GLASS FOR SOLDERING OF FERRITE MAGNETIC HEAD MEMBERS Russian patent published in 1994 - IPC

FIELD: glass industry. SUBSTANCE: glass has, wt.-%: SiO₂ 5.7-8.7; B₂O₃ 10.70-21.70; ZrO₂ 2.7-8.8; ZnO 0.02-1.00; K₂O 0.01-0.70; CdO 36.10-50.80; La₂O₃ 15.50-21.40; Nb₂O₅ 3.50-6.90; Li₂O 0.01-0.50; Na₂O 0.01-0.55; Tl₂O 0.01-7.05. Properties: deformation temperature is 570-615 C, spreading temperature is 780-810 C, loss of glass sample mass at boiling in 1M solution of Na₂CO₃ is 0.7-1.0 m²/cm ·h, loss of glass sample mass in 2N HCl solution at the room temperature is 5.3-5.9 mg/cm²·h, time for appearance of the first symptoms of crystallization in glass drop spreading on the ferrite backing in the form of separate crystals or film is 35-55 min, microhardness is 670-705 kgf/mm². Glass is used in electronics, photography, videorecording equipment, etc. EFFECT: decreased spreading temperature, enhanced chemical and crystallizating stability and microhardness. 2 tbl