Pengaruh Massa Magnesium Oksida (MgO) dan Alumina (Al2O3) Terhadap Karakteristik Keramik Kordierit dari Abu Vulkanik Gunung Sinabung

Abstract

Telah dilakukan penelitian tentang pengaruh massa magnesium oksida (MgO) dan alumina (Al₂O₃) terhadap karakteristik keramik cordierite dari abu vulkanik gunung sinabung. Karakteristik yang diuji meliputi susut bakar, porositas, densitas, kekerasan, struktur fasa, ukuran kristal dan fasa apa yang terbentuk selama proses pembuatan sampel.  Pembuatan silika diekstraksi dari abu vulkanik dengan metode sol-gel yang direaksikan dengan NaOH 4 M dan dengan penambahan HCl 8 M untuk pembuatan silika gel.  Keramik cordierite disintesis dengan metode solid state dengan perbandingan 14% massa MgO : 35% massa Al₂O₃ dan 51% massa SiO₂.  Selanjutnya serbuk keramik kordierit tersebut dicampur dengan masing-masing 0%, 10% dan 15% massa MgO dan Al₂O₃.  Pengujian yang dilakukan meliputi uji sifat fisis (susut bakar, porositas dan densitas) dan uji kekerasan menggunakan Vickers Tester, serta karakterisasi dilakukan menggunakan X-Ray Diffraction (XRD) untuk menentukan ukuran kristal dan struktur fasa yang terbentuk.  Berdasarkan hasil pengujian yang dilakukan, bahwa pada penambahan massa 10% (MgO & Al₂O₃) didapatkan nilai susut bakar, densitas dan kekerasan semakin menurun sementara porositas semakin meningkat. Namun seiring dengan penambahan massa 15% (MgO &Al₂O₃) nilai susut bakar, densitas dan kekerasan semakin meningkat sementara porositas semakin menurun. Hasil karakterisasi XRD menunjukkan bahwa struktur fasa yang terbentuk pada sampel penambahan 0% (MgO & Al₂O₃), 10% (MgO & Al₂O₃) dan 15% (MgO & Al₂O₃) adalah cordierite dan albite. 

Research on the effect of the mass of magnesium oxide (MgO) and alumina (Al₂O₃) on the characteristics of cordierite ceramics from volcanic ash of Mt. Sinabung. The characteristics tested include burn losses, porosity, density, hardness, phase structure, crystal size and what phases are formed during the sample making process. The making of silica was extracted from volcanic ash by the sol-gel method which was reacted with 4 M NaOH and with the addition of 8 M HCl for the making of silica gel. Cordierite ceramics were synthesized by the solid state method with a ratio of 14% MgO mass: 35% mass Al₂O₃  and 51% mass SiO₂. Then the cordierite ceramic powder is mixed with 0%, 10% and 15% mass of MgO and Al₂O₃ respectively. Tests carried out include tests of physical properties (burn losses, porosity and density) and hardness tests using Vickers Tester, and characterization is carried out using X-Ray Diffraction (XRD) to determine the size of the crystals and the structure of the phase formed.  Based on the results of tests carried out, that with the addition of a mass of 10% (MgO & Al₂O₃), the value of burn losses, density and hardness decreases while porosity increases. But along with the addition of a mass of 15% (MgO & Al₂O₃) the value of burn losses, density and hardness are increasing while porosity decreases. The XRD characterization results showed that the phase structure formed in the addition of 0% samples (MgO & Al₂O₃), 10% (MgO & Al₂O₃) and 15% (MgO & Al₂O₃) were cordierite and albite.