scholarly journals Investigation on corrosion mechanism of stirring paddles of different iron-based materials in ZL101 aluminum melt

Author(s):  
Bei Yuan ◽  
Dunming Liao ◽  
Wenming Jiang ◽  
Han Deng ◽  
Guangyu Li
2019 ◽  
Vol 63 (3) ◽  
pp. 113-120
Author(s):  
R. Gorejová ◽  
R. Oriňaková ◽  
A. Oriňak ◽  
M. Kupková ◽  
M. Hrubovčáková ◽  
...  

Abstract Biodegradable metallic implants are materials that serve as a temporary implants and scaffolds. They degrade directly in vivo and therefore eliminate need for secondary surgical intervention. They are often made of metals such as magnesium, iron, zinc and can be modified by coating with the inorganic or polymeric layer. In this work iron-based biomaterial was prepared and modified with polymeric (polyethyleneimine, PEI) layer. Its degradation behavior was studied under conditions of simulated body fluids at 37 ± 0.2 °C in the form of static immersion tests. It has been shown that the surface modification caused an acceleration of degradation of the material and also had an influence on the corrosion mechanism.


1997 ◽  
Vol 7 (C2) ◽  
pp. C2-439-C2-440
Author(s):  
O. Isnard ◽  
S. Miraglia ◽  
Ch. Giorgetti ◽  
F. Baudelet ◽  
E. Dartyge ◽  
...  
Keyword(s):  
X Ray ◽  

2020 ◽  
Author(s):  
Chet Tyrol ◽  
Nang Yone ◽  
Connor Gallin ◽  
Jeffery Byers

By using an iron-based catalyst, access to enantioenriched 1,1-diarylakanes was enabled through an enantioselective Suzuki-Miyaura crosscoupling reaction. The combination of a chiral cyanobis(oxazoline) ligand framework and 1,3,5-trimethoxybenzene additive were essential to afford high yields and enantioselectivities in cross-coupling reactions between unactivated aryl boronic esters and a variety of benzylic chlorides, including challenging ortho-substituted benzylic chloride substrates. Mechanistic investigations implicate a stereoconvergent pathway involving carbon-centered radical intermediates.


2019 ◽  
Author(s):  
Nikolaus Gorgas ◽  
Berthold Stöger ◽  
Luis F. Veiros ◽  
Karl Kirchner

We report on the first synthesis and structural characterization of the iron based aminoborane complexes. These species are formed upon protonation of a borohydride complex by ammonium salts.<br>


Author(s):  
Dongmei Meng ◽  
Laura Buck ◽  
James Cargo

Abstract Cu needs a higher level of ultrasound combined with bonding force to be bonded to the Al pad properly, not just because Cu is harder than Au, but it is also harder to initiate intermetallic compounds (IMC) formation during bonding. This increases the chances of damaging the metal/low k stack under the bondpad. This paper presents a fundamental study of IMC as well as one example of a failure mode of Cu/Al bonded devices, all based on detailed analysis using scanning electron microscopy, scanning transmission electron microscopy, energy dispersive spectrometers, and transmission electron microscopy. It presents a case study showing a corrosion mechanism of Cu/Al ballbond after 168hr UHAST stress. It is observed that all Cu9Al4 was consumed, while very little copper aluminide remained after 168 hours of UHAST stressing.


Author(s):  
John Butchko ◽  
Bruce T. Gillette

Abstract Autoclave Stress failures were encountered at the 96 hour read during transistor reliability testing. A unique metal corrosion mechanism was found during the failure analysis, which was creating a contamination path to the drain source junction, resulting in high Idss and Igss leakage. The Al(Si) top metal was oxidizing along the grain boundaries at a faster rate than at the surface. There was subsurface blistering of the Al(Si), along with the grain boundary corrosion. This blistering was creating a contamination path from the package to the Si surface. Several variations in the metal stack were evaluated to better understand the cause of the failures and to provide a process solution. The prevention of intergranular metal corrosion and subsurface blistering during autoclave testing required a materials change from Al(Si) to Al(Si)(Cu). This change resulted in a reduced corrosion rate and consequently prevented Si contamination due to blistering. The process change resulted in a successful pass through the autoclave testing.


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