KARAKTERISASI SERBUK LARUTAN PADAT Mg(Ti_0,96Sn_0,04)O₃ HASIL SINTESIS MENGGUNAKAN METODE PENCAMPURAN LARUTAN

CHARACTERIZATION OF Mg(Ti_0.96Sn_0.04)O₃ SOLID SOLUTION POWDER SYNTHESIZED USING LIQUID MIXING METHOD

Penelitian ini melaporkan pengaruh variasi waktu tahan kalsinasi terhadap struktur dan mikrostruktur serbuk Mg(Ti_0,96Sn_0,04)O₃ (disingkat MTS004) sebagai kandidat material dielektrik setelah sites ion Ti⁴⁺ didoping dengan ion Sn⁴⁺. Serbuk MTS004 disintesis dengan mencampur ketiga larutan prekursor, yaitu MgCl₂, TiCl₄, dan SnCl₄ berdasarkan stoikiometrinya secara homogen dan dipanaskan hingga kering kemudian dikalsinasi pada suhu 800 ℃ selama 4, 6 dan 8 jam. Pengaruh variasi waktu tahan kalsinasi diuji terhadap komposisi fasa, ukuran kristalit, mikrostrain, dan distribusi ukuran partikel. Komposisi fasa, ukuran kristalit dan mikrostrain dikarakterisasi menggunakan data XRD sedangkan distribusi ukuran partikel menggunakan PSA dan morfologi serta ukuran butir menggunakan TEM. Ternyata fasa MgTiO₃ terdeteksi pertama kali pada suhu serendah 480 ℃ dengan sisanya fasa impuriti TiO₂. Keberadaan fasa MgTiO₃ tersebut berlanjut hingga suhu 800 ℃ dengan % berat 91,35 ± 2,41 (4 jam), 91,36 ± 2,44 (6 jam) dan 91,19 ± 2,63 (8 jam). Kenaikan densitas fasa MgTiO₃ dari waktu tahan kalsinasi 6-8 jam berkaitan erat dengan turunnya nilai mikrostrain pada waktu tahan tersebut. Mikrostrain yang ditandai dengan pelebaran puncak difraksi (FWHM) diduga akibat doping ion Sn⁴⁺ pada sites ion Ti⁴⁺ mengindikasikan adanya cacat kristal. Asumsi cacat tersebut sekaligus menjelaskan tren turunnya ukuran kristalit fasa MgTiO₃ yang berbanding terbalik dengan naiknya nilai mikrostrain. Morfologi butir berbentuk poligon dengan rata-rata ukuran butir 170,09 nm (4 jam). Pada waktu tahan 4 jam ukuran partikel terdistribusi secara normal dengan rata-rata 311,6 nm ± 6,15% dimana setiap partikel diperkirakan mengandung 1-2 butir. Dengan demikian, naiknya waktu tahan kalsinasi dari 6 hingga 8 jam meningkatkan densitas dan ukuran kristalit fasa MgTiO₃ diikuti dengan turunnya nilai mikrostrain. Cacat kristal serta doping ion Sn⁴⁺ pada sites ion Ti⁴⁺ diduga memiliki kontribusi dalam pembentukan mikrostrain tersebut.

Kata Kunci: Serbuk MTS004; doping ion Sn⁴⁺; komposisi fasa; mikrostrain; ukuran kristalit; distribusi ukuran partikel; ukuran butir

This study reports the effect of variations in calcination holding time on the structure and microstructure of Mg(Ti_0.96Sn_0.04)O₃ powder (abbreviated as MTS004) as a dielectric material candidate after the Ti⁴⁺ ion sites are doped with Sn⁴⁺ ions. MTS004 powder was synthesized by mixing the three precursor solutions, namely MgCl₂, TiCl₄, and SnCl₄ based on their stoichiometry homogeneously and heated to dryness and then calcining at 800 ℃ for 4, 6 and 8 hours. The effect of variations in calcination holding time was tested on phase composition, crystallite size, microstrain, and particle size distribution. Phase composition, crystallite size and microstrain were characterized using XRD data while the particle size distribution used PSA and morphology and grain size used TEM. It turned out that the MgTiO₃ phase was detected at temperatures as low as 480 ℃ as the main phase with the rest being the impurity TiO₂ phase. The presence of the MgTiO₃ phase continued up to 800 ℃ with wt% 91.35 ± 2.41 (4 hours), 91.36 ± 2.44 (6 hours) and 91.19 ± 2.63 (8 hours). The increase in the density of the MgTiO₃ phase at 6 to 8 hours of calcination holding time is closely related to the decrease in the microstrain value at that holding time. The microstrain marked by broadening of the diffraction peaks (FWHM) suspected due to doping of Sn⁴⁺ ions at some of the Ti⁴⁺ ion sites indicates the presence of crystal defects. The defects assumption also explains the trend of decreasing crystallite size of the MgTiO₃ phase which is inversely proportional to the increase in the microstrain value.  The grain morphology is a polygon with an average grain size of 170.09 nm (4 hours).  At 4 hours of holding time the particle sizes are normally distributed with an average of 311.6 nm ± 6.15% (4 hours) where each particle was estimated to contain 1-2 grains. Thus, an increase in the calcination holding time of 6-8 hours increases the density and crystallite size of the MgTiO₃ phase followed by a decrease in the microstrain value. Crystal defects and doping of Sn⁴⁺ ions at Ti⁴⁺ ion sites are thought to have contributed to the formation of these microstrains.

Keywords: MTS004 powder; doped Sn⁴⁺ ions; phase composition; microstrains; crystallite size; particle size distribution; grain size