RESEARCH Low-temperature metastable tetragonal zirconia nanoparticles (NpMTZ) synthesized from local zircon by a modified sodium carbonate sintering method Rifki Septawendar 1,2 & Ahmad Nuruddin 1 & Suhanda Sutardi 2 & Eneng Maryani 2 & Lia A. T. W. Asri 1,3 & Bambang Sunendar Purwasasmita 1,4 Received: 16 May 2017 /Revised: 1 February 2018 /Accepted: 10 April 2018 # Australian Ceramic Society 2018 Abstract The metastable tetragonal zirconia is an interesting material exhibiting a high surface area and photoluminescence properties. The present work studies the characteristics of the metastable tetragonal zirconia nanoparticles that were successfully prepared from local zircon without using a template by a modified sodium carbonate sintering method, followed by leaching, slow hydrolysis, and calcination at a low temperature. Zircon and alkaline were combined at a mole ratio of 1:2 and sintered at 1000 °C. The sintered material was washed with water to dissolve the silica and followed by leaching with sulfuric acid at pH 1–2 to dissolve the zirconia then followed by slow hydrolysis until pH 9 to precipitate zirconium hydroxide. The final product was evaluated including thermal behavior, phase transformation, chemical composition, infrared spectra, microstructure, and textural properties. Crystallization of zirconia occurred at 564.29 °C. Good crystallinity of the zirconia phase was obtained at 800 °C consisting of 80% tetragonal zirconia with a crystal size of 11 nm corresponding to its crystal plane of (101) and 20% monoclinic zirconia. At this temperature, zirconia attains 83.19% in purity, shows typical infrared spectrum, and consists of particles less than 40 nm in sizes that agglomerate, belongs to a mesoporous material exhibiting a high surface area of 46.990 m 2 /g. Increase in calcination temperature at 1050 °C transformed the tetragonal phase to the monoclinic phase of zirconia. Overall, the present work reveals a promising template-free method on the preparation of the metastable tetragonal zirconia nanoparticles from local zircon. Keywords The local zircon of West Borneo . Modified sodium carbonate sintering . Sulfuric acid leaching . Slow hydrolysis . The metastable tetragonal zirconia nanoparticles Introduction Having excellent physical and mechanical properties as com- pared to other oxides and exhibiting typical polymorph structures, zirconia (ZrO 2 ) is an important material that can be modified for any purposes [1–3]. Recent studies have found that un-doped ZrO 2 exhibiting a tetragonal structure could be obtained at temperatures below 900 °C [4–8]. The * Rifki Septawendar rifkiseptawendar@gmail.com * Bambang Sunendar Purwasasmita purwa@tf.itb.ac.id Ahmad Nuruddin nuruddin@tf.itb.ac.id Suhanda Sutardi suhandabbk@gmail.com Eneng Maryani maryani_eneng@yahoo.co.id Lia A. T. W. Asri tresna.asri@gmail.com 1 Laboratory of Advanced Material Processing, Department of Engineering Physics, Faculty of Industrial Technology, Institut Teknologi Bandung, Gd. TP Rachmat (Labtek VI) Jl. Ganesha 10, Bandung 40132, Indonesia 2 Department of Advanced Ceramics, Glass, and Enamel, Center for Ceramics, Ministry of Industry of Indonesia, Bandung 40272, Indonesia 3 Materials Science and Engineering Study Program, Institut Teknologi Bandung, Bandung 40132, Indonesia 4 Research Center for Nanosciences and Nanotechnology, Institut Teknologi Bandung, Bandung 40132, Indonesia Journal of the Australian Ceramic Society https://doi.org/10.1007/s41779-018-0193-4