scholarly journals Kinetics Investigation of the Formation of a Gas-Resistant Glass-Forming Layer during the Oxidation of ZrB2-MoSi2-Y2O3-Al Coatings in the Air Atmosphere

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1018
Author(s):  
Marina Kovaleva ◽  
Viacheslav Sirota ◽  
Igor Goncharov ◽  
Vseslav Novikov ◽  
Maxim Yapryntsev ◽  
...  
Keyword(s):  
Heterogeneous Reaction ◽  
Carbon Composite ◽  
Fine Tuning ◽  
Glassy Matrix ◽  
Formation Processes ◽  
Temperature Oxidation ◽  
Glass Forming ◽  
Air Atmosphere ◽  
X 24 ◽  
Ratio Of Components

In this article, the coatings of ZrB2-xMoSi2-Y2O3-yAl (x = 24, 35, 45 wt %; y = 10, 15, 20 wt %) were applied to the surface of a carbon/carbon composite to protect against high-temperature oxidation using a multi-chamber detonation accelerator. The kinetic analysis of the formation processes of a glass-forming layer during the oxidation of the initial components of the system ZrB2-MoSi2-Y2O3-Al in an air atmosphere at a temperature of 1400 °C was carried out and the kinetically significant stages of the heterogeneous reaction were determined. It is shown that the speed and density of the formation of a glassy matrix can be adjusted by fine-tuning the ratio of components in the initial powder.

Controlled Elasticity in Nano-Structured Metallic Glass by Ion Implantation Method

2007 ◽  
Vol 561-565 ◽  
pp. 1315-1318
Author(s):  
Shinji Muraishi ◽  
Hirono Naito ◽  
Jhi Shi ◽  
Yoshio Nakamura ◽  
Tatsuhiko Aizawa
Keyword(s):  
Metallic Glass ◽  
Glassy Phase ◽  
Glassy Matrix ◽  
Nano Structure ◽  
Glass Forming ◽  
Nitride Formation ◽  
Indentation Tests ◽  
The Mean ◽  
Implantation Method ◽  
Critical N Concentration

Different reactivity of ions has been implanted into Zr-Cu metallic glass to obtain nano-structured surface with controlled elasticity. The penetration of glass forming element of Ni+ into crystalline Zr-Cu stabilizes glassy phase to induce crystalline-amorphous (c-a) transition during implantation process. In the meanwhile, penetration of N+ into glassy matrix induces precipitation of (Zr, Cu)N at the mean penetration depth of N. Critical N concentration for nitride formation is estimated to be (Zr,Cu)-20at%N, which also suggests existing of N solid solution of glassy phase. Inert element of Ar+ yields dispersion of nano-voids among glassy matrix. Nano-indentation tests reveal that Young’s modulus of ion implanted glassy film dramatically changes with respect to the induced nano-structure, to decrease 0.4 times for Ar+, to increase 1.3 times for N+ as comparison with that for as-deposited state.

Comments on “Fabrication of ternary Mg–Cu–Gd bulk metallic glass with high glass-forming ability under air atmosphere” [H. Men and D.H. Kim, J. Mater. Res. 18, 1502 (2003)]

2004 ◽  
Vol 19 (2) ◽  
pp. 427-428 ◽  
Author(s):  
Z.P. Lu ◽  
C.T. Liu
Keyword(s):  
Glass Transition ◽  
Metallic Glasses ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Glass Forming Ability ◽  
Bulk Amorphous Alloy ◽  
Liquid Region ◽  
Glass Forming ◽  
Air Atmosphere ◽  
Acta Mater

A new Mg-based bulk amorphous alloy (i.e., Mg65Cu25Gd10) has successfully been developed by Men and Kim [H. Men and D.H. Kim, J. Mater. Res. 18, 1502 (2003)]. They showed that this alloy exhibits significantly improved glass-forming ability (GFA) in comparison with Mg65Cu25Y10 alloy. However, this improved GFA cannot be indicated by the supercooled liquid region ΔT and the reduced glass-transition temperature Trg. As shown in the current comment, the new parameter γ, Tx/(Tg + Tl) defined in our recent papers [Z.P. Lu and C.T. Liu, Acta Mater. 50, 3501 (2002); Z.P. Lu and C.T. Liu, Phys. Rev. Lett. 91, 115505 (2003)] can well gauge GFA for bulk metallic glasses, including the current Mg-based alloys.

High-Temperature Oxidation of Carbon-Carbon Composite Materials in Air

MICC 90 ◽  
1991 ◽  
pp. 650-659
Author(s):  
V. Zh. Shemet ◽  
A. P. Pomytkin ◽  
T. G. Protsenko ◽  
P. I. Zoikin ◽  
V. A. Lavrenko
Keyword(s):  
High Temperature ◽  
Composite Materials ◽  
High Temperature Oxidation ◽  
Carbon Composite ◽  
Temperature Oxidation ◽  
Carbon Composite Materials

Anatase Type Titanium Dioxide Prepared by Oxidation of Titanium Carbide

2016 ◽  
Vol 860 ◽  
pp. 92-96
Author(s):  
Junichi Matsushita ◽  
Tomoyuki Tsuchiyama ◽  
Kazuya Hamaguchi ◽  
Naoya Iwamoto ◽  
Xiao Ling Wang ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
High Temperature ◽  
Titanium Carbide ◽  
Radiant Energy ◽  
High Hardness ◽  
Mass Gain ◽  
Carbide Powder ◽  
Temperature Oxidation ◽  
Air Atmosphere ◽  
Powder Samples

Titanium carbide has been attractive for years an engineering ceramics due to its high hardness, high melting point, and good chemical stability. Similarly, titanium dioxide has excellent anti-microbial ceramic material by photon energy. In this study, the anatase type titanium dioxide layer prepared by oxidation of the titanium carbide powder by high temperature oxidation in air atmosphere was investigated in order to determine the possibility of its photocatalyst materials by radiant energy. TiC powder samples of different grain size were gained by ball mill. These samples were oxidized at room temperature to high temperature. The samples exhibited a steady mass gain with increasing oxidation temperature. Based on the results of the X-ray diffraction analysis, anatase type TiO2 was detected on the titanium carbide samples. It is considered, the titanium carbide showed convension anatase type titanium dioxide layer produced by oxidation.

Effect of Water Vapor on Oxidation of Ferritic Stainless Steel 21Cr-0.6Mo-Nb-Ti in Simulated Reheating Environment

2013 ◽  
Vol 690-693 ◽  
pp. 280-289 ◽  
Author(s):  
Xia Wei Cheng ◽  
Zheng Yi Jiang ◽  
Dong Bin Wei ◽  
Liang Hao ◽  
Jing Wei Zhao ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Water Vapour ◽  
Ferritic Stainless Steel ◽  
Metal Interface ◽  
Water Vapour Content ◽  
Breakaway Oxidation ◽  
Temperature Oxidation ◽  
Air Atmosphere ◽  
High Oxidation Resistance ◽  
Very High

High temperature oxidation of ferritic stainless steel 21Cr-0.6Mo-Nb-Ti was carried out isothermally at 1100 oC under different water vapour content conditions in an electrical furnace. Water vapour does accelerate the formation of oxide scale of stainless steel 21Cr-0.6Mo-Nb-Ti, however, it is not significant. Some oxide grains consist of spinel crystal structure, which should be spinel Manganese Chromite. In dry air atmosphere, the grain of the spinel is more and bigger than that in wet air. No breakaway oxidation occurs in the experiment indicating that 21Cr-0.6Mo-Nb-Ti has very high oxidation resistance, which might be contributed by the formation of MnCr2O4and compact protective chromia. In addition, continuous silica formed along and accumulated at the oxide metal interface performs like a diffusion barrier.

Combined Effect of Mg and Ca on Oxidation Behaviors of Zn–Mg Based Alloys Containing a Trace of Ca at High Temperature

2021 ◽  
Vol 21 (3) ◽  
pp. 2063-2066
Author(s):  
Seong-Ho Ha ◽  
Bong-Hwan Kim ◽  
Young-Ok Yoon ◽  
Hyun-Kyu Lim ◽  
Shae K. Kim
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Intermetallic Phase ◽  
Combined Effect ◽  
Rapid Weight Gain ◽  
Temperature Oxidation ◽  
Air Atmosphere ◽  
Behavior Observation ◽  
Constituent Elements ◽  
Oxidation Behaviors

In this study, the combined effect of Mg and Ca on the high temperature oxidation behaviors of Zn–Mg based alloys containing trace Ca was investigated. Phase diagrams for the oxygen partial pressure versus contents of constituent elements were conducted on the basis of thermodynamic calculations to predict oxide scale behavior. Observation of Zn-1/3/5 mass%Mg alloys showed the distribution of a Zn–Zn11Mg2 eutectic phase after primary formation. As-cast microstructures of the Ca-containing alloys included the formation of a Ca-based intermetallic phase. The change in oxidation resistance with variation of the Mg and Ca contents was experimentally examined via thermogravimetric analysis (TGA). The addition of trace Ca led to the formation of Zn13Ca and a CaO/MgO mixed oxide layer on the surface at 460 °C. After TGA at 460 °C under air atmosphere for 1 h, the Ca-free alloys showed rapid weight gain by oxidation, whereas the oxidation resistance of the Ca-added alloys was substantially increased.

scholarly journals HIGH TEMPERATURE OXIDATION OF AISI 439 FERRITIC STAINLESS STEEL IN SYNTHETIC AIR ATMOSPHERE

2018 ◽  
Vol 80 (5) ◽  
Author(s):  
Maria de Fatima Salgado ◽  
Jackeline Macêdo de Sousa Santos ◽  
Giscard Eanes Dias Viana ◽  
João Alberto Santos Porto ◽  
Gabriel de Souza Veras Fontinele ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Oxidation Kinetics ◽  
Principal Element ◽  
Oxidation Treatment ◽  
Temperature Oxidation ◽  
X Ray ◽  
Air Atmosphere ◽  
Steel Oxidation ◽  
Kinetics Of

Stainless steels may be used and exposed to aggressive gases at high temperatures. The oxidation behavior of AISI 439 ferritic stainless steel, was investigated by oxidation treatment at 850 ºC and 950 ºC, for 50h in Synthetic Air with 20% O2 atmosphere in a tubular oven and in a thermobalance. The oxidation kinetics of films are determined by measuring the mass versus oxidation time. The microstructure and chemical composition of the oxides were determined by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS).  Chemical analysis by EDS showed that films formed on AISI 439 stainless steel exhibited Cr as the principal element in the oxide film, in proportions to form the chromium oxide (Cr2O3) and the following elements: Mn, Fe, Ti and Si. Based on the oxidation kinetics, it was observed that steel oxidation follows the parabolic behaviour with increase in temperature and it produced the highest oxidation rate at 950 ºC and the lowest rate at 850 ºC. 

Fabrication of ternary Mg–Cu–Gd bulk metallic glass with high glass-forming ability under air atmosphere

2003 ◽  
Vol 18 (7) ◽  
pp. 1502-1504 ◽  
Author(s):  
H. Men ◽  
D. H. Kim
Keyword(s):  
Metallic Glass ◽  
Cooling Rate ◽  
Bulk Metallic Glass ◽  
Glass Formation ◽  
Glass Forming Ability ◽  
Casting Method ◽  
Glass Forming ◽  
Air Atmosphere ◽  
Mold Casting ◽  
Order Of Magnitude

A new Mg65Cu25Gd10 alloy having significantly improved glass-forming ability (GFA) has been developed. In this article, we show that the ternary Mg65Cu25Gd10 bulk metallic glass with diameter of at least 8 mm can successfully be fabricated by a conventional Cu-mold casting method in air atmosphere. The critical cooling rate for glass formation was estimated on the order of magnitude of approximately 1 K/s. When compared with the GFA of Mg65Cu25Y10 alloy, the significantly improved GFA of Mg65Cu25Gd10 alloy cannot be explained by ΔTx and Trg values.

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