vi
PENGARUH VARIASI KOMPOSISI Al2O3 TERHADAP SIFAT FISIS, MEKANIS, STRUKTUR MIKRO, DAN FASA DALAM PEMBUATAN
KERAMIK BERBASIS BENTONIT DAN GLASS BEAD
ABSTRAK
Telah dilakukan pembuatan keramik berbasis bentonit dan glass bead dengan variasi komposisi Al2O3 dalam %berat. Proses preparasi bahan menggunakan metode metalurgi serbuk dengan komposisi bentonit : glass bead : Al2O3 adalah 50:50:0 ; 45:45:10 ; 40:40:20 ; 35:35:30 %berat dan campuran serbuk tersebut kemudian digiling basah dengan media toluena menggunakan HEM selama 2 jam. Sampel serbuk kemudian dikeringkan didalam oven pada suhu 100oC selama 24 jam dan dikarakterisasi meliputi pengujian true density dan Particle Size Analyzer (PSA). Kemudian sampel serbuk dicetak tekan dengan tekanan 80 kgf/cm2 pada suhu ruang menjadi pelet dengan diameter 16 mm, tebal 6 mm, dan massanya 2,5 gram. Sampel pelet kemudian disintering hanya pada suhu 900oC dengan penahanan selama 4 jam dan dikarakterisasi meliputi : pengujian sifat fisis yaitu bulk density, porositas, dan
water absorption dengan prinsip Archimedes. Pengujian sifat mekanis yaitu kekerasan dengan metode Hardness Vickers (HV). Analisa struktur mikro dan fasa menggunakan Optical Microscope (OM) dan X-Ray Diffraction (XRD). Hasil pengujian menunjukkan nilai true density, bulk density, dan kekerasan cenderung semakin meningkat sedangkan nilai porositas dan water absorption cenderung semakin menurun dengan penambahan Al2O3 yang semakin banyak. Kondisi optimum diperoleh pada penambahan 30 %berat Al2O3 yang menghasilkan nilai true density 2,32 g/cm3,bulk density 2,39 gr/cm³, porositas 5,57 %, water absorption 2,46 %, kekerasan 631,76 kgf/mm², dan ukuran rata-rata diameter partikel 4,27 µ m. Hasil analisis menggunakan XRD terdapat 2 fasa yang terbentuk yaitu fasa mayor
anorthite (Al2CaSi2O8) dan fasa minor microline (KalSi3O8).
Kata kunci : Al2O3, Fasa, Keramik, Komposisi, Sifat fisis
vii
THE EFFECT OF COMPISITION VARIOUS Al2O3 TO PHYSICAL PROPERTIES, MECHANICAL, MICROSTRUCTURE, AND PHASE IN
MANUFACTURING CERAMICS BASED ON BENTONITE AND GLASS BEAD
ABSTRACT
Has been made the manufacture of ceramics based on bentonite and glass bead with various of composition Al2O3 in wt%. The process of preparation material by using powder metallurgy method with composition of bentonite : glass bead : Al2O3 are 50:50:0 ; 45:45:10 ; 40:40:20 ; 35:35:30 wt% and then the powder mixture was wet milling with toluene media using HEM for 2 hours. Then powder sample was dried in the oven at 100oC for 24 hours and characterized including true density and Particle Size Analyzer (PSA). Next powder sample was compressed with pressure 80 kgf/cm2 in room temperature into a pellet with diameter 16 mm, thickness 6 mm, and mass 2,5 grams. Then pellet sample was sintered only at 900oC with 4 hours detention and characterized including : Physical properties testing is bulk density, porosity, and water absorption by using Archimedes principle. Testing mechanical properties namely hardness by using Hardness Vickers (HV) method. Analysis of microstructure and phase used Optical Microscope (OM) and X-Ray Diffraction. The test result showed value of true density, bulk density, and hardness tends to increase while the porosity value and water absorption tends to decrease with the addition of Al2O3 more a lot. The optimum condition was obtained in addition of 30 wt% of Al2O3 which resulted the value of true density 2,32 g/cm3,bulk density 2,39 gr/cm³, porosity 5,57 %, water absorption 2,46 %, hardness 631,76 kgf/mm², and averages size of particle diameter 4,27 µ m. The result of analysis by using XRD there are 2 phases which formed namely major anorthite (Al2CaSi2O8) phase and microline minor phase (KalSi3O8).
Keywords : Al2O3, phase, ceramic, composition, physical properties
