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Li Y.-L.,Jiujiang Key Laboratory of Green Remanufacturing | Li Y.-L.,Jiujiang University | Pan D.,Jiujiang Key Laboratory of Green Remanufacturing | Pan D.,Jiujiang University | And 3 more authors.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2012

Laser cladding of Fe-based alloy on ductile cast iron QT-500 substrate was carried out by DL-T5000 CO 2 laser. The microstructure, microhardness, and wear resistance of the laser clad layers were analyzed and tested. The results show that the clad layer has compact and flawless microstructure that was integrated metallurgically bonded with ductile cast iron QT-500 substrate. Microstructure of the clad zone consists of branch crystal, equiax crystal and branch crystal in turn from the clad layer surface to heat-affected zone of ductile cast iron QT-500 substrate. The microhardness of the laser clad layers is increased 5 times than that of the ductile cast iron QT-500, and the wear rate is just about one sixth of the QT-500 substrate. The improvement of abradability are mainly attributed to the solution strengthening of Ni and Cr elements and the precipitation hardening of carbides.


Li Y.-L.,Jiujiang University | Li Y.-L.,Jiujiang Key Laboratory of Green Remanufacturing | Pan D.,Jiujiang University | Pan D.,Jiujiang Key Laboratory of Green Remanufacturing | And 6 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2013

Fe-based coatings contained rare-earth oxide La2O3 was prepared on 45 steel by laser cladding with CO2 laser. Microstructure, phases, composition, microhardnesss and wear resistance of the coatings were analyzed by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) analysis, microhardness and wear tests. The results show that the addition of rare-earth can reduce or even eliminate the microholes of the coatings, improve compactness. The microhardness test and the observation of worn surface of the coatings indicate that the addition of the rare-earth slightly influences hardness of the coatings but improves the uniformity of its hardness and wear-resistance. The wear mechanism of Fe-based alloy coatings exhibits mild abrasive wear and that of 45 steel substrate is a combination of abrasive wear and adhesive wear.


Chen X.,Jiujiang Key Laboratory of Green Remanufacturing | Chen X.,Jiujiang University | Wang H.-T.,Jiujiang Key Laboratory of Green Remanufacturing | Wang H.-T.,Jiujiang University | And 4 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2014

TiB2-25Ni cermet composite particles with the mass ratio of 3:1 for TiB2 ceramic phase and Ni binder phase were fabricated by mechanical alloying, three kinds of TiB2-25Ni coatings were fabricated on Q235 steel by high velocity oxygen fuel (HVOF) method with spraying processing of different oxygen flow rates. The microstructure and phase compositions of the coatings were analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. The microhardness of the coatings was measured by HVS-1000, and the properties of thermal shock resistance, corrosion resistance and abrasive wear resistance of the molten Al-12.07% Si alloy were studied. The results show that three kinds of coatings exhibit dense microstructure and layer structure, the main phases of the coatings are TiB2 and Ni. The microhardness of the coatings is (408±87) HV0.3, (513±90) HV0.3 and (553±77) HV0.3, respectively. The coatings with the oxygen flow rate of 462 L/min have the best performance of thermal shock resistance, and all the coatings especially the coating with the oxygen flow rate of 462 L/min have better corrosion resistance in the molten Al-12.07% Si alloy after immersion test for 60 h. The weight loss of abrasive wear of Q235 steel is 6 times larger as much as the loss of the coating (oxygen flow rate 462 L/min). ©, 2014, Editorial Office of Transactions of Materials and Heat Treatment. All right reserved.


Wang H.-T.,Jiujiang Key Laboratory of Green Remanufacturing | Wang H.-T.,Jiujiang University | Chen X.,Jiujiang Key Laboratory of Green Remanufacturing | Chen X.,Jiujiang University | And 7 more authors.
International Journal of Refractory Metals and Hard Materials | Year: 2014

In the present paper, three multimodal WC-17Co deposits with different content of nano-sized WC (10%, 30% and 50%, in wt.%) were prepared by cold spraying process. The effect of micro/nano ratio of WC particles on the microstructure, phase composition and properties such as microhardness, fracture toughness and wear performance of cold-sprayed multimodal WC-12Co coating was investigated. The experimental results demonstrated that the cold-sprayed multimodal WC-17Co deposits exhibited dense microstructure with some stripes composing of Co and nano WC, and their phase structures were similar to that of feedstock. The microhardness and fracture toughness of cold sprayed multimodal WC-17Co deposits respectively increased and decreased with increasing the content of nano-sized WC. The obtained multimodal WC-17Co deposits had both a high hardness and high fracture toughness and exhibited a greatly enhanced wear resistance in comparison to the conventional high-velocity oxy-fuel (HVOF) sprayed WC-12Co coating. The abrasive wear behavior of cold sprayed multimodal WC-17Co deposits was mainly dominated by cutting or gouging related to the preferential wear of Co and the fracture and the peel-off of WC particle. © 2014 Published by Elsevier Ltd.


Chen X.,Jiujiang Key Laboratory of Green Remanufacturing | Chen X.,Jiujiang University | Wang H.,Jiujiang Key Laboratory of Green Remanufacturing | Wang H.,Jiujiang University | And 7 more authors.
Hanjie Xuebao/Transactions of the China Welding Institution | Year: 2013

Four kinds of WC-17%Co powders with different proportional of nano and micro carbides were fabricated by agglomerate-sintering and mechanical mixing method, and were deposited on the stainless steel substrate. The microstructure, phase composition and microhardness of coatings were investigated by means of scanning electron microscopy, X-ray diffraction and microhardness tester. Abrasive wear test was carried out on coatings and weight loss of coatings was tested. The results showed that four kinds of coatings have dense structure and WC and cobalt phases were retained in the coatings from powders. The microhardness of coatings was in 12897-15925 MPa with the change of carbide size. Deposition coating with weight ratio 50/50 of nano and micro WC particles has higher abrasive wear resistance, and weight loss of coatings was in the scope of 2.67-5.53 mg after abrasive wear test.


Chen X.,Jiujiang Key Laboratory of Green Remanufacturing | Chen X.,Jiujiang University | Huang S.-W.,Jiujiang University | Duan X.-H.,Jiujiang University | And 4 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2014

TiB2-50%Co (TiB2-50Co) cermet composite powders with the mass ratio of 1:1 for TiB2 ceramic phase and Co binder phase were fabricated by mechanical alloying, and TiB2-50Co coating was prepared by high velocity oxygen fuel (HVOF) method. The microstructure of TiB2-50Co powder particles and coating was examined by scanning electron microscopy, and phases of the powder particles and the coating were investigated by means of X-ray diffraction. The wear properties and corrosion resistance of the TiB2-50Co coating in the molten Al-12.07%Si alloy were studied. The results show that with the milling time prolonging, binder phase Co is deformd seriously and TiB2 has good bond to Co powder particles. The main phase components of the TiB2-50Co powder and coating with dense microstructure are TiB2 and Co. And the TiB2-50Co coating exhibits good abrasive wear performance. The coating shows good corrosion resistance in the molten Al-12.07%Si after immersion test for 60 h. ©, 2014, Editorial Office of Transactions of Materials and Heat Treatment. All right reserved.


Li Y.,Jiujiang Key Laboratory of Green Remanufacturing | Li Y.,Jiujiang University | Zhao X.,Jiujiang Key Laboratory of Green Remanufacturing | Zhao X.,Jiujiang University | And 5 more authors.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2012

The Ni-Cr-B-Si coating was clad on copper surface by CO 2 laser cladding process. Microstructure and hardness of the clad layer were observed and analyzed by means of SEM, XRD, EDS, and micro-hardometer, and the erosion wear resistance of the coating and the substrate was also tested. The results show that the interface of the coating and substrate is metallurgical bonded, the microstructure is fine and compact, and above all it is crack-free, porosity-free, and slag inclusion free. The laser clad layer consists of equiaxed crystal, branch crystal, plane crystal and strengthening phase particles of Cr, B, Ni phases. Both the mass losses of the clad layer and the substrate are relatively higher when wear test at eroding angle of 60°. With increasing wearing time, the mass loss of the clad coating decreases and is less than that of copper substrate. Erosion wear resistance of the clad layer is obviously enhanced and is three times than that of the substrate.


Ji G.-C.,Jiujiang Key Laboratory of Green Remanufacturing | Ji G.-C.,Jiujiang University | Wang H.-T.,Jiujiang Key Laboratory of Green Remanufacturing | Wang H.-T.,Jiujiang University | And 7 more authors.
Surface and Coatings Technology | Year: 2013

In present work, the deposition behaviors of individual bimodal WC-12Co particles impacting on stainless steel and WC-12Co substrates were investigated. The microstructure and properties of the cold-sprayed WC-12Co coating were characterized. The results showed that the WC-12Co particles partially penetrated into the stainless steel substrate. Flattening of the particles occurred with splashes at its periphery when impacting on the WC-12Co substrate. A movement of small WC particles accompanied with a plastic flow of the Co binder occurred during the impacting and flattening process of the powders. The sprayed coating exhibited a characteristic microstructure with a wide range of WC particle sizes varying from less than 100. nm up to a micron scale. The obtained multimodal coating exhibited both a high hardness and high fracture toughness, e.g. the microhardness is similar to that of a cold sprayed nano WC-12Co coating and the fracture toughness is comparable to that of a bulk material of micro WC-12Co. The cold sprayed coating exhibited a greatly enhanced wear resistance in comparison to the conventional high-velocity oxy-fuel (HVOF) sprayed WC-12Co coating. © 2013 Elsevier B.V.

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