Background: We compared the raw Ti-Al-V super alloy transpedicular implant screws with boronized and surface-hardened transpedicular implant screws.
Objective: To improve patients' postoperative prognosis with the production of harder and less fragile screws.
Methods: Surface hardening was achieved by applying green-body encapsulation of the specimen with elemental boron paste which is sintered at elevated temperatures to ensure the boron-metal diffusion.
Boron carbide powders were synthesized by mechanically activated annealing process using anhydrous boron oxide (BO) and varying carbon (C) sources such as graphite and activated carbon: The precursors were mechanically activated for different times in a high energy ball mill and reacted in an induction furnace. According to the Raman analyses of the carbon sources, the I(D)/I(G) ratio increased from ~ 0.25 to ~ 0.
View Article and Find Full Text PDFJ Phys Condens Matter
September 2010
The defect structure of Fe(3+)-, Cu(2+)-, Mn(4+)- and Gd(3+)-doped PbTiO(3) nano-powders has been studied by electron paramagnetic resonance (EPR) spectroscopy. Analogous to the situation for 'bulk' ferroelectrics, Fe(3+) and Cu(2+) act as acceptor-type functional centers that form defect complexes with charge-compensating oxygen vacancies. The corresponding defect dipoles are aligned along the direction of spontaneous polarization, P(S), and possess an additional defect polarization, P(D).
View Article and Find Full Text PDF