scholarly journals Investigation of Element Effect on High Temperature Oxidation of HVOF NiCoCrAlX Coatings

2018 ◽  
Author(s):  
Pimin Zhang ◽  
Ru Lin Peng ◽  
Xin-Hai Li ◽  
Sten Johansson
Keyword(s):  
Gas Turbines ◽  
Cyclic Oxidation ◽  
Isothermal Oxidation ◽  
Oxidation Behaviour ◽  
Temperature Oxidation ◽  
Oxidation Test ◽  
Minor Elements ◽  
Cyclic Oxidation Test ◽  
Boundary Model ◽  
Comprehensive Study

MCrAlX (M: Ni or Co or both, X: minor elements) coatings have been widely used to protect hot components in gas turbines against oxidation and hot corrosion at high temperatures. Understanding the influence of the X-elements on oxidation behaviour is important in the design of durable MCrAlX coatings. In this study, NiCoCrAlX coatings doped with Y+Ru and Ce, respectively, were deposited on Inconel-792 substrate by HVOF. The samples were subjected to isothermal oxidation test in laboratory air at 9000, 1000, 1100 ºC and cyclic oxidation test between 100 ºC and 1100 ºC with 1 hour dwell time at 1100 ºC. It was observed that the coating with Ce shows a much higher oxidation rate than the coating with Y+Ru under both isothermal and cyclic oxidation tests. Besides, β-depletion due to interdiffusion between coating and substrate was significantly lower with Ru addition. Simulations results using both a moving phase boundary model and an established oxidation-diffusion model show that Ru stabilize β grains which reduces β-depletion of coating due to substrate interdiffusion. This paper presents a comprehensive study of the influence of Ce and Ru on oxidation behaviour including investigation of the microstructure evolution influenced by oxidation time at coating surface and coating-substrate interface combining experiment and simulation results.

Microstructural Features and Oxidation Behaviour of NiCrAlY Coatings Obtained by HVOF Process

2012 ◽  
Vol 585 ◽  
pp. 507-511 ◽  
Author(s):  
Nidhi Rana ◽  
R. Jayaganthan ◽  
Satya Prakash
Keyword(s):  
Gas Turbines ◽  
High Temperature Oxidation ◽  
Parabolic Rate Constant ◽  
Oxidation Behaviour ◽  
Coating System ◽  
Temperature Oxidation ◽  
Hvof Process ◽  
Nicraly Coating ◽  
Oxidation And Corrosion ◽  
Substrate Alloy

NiCrAlY coating system has been widely used for the advanced gas turbines to provide protection against high temperature oxidation and corrosion. Various methods have been used to develop these superalloy coatings. In present investigation, NiCrAlY superalloy coatings have been deposited on the superalloy substrate (Superni76) using commercially available NiCrAlY powder and High Velocity Oxide Fuel (HVOF) process. These coatings have been characterised in terms of their microhardness, porosity, microstructure features and surface roughness. The coatings have been oxidized cyclically (1hour heating and 20minutes cooling) in air at 900οC. The weight change curves have been plotted and the parabolic rate constant has been evaluated. The oxides formed after oxidation has been studied by using various techniques like optical microscopy, FESEM/EDAX and XRD. It has been observed Al¬2O3, NiCr2O4 and Cr2O3 formed upon oxidation of the coatings provide protection to the substrate alloy.

Oxidation Behaviour of Nickel-Based Alloys Containing High Re Contents Comparable to the Third Generation Nickel-Based Superalloys

2004 ◽  
Vol 449-452 ◽  
pp. 349-352 ◽  
Author(s):  
Yoshinori Murata ◽  
Masahiko Morinaga ◽  
Ryokichi Hashizume
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Oxidation Behaviour ◽  
The Other ◽  
Third Generation ◽  
Temperature Oxidation ◽  
Oxidation Test ◽  
Al Content ◽  
The Third

In order to elucidate the Re effect on oxidation resistance, a high-temperature oxidation test was conducted with two groups of Ni-based superalloys. One group of alloys was characterized by 10mol%Al content (10-Al series). The other group of alloys was characterized by 15mol%Al content (15-Al series). The oxidation resistance decreased clearly with increasing Re content in the 10-Al series alloys, but did not in the 15-Al series alloys.

scholarly journals In Situ Thermal Gradient Controlled Investigation of Spallation -Experimental Design and Preliminary Results

2008 ◽  
Vol 595-598 ◽  
pp. 1135-1143 ◽  
Author(s):  
Julien Sniezewski ◽  
Yannick Le Maoult ◽  
Philippe Lours
Keyword(s):  
Experimental Design ◽  
Thermal Gradient ◽  
Cyclic Oxidation ◽  
Experimental Approach ◽  
Alumina Scale ◽  
Oxidation Test ◽  
Design And Implementation ◽  
Cyclic Oxidation Test ◽  
Cooling Phase

Based on a coupled numerical and experimental approach, the design and implementation of an in situ thermal-gradient-controlled cyclic oxidation test, dedicated to the investigation of the TGO and TBC spallation, is presented. The influence of the specimen through thickness thermal gradient as well as the benefits of the video real-time monitoring of the cooling phase of an oxidation test is discussed in the case of the spallation of an alumina scale grown on FeCrAl alloys.

OXIDATION RESISTANCE AND MICROSTRUCTURE OF Pt AND PtIr DIFFUSION COATINGS ON Ni BASED SINGLE CRYSTAL SUPERALLOYS BY ELECTROPLATING METHOD

2019 ◽  
Vol 57 (6) ◽  
pp. 714
Author(s):  
Tue Chi Dao ◽  
Hideyuki Murakami ◽  
Le Thi Hong Lien
Keyword(s):  
Single Crystal ◽  
Oxidation Resistance ◽  
Cyclic Oxidation ◽  
Treatment Process ◽  
Heat Treatment Process ◽  
Oxidation Test ◽  
Diffusion Coatings ◽  
Cyclic Oxidation Test ◽  
Annealing Heat Treatment ◽  
Kirkendall Voids

In this study, Pt and PtIr diffusion coatings on Ni based single crystal superalloys were fabricated by an electroplating method followed by an annealing heat treatment process. The microstructure and phase constitution of the coatings were studied by SEM/EDS and XRD methods. The cyclic oxidation test at 1150oC was conducted to investigate the oxidation resistance of the coatings. The results showed that the addition of Ir in the coating led to the formation of α(NiPt2Al) phase and reduced the formation Kirkendall voids in the coating after 100 cycle oxidation test.

The High Temperature Oxidation Behavior of Hot-Dipping Al Coating on 0Cr18Ni10Ti Stainless Steel

2014 ◽  
Vol 905 ◽  
pp. 123-127 ◽  
Author(s):  
Jin Lou ◽  
Jie Ke Wang ◽  
Yu Bin Wang
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
High Temperature Oxidation ◽  
Cyclic Oxidation ◽  
Isothermal Oxidation ◽  
Aluminum Coating ◽  
Diffusion Annealing ◽  
Temperature Oxidation ◽  
Aluminized Steel ◽  
Oxidation Behaviors

0Cr18Ni10Ti stainless steel was coated by hot-dipping in a molten aluminum bath, and then diffusing annealing at 950°C for 2h. The high temperature isothermal oxidation behaviors of the hot-dipped aluminized steel and 0Cr18Ni10Ti steel were tested at 900 °C for 24h using Thermo gravimetric analyzer. The high temperature cyclic oxidation behaviors of the hot-dipped aluminized steel and 0Cr18Ni10Ti steel were tested at 900 °C for 24h using resistance furnace. The morphology was studied by SEM, the phase composition was characterized by EDS. The result of high temperature isothermal and cyclic oxidation test showed that the hot-dipped aluminum can dramatically improve the isothermal and cyclic oxidation of the 0Cr18Ni10Ti steel. The hot-dipping aluminum coating is consists of an outer layer of FeAl and an inner Iron solid solution with aluminum, after diffusion annealing at 950°C for 2 h. The Al2O3 oxide layer was formed on the hot-dipped aluminum coating during isothermal and cyclic oxidation process, which provides an additional protection for the steel from high temperature oxidation.

High Temperature Oxidation of Al-Alloyed SiMo Cast Iron in CO2-Containing Atmospheres

2013 ◽  
Vol 813 ◽  
pp. 132-135
Author(s):  
Somrerk Chandra-ambhorn ◽  
Thublaor Tummaporn ◽  
Pongpankasame Jiradech
Keyword(s):  
Cast Iron ◽  
High Temperature Oxidation ◽  
Cyclic Oxidation ◽  
Cast Alloy ◽  
X Ray Diffraction ◽  
Temperature Oxidation ◽  
X Ray ◽  
Cyclic Oxidation Test ◽  
Thermal Oxide ◽  
Kinetics Of

The SiMo cast iron with 5.45 wt% of Al has been developed for using as an automotive exhaust manifold. Cyclic oxidation test of that alloy and the conventional SiMo cast iron was conducted at 850 oC in 5%CO2+12%O2+83%N2 and 10%CO2+12%O2+78%N2. It was found that oxidation kinetics of the SiMo cast iron alloyed with 5.45 wt% of Al was lower than that of the SiMo cast iron. An X-ray diffraction technique and a scanning electron microscope equipped with energy dispersive spectroscopy were performed for characterisation. Thermal oxide scale on the SiMo cast iron consisted of hematite, magnetite and silica, while it was mainly alumina, additionally with hematite and magnetite, for the SiMo cast iron alloyed with 5.4 wt%. Formation of the alumina promoted oxidation resistance of the later cast alloy.

The High-Temperature Oxidation Behavior of the Fe-Ni Based Alloy Coating Produced by Plasma Cladding

2011 ◽  
Vol 189-193 ◽  
pp. 781-785
Author(s):  
Li Min Zhang ◽  
Bang Wu Liu
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Low Carbon Steel ◽  
Alloy Coating ◽  
Isothermal Oxidation ◽  
Low Carbon ◽  
Temperature Oxidation ◽  
Oxidation Test ◽  
Plasma Cladding

In the paper the efficient and low-cost plasma cladding technique has been used to prepare Fe-Ni based alloy coatings on the surface of low carbon steel. The high-temperature isothermal oxidation behavior of the specimens has been tested at 700 °C and 800 °C in air using an electrical furnace for 100 h. The elements distribution, phase composition, and morphology of the alloy coatings after the oxidation test have been characterized by SEM/EDS and XRD. Isothermal oxidation test show that the Fe-Ni based alloy coating has excellent high temperature oxidation resistance at 700 °C and 800 °C. The oxidation rate of Fe-Ni based coating at 800 °C is higher than that of at 700 °C. At 800 °C, the oxidation kinetics basically follows the parabolic rate law before 80 h. A protective Fe0.99Fe1.97Cr0.03Ni0.01O4 and Cr1.3Fe0.7O3 based oxide film has been formed on the surface of the coating after oxidation.

Synthesis Nano-SiCp/MoSi2 Composites by In Situ Reaction Sintering and Low Temperature Oxidation Behavior

2010 ◽  
Vol 105-106 ◽  
pp. 150-153 ◽  
Author(s):  
Peng Chao Kang ◽  
Guo Qin Chen ◽  
Gao Hui Wu
Keyword(s):  
Low Temperature ◽  
Cyclic Oxidation ◽  
Volume Fraction ◽  
Isothermal Oxidation ◽  
X Ray Diffraction ◽  
Temperature Oxidation ◽  
Transmission Electron ◽  
Oxidation Resistant ◽  
Hot Press Sintering

Nano-SiCp/MoSi2 composites with different SiC volume fraction have been synthesized by in situ reactive hot press sintering with the milled Mo, Si and C elements powders. The X-ray diffraction (XRD) detection shows the composites are composed of α-MoSi2 and β-SiC, and transmission electron microscopy (TEM) shows that the particle sizes of β-SiC formed by in situ reaction are in range of 20-100nm, and most of the them locate in grain boundary and some particles embed in MoSi2 grain. The isothermal oxidation and thermal cycling test of nano-SiCp/MoSi2 composites were carried out in air at temperatures of 500°C. The pest phenomenon was not found during oxidation and cyclic oxidation at 500°C for 500 hours and 50 cycles, respectively. All the composites have both excellent oxidation resistant and good cyclic oxidation resistant. The mechanisms of oxidation at low temperature were discussed also.

Isothermal and Cyclic Oxidation Behavior of Turbine Blade Alloys

2006 ◽  
Author(s):  
N. S. Cheruvu ◽  
K. T. Chiang
Keyword(s):  
Turbine Blade ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Parabolic Rate Constant ◽  
Isothermal Oxidation ◽  
Isothermal Exposure ◽  
Temperature Oxidation ◽  
Rate Laws ◽  
Parabolic Rate ◽  
Kinetics Of

Oxidation behavior of two nickel-based turbine blade alloys has been investigated at three temperatures ranging from 950°C to 1066°C. Thermogravimetric analysis (TGA), isothermal exposure and cyclic oxidation tests were conducted on GTD-111 (Ni-14.1Cr-3.7W-9.2Co-1.5Mo-3.1A1-4.9Ti-0.02Cb-2.93Ta-0.11C) and IN-738 (Ni-16.0Cr-2.6W-8.1Co-1.6Mo-3.5A1-3.4Ti-0.7Cb-1.6Ta-0.10C) blade alloys. TGA results showed that the oxidation kinetics of both alloys obey parabolic rate laws. The GTD-111 material exhibited a higher parabolic rate constant than IN 738 at all temperatures investigated. Cyclic oxidation behavior of these alloys was compared by plotting the weight change results as a function of thermal cycles. Consistent with the TGA results, cyclic oxidation test results also showed that GTD-111 was less resistant to high-temperature oxidation as compared to the IN-738 alloy. To characterize the oxide scales, a series of short term isothermal oxidation tests were conducted and the spalled scale after oxidation exposure was collected and analyzed by energy-dispersive x-ray analysis (EDX) as a function of aging time. The composition of the scales varied between the alloys. The variation of oxidation behavior of these alloys is discussed with respect to the composition differences between the two alloys.

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