scholarly journals Tribological Behavior of Cermet Coatings Deposited from Submicron WC-10Co-4Cr Powders Using HVOF Spraying

2019 ◽  
Vol 25 (3) ◽  
pp. 303-308
Author(s):  
Sheng HONG ◽  
Yuping WU ◽  
Bo WANG

In this paper, we prepared cermet coatings deposited from submicron WC-CoCr powders using high-velocity oxygen-fuel (HVOF) spraying process. The detailed microstructures, slurry erosion and sliding wear resistance of as-sprayed coatings were investigated. The slurry erosion test was performed in a rotating disk rig facility with circulating system using distilled water and 3.5 wt.% NaCl slurries. The sliding wear properties were evaluated by a pin-on-disk tribometer under different loads. The results showed that submicron coatings exhibited higher slurry erosion resistance in distilled water slurry than that in 3.5 wt.% NaCl slurry after three tests. The slurry erosion mechanism of the coatings was characterized by scratches and pull-out of carbide particle. With increasing load (from 10 N to 50 N), the coatings showed a reduction in average friction coefficient (from 0.52 to 0.44), and an increase in mass loss (from 3.3 mg to 11.4 mg). The evolution of the sliding wear characteristics of the coatings with the increase of the load was micro-cracks, carbide particle pull-out, spallation, and massive exfoliation. The sliding wear mechanism of the coatings under different loads was primarily abrasive wear. DOI: http://dx.doi.org/10.5755/j01.ms.25.3.19507

2016 ◽  
Vol 254 ◽  
pp. 231-236 ◽  
Author(s):  
Ion Dragoş Uţu ◽  
Gabriela Marginean ◽  
Iosif Hulka ◽  
Viorel Aurel Şerban

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.


2007 ◽  
Vol 534-536 ◽  
pp. 629-632
Author(s):  
Süleyman Tekeli ◽  
Ahmet Güral ◽  
Metin Gürü

The effect of tempering temperature and microstructure on dry sliding wear behavior of quenched and tempered PM steels was investigated. For this purpose, atomized iron powder was mixed with 0.3 % graphite and 1-2 % Ni powders. The mixed powders were cold pressed and sintered at 1200°C. The sintered specimens were quenched from 890°C and then tempered at 200°C and 600°C for 1 hr. Wear tests were carried out on the quenched+tempered specimens under dry sliding wear conditions using a pin-on-disk type machine at constant load and speed. The experimental results showed that the wear coefficient effectively increased with increasing tempering temperature. With increasing Ni content, the wear coefficient slightly decreased at all tempering temperatures due to the high amount of Ni-rich austenitic areas.


An investigational analysis was conducted to study the effect of basalt/curaua hybrid composite focusing on wear properties. The hybrid composites are fabricated by resin transfer molding and the tests are conducted by pin on disk as per ASTM G99. Basalt/Curaua relative fiber weight percentage as 0/100,40/60, 60/40, 100/0 are fabricated and analyzed for abrasion wear resistance. Specimens are tested for the load of 50N at 1 m/s using Pin on Disc wear testing machine by varying abrading distance. Worn out surfaces of the abraded composites are studied by using scanning electron microscopy (SEM) and Fourier- transform infrared spectroscopy (FTIR). Roughness of the worn and pure surfaces is also accounted to measure significance of hybridization on tribological properties of the hybrid composites. Result shows that coefficient of friction is increasing in higher the curaua fiber in hybrid composites. Morphology evident the wear mechanism and internal compatibility of hybrid fibers.


Author(s):  
T. Akasawa ◽  
K. Ai

Abstract A tungsten carbide/cobalt hard coating was deposited on steel substrates using plasma-arc and high velocity oxyfuel flame (HVOF) spraying. The characteristics of the coatings made by the two spraying methods were evaluated under identical conditions. The microstructure and the chemical composition ofthe coatings were different depending on the powderheating temperature and the velocity of particles. The sliding wear properties of the coatings against hardened steel at high sliding speeds showed different tendencies from those at low speeds. The plasma sprayed coatings resulted in better abrasive wear properties than HVOF coatings did. Material removal by solid particle erosion depended on the striking angle ofparticles on the substrate surface but there are no clear differences in wear properties between the two coatings.


2007 ◽  
Vol 201 (8) ◽  
pp. 4718-4727 ◽  
Author(s):  
Yasunari Ishikawa ◽  
Seiji Kuroda ◽  
Jin Kawakita ◽  
Yukihiro Sakamoto ◽  
Matsufumi Takaya

Author(s):  
Y. Ishikawa ◽  
J. Kawakita ◽  
S. Kuroda

An improved HVOF spray process called “Gas-shrouded HVOF” (GS-HVOF) has been developed over the past several years. By using an extension nozzle at the exit of a commercial HVOF spray gun, GS-HVOF is capable of controlling the oxidation of sprayed materials during flight as well as achieving higher velocity of sprayed particles. These features result in extremely dense and clean microstructure of the sprayed coatings. The process has been successfully applied to corrosion resistant alloys such as SUS316L, HastelloyC, and alloy 625 as well as cermets such as WC-Cr3C2-Ni. Wear properties of WC cermet coatings were measured by using a pin-on-disk wear tester. The specific wear rates of the coatings prepared by the GS-HVOF with a reducing (fuel rich) flame were close to that of chrome plating. The wear amount of the heat-treated GS-HVOF coatings could not be detected after testing. It is believed that transition to mild wear appeared early because of the increased surface oxidation due to the heat treatment.


2021 ◽  
Vol 63 (1) ◽  
pp. 85-91
Author(s):  
Güven Yarkadaş ◽  
Levent Cenk Kumruoğlu ◽  
Selma Özarslan ◽  
Hüseyin Şevik

Abstract In the present study, the effect of an La alloying element with different quantities (1, 3 and 5 wt.-%) on the microstructure, mechanical and dry sliding wear properties of Mg- 3Al-3Sn-3Sb alloy was investigated. The wear tests were done on the alloys using pin on-disk equipment against a 4140 steel disc as counterpart under three different sliding velocities of 0.3, 0.6 and 1.2 ms-1 and four different loads of 5, 10, 20 and 40 N. The microstructural results showed that the new intermetallic phases (La5Sn3 and LaSnSb2) were formed with addition of La to the main alloy. Also, it was observed that the hardness of the Mg-3Al-3Sn-3Sb alloy was raised with increasing La addition. Furthermore, the tensile properties of the Mg-3Al-3Sn-3Sb alloy improved with rising La content at room and elevated temperature. The wear rates of the alloys increase with increasing of the sliding speed and load. In addition to this, the wear rate of the Mg-3Al-3Sn-3Sb alloy was found to be higher than that of the La content alloys for all test conditions.


Author(s):  
Sarbjeet Kaushal ◽  
Satnam Singh ◽  
Dheeraj Gupta

Processing of nickel-based high strength composites and alloys is a difficult and thought-provoking task. In this work, a strategy of heating through microwaves radiation is utilized to process the high strength hybrid Ni-based composite clad on SS 316L steel surface containing 15% (WC-8Co) and 5% Mo. The premixed composite powder was placed on the steel surface and irradiated with domestic microwave applicator having 2.45 GHz fixed frequency and 900 W power. The hybrid clad was successfully developed within 12–15 min of microwave exposure. The processed clad was subjected to various metallurgical and mechanical characterizations to understand the microstructures and phase changes. Microstructural analysis study revealed that the clad of ∼0.85 mm thickness was obtained and presence of dispersed reinforced particles of WC-8Co and Mo in nickel matrix were observed. Some inter-metallic phases of W2C, Ni2Mo4C, Ni4W and NiSi2 were observed in the clad. The average microhardness of the composite clad was712 ± 58 HV. The microwave processed clad exhibited a flexural strength of 852 ± 6 MPa with deformation index of 35 × 10−5 mm/N. Further, the sliding wear study revealed that the sliding velocity of 1.0 m/s favoured the formation of oxide tribo layers. The various mechanisms of wear revealed by the analysis of worn-out surfaces were abrasion, adhesion, surface pull-out and deformation of surfaces. The microwave processed clad revealed significant improvement in wear resistance in comparison to the steel substrate.


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