Phase Analyisis Of KNN Type Piezoelectric Material

Rahim Noor, Yusuf (2018) Phase Analyisis Of KNN Type Piezoelectric Material. [Final Year Project Report] (Unpublished)

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Abstract

The usage of the current piezoelectric material which is the PZT (Lead Zirconate Titanate) was found to be harmful and non-evironmental friendly due to the lead waste released during production of the material. Therefore, a need to replace the current PZT material lead to the discovery of the new lead-free piezoelectric material which is KNN (Potassium Sodium Niobate) a piezoelectric ceramics. There are many variables in the process of producing the KNN in order to achieve the most ideal material in terms of its physical properties or piezoelectric properties. The physical properties include density which involves examine the percentage of densification of the materials after the sintering process. The presence of the KNN near chemical formula (K0.5Na0.5) NbO3 was found to possess the most ideal piezoelectric properties of KNN. Thus the aim of the experiment is to determine the suitable variables that gives the best physical properties near the ideal chemical composition. The most crucial steps is the processing of the raw materials which are: (1) Drying; remove moisture content. (2) Milling; further reduce the grains size. (3) Calcination; remove excess volatile substance as well as KNN pre forming. (4) Dry pressing; enable the grain to have full contact with each other. (5) Sinter; production of 100% KNN as well as densification of materials. (6) Polishing; good surface finish. After the calcination, it was found that the calcination temperature of the samples which give the best results and chosen for sintering are the samples being calcined at 750°C. The samples that gives better physical properties is the samples which had been calcined at 750°C for 2 hours with sintering temperature of 1110°C with percentage of densification of 53%. In terms of ideal KNN, the sample that gives the best matched with the KNN near chemical formula of (K0.507Na0.537) NbO3 is the sample calcined at 750°C for 6 hours and sintered at 1060°C which possess an orthorhombic lattice and chemical composition of (K0.507Na0.537) NbO3.

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