Investigation of Microstructure and Properties of Ni/CNT Nanocrystalline Coating Deposited by Brush Plating

2007 ◽  
Author(s):  
Jun Tan ◽  
Tiantian Yu ◽  
Binshi Xu ◽  
Bin Zhu
Keyword(s):  
Carbon Nanotubes ◽  
Grain Size ◽  
Wear Resistance ◽  
Direct Current ◽  
Pulse Width ◽  
Pulse Current ◽  
Heating Temperature ◽  
Current Source ◽  
Average Grain Size ◽  
Brush Plating

Nickle-carbon nanotube (Ni/CNT) nanocrystalline coatings with different parameter were prepared by brush plating. The carbon nanotubes were added into common nickel solution for brush plating and ball milling was used to disperse the carbon nanotubes in the solusion. The concentration of carbon nanotubes in the solution was 3 g/l. The SEM and XRD were applied to investigate the grain size, microstructure and morphology of the coatings. The hardness and the wear mass loss of the coatings were examined on micro hardness tester and ball on disk tribotester. The results show that under a direct-current source, the grain size of the Ni/CNT coating was about 20 nm. Under a pulse-current source, the grain size of the Ni/CNT coatings decreased and the coatings gained smoother surface when the pulse-width became shorter. The grain size of the Ni/CNT coating increased with the heating temperature increasing and the average grain size of the coating heated at 500 degrees centigrade was over 50 nm. The microhardness of the Ni/CNT coating under a pulse-current source was higher than that of the coating under a direct-current source. Under a pulse-current source, the microhardness of the Ni/CNT coating increased when the pulse-width became shorter. The microhardness of the Ni/CNT coating changed slightly below 300 degrees centigrade, while decreased obviously after heated up to 400 degrees centigrade. The wear resistance of the Ni/CNT coating under a pulse-current was higher than that of the coating under a direct-current. Under a pulse-current, the wear resistance of the Ni/CNT coating increased when the pulse-width became shorter.

ELECTROCHEMICAL AND PHYSICAL PROPERTIES OF NANOCRYSTALLINE COPPER DEPOSITS PRODUCED BY PULSE ELECTRODEPOSITION

2008 ◽  
Vol 22 (18n19) ◽  
pp. 3005-3012 ◽  
Author(s):  
MOHSEN SAREMI ◽  
MARYAM ABOUIE ◽  
R. VAGHAR
Keyword(s):  
Grain Size ◽  
Physical Properties ◽  
Direct Current ◽  
Pulse Current ◽  
Copper Deposits ◽  
Deposition Parameters ◽  
Plating Method ◽  
Nanocrystalline Layer ◽  
Off Time ◽  
Frequency Current

This paper reports our recent studies on nanocrystalline layer of copper produced using pulse plating method. The grain size of the copper layer was about 60 nm. Electrochemical and physical Properties of the nanocrystalline surface were investigated using Potentiostatic scanning and Impedance measurements. Microcrystalline copper deposits were also produced by direct current electrodeposition processes and compared with pulse plated ones. Effects of deposition parameters, such as the peak Density, frequency, current-on time and current-off time of the pulse current (PC), on the grain size were investigated for the purpose of process optimization. It was demonstrated that the nanocrystalline film was markedly superior to regularly grained film made by direct current (DC) plating; the nanocrystalline deposit shows higher electrochemical stability and lower electrical resistance.

scholarly journals Development of Functionally Graded Metal Composite (LM25-SiC) Using Centrifugal Casting Process and their Characterisation

10.29007/1zb1 ◽  
2018 ◽  
Author(s):  
Kinjal Patel ◽  
Viral Panara ◽  
Mayur Sutaria
Keyword(s):  
Grain Size ◽  
Wear Resistance ◽  
Rotation Speed ◽  
Centrifugal Casting ◽  
Research Work ◽  
Outer Region ◽  
Functionally Graded ◽  
Metal Composite ◽  
Sic Particles ◽  
Average Grain Size

The research work includes development of vertical centrifugal casting set-up for functionally graded metal composite (LM25-SiC) preparation. Material parameters like wt % of SiC Particles (2, 3.5, and 5%), average grain size of SiC particles (75, 44, and 6.5 μm) and process parameter like rotational speed of the mould (1000, 1100, 1200 RPM) are selected for characterization. Samples were tested for hardness and wear resistance to investigate the effect parameters on change of properties. Microstructure analysis was also performed. Total 11 FGM samples were made by varying different process parameters. It is found that hardness and wear resistant property improves with increase in wt% of SiC particles and mould rotation speed. It is also found that hardness and wear resistance value increases with reduction of average grain size of SiC particles. Increased mould rotation speed improves the level of distribution of reinforcing particles from inner to outer region.

scholarly journals Wear-Resistance Improvement of 65Mn Low-Alloy Steel through Adjusting Grain Refinement by Cyclic Heat Treatment

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7636
Author(s):  
Ying Tong ◽  
Yu-Qing Zhang ◽  
Jiang Zhao ◽  
Guo-Zheng Quan ◽  
Wei Xiong
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Wear Resistance ◽  
Grain Refinement ◽  
Alloy Steel ◽  
Low Alloy Steel ◽  
Cyclic Heat Treatment ◽  
Average Grain Size ◽  
Cyclic Heat ◽  
Cyclic Quenching

Refined microstructures achieved by cyclic heat treatment significantly contribute to improving the wear resistance of steels. To acquire the refined microstructures of 65Mn low-alloy steel, first, the specimens were solid solution-treated; then, they were subjected to cyclic heat treatment at cyclic quenching temperatures of 790–870 °C and quenching times of 1–4 with a fixed holding time of 5 min. The mechanical properties of 65Mn low-alloy steel in terms of hardness, tensile strength, elongation and wear resistance were characterized. Afterwards, the effect of cyclic heat treatment on microstructure evolution and the relationships between grain refinement and mechanical properties’ improvement were discussed. The results show that the average grain size firstly decreased and then increased with the increase in the quenching temperature. Hardness increased with grain refinement when the temperature was lower than 830 °C. Once the temperature exceeded 830 °C, hardness increased with the temperature increase owing to the enrichment of carbon content in the martensite. With the increase in cyclic quenching times, hardness continuously increased with grain refinement strengthening. In addition, both tensile strength and elongation could be significantly improved through grain refinement. The relationships among wear loss, hardness and average grain size showed that wear resistance was affected by the synthesis reaction of grain refinement and hardness. Higher hardness and refined grain size contributed to improving the wear resistance of 65Mn low-alloy steel.

Preparation and Characterization of Ca0.8Sr0.2ZrO3 Powders Prepared by Soft Chemical Route

2007 ◽  
Vol 336-338 ◽  
pp. 968-970
Author(s):  
Ji Xia Lei ◽  
Xiao Lin Liu ◽  
Tao Yan ◽  
Jian Feng Chen
Keyword(s):  
Grain Size ◽  
Room Temperature ◽  
Heating Temperature ◽  
Strontium Zirconate ◽  
Chemical Route ◽  
Average Grain Size ◽  
Conventional Sintering ◽  
Oxalate Coprecipitation ◽  
Soft Chemical Route

Precursors of calcium strontium zirconate (Ca0.8Sr0.2ZrO3) were synthesized by oxalate coprecipitation method. TG-DTA was used to characterize the thermal decomposition behaviors of the precursors. The XRD results revealed that the powders crystallized as cubic Ca0.8Sr0.2ZrO3 with increasing heating temperature up to 1000°C. Calcium strontium zirconate ceramics were obtained under conventional sintering conditions by using the as-prepared Ca0.8Sr0.2ZrO3 powders. The SEM micrographs of the ceramics sintered at 1450oC exhibited narrow grain-size distribution with the average grain size around 0.7 4m. The dielectric properties showed that, dielectric constant of the Ca0.8Sr0.2ZrO3 was about 24.0 and dielectric loss was 0.002 at the frequency of 1GHz and the room temperature.

Wear Property of Superfine Grained Si2N2O-Si3N4 Composites

2008 ◽  
Vol 368-372 ◽  
pp. 917-919
Author(s):  
Jun Ting Luo ◽  
Qing Zhang ◽  
Hong Bo Li
Keyword(s):  
Grain Size ◽  
Wear Resistance ◽  
Silicon Nitride ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
High Hardness ◽  
Liquid Phase Sintering ◽  
Wear Property ◽  
Average Grain Size ◽  
Bearing Ball

Si3N4-Si2N2O composites were fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering. The mass loss, relative density and average grain size increase with increasing sintering temperature. The average grain size is less than 500nm when the sintering temperature is lower than 1700°C. Friction coefficient is from 0.35 for sintering temperature 1650°C to 0.74 for 1600°C when the composites were worn by silicon nitride bearing ball. High hardness of 21.5GPa and relative wear resistance of 32 were observed at a sintering temperature of 1600°C. The wear surface are very smooth and no grooving and subsurface fracture, which indicates that they are worn slightly.

scholarly journals Quantification of the Effects of Coating Parameters on the Properties of TiAlZrN Coatings

2020 ◽  
Vol 1 (4) ◽  
pp. 1-8
Author(s):  
Yaşar Sert
Keyword(s):  
Grain Size ◽  
Wear Resistance ◽  
Adhesion Strength ◽  
Bias Voltage ◽  
Ambient Pressure ◽  
Closed Field ◽  
Substrate Bias ◽  
Substrate Bias Voltage ◽  
Deposition Parameters ◽  
Average Grain Size

In this study, TiAlZrN layer was coated on AISI H13 substrate surface with variable substrate bias voltage, Zr target current, and ambient pressure deposition parameters by using closed field unbalanced magnetron sputtering (CFUBMS) technique. The main goal of this paper is to determine the effect percentages of these variable parameters on the properties of TiAlZrN coatings by Analysis of Variance (ANOVA). These coating properties include average grain size, thickness, hardness, adhesion strength and wear resistance. The numerical data obtained as a result of this study will shed light on the select of parameters which have a direct effect on coatings to the researchers who will work on this topic. The parameters used as variables in the deposition process were leveled with Taguchi experimental (33) design method. Average grain size and thickness of coatings were established by SEM images. The average grain sizes of coatings were between 290 and 440 nm and the most effective parameter was substrate bias voltage with 58.4 %. The hardness, adhesion strength and wear properties of the coatings were determined using micro hardness tester, scratch test and ball on disc wear device respectively. The maximum hardness of coatings was 1674 HV, while the wear resistance was increased by 37 times compared to the substrate material. The maximum adhesion strength value of the coatings was reached 56N. The superiority of the effect of substrate bias voltage on the hardness, adhesion strength and wear resistance of the coatings compared to other deposition parameters was again prominent (respectively 86.15%, 53.63% and 70.86%). Also, the hardness and wear resistance properties were found to be directly related to each other. The sample with the highest coating hardness also showed the highest wear resistance performance. In the sample with the lowest hardness, this situation found to be similar.

scholarly journals Improvement of the mechanical properties of spark plasma sintered hap bioceramics by decreasing the grain size and by adding multi-walled carbon nanotubes

2013 ◽  
Vol 45 (2) ◽  
pp. 233-243 ◽  
Author(s):  
Dj. Veljovic ◽  
G. Vukovic ◽  
I. Steins ◽  
E. Palcevskis ◽  
P.S. Uskokovic ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Grain Size ◽  
Sintering Temperature ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Multi Walled Carbon Nanotubes ◽  
Spark Plasma ◽  
Walled Carbon Nanotubes

Composites based on HAP and oxidized multi-walled carbon nanotubes (o-MWCNT) and monophase HAP materials were processed by spark plasma sintering. Starting from stoichiometric nano-sized HAP powder, monophase bioceramics were obtained with a density close to the theoretical one and with an average grain size of several hundred nanometers to micron dimensions. It was shown that decreasing the sintering temperature resulted in a decrease of the grain size, which affected an increase in the fracture toughness and hardness. The fracture toughness of an HAP/ o-MWCNT bioceramic processed at 900?C for only 5 min was 30 % higher than that of monophase HAP materials obtained under the same conditions. The addition of MWCNT during SPS processing of HAP materials caused a decrease in the grain size to the nano-dimension, which was one of the reasons for the improved mechanical properties.

Surface Modification and its Influence on the Microstructure and Creep Resistance of Nickel Based Superalloy René 77 / Modyfikacja Powierzchniowa Oraz Jej Wpływ Na Mikrostrukture I Wytrzymałosc Na Pełzanie Odlewów Z Nadstopu Niklu Ren´E 77

2013 ◽  
Vol 58 (1) ◽  
pp. 95-98 ◽  
Author(s):  
M. Zielinska ◽  
J. Sieniawski
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Surface Modification ◽  
Turbine Blades ◽  
Processing Parameters ◽  
Grain Structure ◽  
Creep Tests ◽  
Cobalt Aluminate ◽  
Nickel Based Superalloy ◽  
Average Grain Size

Superalloy René 77 is very wide used for turbine blades, turbine disks of aircraft engines which work up to 1050°C. These elements are generally produced by the investment casting method. Turbine blades produced by conventional precision casting methods have coarse and inhomogeneous grain structure. Such a material often does not fulfil basic requirements, which concern mechanical properties for the stuff used in aeronautical engineering. The incorporation of controlled grain size improved mechanical properties. This control of grain size in the casting operation was accomplished by the control of processing parameters such as casting temperature, mould preheating temperature, and the use of grain nucleates in the face of the mould. For nickel and cobalt based superalloys, it was found that cobalt aluminate (CoAl2O4) has the best nucleating effect. The objective of this work was to determine the influence of the inoculant’s content (cobalt aluminate) in the surface layer of the ceramic mould on the microstructure and mechanical properties at high temperature of nickel based superalloy René 77. For this purpose, the ceramic moulds were made with different concentration of cobalt aluminate in the primary slurry was from 0 to 10% mass. in zirconium flour. Stepped and cylindrical samples were casted for microstructure and mechanical examinations. The average grain size of the matrix ( phase), was determined on the stepped samples. The influence of surface modification on the grain size of up to section thickness was considered. The microstructure investigations with the use of light microscopy and scanning electron microscopy (SEM) enable to examine the influence of the surface modification on the morphology of ’ phase and carbides precipitations. Verification of the influence of CoAl2O4 on the mechanical properties of castings were investigated on the basis of results obtained form creep tests.

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