Effect of Annealing Treatment on the Structure and Microhardness of Cold-Sprayed Nanostructured FeAl/WC Composite Coating

2008 ◽  
Vol 373-374 ◽  
pp. 73-76 ◽  
Author(s):  
Hong Tao Wang ◽  
Guan Jun Yang ◽  
Chang Jiu Li ◽  
Cheng Xing Li
Keyword(s):  
Solid Solution ◽  
Annealing Time ◽  
Composite Coatings ◽  
Annealing Treatment ◽  
Nanocrystalline Structure ◽  
Intermetallic Phases ◽  
Coating Structure ◽  
Intermetallic Composite ◽  
Sprayed Coating ◽  
Sprayed Coatings

Nanostructured FeAl/WC intermetallic composite coatings were prepared by cold spaying of the ball-milled powders. The effect of annealing on the coating structure and microhardness was examined. It was found that the nanocrystalline structure of the milled feedstock was retained in the cold sprayed coatings. The FeAl intermetallic phases were formed from the milled Fe(Al) solid solution during the post-spraying annealing at 550oC. The microhardness of the as-sprayed coating was about 680HV0.1 and it decreased a little with increasing the annealing time at 550oC.

scholarly journals Structure and Selected Properties of Arc Sprayed Coatings Containing In-Situ Fabricated Fe-Al Intermetallic Phases

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1059 ◽  
Author(s):  
Tomasz Chmielewski ◽  
Piotr Siwek ◽  
Marcin Chmielewski ◽  
Anna Piątkowska ◽  
Agnieszka Grabias ◽  
...  
Keyword(s):  
Protective Coatings ◽  
Composite Coatings ◽  
Thermal Spraying ◽  
Intermetallic Phases ◽  
Arc Spraying ◽  
Coating Materials ◽  
Two Phases ◽  
Sprayed Coatings ◽  
Spraying Process

The paper presents the results of research on the production by means of arc spraying of composite coatings from the Fe-Al system with participation of in-situ intermetallic phases. The arc spraying process was carried out by simultaneously melting two different electrode wires, aluminum and steel. The aim of the research is to create protective coatings with a composite structure with a significant participation of FexAly as an intermetallic phases reinforcement. The synthesis of intermetallic phases takes place during the (in-situ) spraying process. Currently most coatings involving intermetallic phases are manufactured by different thermal spraying methods using coating materials in the form of prefabricated powders containing intermetallic phases. The obtained results showed the local occurrence of intermetallic phases from the Fe-Al system, and the dominant components of the structure have two phases, aluminum solid solutions in iron and iron in aluminum. The participation of intermetallic phases in the coating is relatively low, but its effect on the properties of the coating material is significant.

Effect of Solution Annealing Time on the Microstructure and Corrosion Resistance of Duplex Stainless Steel

2018 ◽  
Vol 930 ◽  
pp. 374-379 ◽  
Author(s):  
Stephania Capellari de Rezende ◽  
Maria Eurenice Rocha Cronemberger ◽  
Rodrigo Silva ◽  
Carlos A. Della Rovere ◽  
Sebastião Elias Kuri ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Annealing Time ◽  
Annealing Treatment ◽  
Intermetallic Phases ◽  
Air Cooling ◽  
Thermal Treatments ◽  
Solution Annealing ◽  
Electrochemical Tests ◽  
Cyclic Potentiodynamic Polarization ◽  
Saf 2205

The formation of intermetallic phases during thermal treatments is a decisive point for the performance of duplex stainless steels, which may prevent the obtaining or provoke degradation of their properties. This paper presents an investigation on the corrosion resistance of duplex SAF 2205 steel as received and after solution annealing treatment. The objective was to evaluate the correlation between the solution annealing time, the resulting microstructural changes and the corrosion resistance of the steel through electrochemical tests of cyclic potentiodynamic polarization and double-cycle potentiokinetic reactivation (DL-EPR). The heat treatments were performed at 1100° C for 30, 120 and 240 min with subsequent air cooling. The results of the DL-EPR showed that although there was no presence of intermetallic phases even with the absence of intermetallic phases, the solution annealing time influenced the degree of chromium depletion of the samples, so that with the increase of time, there was an increase in the degree of chrome depletion.

scholarly journals Microstructure and Microhardness of Ni/Al-TiB2 Composite Coatings Prepared by Cold Spraying Combined with Postannealing Treatment

Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 565 ◽  
Author(s):  
Xiao Chen ◽  
Chengdi Li ◽  
Shunjian Xu ◽  
Yao Hu ◽  
Gangchang Ji ◽  
...  
Keyword(s):  
Intermetallic Compounds ◽  
Composite Coatings ◽  
Cold Spraying ◽  
Tib2 Particle ◽  
Gas Temperature ◽  
Composite Powders ◽  
Average Porosity ◽  
Sprayed Coating ◽  
Tib2 Particles ◽  
Sprayed Coatings

Ni/Al-TiB2 composite powders were deposited on the surface of 316L stainless-steel substrates by cold spraying at gas temperatures of 250 and 450 °C, respectively. Then, the as-sprayed coatings were annealed at 650 °C for 10, 20, and 30 h. The experimental results showed that the average porosity of as-sprayed coating dropped from about 0.68% to 0.054% as the cold spraying gas temperature increased. The contents of Ni, Al, and TiB2 in the as-sprayed coatings were different from that of the Ni/Al-TiB2 composite powders. The main phase compositions of the as-sprayed Ni/Al-TiB2 coatings were the same as those of composite powder, consisting only of pure Ni, Al, and TiB2 phases. TiB2 as a reinforced particle in the as-sprayed coating could obviously increase the microhardness of the coatings. NiAl3 and Ni2Al3 intermetallic compounds were synthesized in situ in all of the annealed coatings, and the average contents of NiAl3 and Ni2Al3 intermetallic compounds increased as the cold spraying gas temperature increased. The distribution of TiB2 particle was changed as the annealing times increased, which changed from more comparative uniform distribution to accumulation. The average porosity of the annealed coatings increased as the annealing time increased. The microhardness of Ni/Al-TiB2 coatings annealed at 650 °C for 10 h was increased remarkably due to the reinforcement role of TiB2 particles and NiAl3 and Ni2Al3 intermetallic compounds.

scholarly journals Refractory Metal (Nb) Intermetallic Composites, High Entropy Alloys, Complex Concentrated Alloys and the Alloy Design Methodology NICE—Mise-en-scène † Patterns of Thought and Progress

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 989
Author(s):  
Panos Tsakiropoulos
Keyword(s):  
Solid Solution ◽  
Refractory Metal ◽  
Design Methodology ◽  
Alloy Design ◽  
High Entropy Alloys ◽  
Laves Phases ◽  
High Entropy ◽  
High Temperature Materials ◽  
Mise En Scene ◽  
Intermetallic Composite

The paper reflects on the usefulness of the alloy design methodology NICE (Niobium Intermetallic Composite Elaboration) for the development of new Nb-containing metallic ultra-high-temperature materials (UHTMs), namely refractory metal (Nb) intermetallic composites (RM(Nb)ICs), refractory high entropy alloys (RHEAs) and refractory complex concentrated alloys (RCCAs), in which the same phases can be present, specifically bcc solid solution(s), M5Si3 silicide(s) and Laves phases. The reasons why a new alloy design methodology was sought and the foundations on which NICE was built are discussed. It is shown that the alloying behavior of RM(Nb)ICs, RHEAs and RCCAs can be described by the same parameters. The practicality of parameter maps inspired by NICE for describing/understanding the alloying behavior and properties of alloys and their phases is demonstrated. It is described how NICE helps the alloy developer to understand better the alloys s/he develops and what s/he can do and predict (calculate) with NICE. The paper expands on RM(Nb)ICs, RHEAs and RCCAs with B, Ge or Sn, the addition of which and the presence of A15 compounds is recommended in RHEAs and RCCAs to achieve a balance of properties.

Sliding Wear Behavior of Remelted Al2O3-TiO2 Plasma Sprayed Coatings on Titanium

2016 ◽  
Vol 254 ◽  
pp. 231-236 ◽  
Author(s):  
Ion Dragoş Uţu ◽  
Gabriela Marginean ◽  
Iosif Hulka ◽  
Viorel Aurel Şerban
Keyword(s):  
Sliding Wear ◽  
Wear Behavior ◽  
Pure Titanium ◽  
Titanium Substrate ◽  
Atmospheric Plasma ◽  
Wear Properties ◽  
Before And After ◽  
Sprayed Coating ◽  
Pin On Disk ◽  
Sprayed Coatings

Microstructure and wear properties of the Al2O3-13.wt% TiO2 thermally sprayed coatings before and after remelting were investigated in this study. The coatings were deposited on a pure titanium substrate using the atmospheric plasma spraying (APS) process. The as-sprayed coatings were electron beam (EB) modified in order to improve their compactness and bonding strength.The effect of EB remelting on the microstructure, phase constituents and wear properties was investigated using scanning electron microscopy (SEM), X-Ray diffraction technique and hardness measurements. The sliding wear behavior was tested using a pin on disk method.The results showed that the remelting process had a positive effect removing the lamellar defect of the as-sprayed coating and improving the compactness, hardness and wear behavior.

Fabrication of Porous Al2O3 Ceramics by Freeze Drying Technique and Annealing Treatment

2016 ◽  
Vol 848 ◽  
pp. 272-278 ◽  
Author(s):  
Sha Qiu ◽  
Yu Fei Tang ◽  
Kang Zhao
Keyword(s):  
Compressive Strength ◽  
Pore Structure ◽  
Pore Size ◽  
Annealing Time ◽  
Open Porosity ◽  
Sucrose Solution ◽  
Annealing Treatment ◽  
Porous Ceramics ◽  
Crystalline Solid ◽  
Directional Freezing

Porous Al2O3 ceramics were fabricated by directional freezing and low pressure drying with sucrose solution as the cryogenic medium. The pore structure of the porous ceramics was changed by annealing in the environment of higher than the glass transition temperature of sucrose solution after directional freezing because of changing the size and distribution of crystalline solid. The effects of the annealing time on the pore structure, open porosity and mechanical property of porous ceramics were investigated. The results showed that the pore size of porous ceramics increased substantially with the increase of annealing time. The open porosity of porous ceramics changed slightly with the increase of annealing time, while the compressive strength of porous ceramics showed a trend of decrease. The pore size range of porous Al2O3 ceramics fabricated is from 6.0μm to 110.2μm, the range of porosity was 40.35%-64.58%, the compressive strength range of porous Al2O3 ceramics was from 25.9MPa-126.6MPa. The porous Al2O3 ceramics with different pore structure can be obtained by changing the annealing time.

Thermally Sprayed Quasicrystal Composite Coatings for Bearings and Other Friction Threaded Applications

2000 ◽  
Author(s):  
E. Lugscheider ◽  
C. Herbst-Dederichs ◽  
A. Reimann
Keyword(s):  
Composite Coatings ◽  
High Hardness ◽  
Atmospheric Plasma ◽  
Ductile Material ◽  
Metallurgical Analysis ◽  
The Matrix ◽  
Material Forming ◽  
Alloy Properties ◽  
Thermally Sprayed ◽  
Sprayed Coatings

Abstract Quasicrystalline phases improve many alloy properties such as thermomechanical stability, thermal and electrical conductivity, and tribological performance. High hardness, however, is accompanied by brittleness, an undesired property in many applications. Reduced brittleness can be achieved by embedding quasicrystalline phases in a more ductile material, forming a metal-matrix composite that retains some quasicrystalline properties. This study evaluates thermally sprayed coatings made from different compositions of such composites. The coatings assessed were produced by arc-wire, HVOF, and atmospheric plasma spraying using various forms of feed material, including blended, agglomerated, chemical encased, and attrition-milled powders and filled wires. The investigation involved metallurgical analysis, proving the existence of quasicrystal content and assessing the matrix phase, and tests showing how sliding wear is influenced by the composition of quasicrystalline phases.

Formation of Solid Solution and Metallic Nickel Phases During Suspension Plasma Spraying of Co Oxide and Ni Oxide

2021 ◽  
Author(s):  
Vahid Jalilvand ◽  
Ali Dolatabadi ◽  
Christian Moreau ◽  
Saeed Mohammadkhani ◽  
Lionel Roué ◽  
...  
Keyword(s):  
Solid Solution ◽  
Inert Anode ◽  
Metallic Nickel ◽  
Aluminum Production ◽  
X Ray Diffraction ◽  
Oxide Coatings ◽  
Cobalt Nickel ◽  
Sprayed Coatings ◽  
Insight Into

Abstract The focus of this study is the formation of a solid solution and metallic nickel in the cobalt-nickel mixed oxide coatings during suspension plasma spray (SPS) deposition. The (Co,Ni)O solid solution is a potential material for inert anode applications in aluminum production. SPS coatings and in-flight collected particles are studied to gain further insight into the melting and mixing phenomena of the NiO and CoO powders as well as phase formation in the deposited coatings. Moreover, the role of suspension feedstock particle sizes on the microstructure of coatings is discussed. SEM, EDS and X-ray diffraction studies helped better understanding the formation of different crystalline phases within the as-sprayed coatings. It was found that the formation of metallic nickel is possible in the coatings. The results support the importance of substrate temperature on the formation of metallic Ni, so that keeping the substrate at low temperature results in an increase of the Ni content in the coatings. In this study, possible causes for the formation of metallic Ni during spraying are discussed.

Sealing Treatment of Plasma Sprayed Cr3C2-NiCr/Al2O3-TiO2 Coating by Aluminum Phosphate Sealant Containing Al2O3 Nanoparticles

2021 ◽  
Author(s):  
Tuan Nguyen Van ◽  
Tuan Anh Nguyen ◽  
Ha Pham Thi ◽  
Ly Pham Thi ◽  
Phuong Nguyen ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Aluminum Phosphate ◽  
Al2o3 Nanoparticles ◽  
Treatment Efficiency ◽  
Typical Structure ◽  
Sprayed Coating ◽  
Plasma Sprayed ◽  
Sealing Treatment ◽  
Sprayed Coatings

Abstract A typical structure of thermal spray coatings consisted of molten particles, semi-molten particles, oxides, pores and cracks. These factors caused the porosity of sprayed coatings, leading to a great influence on the coating properties, especially their wear-corrosion resistance. In this study, a post-spray sealing treatment of Cr3C2-NiCr/Al2O3-TiO2 plasma sprayed coatings was carried out, then their corrosion properties were evaluated, before and after the treatment. For sealing process, aluminum phosphate (APP) containing aluminum oxide (Al2O3) nanoparticles (~10 nm) was used. The permeability of APP into the sprayed coating was analyzed by scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). The treatment efficiency for porosity and corrosion resistance of sprayed coatings were evaluated by electrochemical measurements, such as the potentiodynamic polarization and electrochemical impedance spectroscopy. In addition, the wear-corrosion resistance of the sealed coating was examined in 3.5 wt.% NaCl circulation solution containing 0.25 wt.% SiO2 particles. The obtained results showed that APP penetrated deeply through the sprayed coating. The incorporation of Al2O3 nanoparticles into APP sealant enhanced the treatment efficiency of porosity for sprayed coating. The effect of the post-treatment on corrosion protection of the sprayed coating has been discussed.

Hard Arc-Sprayed Coating with Enhanced Erosion and Abrasion Wear Resistance

2000 ◽  
Author(s):  
S. Dallaire
Keyword(s):  
Ceramic Coatings ◽  
High Energy ◽  
Arc Spraying ◽  
Cored Wire ◽  
Industrial Sectors ◽  
Wear Protection ◽  
Abrasion Wear ◽  
Sprayed Coating ◽  
Impact Angles ◽  
Sprayed Coatings

Abstract Exposed to particle erosion environments, metal-sprayed coatings are damaged by micro-machining and ploughing at low impact angles. The generation and propagation of subsurface lateral cracks at high impacting angles damage single-phase ceramic coatings. Therefore, multicomponent coatings deposited by high-energy processes have been widely used to provide wear protection in most of the applications. As commercial arc-sprayed coatings have been used to a limited extent in applications involving erosion and abrasion wear, developing attractive wear resistant arc-sprayed coatings has been found necessary. A cored wire formulation, referred to as Alpha-1800, has been developed to produce tailored arc-sprayed coatings that are tough enough to resist particle impacts at 90° and sufficiently hard to deflect eroding particles at low impact angles. Typical 1 mm-thick coatings composed of ductile and hard phases with Knoop hardness reaching 1800 kg/mm2 were easily produced by arc spraying the cored wire with air. Coatings were: 1) erosion tested at 25°C and higher temperatures at impact angles of 25° and 90° in a gas-blast erosion rig, 2) slurry erosion tested at impact angles of 25° and 90°, 3) abrasion wear tested using the ASTM G-65 test procedure. Results show that coatings produced with the new cored wire are at least 5 times more erosion resistant and 10 times more abrasion resistant than coatings produced by arc spraying commercial cored wires. The performance of the new arc-sprayed coating can be compared with that of high-energy WC-based coatings. Being thermally stable up to 850°C, arc-sprayed coatings produced with the new cored wire are attractive for applications in many industrial sectors up to high temperatures.

Sign in / Sign up

Export Citation Format

Share Document