Effect of TaC on W-Ti-Co Ultrafine Cemented Carbides

2011 ◽  
Vol 306-307 ◽  
pp. 598-602 ◽  
Author(s):  
Chong Cai Zhang ◽  
Qun Qun Yuan ◽  
Quan Wang ◽  
Zhi Yong Sheng ◽  
Long Wang
Keyword(s):  
Rupture Strength ◽  
Average Particle Size ◽  
High Energy ◽  
The Other ◽  
Cemented Carbides ◽  
Average Particle ◽  
Transverse Rupture Strength ◽  
Comprehensive Performance ◽  
Energy Ball ◽  
Different Content

The W-Ti-Co powders was doped different content of TaC with an average particle size of 270nm were prepared by 72 hours high-energy ball milling. The powder was cold isostatic pressed and vacuum sintered at 1380°C. The physical properties and the micrographs of samples were detected. The main conclusions were as follow: the density and Cobalt magnetic decreased with the content of TaC increasing, the coercivity increased at first and then decreased, the coercivity of alloy with 0.6wt.% TaC was higher than the other. When the content of TaC was less than 0.6wt.%, the hardness increased with the content of TaC increasing .While when the content of TaC was more than 0.6wt.%, the hardness decreased obviously. Comparing with the alloy without TaC doped, the transverse rupture strength (TRS) of the alloy with 0.4wt.%TaC increased to a larger extent. When the content of TaC was more than 0.4wt.%, the transverse rupture strength (TRS) decreased with the content of TaC increasing. The TaC could inhibit the grain growth, and the comprehensive performance of the alloy with 0.4wt.% TaC was best.

Effect of VC/Cr3C2 Additions on Microstructure and Mechanical Properties of WC-16TiC-XTaC-10Co Ultrafine Cemented Carbides

2012 ◽  
Vol 476-478 ◽  
pp. 1214-1217 ◽  
Author(s):  
Chong Cai Zhang ◽  
Quan Wang ◽  
Qun Qun Yuan ◽  
Long Wang
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Ball Milling ◽  
Rupture Strength ◽  
Average Particle Size ◽  
High Energy ◽  
Cemented Carbides ◽  
Average Particle ◽  
Hardness Increase ◽  
Energy Ball

In this paper, the WC-16TiC-xTaC-10Co mixture mixed by WC 0.52μm, (W, Ti, Ta)C 2.9μm and Co1.36μm and prepared by high-energy ball milling, changed the VC and Cr3C2 adding amount. After ball milling for 60 hours, an average particle size of 220nm powder was prepared and it was cold isostatic pressed at 300MPa and vacuum sintered at 1410°C. The physical properties and the micrographs of samples were detected. The main conclusions are as follow: the coercivity and hardness increase and Cobalt magnetic decreases with the content of Cr3C2 increasing, the transverse rupture strength (TRS) does not vary. The VC and Cr3C2 inhibit the growth of WC grain, but can’t inhibite the (W, Ti, Ta)C grain growth effectively.

Effect of Sintering Temperature on Microstructure and Mechanical Properties of WC-16TiC-xTaC-9Co Cemented Carbides

2012 ◽  
Vol 268-270 ◽  
pp. 340-343
Author(s):  
Chong Cai Zhang ◽  
Quan Wang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Sintering Temperature ◽  
Rupture Strength ◽  
High Energy ◽  
Cemented Carbides ◽  
Average Grain Size ◽  
Comprehensive Performance ◽  
Energy Ball ◽  
Average Size

In this paper, the WC-16TiC-xTaC-9Co and Co are mixed together preparing for WC, (W, Ti, Ta) C. By high-energy ball milling, the powder is cold isostatic pressed and vacuum sintered by 1410°C, 1430°Cand 1450°C.The physical properties and the micrographs of samples are detected. The main conclusions are as following: sintered samples have the best comprehensive performance at 1450°C, the density of the sample is 99.7% and the actual density is 10.91g/cm3. The hardness is 92.8 HRA and the transverse rupture strength (TRS) is 1100MPa. The grain size grows up obviously with the high temperature. The average grain size of WC is 0.7μm and the average size of (W, Ti, Ta)C is 3μm.

Diffusion in Nanocrystalline Ion Conductors Studied by Solid State NMR and Impedance Spectroscopy

2009 ◽  
Vol 283-286 ◽  
pp. 705-715 ◽  
Author(s):  
Paul Heitjans ◽  
Martin Wilkening
Keyword(s):  
Dynamic Properties ◽  
Average Particle Size ◽  
High Energy ◽  
Average Particle ◽  
Ion Dynamics ◽  
Ionic Conductors ◽  
Present Contribution ◽  
Energy Ball ◽  
Phase Systems ◽  
Ion Conductors

Materials with an average particle size of less than about 50 nm often show new or at least enhanced physical properties. In many cases nanocrystalline ionic conductors exhibit a high increase of cation, e. g. Li+, or anion, e. g. F−, diffusivity. In the present contribution we review recent studies on ion dynamics in nanocrystalline ion conductors, both single-phase systems and composites, being prepared by high-energy ball milling. These include, e.g., LiTaO3, Li2O:Al2O3, LiF:Al2O3, BaF2, CaF2, BaF2:CaF2 and (BaF2:CaF2):Al2O3. Dynamic properties were probed by 7Li and/or 19F NMR line shape and relaxation as well as ion conductivity measurements.

Densification Process of WC-MgO Nanocomposite Based on Master Sintering Curve

2012 ◽  
Vol 152-154 ◽  
pp. 232-238
Author(s):  
Chen Xin Ouyang ◽  
Shi Gen Zhu
Keyword(s):  
Average Particle Size ◽  
High Energy ◽  
Average Particle ◽  
Densification Process ◽  
Heating Rates ◽  
Final Density ◽  
Energy Ball ◽  
Constant Heating ◽  
Heating Up ◽  
And Control

The master sintering curve (MSC) of nanocomposite WC-MgO was constructed based on the combined-stage sintering model. Nano-sized WC-4.3wt%MgO powder with average particle size of 35nm was synthesized by high-energy ball milling, and then uniaxially pressed at the pressure of 500MPa to fabricate green compacts. The shrinkage response of the compacts, used to construct the master sintering curve, were studied by dilatometric runs at two constant heating rates of 5°C/min and 10°C/min up to 1900°C. Using the estimated activation energy, the master sintering curves were established and compared to acquire an optimum value (Q=361.8 kJ/mol). The obtained MSC was validated by non-isothermal sintering with the identical green compacts. The results demonstrate that the MSC can be applied successfully to predict and control shrinkage level and final density during heating up regardless of heating rates.

Microstructural Characterization of 66%Co-28%Cr-6%Mo Dental Alloy Powder Obtained by High-Energy Ball Milling

2014 ◽  
Vol 802 ◽  
pp. 51-55 ◽  
Author(s):  
Claudinei dos Santos ◽  
Alexandre Fernandes Habibe ◽  
Durval Rodrigues ◽  
José C. Minatti ◽  
Jefferson Fabrício C. Lins ◽  
...  
Keyword(s):  
Ball Milling ◽  
Average Particle Size ◽  
Microstructural Characterization ◽  
High Energy ◽  
Inert Atmosphere ◽  
High Energy Ball Milling ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Energy Ball

In this work, the microstructural features of the particles based on 66% Co-28% Cr-6% Mo alloy, were investigated by X-ray diffraction and Scanning electron microscopy (SEM). Powders obtained by high-energy ball milling in an inert atmosphere, and held in SPEX mill with times between 15min and 120min, about ball/powder ratio of 6:1, were characterized by X-ray diffraction indicating in all conditions, Co phase as the crystalline phase of the system. The powders have a morphology that indicate a continuous reduction in average particle size as a function of increasing time, however, the shape of the particles initially flat for times up to 30 minutes, becomes spherodized after 30 minutes of grinding.

Production of BaTiO2 Nanocrystalline Powders by High Energy Milling and Piezoelectric Properties of Corresponding Ceramics

2013 ◽  
Vol 547 ◽  
pp. 133-138
Author(s):  
K. Chandramani Singh ◽  
Chongtham Jiten
Keyword(s):  
Particle Size ◽  
Piezoelectric Properties ◽  
Average Particle Size ◽  
Hysteresis Loops ◽  
Functional Materials ◽  
High Energy ◽  
Nanocrystalline Powders ◽  
Average Particle ◽  
Ceramic Samples ◽  
Energy Ball

Barium titanate (BaTiO3 or BT) has become one of the most studied functional materials due to its potential application as multilayer ceramic capacitors, PTC thermistors, electromechanical devices, piezoelectric transducers, actuators, dynamic RAM or logic circuitry as well as a great variety of electro-optical devices. In the present study, high energy ball milling has been used to produce nanocrystalline powders of BT. Two categories of powders having average particle size of 35 nm and 25 nm were prepared by setting the milling speed at 250 rpm and 300 rpm respectively, fixing the milling time at 30 hours. Four ceramic samples, BT35-1350, BT25-1350, BT35-1400 and BT25-1400, were formed by sintering the two types of powders at 1350oC and 1400oC for 3 hours. The ferroelectric and piezoelectric properties of the ceramic samples were studied and found to be dependent on the size of the starting nanopowders. The bulk density and piezoelectric constant (d33) of B25-1350 were found to be less than those of BT35-1350, while the reverse was true in case of BT25-1400 and BT35-1400. Well saturated P-E hysteresis loops were observed for all the ceramics with the size and shape of the loops appearing different for the four samples. For both the pairs of ceramics sintered at 1350oC and 1400oC, the remnant polarization (Pr) decreases with starting particle size, that is, as we go from BT35-1350 to BT25-1350 as well as from BT35-1400 to BT25-1400. However, with decreasing particle size of the starting powders, the coercive field (Ec) increases for the ceramics sintered at 1350oC and decreases for the ceramics sintered at 1400oC. The study reveals the importance of an optimized combination of the size of the starting nanopowders and sintering temperature for obtaining BT ceramics with the desired properties.

Nanocrystalline Diamond Particles Prepared by High-Energy Ball Milling Method

2013 ◽  
Vol 284-287 ◽  
pp. 168-172 ◽  
Author(s):  
Chii Ruey Lin ◽  
Da Hua Wei ◽  
Minh Khoa Ben Dao ◽  
Ren Jei Chung ◽  
Ming Hong Chang
Keyword(s):  
Ball Milling ◽  
Average Particle Size ◽  
Diamond Powder ◽  
High Energy ◽  
Milling Process ◽  
High Energy Ball Milling ◽  
Acid Mixture ◽  
Average Particle ◽  
X Ray ◽  
Energy Ball

In this present work, nanodiamond (ND) particles were successfully prepared from commercial micron diamond powder at room temperature by high energy ball milling process using an oscillatory mill (SPEX8000). The size reduction and structural evolutions of the milled samples were investigated as a function of the milling time by means of X-ray diffraction, and field emission scanning electron microscopy. The line broadening technique was used to determine the crystallite size and lattice strain. After 40 h of milling, obtained ND particles possessed uniform shape and 25 nm of average particle size. Also, energy dispersive X-ray results revealed the high purity of ND and demonstrated that the purification process using harsh acid mixture were effective to remove metal and non-diamond carbon impurities produced in milling stage. All results propose a scalable method to preparation ND particles as well as nanocrystalline materials.

Effect of High-Energy Ball Milling of ZrB2 Powder on the Microstructure and Mechanical Properties of ZrB2-SiC Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 723-728
Author(s):  
Qi Long Guo ◽  
Jun Guo Li ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
Ball Milling ◽  
Average Particle Size ◽  
Sintered Sample ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Sample Introduction ◽  
Second Phase ◽  
Average Particle ◽  
Sic Ceramics ◽  
Energy Ball

The sinterability of ZrB2-20vol.% SiC ceramics by high-energy ball milling as well as introduction of Zr and Al as sintering additives. Densification process and microstructure of ZrB2-SiC ceramics were investigated. After high-energy ball milling, the average particle size decreased to about 500 nm-2 μm, and ZrB2-SiC powder can be sintered to 98.92% theoretical density at 1800 °C, but a trace of amount of oxidation (ZrO2) were detected in sintered sample. Introduction of Zr, Al and C combined with high-energy ball milling enhanced the densification of ZrB2-SiC ceramics and reduced the particle sizes, and the relative density of obtained ceramic reached up to 99.49% at 1800 °C. The additions of Zr, Al and C can remove the oxide impurities of the surface of ZrB2 particles and form a reaction between oxide impurities. The fracture toughness increased of the 40% when ZrB2 powders were milled by high-energy ball milling, and increased to 4.77±0.18 MPa•m1/2. However, the attrition-milled composites had lower hardness and Young’s modulus, which was attributed to the presence of a second phase in the grain boundaries.

scholarly journals Green synthesis: Proposed mechanism and factors influencing the synthesis of platinum nanoparticles

2020 ◽  
Vol 9 (1) ◽  
pp. 386-398 ◽  
Author(s):  
Mahmood S. Jameel ◽  
Azlan Abdul Aziz ◽  
Mohammed Ali Dheyab
Keyword(s):  
Green Synthesis ◽  
Reaction Temperature ◽  
Platinum Nanoparticles ◽  
Energy Requirement ◽  
Average Particle Size ◽  
High Energy ◽  
Energy Utilization ◽  
Critical Parameters ◽  
Synthesis Process ◽  
Average Particle

AbstractPlatinum nanoparticles (Pt NPs) have attracted interest in catalysis and biomedical applications due to their unique structural, optical, and catalytic properties. However, the conventional synthesis of Pt NPs using the chemical and physical methods is constrained by the use of harmful and costly chemicals, intricate preparation requirement, and high energy utilization. Hence, this review emphasizes on the green synthesis of Pt NPs using plant extracts as an alternative approach due to its simplicity, convenience, inexpensiveness, easy scalability, low energy requirement, environmental friendliness, and minimum usage of hazardous materials and maximized efficiency of the synthesis process. The underlying complex processes that cover the green synthesis (biosynthesis) of Pt NPs were reviewed. This review affirms the effects of different critical parameters (pH, reaction temperature, reaction time, and biomass dosage) on the size and shape of the synthesized Pt NPs. For instance, the average particle size of Pt NPs was reported to decrease with increasing pH, reaction temperature, and concentration of plant extract.

Development of Ni/h-BN Self-Lubricating Composite Powder by High-Energy Ball Milling

2016 ◽  
Vol 869 ◽  
pp. 277-282
Author(s):  
Moisés Luiz Parucker ◽  
César Edil da Costa ◽  
Viviane Lilian Soethe
Keyword(s):  
Ball Milling ◽  
Milling Time ◽  
Solid Lubricants ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Second Phase ◽  
Average Particle ◽  
Composite Powders ◽  
The Matrix ◽  
Energy Ball

Solid lubricants have had good acceptance when used in problem areas where the conventional lubricants cannot be applied: under extreme temperatures, high charges and in chemically reactive environments. In case of materials manufactured by powder metallurgy, particles of solid lubricants powders can be easily incorporated to the matrix volume at the mixing stage. In operation, this kind of material provides a thin layer of lubricant that prevents direct contact between the surfaces. The present study aimed at incorporating particles of second phase lubricant (h-BN) into a matrix of nickel by high-energy ball milling in order to obtain a self-lubricating composite with homogeneous phase distribution of lubricant in the matrix. Mixtures with 10 vol.% of h-BN varying the milling time of 5, 10, 15 and 20 hours and their relationship ball/powder of 20:1 were performed. The effect of milling time on the morphology and microstructure of the powders was studied by X-ray diffraction, SEM and EDS. The composite powders showed reduction in average particle size with increasing milling time and the milling higher than 5 hours resulted in equiaxial particles and the formation of nickel boride.

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