#TITLE_ALTERNATIVE#

• Main Author: SITIO (NIM : 13707059); Pembimbing: Dr. Ir. Aditianto Ramelan, DESY
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/15347
• Institution: Institut Teknologi Bandung

Mullite is a type of ceramic which has excellent refractory properties, stable at high temperatures, and can be used as a filter. Mullite can be obtained from the sintering of kaolinite at temperature about 1200oC [16] <br /> <br /> <br /> <br /> <br /> This study is aimed to determine the effect of addition of MgO 4 w/o and borax 10 w/o (Na2B4O7.10H2O) on the formation of mullite with needle morphology. The composition of the samples were varied i.e. sintering temperature at 1100 based on the principle of triaxial body composition. Kaolinite serves as a binder, Na-feldspar serves as a flux, and the silica serves as filler. The addition of MgO as additive and borax as a flux intended to produce mullite with needle morphology. <br /> <br /> <br /> <br /> <br /> 0C and 1400oC and hold for 4 hours. The method used for producing the samples was slip casting. XRD characterization method used to determine whether or not mullite phase is formed and SEM methods used to see the needle morphology is formed. The result shows that the addition of MgO 4 w / o and borax 10 w / o (Na2B4O7.10H2O) on kaolinite could producing mullite with needle morphology , the sintering temperature at 1400oC. XRD result shows, mullite phase is formed by sintering kaolinite at 1100oC. SEM results show, without the addition of MgO or borax, mullite formed with platelet morphology. While the addition of MgO and borax, mullite formed with needle morphology. This is caused by MgO and borax can lower down sintering temperature, so liquid phase sintering temperature could be reached earlier. Liquid phase sintering will facilitate the formation of mullite with needle morphology. [1] The mechanism of needle mullite formation from hexagonal kaolinite has not clearly understood. Based on the journals by William M. Carty [9] and A. Gualtieri [10], this mechanism is modeled according to the release of hydroxyl bonds in kaolinite at a temperature of 400-500oC which causes structural changes of alumina from octahedra to tetrahedra. By measuring the grain size of kaolinite and mullite from SEM results, can be predicted that one grain of kaolinite with a length of about 8&#956;m grow 4 mullite with a length of 2 &#956;m.