The Cyclic Oxidation Behavior of Ti2AlN and Ti2AlN/TiN Composites

2011 ◽  
Vol 393-395 ◽  
pp. 420-423
Author(s):  
Ming Yan ◽  
Yan Lin Chen ◽  
Ying Chang ◽  
Jiu Xin Jiang
Keyword(s):  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Single Phase ◽  
Oxidation Process ◽  
Second Step ◽  
Outward Diffusion ◽  
Shock Resistance ◽  
Oxygen Oxidation ◽  
Better Than ◽  
Oxidation Behaviors

The cyclic oxidation behavior of Ti2AlN and Ti2AlN/TiN composites were investigated at 800°C, 900°C and 1000°C. The phase composition, thickness of oxidation layer and element content of samples were investigated by XRD and SEM coupled with EDS. The cyclic oxidation behaviors generally follow a parabolic rate law, with good thermal shock resistance. The antioxidation property of Ti2AlN/TiN composite is better than Ti2AlN. Oxidation process of single-phase Ti2AlN is composed by the outward diffusion of Al3+ and Ti4+, and inward diffusion of oxygen. Oxidation process of Ti2AlN/TiN composite consists of two parts: firstly, the oxidation of TiN, the oxidation temperature is 500°C; the second step is the oxidation of Ti2AlN, carried out in the 800-1000 °C.

The Isothermal Oxidation Behavior of Ti2AlN and Ti2AlN/TiN in Air

2011 ◽  
Vol 306-307 ◽  
pp. 808-813 ◽  
Author(s):  
Ming Yan ◽  
Yan Lin Chen ◽  
Ying Chang ◽  
Jiu Xin Jiang ◽  
Bing Chu Mei
Keyword(s):  
Oxidation Behavior ◽  
Single Phase ◽  
Oxidation Process ◽  
Isothermal Oxidation ◽  
Second Step ◽  
Outward Diffusion ◽  
Parabolic Law ◽  
Oxygen Oxidation ◽  
Better Than ◽  
Oxidation Behaviors

The isothermal oxidation behaviors at 800-1000°C for 20h in air of bulk Ti2AlN and Ti2AlN/TiN were investigated by TG, XRD and SEM coupled with EDS. The oxidation behaviors generally follow the parabolic law. The activation energies of Ti2AlN and Ti2AlN/TiN composite are 614.93 KJ∙mol-1and 541.35 KJ∙mol-1respectively. The antioxidation property of Ti2AlN/TiN composite is better than Ti2AlN. Oxidation process of single-phase Ti2AlN is composed by the outward diffusion of Al3+and Ti4+, and inward diffusion of oxygen. Oxidation process of Ti2AlN/TiN composite consists of two parts: firstly, the oxidation of TiN, the oxidation temperature is 500 °C; the second step is the oxidation of Ti2AlN, carried out mainly in the 800-1000 °C.

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.

High Temperature Oxidation Behavior of TiNi Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 853-856 ◽  
Author(s):  
J.H. Ko ◽  
Dong Bok Lee
Keyword(s):  
Oxidation Behavior ◽  
Oxidation Mechanism ◽  
Tini Alloy ◽  
Oxide Scales ◽  
Temperature Oxidation ◽  
Outward Diffusion ◽  
Ni Alloy ◽  
Embedded Particles ◽  
High Temperature Oxidation Behavior ◽  
Better Than

The oxidation behavior of the equiatomic TiNi alloy was investigated at 600-900oC. The oxidation resistance of the TiNi alloy was better than the pure Ti alloy, but worse than the pure Ni alloy. The oxide scales consisted of TiO2, with and without embedded particles of TiNiO3 and Ni. The subscale matrix phase was (TiNi3+TiNi) at 600oC, TiNi3 at 700oC, (Ni+TiNi3) at 800oC, and Ni at 900oC. Oxidation was mainly governed by the inward diffusion of oxygen, and the outward diffusion of Ti and a bit of Ni. Detailed microstructures and the oxidation mechanism are proposed.

Cyclic Oxidation Behavior of Aluminide, Platinum Modified Aluminide, and MCrAlY Coatings on GTD-111

1999 ◽  
Vol 122 (1) ◽  
pp. 50-54 ◽  
Author(s):  
N. S. Cheruvu ◽  
K. S. Chan ◽  
G. R. Leverant
Keyword(s):  
Physical Vapor Deposition ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Aluminum Content ◽  
Aluminide Coating ◽  
Scale Spallation ◽  
Outward Diffusion ◽  
Β Phase ◽  
Mcraly Coatings ◽  
Life Model

Cyclic oxidation behavior of aluminide, platinum modified aluminide, and MCrAlY coatings has been investigated at three temperatures. Aluminide and platinum modified coatings were deposited on GTD 111 material using an outward diffusion process. CoCrAlY coating was applied on GTD-111 by Electron Beam Physical Vapor Deposition (EB-PVD). The oxidation behavior of these coatings is characterized by weight change measurements and by the variation of β phase present in the coating. The platinum modified aluminide coating exhibited the highest resistance to oxide scale spallation (weight loss) during cyclic oxidation testing. Metallographic techniques were used to determine the amount of β phase and the aluminum content in a coating as a function of cycles. Cyclic oxidation life of these coatings is discussed in terms of the residual β and aluminum content present in the coating after exposure. These results have been used to calibrate and validate a coating life model (COATLIFE) developed at the Material Center for Combustion Turbines (MCCT). [S0742-4795(00)00801-2]

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.

Oxidation Properties of Three Dimensional (3-D) Carbon Fiber Preform Coated by SiC-SiO2

2007 ◽  
Vol 280-283 ◽  
pp. 1693-1696 ◽  
Author(s):  
Peng Zhao Gao ◽  
Hong Jie Wang ◽  
Zhi Hao Jin
Keyword(s):  
Carbon Fiber ◽  
Oxidation Behavior ◽  
Oxidation Process ◽  
Three Dimensional ◽  
Isothermal Condition ◽  
Gas Diffusion ◽  
Second Step ◽  
Fiber Preform ◽  
Uniform Coating ◽  
Oxidation Properties

A SiO2-SiC coating on 3-D carbon fiber perform (raw perform) was successfully prepared through several steps. The appearance and composition of the coating/3-D carbon fiber preform (coated perform=CP) was studied through IR, XRD and SEM. The isothermal weight-loss and non-isothermal thermogravimetric (TGA) were used to study the oxidation behavior of CP. The results showed that a uniform coating on every fiber of preform was achieved and the coating adhered well with fiber. The oxidation process of CP in isothermal condition was reaction-controlled in the first step, gas diffusion and reaction-controlled in the second step. The characteristic of the oxidation process in non-isothermal condition was self-catalytic.

Predicting Coating Degradation Under Variable Peak Temperatures

1999 ◽  
Author(s):  
Kwai S. Chan ◽  
N. Sastry Cheruvu ◽  
Gerald R. Leverant
Keyword(s):  
Weight Change ◽  
Thermal Cycle ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Peak Temperature ◽  
Degradation Mechanisms ◽  
Outward Diffusion ◽  
Coating Degradation ◽  
Life Model ◽  
Initial Peak

The cyclic oxidation behavior of a CoCrAlY coating on a GTD-111 substrate was characterized by thermal cycling between ambient temperature and a variable peak temperature. The initial peak temperature of the thermal cycle was 954°C (1750°F) and tested for n1 cycles. The peak temperature was then increased to 1010°C (1850°F) for n2 cycles. Finally, the peak temperature was raised again to 1066°C (1950°F) for n3 cycles, where n1, n2, and n3 are in the range of a few hundred to a few thousand cycles. In all three cases, thermal cycles consisting of 55 minutes at the peak temperature and 5 minutes heating/cooling were used. Weight change of the test specimens was measured as a function of thermal cycle. The results were compared against a coating life model that treats coating degradation mechanisms including oxidation, spallation, and aluminum loss due to both inward and outward diffusion. Using this model, the influence of the variable peak temperature on coating life was predicted in accordance with experimental results.

Preparation and Oxidation Behaviour of an Al-Si Coating on a Ni3Al Based Single Crystal Superalloy IC21

2013 ◽  
Vol 747-748 ◽  
pp. 575-581 ◽  
Author(s):  
Yu Zhuo Liu ◽  
Qiong Wu ◽  
Shu Suo Li ◽  
Yue Ma ◽  
Sheng Kai Gong
Keyword(s):  
Phase Transformation ◽  
Oxidation Resistance ◽  
Outer Layer ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Oxidation Behaviour ◽  
Oxide Scales ◽  
Outward Diffusion ◽  
Microstructure Change ◽  
Β Phase

An Al-Si coating was prepared on IC21 alloy by powder pack cementation. The cyclic oxidation tests were carried out at 1150 in air for up to 100 h. The results indicate that the oxidation resistance of IC21 alloy is significantly improved by the Al-Si coating due to the presence of Ni2Al3and β-NiAl enriched outer layer, and Si can effectively supress the outward diffusion of Mo. The oxide scales mainly consist of α-Al2O3, which is the favorite to the oxidation resistance. Phase transformation occurred from β-NiAl to γ-Ni3Al and γ-Ni in the coating during oxidation. The coating still remained a certain amount of β phase after oxidation for 100h, which indicate a good protection. The microstructure change evolution was characterized, and the oxidation behavior of the coating was discussed.

Cyclic Oxidation Behavior of Aluminide, Platinum Modified Aluminide, and MCrAlY Coatings on GTD-111

1998 ◽  
Author(s):  
N. S. Cheruvu ◽  
K. S. Chan ◽  
G. R. Leverant
Keyword(s):  
Physical Vapor Deposition ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Aluminum Content ◽  
Aluminide Coating ◽  
Scale Spallation ◽  
Outward Diffusion ◽  
Β Phase ◽  
Mcraly Coatings ◽  
Life Model

Cyclic oxidation behavior of aluminide, platinum modified aluminide, and MCrAlY coatings has been investigated at three temperatures. Aluminide and platinum modified coatings were deposited on GTD 111 material using an outward diffusion process. CoCrAlY coating was applied on GTD-111 by Electron Beam Physical Vapor Deposition (EB-PVD). The oxidation behavior of these coatings is characterized by weight change measurements and by the variation of β phase present in the coating. The platinum modified aluminide coating exhibited the highest resistance to oxide scale spallation (weight loss) during cyclic oxidation testing. Metallographic techniques were used to determine the amount of β phase and the aluminum content in a coating as a function of cycles. Cyclic oxidation life of these coatings is discussed in terms of the residual β and aluminum content present in the coating after exposure. These results have been used to calibrate and validate a coating life model (COATLIFE) developed at the Material Center for Combustion Turbines (MCCT).

Thin-Film Synthesis and Cyclic Oxidation Behavior of B2-RuAl

2008 ◽  
Vol 1128 ◽  
Author(s):  
Karsten Woll ◽  
Rama Chinnam ◽  
Frank Mücklich
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Reaction Mechanism ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Single Phase ◽  
Oxidation Behaviour ◽  
Compressive Stresses ◽  
Phase Sequence ◽  
Film Synthesis

AbstractB2-RuAl as a potential intermetallic for thin-film applications at high temperatures is studied with respect to thin-film synthesis and cyclic oxidation behaviour. Using the multilayer approach, single phase RuAl thin films were fabricated. The phase sequence from the elements Ru and Al goes through RuAl6 to the final product RuAl. To understand the reaction mechanism calorimetric as well as kinetic experiments were performed. The cyclic oxidation behavior is characterized at 1200 °C up to 47 h. The morphology of the grown alumina shows no cracks or regions of spallation which indicates the good cyclic oxidation behavior. Compressive stresses in the oxidation scale of about 1.2 GPa at maximum were determined.

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