| 摘要 |
PROBLEM TO BE SOLVED: To produce the high strength ferrule by incorporating lead oxide in a specified ratio into a glass ferrule body formed from a glass preform having a specified shape. SOLUTION: This production comprises: drawing a cylindrical glass preform in which a hollow cylindrical bore extending over the entire length of the preform is formed almost coaxially with the preform, to form a glass tube by a well-known glass extrusion technique; cutting the glass tube into plural glass ferrule bodies; and treating such a ferrule body with a potassium nitrate molten salt bath to perform ion exchange with respect to sodium ions and potassium ions to form a high strength glass ferrule. Thus, the objective high strength glass ferrule which is a structural body made of a glass material consisting of sodium aluminum silicate glass contg. 1 to 35% lead oxide, can easily be produced without adversely affecting its mechanical strength.
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