STUDY OF RARE EARTH SUBSTITUTION ON (K0.5Na0.5 )NbO3 CERAMICS

Abstract

One of the greatest issues that the world has faced in recent decades is the energy crisis. Overpopulation, unsustainable use of non-renewable sources of energy, old and inadequate technology of power generating equipment, and misuse of available energy sources such as fuel, electricity, and so on have all contributed to an alarming increase in global energy consumption. Energy harvesting from other sources of energy is becoming increasingly important in order to meet demand, and substantial research is ongoing to find a sustainable solution to the problem of energy crisis. Piezoelectric Energy harvesters have the potential to be integrated into a wide range of human-powered applications, making it a feasible answer to our growing energy demands. The development of new sensors, actuators, and transducers requires the use of functional piezoelectric materials. PZT based piezoelectric materials outperform other multifunctional ceramics in terms of piezoelectric and ferroelectric features. However, due to the toxicity of lead, the usage of PZT ceramics has been strictly restricted. As a result of which new lead-free piezoelectric materials with excellent piezoelectric and ferroelectric characteristic are required. Recent research on Pb-free piezoelectric materials such as BaTiO3 (BT), (Bi,Na)TiO3 (BNT), and (K,Na)NbO3 (KNN) has discovered that Pb-free systems can attain good piezoelectric and ferroelectric characteristics. Out of which KNN ceramics showed great promising

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properties but due to the low evaporation temperature of Na and K, KNN-based ceramics are difficult to sinter. Special additives must be introduced in KNN-based ceramics to inhibit these volatiles from evaporating and to lower the sintering temperature. Enhanced functionality of KNN-based ceramics can be achieved by adding different dopants such as (K,Na)NbO3–BaTiO3, (K,Na)NbO3–LiSbO3, (K,Na)NbO3–LiNbO3, (K,Na)NbO3– SrTiO3, (K,Na)NbO3–LiNbO3–AgTaO3, and (K,Na)NbO3–LiTaO3, which results in KNN-based ceramics with better densification properties. Modification of KNN-based piezoceramics via doping rare-earth ions is a very effective way to enhance properties among other doping ions. So in this study, we chose rare earth metal Ho as dopant and fabricated Ho3+ doped

(K0.5Na0.5)NbO3 ceramic via solid-state reaction method to examine the effect of rare- earth on phase structure of (K0.5Na0.5)NbO3 piezoceramics.