Activation of ferroelectric implant ceramics by corona discharge poling

Electromechanical properties of paper‐derived potassium sodium niobate piezoelectric ceramics

“…The achieved density of the paper‐derived ceramic is slightly lower than that of the conventionally sintered KNN sample, that is, 89%. It is important to note that the sintered density of chemically unmodified KNN is generally relatively low and has been reported to be between 88%–92% 14–16 . Therefore, the observed low sintered density, that is, poor densification of conventionally prepared KNN, is not due to the processing or sintering condition used here, but rather a general phenomenon of this chemically unmodified KNN composition 17 .…”

“…The temperature-dependent permittivity data for conventional and paper-derived KNN (Figure 5A,B) show a typical response with dielectric anomaly around 190 • C and 400 • C, indicating the interferroelectric phase transition from the orthorhombic-tetragonal phase and the ferroelectric-paraelectric phase, respectively. 16 Interestingly, the phase transition temperatures seem to shift to a lower temperature, by approximately 18 • C for the paper-derived KNN. Generally, a shift in the phase transition temperature can be related to stress and/or defects.…”

“…In order to understand the functional dielectric response, for example, capacitance and loss, and their temperature‐dependent variation in the crystal structure, temperature‐dependent dielectric permittivity measurement up to 500°C was conducted. The temperature‐dependent permittivity data for conventional and paper‐derived KNN (Figure 5A,B) show a typical response with dielectric anomaly around 190°C and 400°C, indicating the interferroelectric phase transition from the orthorhombic‐tetragonal phase and the ferroelectric–paraelectric phase, respectively 16 . Interestingly, the phase transition temperatures seem to shift to a lower temperature, by approximately 18°C for the paper‐derived KNN.…”

“…It is important to note that the sintered density of chemically unmodified KNN is generally relatively low and has been reported to be between 88%-92%. [14][15][16] Therefore, the observed low sintered density, that is, poor densification of conventionally prepared KNN, is not due to the processing or sintering condition used here, but rather a general phenomenon of this chemically unmodified KNN composition. 17 The SEM images (Figure 2) show an overall homogenous microstructure for the paper-derived ceramic without observable individual layers, indicating excellent lamination and adhesion.…”

Additively Manufactured Ferroelectric Particulate Composites for Antimicrobial Applications

“…Therefore, omitting this step from the manufacturing process would not only reduce this risk but also the cost of production. [ 34 ] For these reasons, the possibility to pole ferroelectric implants without the need of electrodes is of high interest. In order to ensure uniform charges deposition which results in the effective poling of the whole sample, the needle‐base distance which is approximately equal the radius of the electric field at the base of the corona poling setup, has to be set accordingly, in order for the area of electric field at the base to cover the top surface of the samples.…”