Method of producing optically transparent ceramics

A method for producing an optically transparent ceramic having a perovskite-type crystal structure and represented by the general formula of ABO.sub.3, wherein A consists of Pb and at least one other element selected from the group consisting of Ba and Sr, and B, is selected from the group consisting of Zr or a mixture of Zr and Ti, said method comprising

• forming a powdery mixture containing elements A, B and O in the form of oxides and titanates and/or zirconates, the ratio of elements A, B and O in said mixture corresponding to the ratio of elements A, B and O in said ABO.sub.3, said at least one other element being present in said powdery mixture in the form of a zirconate, a titanate or both a zirconate and a titanate,
• forming a green compact from said powdery mixture by calcining said powdery mixture to produce a complex oxide and moulding the powdery mixture so calcined under pressure, and
• hot pressing said green compact in an oxygen atmosphere under a pressure of higher than 70 kg/cm.sup.2 at a temperature of 1,200.degree. to 1,500.degree. C for more than two hours.

A method for producing an optically transparent ceramic having a perovskite-type crystal structure and represented by the general formula of ABO.sub.3, wherein A consists of Pb and at least one other element selected from the group consisting of Ba and Sr, and B, is selected from the group consisting of Zr or a mixture of Zr and Ti, said method comprising

• forming a powdery mixture containing elements A, B and O in the form of oxides and titanates and/or zirconates, the ratio of elements A, B and O in said mixture corresponding to the ratio of elements A, B and O in said ABO.sub.3 except that said powdery mixture contains a 3 to 20 mole % excess of PbO, said at least one other element being present in said powdery mixture in the form of a zirconate, a titanate or both a zirconate and a titanate,
• forming a green compact from said powdery mixture by calcining said powdery mixture to produce a complex oxide and moulding the powdery mixture so calcined under pressure, and
• hot pressing said green compact by in an oxygen atmosphere under a pressure of higher than 70 kg/cm.sup.2 at a temperature of 1,200.degree. to 1,500.degree. C for more than two hours.