On the origin of the sigmoid shape in the UO2 oxidation weight gain curves

In this study, Fe-25Mn-9Al-8Ni-1C-xTi alloy (x = 0, 0.1, 0.2, 0.3, 0.4 wt.%) was prepared by vacuum arc melting, and the corresponding microstructure and oxidation behavior at 600 °C were studied. The results show that Fe-25Mn-9Al-8Ni-1C-xTi alloy mainly contains austenite phase, ferrite phase and TiC phase. With Ti content increasing, the austenite phase content decreases, while the contents of ferrite phase and TiC phase increase. The oxidation performance test results show that the addition of Ti element greatly reduces the oxidation weight gain of the alloys at the initial oxidation stage. With the extension of the oxidation time and the further increase of the Ti content, the alloys oxidation weight gain shows a trend of first increasing and then decreasing. When the Ti content is 0.2 wt.%, the oxidation weight gain of this series of alloy reaches the lowest value during the stable oxidation period. Compared with Fe-25Mn-9Al-8Ni-1C alloy, its weight gain per unit area is reduced by 21.1%. Fe-25Mn-9Al-8Ni-1C-xTi alloy oxide layer exhibits a double-layer structure. The outer oxygen layer is mainly loose iron-oxides, while in the inner oxygen layer, the oxides are mainly composed of manganese-oxides and aluminum-oxides, which are relatively dense.

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Study on Exfoliation Resistance of Ferro Superalloy Composite Oxide Scale

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.204-208.4011 ◽

2012 ◽

Vol 204-208 ◽

pp. 4011-4014

Author(s):

Hai Tao Wang ◽

Shen Jie Zhou ◽

Hua Shun Yu ◽

Zhong Chu

Keyword(s):

Weight Gain ◽

Induction Furnace ◽

Intermediate Frequency ◽

Resistant Steel ◽

Heat Resistant Steel ◽

Composite Scale ◽

Gain Rate ◽

Oxidation Weight Gain ◽

Weight Gain Rate ◽

Complete Exfoliation

Based on ferro based superalloy K273 and heat resistant steel ZG40Cr24, test alloys were cast by intermediate frequency induction furnace with non-oxidation method by alloying of aluminium and silicon. The oxidation resistance at 1100°C for 500 hours of test alloys was carried out according to oxidation weight gain method. Experimental results show that the scale exfoliation resistance of K273 and ZG40Cr24 is reinforced greatly by Al2O3 and SiO2. The scale exfoliation weight gain rate at 1100°C descends from 1.2681g.m-2.h-1 to zero, reaching complete exfoliation resistance for ZG40Cr24 test alloy. Because of 1.5<PBR(Al2O3⁄Fe)<2 and the growing of Al2O3 and SiO2 from out side of scale-scale/oxygen interface, the composite scale grows intact and compact without accumulation of growing stress.

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Oxidation Kinetics of ZrB2 Ceramic Matrix Composite Materials

Materials Science Forum ◽

10.4028/www.scientific.net/msf.900.116 ◽

2017 ◽

Vol 900 ◽

pp. 116-120

Author(s):

Hong Yu ◽

Qun Huang ◽

Wei Wang ◽

Long Tao Liu ◽

Cai Wen Li ◽

...

Keyword(s):

Weight Gain ◽

High Temperature ◽

Composite Materials ◽

Oxidation Kinetics ◽

Ceramic Matrix Composite ◽

Ceramic Matrix ◽

Oxidation Time ◽

Molar Ratio ◽

Kinetics Of ◽

Oxidation Weight Gain

Zirconium diboride is widely applied because of some excellent performances. The oxidation kinetics of ZrB2-YAG-Al2O3 composite materials were researched, which helps to improve the performance of ultra-high-temperature composite materials. The results show the oxidation weight gain is decreased with increasing the content of YAG-Al2O3 and the molar ratio of Al2O3. The oxidation weight gain is increased with prolonging the oxidation time under 1300°Cæ, the oxidation weight gain ratio is decreased with prolonging the oxidation time. The effecting tendency of oxidation weight gain is not abvious with varying the contend of YAG-Al2O3 upon 1300°Cæ, however, the effecting tendency of oxidation weight gain is very abvious with varying the molar ratio of Al2O3.

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Effect of Y on the Oxidation Behavior of a Directionally Solidified Ni-based Single Crystal Superalloy

10.21203/rs.3.rs-95133/v1 ◽

2020 ◽

Author(s):

Zihan Zhao ◽

Kai Guan ◽

Renjie Cui ◽

Jianchao Qin ◽

Zhaohui Huang

Keyword(s):

Weight Gain ◽

Single Crystal ◽

Oxide Scale ◽

Oxidation Rate ◽

Oxidation Behavior ◽

Isothermal Oxidation ◽

Oxidation Products ◽

Single Crystal Superalloy ◽

Directionally Solidified ◽

Oxidation Weight Gain

Abstract The effect of Y addition on the oxidation behavior of a Ni-based directionally solidified single crystal superalloy was investigated. Isothermal oxidation test for the samples with different-level Y addition was conducted at 1100℃ in air. The Y content of the samples was demarcated by the actual pickup amount resulted from ICP-AES test. It was found that the addition of Y increased the oxide resistance by an adhesive double-layer oxide scale which was composed of Al2O3 and spinel Ni(Cr,Al)2O4. With 70ppm Y addition, the oxidation weight gain was decreased from 12.6g/m2 for the alloy without Y addition to 5.3g/m2, and the oxidation rate was significantly decreased. Besides, the internal nitride also disappeared after Y doping because of the increasing oxidation scale adherence and the decreasing of oxidation products. In this study, 660ppm Y addition alloy showed the best oxidation resistance.

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Effects of Nickel on Structure and Properties of Ferro Superalloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.250-253.733 ◽

2011 ◽

Vol 250-253 ◽

pp. 733-736

Author(s):

Hai Tao Wang ◽

Chang Lu Chen ◽

Dian Cai Kang

Keyword(s):

Tensile Strength ◽

Weight Gain ◽

High Temperature ◽

Oxidation Resistance ◽

Structure And Properties ◽

Temperature Oxidation ◽

Gain Rate ◽

High Temperature Tensile ◽

Oxidation Weight Gain ◽

Weight Gain Rate

The affecting law of nickel on structure and properties of ferro superalloy, which was cast by intermediate frequency induction furnace, were studied by orthogonal experimental method. The tensile strength and oxidation weight gain rate at 1000°C were tested. The matrix microstructure and scale morphologies and composition were studied using scanning electron microscope (SEM) and X-ray diffraction (XRD) respectively. It was found that the high temperature tensile strength went up with the increase of nickel by the forming of high temperature strengthening phase of γ’. After 100 hours aging at 1000°C, γ’ phase separated in blocks. Certain content of nickel improved the high temperature oxidation resistance of test alloys, but excess of it caused the higher oxidation weight gain rate and loose structure oxide scales with holes and exfoliating. In considering of high temperature tensile strength and oxidation resistance, the ideal content of nickel in ferro superalloy should be 9wt.%, with which at 1000°C the tensile strength of test alloys mostly exceeded 70MPa, and the average oxidation weight gain rate was only 0.55g.m-2.h-1, reaching the strong oxidation resistance. Such scale was compounded by Cr2O3 and Fe(Ni)Cr2O4 with compact structure, fine and even oxide grains.

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Prediction of surface oxidation weight gain on 7.8 wt% Cr-containing stainless steel electrode during electroslag remelting

Materials at High Temperatures ◽

10.1080/09603409.2018.1503444 ◽

2018 ◽

Vol 36 (3) ◽

pp. 212-219 ◽

Cited By ~ 2

Author(s):

Yu Liu ◽

Guangqiang Li ◽

Ruiting Wang ◽

Qiang Wang ◽

Yong Wang ◽

...

Keyword(s):

Stainless Steel ◽

Weight Gain ◽

Surface Oxidation ◽

Electroslag Remelting ◽

Stainless Steel Electrode ◽

Steel Electrode ◽

Oxidation Weight Gain

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Study of Thermal Diffusion on Oxidation Resistance of ZG40Cr24

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.488-489.14 ◽

2014 ◽

Vol 488-489 ◽

pp. 14-17

Author(s):

Hai Tao Wang ◽

Shen Jie Zhou ◽

Hua Shun Yu

Keyword(s):

Diffusion Coefficient ◽

Weight Gain ◽

Oxide Scale ◽

Oxidation Resistance ◽

Thermal Diffusion ◽

Intermediate Frequency ◽

Heat Resistant Steel ◽

Thermal Diffusion Coefficient ◽

Thickness Meter ◽

Oxidation Weight Gain

Based on heat resistant steel ZG40Cr24, test alloys were cast by intermediate frequency induction furnace with non-oxidation method by alloying of aluminium and silicon. The oxidation resistance at 1100°C for 500 hours of test alloys was carried out according to oxidation weight gain method. The thermal diffusion were tested by Laser Heat Conductivity. The thickness of oxide scale was detected by Coating Thickness Meter. Experimental results showed that the thermal diffusion of oxide scale affected its oxidation resistance exactly, the lower thermal diffusion coefficient matched the higher oxidation resistance. The oxide scale thermal diffusion coefficient of ZG40Cr24+2%wt.Si+4%wt.Al was only 0.00092cm2.s-1, endowing itself 0.0633g.m-2.h-1 oxidation weight gain rate, reaching the complete oxidation resistance. The mechanism of the effect of thermal diffusion on oxidation resistance lay in that the lower thermal diffusion represented the inert inner particles of materials, the few quantity of diffusion particles, and lower transporting and moving rate. So the oxidation rate slowed down, realizing higher oxidation resistant property for oxide scales.

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