Cyclic Oxidation Resistance of Co-10Cr-5Al-0.3Y Alloy at 800 oc

2014 ◽  
Vol 1015 ◽  
pp. 505-508
Author(s):  
Ling Yun Bai ◽  
Hong Hua Zhang ◽  
Huai Shu Zhang ◽  
Yun Xiang Zheng ◽  
Jun Huai Xiang
Keyword(s):  
Oxidation Resistance ◽  
Oxidation Rate ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Oxidation Process ◽  
Oxidation Mechanism ◽  
Local Zone

The cyclic oxidation behavior of Co-10Cr-5Al alloys with and without 0.3 at% Y doped in atmosphere at 800oC was investigated. The addition of 0.3 at.% Y increased the oxidation rate of the alloy and changed the oxidation mechanism. The scales grown the alloys with and without Y were both composed of an outer Co2O3layer and an inner complex layer of Al2O3, Co2O3and Cr2O3, except that the addition of 0.3 at% Y enhanced the adhesion of the scale. 0.3 at% Y agglomerated in local zone which accelerated the oxidation rate and was not conductive to the oxidation process of the Co-10Cr-5Al alloy.

Effects of Yttrium on Cyclic Oxidation Resistance of Co-10Cr-5Al Alloy

2013 ◽  
Vol 785-786 ◽  
pp. 844-847
Author(s):  
Jun Huai Xiang ◽  
Xian Chao Xu ◽  
Ling Yun Bai ◽  
Yun Xiang Zheng ◽  
Huai Shu Zhang
Keyword(s):  
Oxidation Resistance ◽  
Oxidation Kinetics ◽  
Oxidation Rate ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Oxidation Process ◽  
Local Zone ◽  
Rate Law ◽  
Parabolic Rate

The cyclic oxidation behavior of Co-10Cr-5Al alloys with and without Y in atmosphere at 800 °C was investigated. The addition of 0.3 at.% Y increased the oxidation rate of the alloy and changed the behavior from irregular oxidation kinetics to approximate parabolic rate law. The scales grown the alloys with and without Y were both composed of an outer Co2O3layer and an inner complex layer of Al2O3, Co2O3and Cr2O3, except that the addition of Y impaired the adhesion of the scale. Over-doped Y agglomerated in local zone plays an adverse role in the oxidation process by accelerating the oxidation rate.

Effects of Yttrium on Cyclic Oxidation Resistance of Co-10Cr-5Al Alloy at 700 °C

2014 ◽  
Vol 528 ◽  
pp. 25-29
Author(s):  
Ling Yun Bai ◽  
Xian Chao Xu ◽  
Jun Huai Xiang ◽  
Yun Xiang Zheng ◽  
Jun Wang
Keyword(s):  
Oxide Scale ◽  
Oxidation Resistance ◽  
Oxidation Rate ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Adhesive Property ◽  
Complex Mode ◽  
Rate Law ◽  
Parabolic Rate

The cyclic oxidation behavior of Co-10Cr-5Al alloys in atmosphere at 700 °C was investigated. The addition of 0.3 at.% Y changed the oxidation behavior from the approximate parabolic rate law to complex mode. The scale grown on the surface of Co-10Cr-5Al cracked seriously, while the oxide scale the Y doped alloy had better adhesive property. Yttrium doped in the sample promoted the forming of continuous Al2O3layer and decreased the oxidation rate of Co-10Cr-5Al alloys.

scholarly journals Effects of Al Sputtering Film on the Oxidation Behavior of NiCrAlY Bondcoat

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 376
Author(s):  
Yong Zhang ◽  
Gengfei Zhang ◽  
Qiang Yang ◽  
Weicheng Cao ◽  
Jian Pu ◽  
...  
Keyword(s):  
Oxidation Resistance ◽  
Thermal Barrier Coatings ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Mixed Oxides ◽  
Oxidation Mechanism ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Al Content ◽  
Α Al2o3

In this study, the oxidation behavior of Al coated NiCrAlY bondcoat is investigated. It is known that many methods are applied to improve the lifetime of bondcoat in thermal barrier coatings. Herein, the Al sputtering method is selected to increase the Al content, which does not change the structure of bondcoat. Thin Al film of ~2 µm was sputtered on the surface of bondcoat, which improved the oxidation resistance of NiCrAlY bondcoat. Experimental results showed that, after oxidation for 200 h at 1200 °C, the formation of a dense and continuous α-Al2O3/Cr2O3 multilayer was observed on the Al coated bondcoat surface. In contrast, a mixed oxides (NiO, Cr2O3 and spinel oxides) layer formed on the surface of the as-sprayed bondcoat samples. Results of the cyclic oxidation at 1050 °C within 204 h indicated that the Al sputtering method can improve the oxidation resistance of bondcoat. This study offers a potential way to prolong the lifetime of thermal barrier coatings and provides analysis of the oxidation mechanism.

Influence of Micro-Structure on Oxidation Behavior of a Ni-Based Superalloy at 1000°C

2008 ◽  
Vol 595-598 ◽  
pp. 87-94 ◽  
Author(s):  
Li Liu ◽  
Ying Li ◽  
Fu Hui Wang
Keyword(s):  
Oxide Scale ◽  
Oxidation Resistance ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Flat Surface ◽  
Cast Alloy ◽  
Oxidation Mechanism ◽  
Micro Structure ◽  
Al2o3 Layer ◽  
Oxidation Behaviors

The isothermal and cyclic oxidation behaviors of a Ni-based superalloy with singlecrystalline (SC), polycrystalline and nanocrystalline (NC) structures were studied at 1000°C. Results indicated that a uniform oxides scale consisted of external Cr2O3 with little TiO2 and internal continuous Al2O3 formed on SC alloy. A non-uniform external oxide of which some locations were nodule-like scale was formed on surface of cast alloy. The nodule-like parts consisted of TiO2, Cr2O3 and serious internal oxidation of Al, and rest flat surface was a Cr2O3 and Al2O3 layer. A continuous Al2O3 layer formed on the sputtered NC coating. The micro-structure influenced the oxidation mechanism and resulted in different oxide scale formed on three materials, which greatly influenced materials’ oxidation and cyclic-oxidation resistance.

Effect of Y on Cyclic Oxidation Behavior of FeCrNi Heat-Resisting Steel

2012 ◽  
Vol 557-559 ◽  
pp. 170-174
Author(s):  
Xiao Liu ◽  
Long Mei Wang
Keyword(s):  
Silicon Dioxide ◽  
Oxidation Resistance ◽  
Internal Oxidation ◽  
Oxidation Rate ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Experimental Sample ◽  
Oxidation Layer ◽  
Pinning Effect

The oxidation resistance of FeCrNi heat-resisting steel at 1150°C and 1200°C is analyzed and studied using XRD, SEM and EDS techniques. The results show that the oxidation resistance of the heat-resisting steel is improved remarkably after adding yttrium. The value of oxidation rate of experimental Sample 1 (without adding Y) is 3.25 times and 1.56 times higher than Sample 2, respectively at 1150°C and 1200°C after oxidizeing for totally 144h. On the surface of the heat-resisting steel containing Y, the dense and adherent Cr2O3 scale and FeCr2O4 scale are formed and played the protection role. In the internal oxidation layer, the pinning effect of silicon dioxide is strengthened by Y, and Y has a pining effect directly.

Temperature-Driven Oxidation Behavior of Pure Iron Surface Investigated by Time-Resolved EXAFS Measurements

1998 ◽  
Vol 524 ◽  
Author(s):  
S. J. Doh ◽  
J. M. Lee ◽  
D. Y. Noh ◽  
J. H. Je
Keyword(s):  
Heat Treatment ◽  
Oxidation Behavior ◽  
Oxidation Process ◽  
Rapid Heating ◽  
Oxidation Mechanism ◽  
Front Surface ◽  
Time Resolved ◽  
Treatment Conditions ◽  
Surface Front ◽  
Prolonged Heat

ABSTRACTThe surface-front oxidation mechanism of iron was investigated by time-resolved, glancingangle Fe K-edge fluorescence EXAFS measurements at various oxidation temperatures of 200-700 C. The glancing angle was chosen according to the depth of the oxide layer, roughly 1500-2000A. The oxidation behavior under rapid heating(up to 600°C within 10 minutes) was compared with the slowly heated oxidation process using the Quick-EXAFS measurements. In the slowly heated process, Fe3O4 was the dominating phase at a relatively low temperature (300-400 C) initially. However, at a relatively high temperature (above 600°C), the Fe2O3 and FeO crystalline phases are gradually enriched as the successive oxidation process involving intrusive oxygen proceeded. Remarkably under a prolonged heat treatment above 600°C, the stable FeO phase that exists in a deep-lying interface structure and Fe2O3 phase eventually dominates the thick front-surface structure. In a quickly heated process, however, Fe3O4 phase is less dominating, which is contradictory to the commonly accepted oxidation models. The EXAFS results are discussed in conjunction with the x-ray diffraction features under the same heat treatment conditions.

An Effective Approach to Improve the Oxidation Resistance of Ti-6Al-4V Alloy by Combination of Phosphorization and Silica Coating

2011 ◽  
Vol 148-149 ◽  
pp. 534-537
Author(s):  
Chun Xiang Gao
Keyword(s):  
Oxidation Resistance ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Sol Gel ◽  
Synergetic Effect ◽  
Silica Coating ◽  
Dip Coating ◽  
Sio2 Coating ◽  
Amorphous Sio2 ◽  
Dip Coating Technique

A very effective approach to improve the oxidation resistance of Ti-6Al-4V alloy was proposed. The Ti-6Al-4V alloy was firstly phosphated and then coated by silica using sol-gel dip-coating technique. A duplex layer of TiP2O7 and amorphous silica was synthesized at the alloy surface. The isothermal and cyclic oxidation behavior of the treated alloy with silica coating and the corresponding bare alloy was investigated at 600 oC in static air to investigate the synergetic effect of phosphorization and amorphous SiO2 coating on the oxidation resistance of the alloy. The isothermal and cyclic oxidation resistances of the alloy were greatly improved.

Comparison Study of Oxidation Behavior of Low Carbon Steel at Elevated Temperatures

2014 ◽  
Vol 1025-1026 ◽  
pp. 504-508 ◽  
Author(s):  
Sang An Ha ◽  
Dong Kyun Kim ◽  
Woo Jin Lee ◽  
Chang Yong Kang ◽  
Kwon Hoo Kim ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Oxidation Rate ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Elevated Temperatures ◽  
Low Carbon Steel ◽  
Comparison Study ◽  
Low Carbon ◽  
Increasing Temperature ◽  
Continuous Oxidation

Comparison study of oxidation behavior of low carbon steel was conducted at the temperature range of 500°C to 700°C under a 0.2 atm oxygen pressure by continuous and discontinuous oxidation methods. Oxidation rate of both cases was found to be increased with increasing temperature from 500°C to 700°C and obeyed parabolic rate law. In addition, activation energy for the continuous oxidation of steel was found to be a 164.8 kJ/mole, which means that oxidation rate is proportionally dependant on temperature. In case of cyclic oxidation, the oxidation rate was shown to faster than continuous oxidation at all temperatures due to direction oxidation through spallation of the oxide layer.

Oxidation Behavior of K38 Superalloy with Different Amounts of Yttrium Addition at 1173K in Air

2011 ◽  
Vol 366 ◽  
pp. 40-44 ◽  
Author(s):  
Ping Yu ◽  
Long Shi ◽  
Wen Wang ◽  
Fu Hui Wang
Keyword(s):  
Oxidation Resistance ◽  
Selective Oxidation ◽  
Internal Oxidation ◽  
Oxidation Rate ◽  
Oxidation Behavior ◽  
Rich Phase ◽  
Al2o3 Scales ◽  
Yttrium Addition ◽  
Negative Effect ◽  
Cast Alloys

The oxidation behavior of K38 alloy with 0, 0.05, 0.1, 0.5wt% yttrium concentrations has been investigated during exposures in air at 1173K for 100 hours. The results indicated that Cr2O3 and TiO2 scale mainly formed on the surface of the alloy without yttrium. Yttrium addition promoted the selective oxidation of aluminum and reduced the internal oxidation. The alloy with 0.1 wt.% yttrium addition exhibits excellent oxidation behavior among the four types of the alloys for its decreasing the oxidation rate and forming more continuous and compact Al2O3 scales. Yttrium-rich phase formed in the alloy with 0.5wt.% yttrium, result in a negative effect on the oxidation resistance of cast alloys.

On the oxidation resistance of superhard Ti–Si–C–N coatings

2008 ◽  
Vol 23 (9) ◽  
pp. 2420-2428 ◽  
Author(s):  
Yan Guo ◽  
Shengli Ma ◽  
Kewei Xu ◽  
Tom Bell ◽  
Xiaoying Li ◽  
...  
Keyword(s):  
Grain Size ◽  
Chemical Vapor Deposition ◽  
Oxidation Resistance ◽  
Vapor Deposition ◽  
Silicon Content ◽  
Oxidation Behavior ◽  
Oxidation Process ◽  
Chemical Vapor ◽  
Surface Morphologies ◽  
The Relationship

The oxidation behavior of three types of plasma-enhanced chemical vapor deposition (PECVD) processed Ti–Si–C–N coatings with silicon content ranging from 4.3 to 11.6 at.% has been investigated at high temperatures. Systematic characterization was conducted to study the evolution of composition, phase constituents, hardness, surface morphologies, microstructures, and grain size during oxidation. A two-stage oxidation process was observed between 700 and 1000 °C for all three coatings. Experimental results indicate that a superhardness of 40 GPa can be maintained up to 700, 800, and 850 °C for 4.3, 7.4, and 11.6 at.% Si coatings, respectively; the dual-phased 7.4 and 11.6 at.% Si coatings show a better oxidation resistance than the single-phased 4.3 at.% Si coating. On the basis of the results, a mechanism is proposed to explain the relationship between the nanostructure and oxidation behavior.

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