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 Microstructure, Microhardness, Fracture Toughness, and Abrasive Wear of In-Situ Synthesized TiC/Ti-Al Composite Coatings by Cold Spraying Combined with Heat Treatment

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1034 ◽  
Author(s):  
Xiao Chen ◽  
Chengdi Li ◽  
Xiaobo Bai ◽  
Hao Liu ◽  
Shunjian Xu ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Intermetallic Compounds ◽  
Composite Coatings ◽  
Cold Spraying ◽  
Xrd Analysis ◽  
Gas Temperature ◽  
Al Composite ◽  
Average Porosity ◽  
Annealed Coating

TiAl intermetallic compounds, as a new kind of high-performance light-weight structural material, are widely applied in many fields. Titanium carbide (TiC) as the reinforcing phase could improve the mechanical properties, wear resistance, and heat-resistance stability of TiAl intermetallic compounds. Ti(Al, C) mixture powders were deposited by cold spraying at gas temperature of 250 °C, 450 °C, and 550 °C. Then, Ti(Al, C) coatings were annealed at temperatures of 650 °C for different times and following holding at 1100 °C for 3 h. The microstructure, microhardness, fracture toughness, and abrasive wear of Ti-Al composite coatings were investigated. The research results were that the particle size of mixture powders decreased as the ball milling time prolonging. Ti(Al) solid solution appeared in the mixture powders as the milling time increased to 30 h. The average porosity of the coating sprayed at 550 °C was the lowest (0.85%). The as-sprayed coatings exhibited the same phase compositions with the mixture powders. The coating sprayed at gas temperature of 550 °C has the highest microhardness and the lowest weight loss. Ti-Al intermetallic was in-situ synthesized after annealing at 650 °C. The average porosity of the annealed coating (sprayed at 450 °C) was the lowest. The content of Ti-Al intermetallic compounds of the annealed coating sprayed at 450 °C is the highest. The X-ray diffraction (XRD) analysis results are consistent with the EDS analysis of the annealed coatings after annealing at 650 °C. Ti-Al intermetallic compounds were almost completely formed in the three kinds of the coatings after annealing at 650 °C for 20 h and following holding at 1100 °C for 3 h. TiAl and TiAl3 intermetallic phases were in-situ synthesized in the coatings based on the energy dispersive spectroscopy (EDS) and XRD analysis. TiC was also in situ synthesized in the coatings as the annealing temperature increased to 1100 °C. The annealed coating (sprayed at 450 °C) has the highest microhardness, fracture toughness, and wear resistance properties after annealing at 1100 °C for 3 h.

Investigation of in situ synthesized TiB2 particles in iron-based composite coatings processed by hybrid submerged arc welding

2021 ◽  
Vol 63 (7) ◽  
pp. 630-638
Author(s):  
Mustafa Kaptanoglu ◽  
Mehmet Eroglu
Keyword(s):  
Arc Welding ◽  
Composite Coatings ◽  
Tib2 Particle ◽  
Submerged Arc Welding ◽  
Wear Properties ◽  
Gas Atmosphere ◽  
Iron Based ◽  
Tib2 Particles ◽  
Submerged Arc

Abstract In the study for this contribution, production of in situ synthesized TiB2 particles in iron-based composite coatings using four different submerged arc welding powders (fluxes) containing increasing amounts of ferrotitanium and ferroboron with S1 welding wire, were targeted. For this purpose, coating deposition was carried out to improve the hardness and wear properties of the AISI 1020 steel surfaces using hybrid submerged arc welding. In hybrid submerged arc welding, the welding pool is protected by both welding powders and an argon gas atmosphere. To examine the composite coatings, visual, chemical, microstructural analyses and hardness and wear tests were carried out. With the use of increasing amounts of ferrotitanium and ferroboron in the welding powders, it was observed that the microstructure of the coatings changed in terms of TiB2 particle geometries such as rectangular and hexagonal; volume fractions of TiB2 particles in the coating microstructures increased; hardness values of coatings were enhanced from 34 HRC to 41 HRC; the wear resistance of the coatings improved, and worn surface images of the coatings caused by the counter body changed from continuous with deep scratches to discontinuous with fine scratches and crater cavities.

Dry Surface Preparation Using Supercritical Cryogenic Nitrogen Jet Improves the Adhesion Strength of Cold Gas Sprayed Coatings (SCNCS)

2018 ◽  
Vol 941 ◽  
pp. 1668-1673
Author(s):  
Abdel Tazibt ◽  
Guillaume Ezo'o ◽  
Yosri Khalsi ◽  
Mustapha Yahiaoui
Keyword(s):  
Surface Preparation ◽  
Cold Spraying ◽  
Substrate Preparation ◽  
Preparation Methods ◽  
Adhesion Performance ◽  
Pulsed Water Jet ◽  
Sprayed Coating ◽  
Sprayed Coatings ◽  
Required Quality

The adhesion performance of Cold Sprayed coatings depends on the quality of the substrate [1,2,4,8]. Before deposition, the surface of substrate must be prepared to a specific required quality, which promotes the anchoring of sprayed coating. Grit Blasting (Samson et al.) [1] is known as the conventional surface preparation before Cold Spraying. But such method causes issues: a) shallow roughness, which does not strengthen bonds between layer and substrate; b) embedment of particles in the substrate, which creates discontinuity of the material at the interface and causes cracks that degrade the layer. Recently, Laser [2] and Pulsed Water Jet (PWJ) [1] have been tested as substrate preparation methods. These methods have shown their ability to generate improved roughness without particle embedment. PWJ has particularly shown interest in Al substrate to generate crevices, which are anchors for the Cold Sprayed coatings. Nevertheless, Laser affects thermally the substrate and induces constraints that may disadvantage the coating quality. PWJ generates liquid effluents. Besides some substrates such as ferrous metals can react with oxygen of water leading to corrosion and coating adhesion weakness.

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.

Microstructure and Wear Behavior of SiCP-Reinforced Magnesium Matrix Composite by Cold Spraying

2011 ◽  
Vol 314-316 ◽  
pp. 253-258
Author(s):  
Xin Kun Suo ◽  
Xue Ping Guo ◽  
Wen Ya LI ◽  
Marie Pierre Planche ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Composite Coating ◽  
Wear Behavior ◽  
Composite Coatings ◽  
Cold Spraying ◽  
Test System ◽  
Magnesium Matrix ◽  
Sic Particles ◽  
Sliding Test ◽  
Sprayed Coatings ◽  
Ball On Disc

In this paper, dense AZ91D/SiC composite coatings were fabricated by cold spraying. The microstructure and microhardness of the as-sprayed coatings were investigated. The results show that the content of SiC particles in the composite coating was 23.6 ± 7.5 vol.%. The microhardness of the composite coating was improved to 140 HV0.3 due to the enhancement of SiC particles, compared to 98 HV0.3 for the pure AZ91D coating. The wear behavior of the composite coating in an ambient condition was studied through a ball-on-disc dry sliding test system. The composite coating showed higher friction coefficient and lower wear rate than the pure AZ91D coating. The wear mechanism of the composite coating was discussed.

Synthesis of Fine Co/ WC Composite and Application to Supersonic Plasma Spraying

2012 ◽  
Vol 454 ◽  
pp. 110-113
Author(s):  
Lian Wei Yang ◽  
Rui Jie Wang ◽  
Yun Dong ◽  
Xiao Ping Lin
Keyword(s):  
Plasma Spraying ◽  
Composite Coatings ◽  
Composite Particles ◽  
Composite Powders ◽  
Soft Phase ◽  
Mill Time ◽  
Supersonic Plasma ◽  
Sprayed Coating ◽  
Vibration Mill ◽  
Rotary Vibration

Co/ WC composite powders (with 10 wt% content of Co) were synthesized by direct mechanical grinding in a rotary-vibration mill. The powders with different mill time were evaluated. WC and WC/Co composite coatings were prepared by supersonic plasma spraying. The results showed that the milled powders consist of composite particles that were formed in the first 2h of milling. Longer milling times improve the distribution of phases inside the composite particles. The formation of the composite particles involves sequential steps of deformation, fragmentation, cold welding, work hardening and piercing of particles of the hard phase in the soft phase. X-ray spectra of the sprayed coating are shown that only very weak W2C and Co6W6C peaks are observed. Compared with WC coating, the Co/ WC coating is denser, and less large pores within composite coating.

scholarly journals Fabrication and microstrain evolution of Al-TiB2 composite coating by cold spray deposition

2017 ◽  
Vol 233 (6) ◽  
pp. 1044-1052 ◽  
Author(s):  
H Chen ◽  
Z Pala ◽  
T Hussain ◽  
DG McCartney
Keyword(s):  
Composite Coating ◽  
Cold Spray ◽  
Spray Deposition ◽  
Composite Coatings ◽  
Cold Spraying ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
X Ray ◽  
Micro Cracks ◽  
Powder Particles

This paper investigates the microstructure evolution of Al-TiB2 coatings prepared by cold spraying. In situ Al-TiB2 composite powders containing uniformly distributed titanium diboride (TiB2) particles with a size range of 5–100 nm in the Al matrix and Al/Al-TiB2 blended powders were used as the cold spray feedstock for coating fabrication on aluminium alloy substrates. The microstructures of the feedstock powders and as-deposited coatings were characterised using scanning electron microscopy with energy dispersive X-ray analysis and X-ray diffraction. Al/Al-TiB2 blended powder coatings, compromising closely packed powder particles, were sprayed to an approximate thickness of 500 µm. Al-TiB2 composite coatings (approximately 50 µm thick) were obtained retaining the microstructure of the composite powders being sprayed and no evidence of detrimental phase transformation was found. However, micro-cracks were found to exist in the Al-TiB2 coating due to the hardly deformable powder particles. Little or no microstrain was revealed in the as-sprayed Al-TiB2 coating, indicating that annealing may have occurred due to the localised adiabatic heating during the spraying process. It is demonstrated that it is possible to fabricate the Al-TiB2 composite coating by cold spray deposition but further improvements to eliminate coating cracking are required.

Biocompatibility of Cold Sprayed Silver-Doped Hydroxyapatite/Titanium Coatings

2016 ◽  
Vol 848 ◽  
pp. 19-22
Author(s):  
Noppakun Sanpo ◽  
Jirasak Tharajak
Keyword(s):  
Cold Spraying ◽  
Cold Gas Dynamic Spraying ◽  
Human Osteoblast ◽  
Gas Temperature ◽  
Composite Powders ◽  
Low Concentration ◽  
Gas Dynamic ◽  
Spraying Parameters ◽  
Helium Gas ◽  
Titanium Coatings

The deposition using cold gas dynamic spraying of silver-doped hydroxyapatite (HA-Ag) /Titanium (Ti) composite have been fabricated on Al 6061 substrate. The biocompatibility of the obtained HA-Ag/Ti coatings was studied. The ratios of HA-Ag to Ti in their composite powders were 20:80, 50:50 and 80:20 (weight %). The HA-Ag/Ti coatings were successfully deposited using cold spraying parameters of 13-15 bars under helium gas, temperature of between 300-400°C. The biocompatibility results showed that human osteoblast and RAW cells spread and adhered well on the coating surfaces especially at low concentration of HA-Ag contained.

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.

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.

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