scholarly journals Preparation and Characterization of Tungsten Carbide WC/Cobalt Composites by Powder Metallurgy Method

The Tungsten carbide (WC) based composites are good choice to replace the traditional conventional materials for obtaining high hardness and wear resistance. This work investigates the influence of cobalt content on the characterization of Tungsten carbide. The composite specimens are prepared by using powder metallurgy technique. The effect of cobalt material on the performance of Tungsten carbide hardness, fracture toughness is estimated by conducting suitable experiments. While performing experiments, a powder mixture of 89% WC, 11% of Co was manufactured with powder metallurgy, under appropriate milling conditions and Sintering temperature to ensure uniform microstructure. From the present work the optimum sintering temperature of Tungsten carbide mixed nano cobalt composite is identified. The crystalanity of the resulting materials is identified from a rapid analytical technique, X -ray Diffraction.

Author(s):  
Yavuz Kaplan ◽  
Mehmet Gülsün ◽  
Sinan Aksöz

Abstract In this study, powder metallurgy was applied in a furnace atmosphere to form titanium boride layers on a commercially pure Ti surface. Experiments were carried out using the solid-state boriding method at 900 °C and 1000°C for 12 h and 24 h. Samples were produced by pressing the commercially pure Ti powders under 870 MPa. The sintering process required by the powder metallurgy method was carried out simultaneously with the boriding process. Thus, the sintering and boriding were performed in one stage. The formation of the boride layer was investigated by field emission scanning electron microscopy, optical-light microscopy, X-ray diffraction, and elemental dispersion spectrometry analyses. In addition, microhardness measurements were performed to examine the effect of the boriding process on hardness. The Vickers microhardness of the boronized surface reached 1773 HV, which was much higher than the 150 HV hardness of the commercially pure Ti substrate. The X-ray diffraction analysis showed that the boriding process had enabled the formation of TiB and TiB2 on the powder metallurgy Ti substrate surface. Consequently, the production of Ti via powder metallurgy is a potentially cost-effective alternative to the conventional method, and the boriding process supplies TiB and TiB2 that provide super-high hardness and excellent wear and corrosion resistance.


2013 ◽  
Vol 1516 ◽  
pp. 121-126
Author(s):  
Yuki Miura ◽  
Yasuyuki Kaneno ◽  
Takayuki Takasugi ◽  
Atsushi Kakituji

ABSTRACTA Ni3(Si,Ti) intermetalic alloy was synthesized by the powder metallurgy method using elemental powders. The raw powder mixtures with various compositions were sintered by a spark plasma sintering apparatus and then homogenized at high temperatures. Microstructure, hardness, tensile properties and density of the sintered alloys were investigated as functions of the chemical composition and sintering temperature. It was found that a highly-densified Ni3(Si,Ti) sintered alloy was obtained by choosing proper chemical composition and sintering temperature. Also, the Ni3(Si,Ti) sintered alloy with an L12 single-phase microstructure exhibited high hardness and tensile strength.


2012 ◽  
Vol 501 ◽  
pp. 160-164 ◽  
Author(s):  
Iziana Yahya ◽  
Noor Asikin Ab Ghani ◽  
Mohd Arif Anuar Mohd Salleh ◽  
Hamidi Abd Hamid ◽  
Zainal Arifin Ahmad ◽  
...  

The toxicity in the Sn-Pb solder has promoted the development of Pb-free solder in the electronics industries. Among the Pb-solders, the Sn-3.5Ag-1.0Cu solder is considered a potential replacement and being studied by many researchers. In the present study, the characteristics of Sn-3.5Ag-1.0Cu lead-free solder were studied. The raw materials were tin, silver and copper powders in micron size. The solder was prepared using powder metallurgy route which includes blending, compacting and sintering. Four blending times and two compacting pressures were used to investigate for optimum condition. The melting temperature of the samples were studied using differential scanning calorimeter (DSC) and the presence of Sn Ag, Cu were confirmed using x-ray diffraction analysis (XRD). Finally the effect of variables on the hardness of the solders is reported.


Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6609
Author(s):  
Izabela Matuła ◽  
Grzegorz Dercz ◽  
Maciej Sowa ◽  
Adrian Barylski ◽  
Piotr Duda

In view of the aging population and various diseases worldwide, the demand for implants has been rapidly increasing. Despite the efforts of doctors, engineers, and medical companies, the fabrication of and procedures associated with implants have not yet been perfected. Therefore, a high percentage of premature implantations has been observed. The main problem with metal implants is the mechanical mismatch between human bone and the implant material. Zirconium/titanium-based materials with graded porosity and composition were prepared by powder metallurgy. The whole samples are comprised of three zones, with a radial gradient in the phase composition, microstructure, and pore structure. The samples were prepared by a three-step powder metallurgy method. The microstructure and properties were observed to change gradually with the distance from the center of the sample. The x-ray diffraction analysis and microstructure observation confirmed the formation of diffusive connections between the particular areas. Additionally, the mechanical properties of the obtained materials were checked, with respect to the distance from the center of the sample. An analysis of the corrosion properties of the obtained materials was also carried out.


Author(s):  
J. Alias

Much research on magnesium (Mg) emphasises creating good corrosion resistance of magnesium, due to its high reactivity in most environments. In this study, powder metallurgy (PM) technique is used to produce Mg samples with a variation of aluminium (Al) composition. The effect of aluminium composition on the microstructure development, including the phase analysis was characterised by optical microscope (OM), scanning electron microscopy (SEM) and x-ray diffraction (XRD). The mechanical property of Mg sample was performed through Vickers microhardness. The results showed that the addition of aluminium in the synthesised Mg sample formed distribution of Al-rich phases of Mg17Al12, with 50 wt.% of aluminium content in the Mg sample exhibited larger fraction and distribution of Al-rich phases as compared to the 20 wt.% and 10 wt.% of aluminium content. The microhardness values were also increased at 20 wt.% and 50 wt.% of aluminium content, comparable to the standard microhardness value of the annealed Mg. A similar trend in corrosion resistance of the Mg immersed in 3.5 wt.% NaCl solution was observed. The corrosion behaviour was evaluated based on potentiodynamic polarisation behaviour. The corrosion current density, icorr, is observed to decrease with the increase of Al composition in the Mg sample, corresponding to the increase in corrosion resistance due to the formation of aluminium oxide layer on the Al-rich surface that acted as the corrosion barrier. Overall, the inclusion of aluminium in this study demonstrates the promising development of high corrosion resistant Mg alloys.


2009 ◽  
Vol 24 (2) ◽  
pp. 324-332 ◽  
Author(s):  
X.T. Liew ◽  
K.C. Chan ◽  
L.B. Kong

This paper reports on the preparation and characterization of nickel ferrite (NiFe1.98O4) ceramics doped with Bi2O3 as sintering aid. Focus has been on the effects of concentration of Bi2O3 and sintering temperature on the densification, grain growth, dielectric, and magnetic properties of the NiFe1.98O4 ceramics, with an aim at developing magnetodielectric properties, with almost equal real permeability and permittivity, as well as sufficiently low magnetic and dielectric loss tangents, over 3 to 30 MHz (high frequency or HF band). X-ray diffraction results indicated that there is no obvious reaction between NiFe1.98O4 and Bi2O3, at Bi2O3 levels of up to 7 wt% and temperatures up to 1150 °C. The addition of Bi2O3 facilitated a liquid phase sintering mechanism for the densification of NiFe1.98O4 ceramics. The addition of Bi2O3 not only improved the densification but also promoted the grain growth of NiFe1.98O4 ceramics. To achieve sufficiently low dielectric loss tangent, the concentration of Bi2O3 should not be less than 5 wt%. The low dielectric loss tangents of the samples doped with high concentrations of Bi2O3 can be attributed to the full densification of the ceramics. Magnetic properties of the NiFe1.98O4 ceramics, as a function of sintering temperature and Bi2O3 concentration, can be qualitatively explained by the Globus model. Promising magnetodielectric properties have been obtained in the sample doped with 5% Bi2O3 and sintered at 1050 °C for 2 h. The sample has almost equal values of permeability and permittivity of ∼12, together with low dielectric and magnetic loss tangents, over 3 to 30 MHz. This material might be useful for the miniaturization of HF (3 to 30 MHz) antennas.


2015 ◽  
Vol 75 (7) ◽  
Author(s):  
Amir Arifin ◽  
Abu Bakar Sulong ◽  
Norhamidi Muhamad ◽  
Junaidi Syarif

Hydroxyapatite (HA) has been widely used in biomedical applications due to its excellent biocompatibility. However, Hydroxyapatite possesses poor mechanical properties and only tolerate limited loads for implants. Titanium is well-known materials applied in implant that has advantage in mechanical properties but poor in biocompatibility. The combination of the Titanium alloy and HA is expected to produce bio-implants with good in term of mechanical properties and biocompatabilty. In this work, interaction and mechanical properties of HA/Ti6Al4V was analyzed. The physical and mechanical properties of HA/Ti6Al4V composite powder obtained from compaction (powder metallurgy) of 60 wt.% Ti6Al4V and 40 wt.% HA and sintering at different temperatures in air were investigated in this study. Interactions of the mixed powders were investigated using X-ray diffraction. The hardness and density of the HA/Ti6Al4V composites were also measured. Based on the results of XRD analysis, the oxidation of Ti began at 700 °C. At 1000 °C, two phases were formed (i.e., TiO2 and CaTiO3). The results showed that the hardness HA/Ti6Al4V composites increased by 221.6% with increasing sintering temperature from 700oC to 1000oC. In contrast, the density of the composites decreased by 1.9% with increasing sintering temperature. 


2014 ◽  
Vol 906 ◽  
pp. 18-24 ◽  
Author(s):  
Bao Lin Zhang ◽  
Bin Bin Zhang ◽  
Ning Ning Wang ◽  
Jing Ming Fei

The effect of milling time and sintering process on the dielectric properties of BaTiO3-based X9R ceramics was investigated. The characterization of the raw powders and the sintered ceramic was carried out by X-ray diffraction and scanning electron microscopy. The particle size distribution of the mixed powders was examined by Laser Particle Size Analyzer. The results shown that with the milling time extended, the Cruie Peak was depressed, or even disappeared. Moreover, with the rise of sintering temperature, the dielectric constant of the ceramics increased and the dielectric loss decreased gradually. Eventually, by milling for 11h and sintering at 1090°Cfor 2h, good dielectric properties were obtained, which were ε25°C≥ 2526, εr/εr25°C≤± 12% (–55~200°C), tanδ≤1.12% (25°C).


Rare Metals ◽  
2016 ◽  
Vol 36 (10) ◽  
pp. 806-811 ◽  
Author(s):  
M. Anandajothi ◽  
S. Ramanathan ◽  
V. Ananthi ◽  
P. Narayanasamy

Sign in / Sign up

Export Citation Format

Share Document