Pengaruh Variasi Komposisi Al2O3 Terhadap Sifat Fisis, Mekanis, Struktur Mikro, dan Fasa dalam Pembuatan Keramik Berbasis Bentonit dan Glass Bead

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 100 oC 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 µm. 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

vi
Universitas Sumatera Utara

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 900 oC 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 µm. The result of analysis by using XRD there are 2
phases which formed namely major anorthite (Al2CaSi2O8) phase and microline
minor phase (KalSi3 O8).

Keywords : Al2O3, phase, ceramic, composition, physical properties

vii
Universitas Sumatera Utara