scholarly journals Effect of CeO2 on crack sensitivity and tribological properties of Ni60A coatings prepared by laser cladding

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110131
Author(s):  
Gong Yuling ◽  
Wu Meiping ◽  
Miao Xiaojin ◽  
Cui Chen

All the time, the wear resistance of TC4 titanium alloy restricts its application in friction parts. In order to solve this problem, in this work, CeO2/Ni60A composite coatings (0, 1, 2, 3, 4 wt.% CeO2) were prepared on TC4 titanium alloy by laser cladding technology. The detection and characterization of the coatings were mainly carried out by X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy-dispersive spectrometer, Vickers hardness test, and wear test. The results showed that appropriate proportion of CeO2 powder could effectively reduce the crack sensitivity of Ni60A coating on TC4 substrate. While the amount of CeO2 powder was 3wt.%, there were no obvious cracks, pores, and other defects in the coating. Coatings mainly consisted of Ti2Ni, TiC, TiB2, Ce2O3, and the substrate α–Ti. CeO2 has negligible influence on the composition of the phase, but it significantly increased the absorption rate of the powder to light, promoted the fluidity of the molten pool. Among five coatings, the average hardness of the 3Ce coating was the highest and the highest hardness value could reach 1163.7 HV0.3, which was 3.58 times higher than TC4 substrate, the friction coefficient was 0.307, and the wear rate was 1.11 × 10−5 mm3/N m, which reflected extremely high wear resistance performance. Adding an appropriate amount of CeO2 improved the microstructure of the coating, and realized the fine crystal strengthening of the coating.

2017 ◽  
Vol 24 (Supp01) ◽  
pp. 1850009 ◽  
Author(s):  
H. X. ZHANG ◽  
H. J. YU ◽  
C. Z. CHEN ◽  
J. J. DAI

In order to improve the wear resistance of Ti alloys, different mass ratios of Ti-Si-Al powders were designed to fabricate hard phases reinforced intermetallic matrix composite coatings on the Ti-6Al-4V substrate by laser cladding. The corresponding coatings were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and high resolution transmission microscopy (HRTEM). The HV-1000 hardness tester and MM200 wear test machine were employed to test the hardness and the wear resistance of the composite coatings, respectively. The composite coatings mainly consisted of the reinforcements of Ti5Si3, Ti3AlC2 and Ti7Al5Si[Formula: see text] and the matrix of Ti3Al, TiAl, TiAl3 and [Formula: see text]-Ti. The micro-hardness of the Ti-35Al-15Si coating was from 956 HV[Formula: see text] to 1130 HV[Formula: see text], which was approximately 3–4 times of the substrate and the highest in the three samples. The wear rate of the Ti-35Al-15Si coating was 0.023[Formula: see text]cm3[Formula: see text][Formula: see text][Formula: see text]min[Formula: see text], which was about 1/4 of the Ti-6Al-4V substrate. It was the lowest in the three samples.


2017 ◽  
Vol 24 (4) ◽  
pp. 541-546 ◽  
Author(s):  
Hongxia Zhang ◽  
Huijun Yu ◽  
Chuanzhong Chen

AbstractThe composite coatings were fabricated by laser cladding Ni60A/B4C pre-placed powders on the surface of Ti-6Al-4V alloy for improving wear resistance and hardness of the substrate. In this research, the composite coatings were studied by means of X-ray diffraction, scanning electron microscope and energy dispersive spectrometer. The sliding wear tests were performed using MM200 wear test machine. The hardness of the coatings was tested by HV-1000 hardness tester. After laser cladding, it was found that there was a good metallurgical bond between the laser cladding coating and Ti-6Al-4V substrate. The composite coatings were mainly composed of the matrix of γ-Ni and a little Ni3Ti and the reinforcements of TiB2, TiC and CrB. The hardness of the sample of Ni60A-5B4C was approximately 2.5–3.5 times that of the Ti-6Al-4V substrate. The hardness of the sample of Ni60A-10B4C was 30% higher than that of sample 1. The wear resistance of samples 1 and 2 were 11 times and 10 times that of the substrate, respectively.


2015 ◽  
Vol 22 (03) ◽  
pp. 1550044 ◽  
Author(s):  
H. X. ZHANG ◽  
H. J. YU ◽  
C. Z. CHEN

The composite coatings were fabricated by laser cladding Al / TiN pre-placed powders on Ti –6 Al –4 V substrate for enhancing wear resistance and hardness of the substrate. The composite coatings were analyzed by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The sliding wear tests were performed by MM200 wear test machine. The hardness of the coatings was tested by HV-1000 hardness tester. After laser cladding, it was found that there was a good metallurgical bond between the coating and the substrate. The composite coatings were mainly composed of the matrix of β- Ti  ( Al ) and the reinforcements of titanium nitride ( TiN ), Ti 3 Al , TiAl and Al 3 Ti . The hardness and wear resistance of the coatings on four samples were greatly improved, among which sample 4 exhibited the highest hardness and best wear resistance. The hardness of the coating on sample 4 was approximately 2.5 times of the Ti –6 Al –4 V substrate. And the wear resistance of sample 4 was four times of the substrate.


2012 ◽  
Vol 19 (02) ◽  
pp. 1250009 ◽  
Author(s):  
PENG LIU ◽  
WEI GUO ◽  
DAKUI HU ◽  
HUI LUO ◽  
YUANBIN ZHANG

The synthesis of hard composite coating on titanium alloy by laser cladding of Al/Fe/Ni+C/Si3N4 pre-placed powders has been investigated in detail. SEM result indicated that a composite coating with metallurgical joint to the substrate was formed. XRD result indicated that the composite coating mainly consisted of γ- (Fe, Ni) , FeAl , Ti3Al , TiC , TiNi , TiC0.3N0.7 , Ti2N , SiC , Ti5Si3 and TiNi . Compared with Ti-3Al-2V substrate, an improvement of the micro-hardness and the wear resistance was observed for this composite coating.


2009 ◽  
Vol 79-82 ◽  
pp. 795-798 ◽  
Author(s):  
Hong Ye ◽  
X.B. Zhang ◽  
Z.F. Xue ◽  
Y.H. Fan ◽  
Ke Chen

The composite coatings of self-flux alloy matrix reinforced by WC-12%Co were produced on the surface of 45 steel using laser cladding technology. The effects of CeO2 to macro-morphology, microstructure, hardness, wear resistance and corrosion resistance of cladding layer were investigated. The results show that rare earths oxide (CeO2) added laser cladding coating has distribution, dimension phases and less deficiency. CeO2 could promote liquating process of WC, increasing the quantity and distribute uniformity of intermetallic compounds in laser cladding layer. Because of dispersion precipitation and fine-crystal strengthen effect, laser cladding layer with CeO2 has higher microhardness, wearing resistance and better corrosion resistance properties.


Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 684 ◽  
Author(s):  
Jianfeng Li ◽  
Zhencai Zhu ◽  
Yuxing Peng ◽  
Gang Shen

In this study, the effect of carbon fibers (CFs) on the microstructure and wear resistance of Fe-based alloy coating produced by laser cladding was investigated by X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS), and wear tester. The results indicated that with the addition of CFs, the microstructure of the composite coating mainly transformed from α-Fe cellular dendrites and γ-Fe/(Cr, Fe)7C3/CrB eutectics to bulk-like (Cr, Fe)7C3, nano-size B4C, and γ-(Fe, Ni)/(Cr, Fe)23C6 lamellar eutectics. Additionally, the microhardness and wear resistance of the composite coating compared with the original coating both increased by approximately two times. The original coating showed the dominant wear mechanisms of micro-cutting and serious brittle spalling, while the composite coating with CFs showed the main wear mechanism of slight scratching.


Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 601 ◽  
Author(s):  
Tao Chen ◽  
Fan Wu ◽  
Haojun Wang ◽  
Defu Liu

To improve the wear resistance of titanium alloy parts used in the engineering applications, in-situ formed Ti(C,N) particles reinforcing Ni-based composite coatings are fabricated on Ti6Al4V alloys by the laser cladding technique using Ni60, C, TiN, and small amounts of CeO2 nanoparticles mixed powders as the pre-placed materials. Firstly, the formation mechanism of Ti(C,N) particles as a reinforced phase in the coating is investigated. Then, the influences of CeO2 nanoparticles on microstructures and wear resistance of the coatings are analyzed. It is indicated that the large Ti(C,N) particles form around TiN particles, and the small Ti(C,N) particles form through independent nucleation. CeO2 nanoparticles play important roles in increasing the nucleation rate and improving the precipitation of Ti(C,N), hence the microstructures and wear resistance of the coatings are apparently improved after adding CeO2 nanoparticles. It is observed that the 1 wt % content of CeO2 additive in the pre-placed powders is the best choice for the wear resistance of the coatings.


Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 747
Author(s):  
Kaiwei Liu ◽  
Hua Yan ◽  
Peilei Zhang ◽  
Jian Zhao ◽  
Zhishui Yu ◽  
...  

TiN and WS2 + hBN reinforced Ni-based alloy self-lubricating composite coatings were fabricated on TC4 alloy by laser cladding using TiN, NiCrBSi, WS2, and hBN powder mixtures. Energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM), X-ray diffractometry (XRD), and optical microscopy (OM) were adopted to investigate the microstructure. The wear behaviors of the self-lubricating composite coatings were evaluated under large contact load in room temperature, dry-sliding wear-test conditions. Results indicated that the phases of the coatings mainly include γ-Ni, TiN, TiNi, TiW, WS2, and TiS mixtures. The average microhardness of the composite coating is 2.3–2.7 times that of the TC4 matrix. Laser cladding TiN/WS2 + hBN/NiCrBSi self-lubricating composite coatings revealed a higher wear resistance and lower friction coefficient than those of the TC4 alloy substrate. The friction coefficient (COF) of the coatings was oscillating around approximately 0.3458 due to the addition of self-lubricant WS2 + hBN and hard reinforcement TiN. The wear behaviors testing showed that the wear resistance of the as-received TC4 was significantly improved by a laser cladding TiN/WS2 + hBN/NiCrBSi self-lubricating composite coating.


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