The Relationship between Nanocrystalline Structure and Frictional Properties of Nanodiamond/Ni Composite Coatings by Brush Plating

2011 ◽  
Vol 80-81 ◽  
pp. 683-687 ◽  
Author(s):  
Ying Li ◽  
Bian Xiao Li ◽  
Wen Jun Zou

Nanodiamond/Ni and Ni coatings were fabricated via brush plating. Nanocrystalline structure of the composite coating was investigated by SEM and XRD. The results showed that the composite coatings are nanocrystalline structure. The hardness of the nanodiamond/Ni composite coating is higher greatly than that of Ni coating. At same time, the reasons of formation nanocrystalline were discussed, which include the nucleation rate with the increase of a high over-potential, the reciprocating motion between brush and work piece, the heterogeneous nucleation of nanodiamond. The nanodiamonds as second phases make grain finer. The nanodiamonds of core-shell structure play the important role in wear resistance and antifriction. So the wear resistance of the composite coatings is significantly higher than nickel coating’s.

2011 ◽  
Vol 239-242 ◽  
pp. 616-619
Author(s):  
Ying Li ◽  
Wen Jun Zou ◽  
Bian Xiao Li ◽  
Qi Ming Dong

Nano-diamond/Ni and Ni coatings were prepared by brush plating. SEM and XRD methods were applied to investigate the morphology, nano-crystalline structure and grain size of the coatings. The results show that the grain size of the brush coatings all is in nanometer scale. The surface morphology of the composite brush coatings is a finer and denser cauliflower-like structure. Meanwhile the reasons of formation nano-crystalline structure are the high over-potential, the discontinuous grain growth resulted from the reciprocating motion and friction between the plating pen and the work piece, the heterogeneous nucleation of the nano-diamond, and the point discharge effect. The nano-diamond as the second phases decreases the grain size of the coating and consequently increase the strength of the composite coatings largely.


Author(s):  
YP Vaishnu ◽  
K Bindu Kumar ◽  
S Rani

The development of deposition of different metal processes established on electrodeposition of nickel, different alloy and composite coatings on different surfaces has attested an upsurge in interest among researchers. In latter years, these coatings have exhibited promising corrosion and wear resistance properties. Also, huge number of modern developments became most critical from macro to nano level applications. It is well known that one may shape the microstructure and the phase present in the material to recover the mechanical properties of highly pure materials, specifically metals. Co-deposition of fine particles inside a metal matrix to generate composite coatings has treated as a practical strategy to acquire enhanced mechanical properties like wear resistance, corrosion resistance and lubrication. In this work, CuO/Ni composite coatings are processed on the small cylindrical pin by electro brush plating to evaluate the wear and corrosion resistance. To examine the effects about the different parameters of processes on wear loss of CuO/Ni composite coating, L16(44) orthogonal experiment is designed and conducted with four process parameters (voltage, concentration of nanoCuO particles in g/l, temperature and thickness) which are selected as factors. Design of experiment is employed to resolve the effects of process parameters on the wear loss of composite coatings. It is concluded that concentration of CuO nanoparticle and voltage are the most significant factors for the wear loss.


2011 ◽  
Vol 291-294 ◽  
pp. 197-200 ◽  
Author(s):  
Ying Li ◽  
Wen Jun Zou ◽  
Bian Xiao Li ◽  
Qi Ming Dong

The hardness and the wear resistance of the nano-diamond composite coatings were investigated by the micro-hardness tester and the friction tester. The relationship of the nano-diamond concentration, heat treatment temperature and hardness were revealed. These results show that the composite coatings have higher hardness, better wear resistance and lower friction coefficient under the uniform dispersing of the nano-diamond in the nickel matrix. The maximum hardness of the composite coatings reaches HV654 when the nano-diamond concentration is 30%. Frictional coefficient is decreased from 0.185 to 0.16. Moreover, the hardness does not reduce under annealing at 300°C. The frictional mechanism of the composite coatings indicates that the worn nano-diamond could block the direct contact between the composite coating and the standard ring. Spherical nano-diamond particles play the role in the "micro-ball" among the contact surfaces, the frictional coefficient is reduced and the wear resistance is improved.


2013 ◽  
Vol 20 (4) ◽  
pp. 307-310
Author(s):  
Li Wei

AbstractA hard SiC-B4C reinforced composite coating was fabricated by laser alloying of SiC-B4C+Al-Sn-Mo-Y2O3 mixed powders on a Ti-3Al-2V alloy. Al-Sn-Mo mixed powders were first used in the laser alloying technique to improve the wear resistance of titanium alloys. Proper selection of the laser alloying process parameters allows us to obtain a composite coating with a metallurgical combination with substrate. Under the action of Mo, fine particles with high microhardness were produced in the coating matrix and also hindered the formation of adhesion patches and deep plowing grooves during the sliding wear process, leading to the improvement of wear resistance of a titanium alloy substrate surface.


2007 ◽  
Vol 280-283 ◽  
pp. 1489-1492
Author(s):  
Zhen Ting Wang ◽  
Hua Hui Chen

Micro-nanostructured WC composite coatings were successfully fabricated by induced heating sintering method on the surface of Q235 steel .The microstructure, micro-hardness and the wear resistance of the composite coatings were studied .The results show that the microstructure of induced heat layer is mainly composed of Ni-based solid solutions and WC particles. And there exists excellent metallurgical bonding between coating and substrate. The wear resistance of micro-nanostructured WC Composite Coatings is increased by 1.5 times on an average as compared with that of micron.


2021 ◽  
Author(s):  
Linlin ZHANG ◽  
Dawei ZHANG

Ni-Co-W composite coatings modified by different contents of Co-based alloy powder in the Ni-based alloy with 35 wt.% WC (Ni35WC) were deposited on stainless steel by laser cladding. The influence of compositional and microstructural modification on the wear properties has been comparatively investigated by XRD, SEM, and EDS techniques. It was found that the austenite dendrites in the modified coating adding 50 wt.% Co-based alloy were refined and a lot of Cr23C6 or M23(C, B)6 compounds with fine lamellar feature were formed around austenitic grain boundaries or in the intergranular regions. The contribution of element Co to the modification of Ni35WC coating is that it cannot only promote the formation of more hard compounds to refine austenite grains, but also refine the size of precipitates, and change the phase type of eutectic structure as a result of disappeared Cr boride brittle phases. A noticeable improvement in wear resistance is obtained in the Ni35WC coating with 50 wt.% Co-based alloy, which makes the wear rate decreased by about 53 % and 30% by comparison to that of the substrate and the Ni35WC coating, respectively. It is suggested that the improvement is closely related to the composite coating being strengthened owing to the increase of coating hardness, formation of a fine-grained microstructure caused by Co, and fine hard precipitate phases in the eutectic structure.


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.


2017 ◽  
Vol 62 (4) ◽  
pp. 2421-2424 ◽  
Author(s):  
N. Gidikova ◽  
M. Sulowski ◽  
V. Petkov ◽  
R. Valov ◽  
G. Cempura

AbstractChrome plating is used to improve the properties of metal surfaces like hardness, corrosion resistance and wear resistance in machine building. To further improve these properties, an electrodeposited chromium coating on steel, modified with nanodiamond particles is proposed. The nanodiamond particles (average size 4 nm measured by TEM) are produced by detonation synthesis (NDDS). The composite coating (Cr+NDDS) has an increased thickness, about two times greater microhardness and finer micro-structure compared to that of unmodified chromium coating obtained under the same galvanization conditions. In the microstructure of specimen obtained from chrome electrolyte with concentration of NDDS 25 g/l or more, “minisections” with chromium shell were found. They were identified by metallographic microscope and X-ray analyser on etched section of chromium plated sample. The object of further research is the dependence of the presence of NDDS in the composite coating from the nanodiamond particles concentration in the chroming electrolyte.


2012 ◽  
Vol 454 ◽  
pp. 144-147
Author(s):  
Lian Wei Yang ◽  
Jin Hui Li ◽  
Yun Dong ◽  
Xiao Ping Lin

WC/Co; Composite coating; Plasma spraying; Friction and wear Abstract: WC- Co composite powders were synthesized by direct mechanical grinding in a rotary-vibration mill under 8h, and then analyzed by SEM and XRD. WC and WC/Co composite coatings were prepared by supersonic plasma spraying fine WC-Co composite powders. The wear and friction properties of both coatings were evaluated. The results showed that the wear resistance of the WC/Co composite coating was superior to that of the WC coating. The improvement in wear resistance of the WC/Co composite coating was attributed to its higher fracture toughness and adhesion strength as well as better thermal diffusivity. As for the WC/Co composite coating, the mechanism was mainly adhesion with micro-abrasion and fatigued-induced brittle fracture within splats, and the delamination along splat boundaries only occurred at high load. However, the failure of the WC coating was predominantly detachment of transferred film and brittle fracture within the splats and delamination along splat boundaries, which were enhanced with the increasing load.


2012 ◽  
Vol 19 (05) ◽  
pp. 1250052 ◽  
Author(s):  
X. H. WANG ◽  
M. ZHANG ◽  
B. S. DU ◽  
S. LI

Iron-based composite coatings reinforced with TiB2–TiC multiple ceramic have been fabricated from a precursor of B4C , TiO2 and Al powders by laser cladding. The effect of TiO2 and Al on the microstructure and wear properties of the coatings was investigated. The results showed that the volume fraction, type and size of the reinforcements were influenced by the content of TiO2 and Al . TiB2 and TiC were evenly distributed in the coating; however, most of Al2O3 were ejected from the coatings, only few of them retained in the coating acting as nucleation core of reinforcement or inclusion. The microhardness and wear resistance of the coatings were improved, whereas the friction coefficients of the coatings were considerably lower than that of substrate.


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