Showing 4 results for Sintering.
M .kharaziha, M.h. Fathi,
Volume 29, Issue 1 (6-2010)
Abstract
In this study, forsterite nanopowder was prepared by mechanical alloying and post-heat treatment method. Bioactive properties of forsterite nanopowder were studied by immersing the powder in the SBF. Nanostructure forsterite bulk dense form was prepared by the two step sintering method. It was found that pure forsterite nanopowder with 25-60nm particle size was produced. The results of soaking of forsterite nanopowder in the SBF showed that forsterite nanopowder is bioactive. Also, forsterite dense bulk with the optimal hardness of 940 Hv and fracture toughness of 3.61 MPa.m1/2 was produced. These findings suggest that forsterite nanostructure ceramics possess good biocompatibility, bioactivity and mechanical properties and could be suitable for orthopedic and dental implant materials.
M. Ashuri, F. Moztarzadeh, N. Nezafati, A. Ansari Hamedani, M. R. Tahriri,
Volume 31, Issue 1 (6-2012)
Abstract
In the present study, a bioceramic-based composite with remarkable mechanical properties and in vitro apatite forming ability was synthesized by sintering compacts made up of mixtures of hydroxyapatite (HA) and sol-gel derived bioactive glass (64SiO2-26CaO-5MgO-5ZnO) (based on mole %). HA was synthesized through co-precipitation method. The stabilization temperature of the bioactive glass was set to be 700 ºC according to simultaneous thermal analysis (STA). Laser Particle Size Analysis (LPSA) was used to compare the particle size distributions of the synthetic powders. HA matrix was mixed with different weight percentages of bioactive glass (5, 10, 15, 20, 25 and 30 wt. %) and compressed by 80 MPa pressure. After sintering the uniaxial compression test of the samples was done and the specimen with the highest compressive strength (20 wt. % bioactive glass) was selected to be immersed in the Simulated Body Fluid (SBF) for 3, 7 and 14 days. The results showed that the compressive strength of the sample decreased after keeping it in the SBF. Also, inductively coupled plasma analysis (ICP) was used to study the ion release behavior of the sample in the SBF. Finally, phase composition, microstructure and functional groups in the composite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infra-red spectroscopy (FTIR) techniques, respectively.
M. Hosseinzadeh, M. Bozorgmehr, A. Ghasemi, M. Askari,
Volume 37, Issue 2 (9-2018)
Abstract
NdFeB magnetic alloy is one of the hard magnets having the highest maximum energy in the world. The most popular methods of manufacturing magnetic alloys Nd2Fe14B are powder metallurgy and rapid quenching techniques. In this research, the effect of the hot press temperature on the magnetic properties of the hard magnet Nd2Fe14B was studied. Structural studies were carried out using X-ray diffraction, X-ray fluorescence spectrometer and Scanning Electron Microscope; Spectroscopic energy distribution of Nd2Fe14B bulk magnet and the magnetic tests were done using a vibrating magnetometer to investigate the structures and the magnetic properties of the produced samples. The results showed that in addition to the Nd2Fe14B phase, the α-Fe and Nd-rich phase also existed in the structure of the provided magnet. These secondary phases had effectively created exchange couplings with the main phase, improving the magnetic properties. The magnetic properties of the sintered magnets were improved by increasing the press temperature; finally, Nd2Fe14B magnet was made with the maximum energy, which was d higher than 290 kj/m3 .
S. Masoomi Ganjgah , M. Abbasi,
Volume 39, Issue 4 (2-2021)
Abstract
This study aims at investigating changes in microstructure and strength of W alloy and Cu bimetals with varying spark plasma sintering (SPS) temperature and percentage of copper in W-Cu-Ni alloy. After SPS of W (12 wt%)-Cu (14 wt%)-Ni (3 wt%) alloy powder into consolidated discs at 1350 ° C, they were spark plasma sintered to copper discs at various temperatures. Assessment of the interface microstructure and shear strength was performed by field emission scanning electron microscpe (FESEM) and shear strength test, respectively. Results indicated SPS is successful in forming a perfect metallic bond with monolithic interface and high shear strength of about 45 MPa in Cu/W-12Cu-3Ni bimetal that is extra high quality and not reported in previous investigations.
