| Summary: | 碩士 === 國立交通大學 === 應用化學系 === 83 === The purpose of this study is to investigate the low temperature
sintered yttrium oxide-riched ceramic shell mold. Because of
the expensive cost and high sintering temperature (above
1600.DEGREE.), we try to add another refractory powder to
improve them. In addition, the manfacturing process of the
ceramic shell molds : about the composition of slurry and its
rheology behavior , the control of the drying, the steps of
losing wax, and the temperature control of sintering, we would
discuss and optimize them. The optimal slurry for making
ceramic shell molds demands high solid content, stable and
sutiable viscosity state, and shear thining behavior.We add the
yttrium oxide sols as the binder, methylcellouse as the polymer
dispersion agent and add the buffer solution if the powder is
unstable. The buffer solution is composed of acetic acid and
sodium acetate, it can let the solution far from isoelectric
point and keep stable longer. In our experiment the final
products: there are two kinds of ceramic shell molds. The first
molds sintered at 1400.degree. for 10 hours, and the strength
is 950psi. The second molds sintered at 1400.degree. for 5
hours, and the strength is 1000psi. The density are 2.7and 3.5,
respectly . Both of specimens are satified with the properties
of shell molds.
|
|---|
