Characterization and Oxidation Behavior of Iron-Based Coatings Prepared by Supersonic Arc Spraying at 800°C

2014 ◽  
Vol 697 ◽  
pp. 90-94 ◽  
Author(s):  
Tian Quan Liang ◽  
Xian Fang Yang ◽  
Yi Li Wang ◽  
Cui Hua Zhao

The characterization in microstructure, morphology and oxidation behavior of three iron-based coatings by Supersonic Arc Spraying (HVAS), were investigated by XRD, FESEM, EDS and thermal exposure in furnace in this paper. It is indicated that the three coatings are typical layer and compact structure. The coatings are composed of Fe (s.s) phase and kinds of ferric oxides, chrome carbides and/ or intermetallic phase distributing along the interface of lamellar layers. More Cr and Ti, Al elements can alternate the diameter and morphologies of the holes, resulting from the formation of oxides, carbides and intermetallic phase. The results indicate that SXTiAlC coating shows the most excellent oxidation resistance with 2.70 mg·cm-2 in mass gain, while that are 88.08 mg·cm-2 and 16.64 mg·cm-2 after 100 h thermal exposure at 800°C for LX88A and SXHCrA coatings, respectively. The oxidation behavior is discussed.

2014 ◽  
Vol 670-671 ◽  
pp. 554-559
Author(s):  
Sheng Shou Li ◽  
Tian Quan Liang ◽  
Xian Fang Yang ◽  
Cui Hua Zhao

The characteristics in microstructure, surface morphology, chemical composition, hardness and wear resistance of the three protective iron-based compound coatings prepared by Supersonic Arc Spraying (HVAS), were investigated by X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Energy disperse spectroscopy (EDS) and Rockwell apparatus in this paper. It is indicated that the three coatings are typical layer and compact structures. The coatings are composed of Fe (s.s) phase and various kinds of ferric oxides, chrome carbides and/or intermetallic phase distributing along the interface of lamellar layers. More Cr and Ti, Al elements in the cored wires can degrease the diameter and alternate the morphologies of the holes in the coating, resulting from the formation of oxides, carbides and intermetallic phase during depositing the coating. The results indicate the SXTiAlC coating shows the most excellent wear performance among the three coatings. The wear behavior and mechanism are discussed.


2004 ◽  
Vol 842 ◽  
Author(s):  
Akira Yamauchi ◽  
Kyousuke Yoshimi ◽  
Shuji Hanada

ABSTRACTIsothermal oxidation behavior of Mo/Mo5SiB2in-situ composites containing small amounts of Al was investigated under an Ar-20%O2 atmosphere in the temperature range of 1073–1673 K. The Mo/Mo5SiB2in-situ composites, (Mo-8.7mol%Si-17.4mol%B)100-xAlx (x=0, 1, 3, and 5mol%), were prepared by Ar arc-melting, and then homogenized at 2073 K for 24 h in an Ar-flow atmosphere. Without addition of Al, Mo/Mo5SiB2in-situ composite exhibits a rapid mass loss at the initial oxidation stage, followed by passive oxidation after the substrate is sealed with borosilicate glass in the temperature range of 1173–1473 K, whereas it exhibits a rapid mass gain around 1073 K. On the other hand, small Al additions, especially of 1 mol%, significantly improve the oxidation resistance of Mo/Mo5SiB2in-situ composites at temperatures from 1073–1573 K. The excellent oxidation resistance is considered to be due to the rapid formation of a continuous, dense scale of Al-Si-O complex oxides. The protective oxide scales contain crystalline oxides, and the amounts of the crystalline oxides obviously increase with Al concentration.


2016 ◽  
Vol 23 (05) ◽  
pp. 1650031
Author(s):  
JINGJIE DAI ◽  
HUIJUN YU ◽  
JIYUN ZHU ◽  
FEI WENG ◽  
CHUANZHONG CHEN

Ti–Al alloyed coating reinforced by nitrides was fabricated by laser surface alloying technique to improve mechanical properties and high temperature oxidation resistance of Ti–6Al–4V titanium alloy. Microstructures, mechanical properties and high temperature oxidation behavior of the alloyed coating were analyzed. The results show that the alloyed coating consisted of Ti3Al, TiAl2, TiN and Ti2AlN phases. Nitrides with different morphologies were dispersed in the alloyed coating. The maximum microhardness of the alloyed coating was 906[Formula: see text]HV. The friction coefficients of the alloyed coating at room temperature and high temperature were both one-fourth of the substrate. Mass gain of the alloyed coating oxidized at 800[Formula: see text]C for 1000[Formula: see text]h in static air was [Formula: see text][Formula: see text]mg/mm2, which was 1/35th of the substrate. No obvious spallation was observed for the alloyed coating after oxidation. The alloyed coating exhibited excellent mechanical properties and long-term high temperature oxidation resistance, which improved surface properties of Ti–6Al–4V titanium alloy significantly.


2013 ◽  
Vol 32 (4) ◽  
pp. 397-403
Author(s):  
Qun Liu ◽  
Guangyan Fu ◽  
Yong Su ◽  
Zhigang Zhang ◽  
Qi Xiong

AbstractThe effect of rare-earth element Y on high-temperature oxidation behavior of Cu-Si alloys at 973 and 1073 K in 0.1 MPa flowing pure O2 has been investigated. Results show at the two temperatures the mass gain of the alloys with different compositions follows the following sequence, Cu-3Si-1.0Y > Cu-3Si-0Y > Cu-3Si-0.5Y alloy. As the Y content increases, the grain size of the alloys decreases, which accelerates the diffusion rate of the alloying elements in the alloys and oxygen under the experimental conditions, increases the ratio of short-path diffusion, and promotes the formation of SiO2 and Y2O3. The three alloys do not form continuous oxide scales of SiO2 or Y2O3, but their rapid formation and dispersed distribution due to the grain-size reduction may also hinder the diffusion of alloying elements and oxygen, which is beneficial to improve the oxidation resistance of the Y-containing alloys. Thereby, the Cu-3Si-0.5Y alloy has good oxidation resistance. The Cu-3Si-1.0Y alloy exhibits largest mass gain among the three alloys, which is due to the fact that in the alloy with higher Y contend and finer grain size, more amount of Y2O3 is more quickly formed, whose mass occupy a more proportion in the whole mass gain of the alloy.


2020 ◽  
Vol 71 (5) ◽  
pp. 106-116
Author(s):  
Alexandra Banu ◽  
Alexandru Paraschiv ◽  
Simona Petrescu ◽  
Irina Atkinson ◽  
Elena Maria Anghel ◽  
...  

The novel Al2O3 / NiCrAlY /alfa2-Ti3Al system obtained by APS technique was tested against long (500h) isothermal oxidation at 850�C in air for prospective use in aerospace applications. EDX-SEM, X-ray diffraction (XRD) and Raman investigations were conducted to substantiate structural, textural and mass gain modifications underwent by the Al2O3 / NiCrAlY /alfa2-Ti3Al system in comparison with bare alfa2-Ti3Al and NiCrAlY /alfa2-Ti3Al system. Improved oxidation resistance of the double-coated system is based on moderate oxygen and thermal barrier role played by the mixture of delta - and alfa-Al2O3 present in the top ceramic coat.


Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 97 ◽  
Author(s):  
Hang Duan ◽  
Yan Liu ◽  
Tiesong Lin ◽  
Hui Zhang ◽  
Zhengren Huang

Ni-(3~10) Ta and Ni-(3~10) Y alloys were fabricated by vacuum arc melting. The oxidation resistance of the alloys was studied by cyclic and isothermal oxidation tests at 800 °C in static air. The present work focused on the investigation of the effects of the alloying elements (Ta and Y) on the oxidation behavior of Ni-based alloys. The oxidation behavior of alloys was evaluated by mass gain, composition, as well as the microstructure of oxidized products. The experimental results indicated that Ta at a low content (3 wt %) had a positive role in enhancing oxidation resistance by decreasing the oxygen vacancy concentration of the oxide layer to prevent the inward diffusion of oxygen during oxidation, and the mass gain decreased from 2.9 mg·cm−2 to 1.7 mg·cm−2 (800 °C/200 h), while Y (3~10 wt %) degraded the oxidation resistance. However, it is worth mentioning that the pinning effect of Y2O3 increased the adhesion between the substrate and oxide layer by changing the growing patterns of the oxide layer from a plane growth to fibrous growth. Among the results, the bonding of the substrate and oxide layer was best in the Ni-3Y alloys.


2018 ◽  
Vol 347 ◽  
pp. 99-112 ◽  
Author(s):  
Yujie Li ◽  
Tianquan Liang ◽  
Run Ao ◽  
Hang Zhao ◽  
Xiyong Chen ◽  
...  

Author(s):  
Huilin Lun ◽  
Yi Zeng ◽  
Xiang Xiong ◽  
Ziming Ye ◽  
Zhongwei Zhang ◽  
...  

AbstractMulti-component solid solutions with non-stoichiometric compositions are characteristics of ultra-high temperature carbides as promising materials for hypersonic vehicles. However, for group IV transition-metal carbides, the oxidation behavior of multi-component non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution has not been clarified yet. The present work fabricated four kinds of (Zr,Hf,Ti)Cx carbide solid solution powders by free-pressureless spark plasma sintering to investigate the oxidation behavior of (Zr,Hf,Ti)Cx in air. The effects of metallic atom composition on oxidation resistance were examined. The results indicate that the oxidation kinetics of (Zr,Hf,Ti)Cx are composition dependent. A high Hf content in (Zr,Hf,Ti)Cx was beneficial to form an amorphous Zr-Hf-Ti-C-O oxycarbide layer as an oxygen barrier to enhance the initial oxidation resistance. Meanwhile, an equiatomic ratio of metallic atoms reduced the growth rate of (Zr,Hf,Ti)O2 oxide, increasing its phase stability at high temperatures, which improved the oxidation activation energy of (Zr, Hf, Ti)Cx.


2010 ◽  
Vol 152-153 ◽  
pp. 940-944
Author(s):  
Hua Chen ◽  
Jing Chao Zhang ◽  
X.Y Lu

The spark plasma sintering (SPS) microstructure and high temperature oxidation behavior of TiH2-45Al-0.2Si-5Nb(at.%) alloy were investigated.Emphasis was placed on the effect of SPS microstructures, obtained by blend powder and mechanical alloying powder. The mass gain due to oxidation was measured using an electro balance. The oxide layers as well as its micro-structure were examined by SEM and EDS, and XRD. The results show that sintered microstructure of blend powder is composed of fully lamellar TiAl/ Ti3Al phase, and that of the mechanical alloying powder is composed of finer granular TiAl/Ti3Al phase. The latter oxidation rate is lower, and forms continuous mixed oxide layer of Al2O3 and TiO2. Both SPS microstructure of blend powder and mechanical alloying powder are superior in oxidation behavior to ordinary vacuum sintering.


Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1144
Author(s):  
Laihao Yu ◽  
Yingyi Zhang ◽  
Tao Fu ◽  
Jie Wang ◽  
Kunkun Cui ◽  
...  

Traditional refractory materials such as nickel-based superalloys have been gradually unable to meet the performance requirements of advanced materials. The Mo-Si-based alloy, as a new type of high temperature structural material, has entered the vision of researchers due to its charming high temperature performance characteristics. However, its easy oxidation and even “pesting oxidation” at medium temperatures limit its further applications. In order to solve this problem, researchers have conducted large numbers of experiments and made breakthrough achievements. Based on these research results, the effects of rare earth elements like La, Hf, Ce and Y on the microstructure and oxidation behavior of Mo-Si-based alloys were systematically reviewed in the current work. Meanwhile, this paper also provided an analysis about the strengthening mechanism of rare earth elements on the oxidation behavior for Mo-Si-based alloys after discussing the oxidation process. It is shown that adding rare earth elements, on the one hand, can optimize the microstructure of the alloy, thus promoting the rapid formation of protective SiO2 scale. On the other hand, it can act as a diffusion barrier by producing stable rare earth oxides or additional protective films, which significantly enhances the oxidation resistance of the alloy. Furthermore, the research focus about the oxidation protection of Mo-Si-based alloys in the future was prospected to expand the application field.


Sign in / Sign up

Export Citation Format

Share Document