scholarly journals Improving the Tribological Performance of MAO Coatings by Using a Stable Sol Electrolyte Mixed with Cellulose Additive

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4226 ◽  
Author(s):  
Wei Song ◽  
Bailing Jiang ◽  
Dongdong Ji

In this study, micro-arc oxidation (MAO) of aluminum 6061 alloy was carried out within a silicate base electrolyte containing 0.75 g/L of cellulose, and the tribological properties of the coating were investigated. The as-prepared coating was detected by Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), a scanning electron microscope (SEM) and an energy-dispersive spectrometer (EDS), respectively. The results suggested that cellulose filled in the microcracks and micropores, or it existed by cross-linking with Al3+. In addition, it was found that the cellulose had little effect on the coating hardness. However, the thickness and roughness of the coating were improved with the increase in cellulose concentration. Moreover, the ball-on-disk test showed that the friction coefficient, weight loss and wear rate of the MAO coating decreased with the increase in cellulose concentration. Further, the performances of the coatings obtained in the same electrolyte, under different preserved storage periods, were compared, revealing that the cellulose was uniformly dispersed in the electrolyte and improved the tribological properties of the MAO coating within 30 days.

2008 ◽  
Vol 47-50 ◽  
pp. 617-620
Author(s):  
C.F. Hong ◽  
J.P. Tu ◽  
R.L. Li ◽  
X.H. Zheng

Amorphous Ti/C multilayers were prepared on titanium-alloy and silicon (100)-wafer substrates by pulsed laser deposition. Films with different Ti concentration were synthesized by changing the ablating time for Ti and C targets. The morphology and microstructure of Ti/C multilayers were characterized by scanning electron microscopy (SEM), Raman spectroscopy and X-ray diffraction (XRD). Both of the Ti and C monolayers were amorphous. The metallic Ti stimulated the formation of more amorphous carbon phase by reducing the sp2 aromatic bonds and elongating the C-C chain bonds. The tribological properties of Ti/C multilayers were investigated by ball-on-disk tribometer. The pure C film and the multilayers containing more than 68.8 at.% of Ti showed low wear resistance. The multilayer contained 36.8 at.% of Ti exhibited the lowest wear rate at 3.54×10–16 m3/N·m. The formation of carbon related interlayer and its effect on tribological performance of the films were discussed.


2012 ◽  
Vol 151 ◽  
pp. 266-270
Author(s):  
Ming Wang ◽  
Hui Yong Guo ◽  
Wen Bo Huang ◽  
Wen Fang Li

Ba0.5Sr0.5TiO3film was successfully fabricated by micro arc oxidation of titanium plate in aqueous solution containing Sr(OH)2and Ba(OH)2for 25 minutes. X-ray diffraction , energy dispersive spectrometer and scanning electron microscopy were used to characterize the crystalline structure, elements composition and surface morphology and HP4284 capacitance prober was used to analyze the dielectric properties of the film. The micro arc oxidation film is mainly composed of tetragonal Ba0.5Sr0.5TiO3 phases and possesses both high dielectric constant of 454.2 and low dielectric loss of 0.052 at the frequency of 100Hz.The surface morphology appeares smooth and homogeneous except that some holes are uniformly distributed outwardly.


Minerals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 533 ◽  
Author(s):  
Xin Zhang ◽  
Guanghui Li ◽  
Jinxiang You ◽  
Jian Wang ◽  
Jun Luo ◽  
...  

Ludwigite ore is a typical low-grade boron ore accounting for 58.5% boron resource of China, which is mainly composed of magnetite, lizardite and szaibelyite. During soda-ash roasting of ludwigite ore, the presence of lizardite hinders the selective activation of boron. In this work, lizardite and szaibelyite were prepared and their soda-ash roasting behaviors were investigated using thermogravimetric-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), and scanning electron microscope and energy dispersive spectrometer (SEM-EDS) analyses, in order to shed light on the soda-ash activation of boron within ludwigite ore. Thermodynamics of Na2CO3-MgSiO3-Mg2SiO4-Mg2B2O5 via FactSage show that the formation of Na2MgSiO4 was preferential for the reaction between Na2CO3 and MgSiO3/Mg2SiO4. While, regarding the reaction between Na2CO3 and Mg2B2O5, the formation of NaBO2 was foremost. Raising temperature was beneficial for the soda-ash roasting of lizardite and szaibelyite. At a temperature lower than the melting of sodium carbonate (851 °C), the soda-ash roasting of szaibelyite was faster than that of lizardite. Moreover, the melting of sodium carbonate accelerated the reaction between lizardite with sodium carbonate.


2011 ◽  
Vol 685 ◽  
pp. 367-370 ◽  
Author(s):  
Min Qi ◽  
Da Yi Yang ◽  
Jing Ying Zhang ◽  
Hong Jun Ai

In order to improve the osteoblast growth and bacteria resistance, Zn-containing hydroxyapatite (Zn-HA) and titanium oxide (TiO2) composite coatings were prepared to improve binding between coating and Ti substrate. TiO2 film was prepared on the surface of Ti by micro-arc oxidation (MAO) and Zn-HA coating was deposited on TiO2 using sol–gel technique. Phase structure, composition and microstructure of the surface coatings were analyzed by X-ray diffraction (XRD) and Energy Dispersive Spectrometer (EDS), respectively. The adhesion strength between the coatings with different Zn content was measured by tensile testing. The results showed that there was no significant influence of Zn content on adhesion strength between coating and Ti substrate.


2014 ◽  
Vol 941-944 ◽  
pp. 280-283
Author(s):  
Xiao Yang Wang ◽  
Hong Qiang Ru

SiC particle-reinforced Cu-Fe based braking materials were fabricated by the P/M hot pressing method. The phase composition, microstructure and the worn surface of the composite were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD).The tribological properties were evaluated using a disk-on-disk type laboratory scale dynamometer. Results indicate that the friction coefficient is 0.42 in 6800rpm, 0.7MPa. With the increase of rotation speeds the coefficient of friction and stable rate were decreased.


2019 ◽  
Vol 26 (04) ◽  
pp. 1850177 ◽  
Author(s):  
YINQIAO PENG ◽  
JICHENG ZHOU ◽  
GUIBIN LEI ◽  
YUANJU GAN ◽  
YUEFENG CHEN

Hydrogenated silicon carbonitride (SiCN:H) thin films were deposited by sputtering of silicon carbide target in hydrogen-doped argon and nitrogen atmospheres. The properties of the SiCN:H films were analyzed by scanning electron microscopy with energy dispersive spectrometer, atomic force microscope, Fourier transform infrared spectroscopy, X-ray diffraction and fluorescence spectrophotometer. No distinct crystal was formed in the SiCN:H films as-deposited and annealed at 600∘C and 800∘C. The SiCN:H films were mainly composed of Si–N, Si–C, Si–O, C–C, C–N, C[Formula: see text]N, N–Hn bonds and SiCxNy network structure. The strong blue photoluminescence observed from the SiCN:H film annealed at 600∘C was attributed to SiCxNy network structure.


Author(s):  
Yaşar Sert ◽  
Tevfik Küçükömeroğlu ◽  
İhsan Efeoğlu

In this study, TiAlZrN films were coated on the hardened 1.2344 (X 40 CrMoV 5 1) steels using DC power supplied closed field unbalanced magnetron sputtering (CFUBMS) technique. Structural investigations of coatings were carried out using scanning electron microscope and X-ray diffraction. The thickness of coatings was measured from the cross-sectional scanning electron microscope images, and the grain size value and residual stress were calculated by using X-ray diffraction data in the Scherrer formula. Nano indentation method was used to investigate the surface hardness for reducing the substrate effect due to very thin coating thickness (∼2–3 µm). Scratch test was performed for determining the adhesion strength of the coatings. As a tribo-test, a ball-on-disk system was used. From the results, it was understood why TiAlZrN coatings were attractive. The highest hardness was observed as 50.67 GPa, and the highest scratch resistance was reached to 56 N. Also, it was determined that the coating having the highest tribological properties (5.46 × 10−5 mm3/Nm) increased the wear resistance of the substrate six times (3.06 × 10−4 mm3/Nm).


2012 ◽  
Vol 624 ◽  
pp. 47-50
Author(s):  
Shi Lei Zhang ◽  
Ben Niu ◽  
Enlei Qi ◽  
Lei Wang ◽  
Jie Qiang Wang

In this paper, KMnO4 was used as raw material, nano-MnO2 with different morphologies such as flowers globular, hollow tubular and rodlike were obtained by the microwave assisted hydrothermal synthesis under the acidic condition. The crystal structure and morphology of the resultant MnO2 were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM), respectively. The elements and content of samples were tested by Energy Dispersive Spectrometer (EDS). The influence of reaction temperature and holding time on crystal forms and morphologies of the MnO2 was analyzed.


2004 ◽  
Vol 19 (4) ◽  
pp. 1050-1057 ◽  
Author(s):  
Hua-Ping Xiong ◽  
Yong-Hui Xie ◽  
Wei Mao ◽  
Yun-Feng Chen ◽  
Xiao-Hong Li

A simple and inexpensive method to modify the surface of a Ti3Al-based alloy, liquid-phase siliconizing and aluminizing by an Al-Si alloy, has been proposed. The surface modification at 1013 K for 10 min using Al-10 wt% Si melt resulted in a modified layer with a thickness of about 21 μm, composed of TiAl3 and TiSi2. The coating improved the isothermal oxidation resistance of the Ti3Al-based alloy at 1073 K. A continuous alumina-rich scale was formed at the outermost surface after oxidation. SiO2 was detectable in the oxide scale. The results of x-ray diffraction and x-ray energy dispersive spectrometer analysis showed that during oxidation, some of the TiSi2 in the coating was oxidized to SiO2. In the meantime, the TiSi2 was reduced to a lower silicide, Ti5Si4. The change of the surface microstructure after oxidation and the diffusion reaction between the coating and the Ti3Al substrate were also discussed.


2009 ◽  
Vol 23 (06n07) ◽  
pp. 1377-1382 ◽  
Author(s):  
SEULKI PARK ◽  
JINMYUNG CHOI ◽  
BONGGYU PARK ◽  
IKMIN PARK ◽  
YONGHO PARK ◽  
...  

Hypereutectic Al - Si alloys with fine and evenly distributed Si precipitates have superior mechanical properties In this study, hypereutectic Al - Si alloy powders which contained 15 and 20wt% Si were prepared by a gas atomization process. 1, 3 and 5wt% AlN particles were blended with the Al - Si alloy powders using turbular mixer. The mixture was consolidated by Hot Press at 550°C for 1h under 60MPa. Relative density of the sintered samples was about 98% of theoretical density. This study was investigated by two ways. One is the effect of reinforcement weight fraction and the other is the effect of Silicon contents on the mechanical properties of the composite. Microstructural characterization and phase evaluation were carried out using X-ray Diffraction, Scanning Electron Microscopy equipped with Energy Dispersive Spectrometer. The results showed that the smaller the reinforcement particle size was and the better its distribution was, the higher ultimate tensile strength and hardness were.


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