scholarly journals Microstructure and selected properties of Ni-Cr-Re coatings deposited by means of plasma thermal spraying

2020 ◽  
Vol 92 (5) ◽  
pp. 15-23
Author(s):  
Konrad Tobota ◽  
Marcin Chmielewski ◽  
Ján Dusza
Keyword(s):  
Thermal Spraying ◽  
High Energy ◽  
Optical Microscope ◽  
Temperature Oxidation ◽  
Hardness Tests ◽  
Molybdenum Steel ◽  
Milling Method ◽  
Energy Ball ◽  
Metallic Rhenium ◽  
Plasma Sprayed

The article presents the results of research on plasma sprayed Ni-Cr-Re coatings. The substrate was 16Mo3 chromium-molybdenum steel used in the production of boilers. The coatings were sprayed with Oerlikon Amdry 4535 80% Ni, 20% Cr powder with 20-45µm granulation. 1% metallic rhenium was added to the base powder using a high energy ball milling method. Rhenium is a heavy, high-density metal. As an alloying addition, it improves the heat resistance of alloys, creep resistance and high temperature oxidation. Rhenium alloys are widely used in the energy and aviation industries as an alloying additive to prevent creep. Observations were made on an optical microscope and a SEM microscope. Hardness tests and optical surface testing with a profilometer were carried out.

scholarly journals Microstructure and selected properties of Ni-Cr-Re coatings deposited by means of HVOF thermal spraying

2019 ◽  
Vol 91 (1) ◽  
Author(s):  
Konrad Tobota ◽  
Tomasz Chmielewski ◽  
Marcin Chmielewski
Keyword(s):  
Ball Mill ◽  
High Temperature Oxidation ◽  
Aerospace Industry ◽  
Thermal Spraying ◽  
High Energy ◽  
Boiler Steel ◽  
Temperature Oxidation ◽  
Hvof Thermal Spraying ◽  
Milling Method ◽  
Metallic Rhenium

The article presents selected results of testing Ni-Cr-Re coatings deposited by means of HVOF supersonic spray. The substrate made of 16Mo3 chromium molybdenum boiler steel was sprayed with a powder material of Oerlikon Amdry 4535 80% Ni, 20% Cr, 20÷45 μm, to which 1% of metallic rhenium was added using the high energy milling method in a ball mill. The Rhenium is an alloying additive that improves the heat resistance of alloys, creep and high temperature oxidation resistance. Alloys with the addition of rhenium are widely used in the aerospace industry (nickel superalloys) and in power industry. Metallographic microscopic examinations, microhardness tests and surface profilometry were carried out.

Plasma Spheroidized Alumina/Zircon Mixtures

2000 ◽  
Author(s):  
Y. Li ◽  
K.A. Khor
Keyword(s):  
Thermal Spraying ◽  
Processing Parameters ◽  
High Energy ◽  
Molten State ◽  
Composite Powders ◽  
Spray Process ◽  
Plasma Spheroidization ◽  
Plasma Spray Process ◽  
Energy Ball ◽  
Spheroidized Powder

Abstract The plasma-spray process is specified by the associated processing parameters, where these influence the properties of the resultant deposits. This article describes the preparation and processing of composite powders for use in thermal spraying by mixing high purity zircon and alumina powders. The spheroidized powder were obtained by high energy ball milling and rapid solidification from the molten state during plasma spraying. The article discusses the processes involved in spray drying and plasma spheroidization, describing thermal analysis and mullitization kinetics in the spheroidized alumina/zircon mixtures.

scholarly journals Development of Evaluation Method for Damage of Oxidation CoNiCrAlY Coating

2019 ◽  
Vol 804 ◽  
pp. 47-51
Author(s):  
Mo Chen ◽  
Kodai Yoshikawa ◽  
Zhen Qiang Song ◽  
Shijie Zhu
Keyword(s):  
Cross Sections ◽  
Gas Turbines ◽  
Evaluation Method ◽  
Thermal Spraying ◽  
Optical Microscope ◽  
Thermally Grown Oxide ◽  
Interfacial Damage ◽  
Barrier Coating ◽  
Plasma Sprayed ◽  
Conicraly Coating

The bond coat plays an important role in the failure of the thermal barrier coating (TBC) system used for gas turbines [1,2]. In this research, the CoNiCrAlY coated Ni-base superalloy specimens were used for developing evaluation method for interfacial damage in the coat. Samples were exposed at 1000°C and 1100°C for up to 1000 hours. The morphology and residual stress in the thermally grown oxide (TGO) layer on the CoNiCrAlY coating were characterized by microscopic observation and luminescence spectroscope, respectively. The microstructure and damage o\n both the coating surfaces and the cross sections were observed by optical microscope and scanning electron microscope. According to the results, the low pressure plasma sprayed CoNiCrAlY coating (LPPS) showed the thinnest TGO layer and lowest residual stress.Residual stress decreased with an increase in exposure time, depending on the morphology of TGO layer. The effects of thermal spraying methods on the oxidation of yttrium in TGO layer and BC layer and its influence on interfacial damage were discussed.

Effect of High-Energy Ball Milling on Microstructure and Microwave Absorbing Properties of NdFe Material

2011 ◽  
Vol 311-313 ◽  
pp. 1281-1285 ◽  
Author(s):  
Pei Hao Lin ◽  
Lei Wang ◽  
Shun Kang Pan ◽  
Hua Mei Wan
Keyword(s):  
Ball Milling ◽  
Particle Morphology ◽  
High Energy ◽  
High Energy Ball Milling ◽  
X Ray ◽  
Microwave Absorbing Properties ◽  
Absorbing Materials ◽  
Milling Method ◽  
Energy Ball ◽  
Microwave Absorbing

The NdFe magnetic absorbing materials were prepared by rapid solidification and high-energy ball milling method. The effect of high-energy ball milling on particle morphology, organizational structure and microwave absorbing properties of NdFe magnetic absorbing materials were analyzed with the aid of X-ray diffractometer, scanning electron microscope and vector network analysis. The results show that the Nd2Fe17 and α-Fe phase are refined, the particles become smaller and thinner; the span-ratio of the particles increases along with time during the process of high-energy ball milling; and meanwhile, the frequency of absorbing peak reduces. The absorbing bandwidth broadens as the increase of the time of ball milling, except that of 48h.The minimum reflectance of the powder decreases from -22dB to - 44dB under the circumstances that the time of high energy ball milling reaches 48h and the thickness of the microwave absorbing coating is 1.5mm. But it rebounds to about - 6dB when the time of ball milling reaches 72h.

Technological Aspects of Fe-Al-Si Intermetallic Alloy Preparation by Mechanical Alloying

2019 ◽  
Vol 810 ◽  
pp. 101-106 ◽  
Author(s):  
Petr Haušild ◽  
Jaroslav Čech ◽  
Veronika Kadlecová ◽  
Miroslav Karlík ◽  
Filip Průša ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Ball Mill ◽  
High Energy ◽  
Intermetallic Alloy ◽  
Alloyed Powder ◽  
Temperature Oxidation ◽  
High Energy Ball Mill ◽  
Speed Up ◽  
Energy Ball ◽  
Kinetics Of

In this paper, recently developed ternary FeAl20Si20 (wt.%) alloy with promising high-temperature oxidation and wear resistance was prepared by mechanical alloying in a high-energy ball mill. The possibility to speed-up the mechanical alloying process by replacing aluminium (and partly silicon) elemental powder by the pre-alloyed powder (AlSi30) with relatively fine dispersion of Si in the Al-Si eutectic was examined. The microstructure, phase composition and mechanical properties after various time of mechanical alloying were characterized. The effect of using the pre-alloyed powders on kinetics of mechanical alloying is compared with the results obtained on batches prepared from elemental powders.

Hydrogen storage in a chemical bond stabilized Co9S8–graphene layered structure

Nanoscale ◽  
2015 ◽  
Vol 7 (47) ◽  
pp. 20180-20187 ◽  
Author(s):  
Wei Qin ◽  
Lu Han ◽  
Hai Bi ◽  
Jiahuang Jian ◽  
Xiaohong Wu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Hydrogen Storage ◽  
Reduced Graphene Oxide ◽  
Layered Structure ◽  
Storage Capacity ◽  
High Energy ◽  
Hydrogen Storage Capacity ◽  
Reduced Graphene ◽  
Milling Method ◽  
Energy Ball

With the high energy ball milling method, a Co9S8-decorated reduced graphene oxide (RGO) composite, which shows excellent hydrogen storage capacity, has been successfully fabricated with a well-organized layered structure.

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