS process. The results showed that gas purging into the melt leads to temperature drop of the melt to its liquidus just after a few seconds from start of gas purging. In fact, copious nucleation was induced by cooling effect of inert gas bubbles. Microstructural features were characterized in semi-solid as well as on conventionally cast samples. The optimum gas purging temperature, injection time, and inert gas flow rate was determined in semi-solid processing to obtain the best globularity in the microstructure of a long freezing range alloy. However, the microstructure of the conventionally cast sample was fully dendritic with shrinkage which affects the soundness of casting products.

Respiratory and inert gas exchange during high-frequency ventilation

1982 ◽  
Vol 52 (3) ◽  
pp. 683-689 ◽  
Author(s):  
H. T. Robertson ◽  
R. L. Coffey ◽  
T. A. Standaert ◽  
W. E. Truog
Keyword(s):  
Gas Exchange ◽  
High Frequency ◽  
Gas Flow ◽  
Inert Gases ◽  
Inert Gas ◽  
High Frequency Ventilation ◽  
Physiological Dead Space ◽  
Volume Ventilation ◽  
Frequency Ventilation ◽  
Carrier Gases

Pulmonary gas exchange during high-frequency low-tidal volume ventilation (HFV) (10 Hz, 4.8 ml/kg) was compared with conventional ventilation (CV) and an identical inspired fresh gas flow in pentobarbital-anesthetized dogs. Comparing respiratory and infused inert gas exchange (Wagner et al., J. Appl. Physiol. 36: 585--599, 1974) during HFV and CV, the efficiency of oxygenation was not different, but the Bohr physiological dead space ratio was greater on HFV (61.5 +/- 2.2% vs. 50.6 +/- 1.4%). However, the elimination of the most soluble inert gas (acetone) was markedly enhanced by HFV. The increased elimination of the soluble infused inert gases during HFV compared with CV may be related to the extensive intraregional gas mixing that allows the conducting airways to serve as a capacitance for the soluble inert gases. Comparing as exchange during HFV with three different density carrier gases (He, N2, and Ar), the efficiency of elimination of Co2 or the intravenously infused inert gases was greatest with He-O2. However, the alveolar-arterial partial pressure difference for O2 on He-O2 exceeded that on N2-O2 by 5.4 Torr during HFV. The finding agrees with similar observations during CV, suggesting that this aspect of gas exchange is not substantially altered by HFV.

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