Effects of Al, Zn, and rare earth elements on flammability of magnesium alloys subjected to sonic burner–generated flame by Federal Aviation Administration standards

2021 ◽  
pp. 095441002098775
Author(s):  
Guangjian Wang ◽  
Zhiwei Zhao ◽  
Song Zhang ◽  
Lili Zheng
Keyword(s):  
Rare Earth ◽  
Oxide Film ◽  
Rare Earths ◽  
Ignition Time ◽  
Federal Aviation Administration ◽  
Mg Alloys ◽  
Alloying Elements ◽  
Mg Alloy ◽  
Protective Oxide ◽  
Protective Oxide Film

Mg alloys are promising structural materials in aerospace industry due to high strength to weight ratio. However, most Mg alloys are limited in aircraft cabins due to their susceptibility to ignition and burning. To improve fire resistance, adding alloying elements is a strategy. Thus, the goal of this study is to explore the effects of alloying elements Al, Zn, and rare earths on Mg-alloy flammability by experiment, using the system and procedures in compliance with the Federal Aviation Administration (FAA) standards for Mg-alloy flammability test. Six commercial Mg alloys with different alloying elements (AZ91E, ZK61A, ZE63A, EZ33A, WE43B, and EV31A) were tested. Results indicate that Mg alloys with Al or Zn elements were of short ignition time and high weight loss. With rare earths, Mg-alloy flammability was suppressed obviously. It appears that this suppression effect with rare earth addition was attributed to the formation of protective oxide film on the surface of molten alloy. Further, a heat transfer model was established to analyze the temperature evolution of the test specimen subjected to the sonic burner–generated flame by FAA standards, and ignition temperatures of all testing Mg alloys were predicted based on the experimental ignition time. The predicted results confirm that with rare earths addition, ignition was delayed after melting by the protective oxide film formed on the surface of the molten alloy.

Characterization of chemically modified thin films for optimization of metal CMP applications

2013 ◽  
Vol 1560 ◽  
Author(s):  
G. Bahar Basim ◽  
Ayse Karagoz ◽  
Zeynep Ozdemir
Keyword(s):  
Thin Films ◽  
Oxide Film ◽  
Metal Oxide ◽  
Film Structure ◽  
Protective Oxide ◽  
Metal Oxide Thin Films ◽  
Chemically Modified ◽  
Surface Active Agents ◽  
Protective Oxide Film ◽  
The Stability

ABSTRACTMetal CMP applications necessitate the formation of a protective oxide film in the presence of surface active agents, oxidizers, pH regulators and other chemicals to achieve global planarization. Formation and mechanical properties of the chemically modified metal oxide thin films in CMP determine the stresses develop at the interfaces delineating the stability and protective nature of the chemically altered films on the surface of the metal wafer. The balance between the stresses built in the film structure versus the mechanical actions provided during the process can be used to optimize the process variables and furthermore help define new planarization techniques for the next generation microelectronic device manufacturing. In this study, the preliminary studies were concentrated on the very well established tungsten CMP applications and furthermore, titanium CMP applications were presented as a part of surface nano-structuring methodology for biomedical applications by stressing the synergistic effect of protective metal oxide film of titanium in this advanced application.

Microstructure and Hot Corrosion Properties of Laser Cladding of a Co-Base Alloy on the Leaf Surface of Gas Turbine

2011 ◽  
Vol 299-300 ◽  
pp. 183-187
Author(s):  
Song Zhang ◽  
Gong You Zhou ◽  
Fang Hu ◽  
Chun Hua Zhang ◽  
Mao Cai Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxide Film ◽  
Gas Turbine ◽  
Hot Corrosion ◽  
Carbon Dioxide Laser ◽  
Base Alloy ◽  
Stainless Steel Surface ◽  
Protective Oxide ◽  
Corrosion Properties ◽  
Protective Oxide Film

The temperatures inside the gas turbine reach up to 1000°C, alloys used for gas turbine components must be oxidation, and corrosion resistant, and stable in structure under high temperature circumstances. A Co-based alloy was cladded on the 1Cr18Ni9Ti stainless steel surface using a high power carbon dioxide laser. The microstructure evolution and hot corrosion properties of samples in 75%Na2SO4+25%NaCl saline were investigated. The results show that the microstructures of the cladded layer is fine, and the hot corrosion resistance of the cladded layer was significantly improved because of the formation of a protective oxide film of CoO and CoO•Cr2O3. Under high temperature corrosive atmosphere, the high content of Co promoted the formation of the protective oxide film. The refinement of dendritic structures and the formation of Co-based alloy oxides lower the penetration rate of the sulphur ions that induce the intergranular corrosion.

High Temperature Corrosion of Microturbine Combustor Material

2007 ◽  
Author(s):  
Hiroshi Yakuwa ◽  
Tadashi Kataoka
Keyword(s):  
High Temperature ◽  
Oxide Film ◽  
High Temperature Corrosion ◽  
Protective Oxide ◽  
Lean Burn ◽  
Protective Oxide Film ◽  
Unburned Hydrocarbons ◽  
The Rich ◽  
Good Heat Resistance ◽  
Good Heat

Two particular types of high temperature corrosion in a microturbine Rich-burn, Quick-mix, Lean-burn (RQL) combustor are discussed and reported in this paper. One type occurred in mixing tubes, part of fuel supply into the combustor. Dense concentrations of carbon monoxide and unburned hydrocarbons in a high temperature environment carburized the mixing tube, leaving it vulnerable to corrosion. The Co-based alloy was selected for the advantage of good heat resistance was exchanged for a Ni-Cr based alloy of good carburization resistance and the life of combustor successfully extended. The second type is a pitting corrosion on the inner wall of liner in the rich-burn zone. It is inferred that the corrosion was metal dusting caused from defects of the oxide film on the inner wall surface. As a countermeasure, a preoxidation step was applied to the combustor to maintain a protective oxide film for a longer period of time. This paper discusses the mechanisms and the countermeasures for these types of corrosion, which relate to carbon from the fuel origin activated in the fuel-rich environment in the combustor.

scholarly journals STUDY OF THE STRUCTURE AND PHASE COMPOSITION OF THE OXIDE FILM ON THE SURFACE OF A LAYERED COATING OF THE Al-Ni SYSTEM

2020 ◽  
pp. 14-18
Author(s):  
V. G. Shmorgun ◽  
A. I. Bogdanov ◽  
V. P. Kulevich ◽  
R. D. Evchits
Keyword(s):  
Phase Composition ◽  
Oxide Film ◽  
Heating Temperature ◽  
Atmospheric Oxygen ◽  
Complex Oxide ◽  
Protective Oxide ◽  
Layered Coating ◽  
Protective Oxide Film ◽  
Temperature Heating ◽  
High Temperature Heating

This work is aimed to the study of the structure and phase composition of the oxide film formed on the surface of the layered coating of the Al-Ni system during high-temperature heating. It was experimentally established that at the initial stages of heat treatment, as a result of the interaction of the Al-Ni system layered coating with atmospheric oxygen, separate sections of Al2O3 oxide are formed on its surface, which are agglomerates of plate crystals of α-modification of nanometer thickness, which increase and grow together with increasing exposure time continuous protective oxide film. An increase in the heating temperature leads to an intensification of oxidation processes and the formation of a complex oxide film of AlO and spinel NiAlO.

The fate of the protective oxide film on stainless steel upon early stage growth of a biofilm

2015 ◽  
Vol 91 ◽  
pp. 352-356 ◽  
Author(s):  
Antoine Seyeux ◽  
Sandrine Zanna ◽  
Audrey Allion ◽  
Philippe Marcus
Keyword(s):  
Stainless Steel ◽  
Oxide Film ◽  
Early Stage ◽  
Protective Oxide ◽  
Protective Oxide Film

scholarly journals Intermetallic compounds and choice of alloying elements for the manufacture of thixomolded creepresistant magnesium alloys

2007 ◽  
Vol 43 (1) ◽  
pp. 85-97 ◽  
Author(s):  
V. Goryany ◽  
P.J. Mauk
Keyword(s):  
Intermetallic Compounds ◽  
Magnesium Alloys ◽  
Rare Earths ◽  
State Of The Art ◽  
Mg Alloys ◽  
Alloying Elements ◽  
Service Properties ◽  
Viable Solution ◽  
Production Problems

This study aims at finding ways to improve the service properties of state-of-the-art creepresistant Mg alloys for Thixomolding and minimise production problems. In doing so, microalloying with Si, Zn, Sr, Li, C, Ba and Bi, as well as the addition of rare earths is a viable solution. .

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