The 0.2Pb(Zn_1/3Nb_2/3)O₃-0.8Pb(Zr_0.5Ti_0.5)O₃ (0.2PZN-0.8PZT) ceramic system exhibits excellent piezoelectric properties; however, its high sintering temperature (~1,250°C) causes severe PbO volatilization, increases processing cost, and limits co-firing with low-melting-point electrodes in multilayer devices. In this study, LiBiO₂ was introduced as a sintering aid to enable lowtemperature densification of 0.2PZN–0.8PZT ceramics. The optimal composition of x = 0.3 mol% sintered at 1,050°C achieved d₃₃ = 367 pC/N, k_p = 0.54, and ε^T₃₃/ε₀ = 1,643. The Curie temperature was also enhanced to 347.8°C, compared with 297.2°C for the reference specimen sintered at 1,250°C. These results demonstrate that LiBiO₂ addition enables a 200°C reduction in sintering temperature while maintaining piezoelectric performance and improving thermal stability.

In this study, image analysis and surface roughness measurements using an optical microscope are presented as a method to quantitatively evaluate the results of screen printing. Using this method, the squeegee speed, which is the printing process condition, and the printability of the electrode according to the screen mesh were evaluated. Increasing the squeegee speed in the printing process acts as a process element that increases the line width precision of the printed electrode and lowers the surface roughness of the printed surface. Furthermore, the edge roughness, which indicates the clarity of printing, was not significantly affected by the speed of the squeegee during printing. The print thickness increases in proportion to the squeegee speed, but is largely dependent on the screen thickness.

In this study, the effect of Tb inward diffusion on the magnetic properties of the Nd-Fe-B sintered magnets was studied. After sintering of the magnets, TbF₃ slurries were dip-coated on the surface of the samples, then heat-treatment was followed for TbF₃ diffusion. The element distribution in the magnets and the diffusion profiles of Tb ions were analyzed by an EPMA (electron probe micro-analyzer). Prolonged heat treatment resulted in a deeper diffusion length of Tb ions. Coercivity of the 1^st heat-treated sample showed 21.86 kOe, while that of the 1^st, 2^nd heat-treated and annealed sample revealed 34 kOe.

Citations

• Study on the Demagnetization and Classification of NdFeB Magnets According to Different Heat Treatment Temperatures
  Byeong Jun Kim, Ik Keun Park, Young Sung Kim
  Journal of the Korean Society of Manufacturing Technology Engineers.2021; 30(2): 119.     CrossRef