Beschreibung:
<jats:p>The subsolidus region of the PbO‐SiO<jats:sub>2</jats:sub> system was studied by DTA and X‐ray diffraction. X‐ray diffraction analysis showed the presence of five compounds: 4PbO.SiO<jats:sub>2</jats:sub>, 3PbO·SiO<jats:sub>2</jats:sub>, 2PbO·SiO<jats:sub>2</jats:sub>, 3PbO·2SiO<jats:sub>2</jats:sub>, and PbO·SiO<jats:sub>2</jats:sub>. The compound 4PbO·SiO<jats:sub>2</jats:sub> has previously been reported to have three polymorphic forms; there are two polymorphs of 2PbO·SiO<jats:sub>2</jats:sub> with the inversion at 460°±15°C. The compounds 3PbO·SiO<jats:sub>2</jats:sub> and 3PbO·2SiO<jats:sub>2</jats:sub> were unstable above 430°±10° and 585°±15°C, respectively; PbO·SiO<jats:sub>2</jats:sub> was unstable below 525°±15°C. DTA patterns were determined for glasses of the composition of each of these compounds.</jats:p>