Sintering of Glass

How to make synthetic quartz glass by sintering?

Synthetic quartz glass can be made by fusion of SiO2 granulates.

The manufacturing process includes:

  • granulating the amorphous SiO2 primary particles to form an open-pore SiO2 granulate.
  • sintering the open-pore SiO2 granulate by heating in a sintering atmosphere at a sintering temperature and for a sintering period to form a densified SiO2 granulate.
  • Sintering the densified SiO2 granulate to form the synthetic quartz glass.

The sintering temperature is usually 1000° C.

Refer to this patent for more information.

How to make opaque quartz glass by sintering?

Opaque quartz glass can be made by mixing a pore forming agent (graphite powder) to an amorphous silica powder by 0.04 % v/v followed by molding and sintering.

The mixture is heated at a temperature at which the pore forming agent is burnt off, followed by sintering of the silica until pores contained in the sintered body become are closed.

The graphite powder has an average particle size of 5-40 μm.

Refer to this patent for more information.

How to manufacture sintered glass filters?

Production of open-pored sintered bodies composed of glass can be done with following steps:

  • First, a parent granular material is produced by mixing fine grain glass powder, coarse grain salt powder, and a bonding agent.
    • The salt in this mixture has a melting point higher than the sintering temperature of the glass to prevent the salt from combining with the glass.
    • The removed salt is soluble in liquids which do not dissolve the glass.
    • The bonding agne is polyethylene glycol solution.
  • 5 to 20% of fine grained glass powder is added to the resulting granulated material with respect to the granular material.
  • The mixture is moulded and heated to the sintering temperature of the glass.
  • Finally, the salt is removed from the sintered glass.

Refer to this patent for more information.

How to manufacture bioactive glass by sintering?

A bioactive glass can be manufactured by mixing a sol-gel precursor followed by sintering.

The precursor includes silicon oxide, calcium oxide, phosphorus pentoxide and a source of Sodium.

The source of Sodium is is either sodium tert-butoxide, sodium hydroxide, sodium oxalate or sodium sulfate.

The precursor is aged and dried to form a sol-gel bioactive glass which is then sintered at 550-650°C. for 15 to 50 hours.

Refer to this patent for more information.

More articles on sintering