Properties of Sputtered NiCrAlY Used for Protective Gun Tube Coatings

2011 ◽  
Vol 686 ◽  
pp. 613-617
Author(s):  
Jian Zhang ◽  
Cean Guo ◽  
Gang Zhang ◽  
Chong Rui Wang ◽  
Shi Ming Hao
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Oxidation Process ◽  
Complex Oxide ◽  
Isothermal Oxidation ◽  
Temperature Oxidation ◽  
Steel Balls ◽  
Steel Substrates ◽  
Micro Indentation

NiCrAlY coatings were deposited on CrNi3MoVA steel substrates by means of magnetron sputtering. The coatings were characterized in terms of their microstructure, hardness, friction coefficient, high-temperature oxidation resistance. Micro-indentation and tribometer testers were employed to measure the mechanical properties of NiCrAlY coatings and CrNi3MoVA steel. The results showed that the hardness of the coatings ranged from 5.7 to 5.9 GPa, with a higher value than that of CrNi3MoVA steel(4.1-4.3 GPa). The coefficient of steady-state friction of the coatings against 45-carbon-steel balls ranged from 0.35 to 0.40, with a lower value than that of CrNi3MoVA steel(0.63-0.68). The isothermal oxidation behavior at 850°C of the coatings were studied in comparison with CrNi3MoVA steel substrates. The results indicated that NiCrAlY coatings substantially increase the high-temperature oxidation resistance of CrNi3MoVA steel and the oxidation process was retarded mainly by the presence of outer complex oxide scales and a continuous Al2O3 inner layer on the coating.

SiC/SiO2 Coating on Matrix Graphite Spheres of HTR Fuel Element Produced by a Two-Step Pack Cementation/High-Temperature Oxidation Process

2016 ◽  
Vol 852 ◽  
pp. 952-958 ◽  
Author(s):  
Ping Zhou ◽  
Zi Qiang Li ◽  
Hong Sheng Zhao ◽  
Kai Hong Zhang ◽  
Xiao Xue Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Oxidation Process ◽  
Reactor Core ◽  
Isothermal Oxidation ◽  
Pack Cementation ◽  
Temperature Oxidation ◽  
Matrix Graphite ◽  
Fuel Elements

Graphite is one of the most important material for the reactor core and fuel elements of high temperature gas-cooled reactor (HTR). Improving the oxidation resistance of graphite is very essential for the research of new fuel elements and the development of HTR. In this study, a gradient SiC layer of 500~700 μm was prepared on matrix graphite spheres by a two-step pack cementation, and the outer SiO2 layer prepared by the high-temperature oxidation process. The phases, microstructure, bonding strength and oxidation resistance of SiC/SiO2 coated matrix graphite spheres were investigated. The SiC/SiO2 coated matrix graphite spheres were carried on rapid thermal shocking tests from 1773 K to room temperature for 50 times without any cracks. The SiC/SiO2 coated matrix graphite spheres exhibits excellent anti-oxidation properties. No obvious weight loss was found after isothermal oxidation in air at 1273 K for 50 h and the weight gain was less than 1% at 1773 K in air for 50 h due to the oxidation of SiC layer.

Properties of Electrospark Deposited Cr Coatings on AISI H13 Steel

2012 ◽  
Vol 472-475 ◽  
pp. 288-292
Author(s):  
Cean Guo ◽  
Jian Zhang ◽  
Li Yang ◽  
Wei Zhou ◽  
Hong Hui Sun
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Wear Behavior ◽  
H13 Steel ◽  
Electrospark Deposition ◽  
Temperature Oxidation ◽  
Aisi H13 Steel ◽  
Aisi H13 ◽  
Steel Substrates

Cr coatings were deposited on AISI H13 steel substrates by means of electrospark deposition (ESD). The coatings were characterized in terms of their microstructure, hardness, friction and wear behavior and high-temperature oxidation resistance. Micro-indentation and tribometer testers were employed to measure the mechanical properties of Cr coatings and AISI H13 steel. The results showed that the hardness of the coatings ranged from 600 to 660 HV, with a higher value than that of AISI H13 steel (510 HV). The coefficient of steady-state friction of the coatings against 45-carbon-steel balls ranged from 0.23 to 0.27, with a lower value than that of AISI H13 steel (0.62-0.68). The isothermal oxidation behavior of the coatings at 850°Cwas studied in comparison with AISI H13 steel substrates. The results indicated that Cr coatings substantially increase the high-temperature oxidation resistance of AISI H13 steel and the oxidation process was retarded mainly by the presence of a Cr2O3 oxide scale on the coatings at 850°C for 100 hours.

Improvement in the Oxidation Resistance of β-SiAlON Ceramics Produced from Mechanically Milled Powders

2012 ◽  
Vol 18-19 ◽  
pp. 281-290
Author(s):  
Onur Eser ◽  
S. Kurama
Keyword(s):  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Oxidation Process ◽  
Isothermal Oxidation ◽  
High Energy ◽  
Particle Sizes ◽  
Temperature Oxidation ◽  
Dry Air ◽  
Milled Powders

In the present study the oxidation behavior of β-SiAlON ceramics, which were produced from conventional and high energy mechanical milled powders, was investigated. High energy mechanically milled powders have lower particle sizes ( 130 nm) than those of conventional powders (216 nm) and fully densified at lower temperatures with less amount of additives. The amount of additive is an important parameter to improve the high temperature oxidation resistance of SiAlON ceramics. The cyclic and isothermal oxidation tests were carried out at 1300 and 1400°C in dry air environment. The weight gain of oxidized samples was measured during the oxidation process. The alteration of oxide layer was analyzed by XRD and SEM. The results indicate that oxidation resistance of the samples produced from mechanically milled powders with less amount of additive is higher than that of conventional one. Therefore, β-SiAlON ceramics which were sintered at 100°C lower temperatures with less amount of additive (3.5 wt. % Y2O3), showed a better oxidation resistance.

Hot Corrosion Behavior of NiCoCrAlYSiHf Coating Deposited by Arc Ion Plating

2012 ◽  
Vol 472-475 ◽  
pp. 395-399
Author(s):  
Jia Hui Qu ◽  
Cean Guo ◽  
Jian Zhang
Keyword(s):  
High Temperature ◽  
Hot Corrosion ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Oxidation Process ◽  
Isothermal Oxidation ◽  
Temperature Oxidation ◽  
Arc Ion Plating ◽  
Ion Plating ◽  
Α Al2o3

Abstract: NiCoCrAlYSiHf coatings have been prepared by arc ion plating (AIP) on CrNi3MoVA steel ,which their microstructure and isothermal oxidation behavior at 950°C studied using SRD,SEM and EDAX. The results indicate that NiCoCrAlYSiHf coatings substantially increase the high-temperature oxidation resistance of CrNi3MoVA steel and the oxidation process was retarded mainly by the presence of α-Al2O3 oxide scale on the coating. Meanwhile, the major diffusion occured between the substrate element Fe and the coating element Co while Cr mainly distributed in the coating.

scholarly journals Effect of Vacuum Heat Treatment on the High-Temperature Oxidation Resistance of NiCrAlY Coating

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1089
Author(s):  
Jiahui Zheng ◽  
Deming Yang ◽  
Yang Gao
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Isothermal Oxidation ◽  
Vacuum Heat Treatment ◽  
Temperature Oxidation ◽  
Different Temperatures ◽  
Exposure Testing ◽  
Α Al2o3

NiCrAlY coatings were prepared using high-velocity oxygen fuel spraying (HVOF), and the coatings were removed from the substrate to achieve a uniform shape. Vacuum heat treatment (VHT) of the as-sprayed coatings was conducted at different temperatures (1000, 1100, and 1200 °C), and the specimens were subjected to isothermal oxidation exposure testing in air at 1100 °C for up to 21 h. The results show that the high temperature oxidation resistance of the coating increased gradually with the increase in VHT temperature, and the coating of VHT1200 had higher oxidation resistance. The high temperature oxidation resistance of the coating was related to the microstructure transformation of the coating. In VHT coatings, β-NiAl became a dispersed irregular block morphology. The γ’-Ni3Al in VHT1000 presented a granular morphology. However, in VHT1100 and VHT1200, γ’-Ni3Al became a lamellar morphology. This transformation of microstructure promotes the form of exclusive α-Al2O3 scale. With the increase in VHT temperature, the content of yttrium on coatings’ surface was increased and the pores were gradually eliminated. The concentration of yttrium on coatings’ surface prevented the formation of θ-Al2O3 and low porosity was beneficial in improving the internal oxidation of the coating.

scholarly journals Effect of CeO2 on High-Temperature Oxidation Performance of Electron Beam Cladding NiCoCrAlY Coating on Ni-Based Alloy

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Hailang Liu ◽  
Yiping Huang ◽  
Xiaoyu Wang ◽  
Ruxue Lu
Keyword(s):  
Electron Beam ◽  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Rare Earth Oxide ◽  
Isothermal Oxidation ◽  
Temperature Oxidation ◽  
Improvement Effect ◽  
Oxidation Performance ◽  
Inconel 617

In order to enhance the high-temperature oxidation resistance properties of Inconel 617 alloy, NiCoCrAlY and NiCoCrAlY CeO2 composite powder coatings metallurgically bonded to substrate were prepared on the surface of Inconel 617 alloy by electron beam cladding. The effect of rare earth oxide CeO2 on the oxidation resistance of NiCoCrAlY coating was investigated. The isothermal oxidation behavior of the substrate and NiCoCrAlY cladding layer with different CeO2 contents (1%, 2%, 3%, and 4%) and without CeO2 oxidized at 1050°C for 20 h, 40 h, 60 h, and 100 h was analyzed. The microstructure and phase composition of the coating after electron beam treatment were tested. The results show that the self-repair of Al2O3 and Cr2O3 oxide film can be improved under a high-temperature oxidation environment with the addition of CeO2, and the oxidation resistance of NiCoCrAlY coating can be effectively strengthened by adding CeO2. The improvement effect is most obvious when the content of CeO2 is 2%.

scholarly journals High Temperature Oxidation Resistance Performance of TiC/Mo Composite by Spark Plasma Sintering

2021 ◽  
Author(s):  
Renheng HAN ◽  
Ziming BAO ◽  
Yanqin ZHU ◽  
Ning LI ◽  
Ming TANG ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxide Film ◽  
Oxidation Resistance ◽  
Spark Plasma Sintering ◽  
High Temperature Oxidation ◽  
Oxidation Process ◽  
Temperature Oxidation ◽  
Plasma Sintering ◽  
The Matrix ◽  
Spark Plasma

In this paper, the Titanium carbide/Molybdenum (TiC/Mo) alloy was prepared by spark plasma sintering (SPS). The oxidation process of the TiC/Mo alloy at different oxidation temperatures was studied, and the oxidation mechanism was discussed in depth. The focus is on the influence of the introduction of TiC particles on the high-temperature oxidation properties of Mo alloys. The phase composition and morphology of the oxide film were analyzed by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The results showed that, after oxidation, the surface oxide film is mainly composed of Titanium dioxide (TiO2), Molybdenum dioxide (MoO2), Molybdenum trioxide (MoO3) and Molybdenum oxide hydrate (MoO3(H2O)2) phases. As the oxidation temperature increases, the surface of the oxide film will warp, and thereby increase porosity. The dense MoO2 will form a protective inner oxide layer and inhibit further progress of the TiC/Mo alloy. Oxygen will undergo violent oxidation through the pores and the inside of the matrix, and the protective MoO2 internal oxide film will disappear. TiC particles dispersed in the matrix will be oxidized to form TiO2, which will be gradually deposited on the surface of the oxide film, hindering the diffusion of oxygen to the matrix. The quantity loss during the entire oxidation process is significantly reduced. Therefore, the introduction of TiC can greatly improve the oxidation resistance of Mo alloys.

scholarly journals Isothermal Oxidation Behavior of Zr-Y Coating on γ-TiAl by Double Glow Plasma Surface Metal Alloying Technique

Coatings ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 361 ◽  
Author(s):  
Feng Ding ◽  
Pingze Zhang ◽  
Dongbo Wei ◽  
Xiaohu Chen ◽  
Shiyuan Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Oxidation Kinetic ◽  
Isothermal Oxidation ◽  
Temperature Oxidation ◽  
Plasma Surface ◽  
Surface Metal ◽  
Glow Plasma ◽  
Plasma Surface Alloying Technique

Oxidation resistance of Zr-Y coating on γ-TiAl alloy prepared by a double-glow plasma surface alloying technique was investigated in static air at 750 °C, 800 °C and 850 °C for 100 h. A pure Zr coating was also prepared for comparison. Addition of Y improved high-temperature oxidation resistance of the alloying coating because of its refining effect and inhibition of cationic diffusion. Oxidation kinetic curves indicated that the high-temperature oxidation resistance of the Zr-Y coating was about eight times higher than that of the bare substrate and about 3 times higher than that of pure Zr coating.

Effect of 10 at.% Nb Addition on Sintering and High Temperature Oxidation of W0.5Cr0.5 Alloy

2012 ◽  
Vol 710 ◽  
pp. 308-313 ◽  
Author(s):  
Suresh Telu ◽  
Vaduganathan Karthik ◽  
Rahul Mitra ◽  
Shyamal Kumar Pabi
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Isothermal Oxidation ◽  
High Energy ◽  
Temperature Oxidation ◽  
Sinter Densification ◽  
High Temperature Oxidation Behavior ◽  
Nb Addition

The effect of 10 at.% Nb on the sintering and high temperature oxidation behavior of W0.5Cr0.5alloy was investigated. Elemental powder blends were made nanostructured by high energy mechanical milling, compacted and finally sintered under reduced atmosphere at 1790°C. The sintered samples were subjected to cyclic isothermal oxidation tests at 800°C to 1200°C in air. The experimental results shows superior sinterability and oxidation protection of W0.5Cr0.5alloy compared to pure W. Characterization of the oxide scales shows porous external W-rich oxide (WO3) formation which is not ideally suitable for oxidation resistance. On the other hand, W-Cr alloy with 10 at.% Nb shows the remarkable sinter densification (~98%) and oxidation resistance up to 1200°C. The oxide scale of the ternary alloy shows formation of stable Cr2O3, Nb2O5oxides and/or complex Cr-Nb oxide (CrNbO4), and there was no evidence of WO3formation in this case.

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