The invention relates to a preparation method of
potassium-
sodium niobate-based nano fine-grain
ceramic with the average grain size of 160nm. 0.5 mol% of
lanthanum oxide is added into raw materials, so that
oxygen vacancies generated by volatilization of
alkali metal elements can be reduced, meanwhile, growth of grains is hindered, and the purpose of refining the grains is achieved. The preparation method comprises the following steps: calcining dried
powder subjected to ball milling for 12-18 hours at 800-900 DEG C for 2-4 hours, carrying out secondary ball milling for 12-18 hours, performing calcining at 800-900 DEG C again after
drying for 2-4 hours, carrying out
tertiary ball milling for 12-18 hours, performing
drying, and carrying out multiple times of ball milling and calcining to enable raw materials to fully react and refine, so the
sintering temperature and the heat preservation time can be reduced, and the purpose of grain refinement is achieved due to insufficient
grain growth. Through
doping modification of a
rare earth element
lanthanum and an improved traditional
solid phase method, a
scanning electron microscope diagram and a
particle size distribution diagram of the finally obtained
potassium-
sodium niobate-based
ceramic are shown in a figure 2, the average grain size of the
potassium-
sodium niobate-based
ceramic is 160nm, and the grain size distribution is uniform and very fine.