STRUKTUR DAN MIKROSTRUKTUR SERBUK Mg(Ti_0,95Sn_0,05)O₃ HASIL SINTESIS DENGAN METODE PENCAMPURAN LARUTAN AKIBAT VARIASI WAKTU TAHAN KALSINASI

STRUCTURE AND MICROSTRUCTURE OF Mg(Ti_0.95Sn_0.05)O₃ POWDER SYNTHESIS BY SOLUTION MIXING METHOD DUE TO VARIATION OF CALCINING HOLDING TIME

Serbuk magnesium titanat dengan struktur ilmenit merupakan salah satu material favorit yang diaplikasikan dalam sistem telekomunikasi gelombang mikro. Pada penelitian ini, serbuk Mg(Ti_0,95Sn_0,05)O₃ (disingkat MTS005) disintesis dengan metode pencampuran antara larutan MgCl₂, TiCl₄, dan SnCl₄. Serbuk amorf dikalsinasi pada suhu 800 ᵒC selama 4, 6 dan 8 jam sehingga didapatkan serbuk kristalin. Uji X-Ray Diffraction (XRD), Particle Size Analyzer (PSA), dan Transmission Electron Microscopy (TEM) digunakan untuk menganalisis fasa kristalin dan komposisinya, Full Widht at Half Maximum, microstrain, ukuran partikel, butir, kristalit dan morfologi butir. Selain itu, serbuk juga dikalsinasi pada beberapa suhu mulai pasca sintesis (room temperature, RT) hingga 800 ᵒC untuk mempelajari evolusi fasa yang terjadi. Didapatkan struktur kristal MTS005 pada ketiga waktu tahan kalsinasi tersebut terdiri dari MgTiO₃ sebagai fasa utama dengan (87,00 – 93,98) %molar, dan sisanya berupa fasa impurity TiO₂. Nilai FWHM tiap waktu tahan pada orientasi (hkl) yang sama menunjukkan perbedaan nilai, dimana hal tersebut menandakan terjadinya pelebaran puncak. Pelebaran puncak tersebut terjadi akibat adanya microstrain dan defect. Naiknya waktu tahan kalsinasi meningkatkan nilai densitas volume fasa MgTiO₃ serta ukuran kristalit. Selain itu nilai keduanya berbanding terbalik dengan microstrain. Ukuran partikel tiap waktu tahan kalsinasi terdistribusi normal dengan ukuran (224,4 – 275,4) nm dengan deviasi kurang dari 7%. Ukuran butir dan morfologinya hanya tersedia untuk sampel waktu tahan 6 jam saja mengingat biaya uji TEM per sampel yang sangat mahal. Pada waktu tahan 6 jam diperoleh ukuran butir sebesar 68,34 nm, sehingga dalam partikel pada sampel dengan waktu tersebut diasumsikan mengandung ~3 butir. Uji evolusi fasa kristalin mulai dari serbuk pasca sintesis hingga 800ᵒ C menghasilkan fasa SnCl₄, TiO₂, dan  dimana suku hidrat ( ) tersebut kemudian terus berkurang seiring naiknya suhu kalsinasi hingga terbentuk fasa akhir berupa MgTiO₃ dan TiO₂ pada suhu 800° C; fasa MgTiO₃ pertama kali terdeteksi pada suhu 480ᵒ C.

Kata Kunci: Serbuk MTS005; doping ion Sn⁴⁺; struktur; microstrain; densitas atom; ukuran kristalit; ukuran butir; distribusi ukuran partikel

Magnesium titanate powder with an ilmenite structure is one of the favorite materials used in microwave telecommunication systems. In this study, Mg(Ti_0.95Sn_0.05)O₃ powder (abbreviated as MTS005) was synthesized by mixing MgCl₂, TiCl₄­­ and SnCl₄ solutions. The amorphous powder was calcined at 800ᵒ C for 4, 6 and 8 hours to obtain a crystalline powder. X-Ray Diffraction (XRD), Particle Size Analyzer (PSA), and Transmission Electron Microscopy (TEM) tests were used to analyze the crystalline phase and its composition, Full Widht at Half Maximum, microstrain, particle size, grains, crystallites and grain morphology. In addition, the powder was also calcined at several temperatures from post-synthesis (room temperature, RT) up to 800 ᵒC to study the phase evolution that occurred. It was obtained that the crystal structure of MTS005 at the three calcination holding times consisted of MgTiO₃ as the main phase with (87.00 – 93.98) molar %, and the remainder was an impurity TiO₂ phase. The FWHM value for each holding time at the same orientation (hkl) shows a different value, which indicates a broadening of the peaks. The widening of the peak occurs due to microstrain and defects. Increasing the holding time of calcination increases the value of the volume density of the MgTiO₃ phase and the size of the crystallites. In addition, the value of both is inversely proportional to the microstrain. The particle size for each calcination holding time is normally distributed with a size of (224.4 – 275.4) nm with a deviation of less than 7%. Grain size and morphology are only available for samples with a holding time of 6 hours considering the very expensive cost of the TEM test per sample. At a holding time of 6 hours, a grain size of 68.34 nm was obtained, so that the particles in the sample with that time were assumed to contain ~3 grains. The crystalline phase evolution test starting from the post-synthesis powder up to 800ᵒ C produced SnCl₄, TiO₂, and  phases where the hydrate ( ) then continued to decrease with increasing calcination temperature until the final phases were formed in the form of MgTiO₃ and TiO2 at 800 ᵒC; the MgTiO3 phase was first detected at 480ᵒ C.

Keywords: MTS005 powder; doped Sn4+ ions; structure; microstrains; atomic density; crystallite size; grain size; particle size distribution