IN2012DE00365AIN365DE2012AIN2012DE00365AIN 2012DE00365 AIN2012DE00365 AIN 2012DE00365AIN 365DE2012 AIN365DE2012 AIN 365DE2012AIN 2012DE00365 AIN2012DE00365 AIN 2012DE00365A
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India
Prior art keywords
alumina
produced
slurry
cast
methyl cellulose
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Papiya Biswas Mrs
Kotikalapudi Rajeswari Mrs
Vittal Mahender Mr
Pandu Ramavath Mr
Anumandla Rajashekhar Reddy Mr
Johnson Dr Roy
Nair Saraswathy Hareesh Dr Unnikrishan
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Internat Advanced Res Ct For Powder Metallurg And New Materials Arci
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Priority to IN365DE2012priorityCriticalpatent/IN2012DE00365A/en
Publication of IN2012DE00365ApublicationCriticalpatent/IN2012DE00365A/en
IR transparent polycrystalline alumina articles having sintered grain sizes averaging in the sub-micrometer region and capable of transmitting >75% of infrared radiation of wavelengths between 3 and 5 micrometers can be produced by employing the thermal gelation property of methyl cellulose. In this process high purity alumina (99.96%) doped with 500ppm of MgO were made into a slurry with solid loading of 76-80wt% and further 0.1-0.5wt% of methyl cellulose was added followed by milling. The slurry was cast into a mould and subjected to thermal gelation temperature of 45-60°C to obtain the green alumina ceramics. The cast alumina ceramics thus produced through the environmentally benign process on sintering and hot isostatic pressing resulted in IR transparent polycrystalline alumina. Thus produced articles of thickness 1-1.4mm have exhibited close to theoretical IR transmission of 80-85% and a hardness of >20GPa.
Method for producing ceramic for heat-radiating members, ceramic for heat-radiating members, and solar cell module and led light-emitting module using said ceramic