| 摘要 |
A method of making a precision shaped internal surface on a glass vessel comprises inserting a pre-shaped mandrel having a gold-rich surface composed of a gold-platinum alloy into a glass vessel, heating the glass vessel to at least a soft condition and shaping the internal surface thereof on the mandrel to the contour of the mandrel surface, permitting the glass vessel to cool and then removing the vessel from the mandrel. The method is particularly applicable to the manufacture of rotameter tubes wherein a tube of borosilicate glass is fitted over the mandrel, heated to softening point and then vacuum collapsed on to the mandrel to become precision shaped, allowed to cool and then removed. The mandrel comprises a stainless steel or molybdenum base having a tapered end portion which is first coated with fused aluminia or zirconia. A thin sleeve of a platinum-rhodium alloy (90%-40% Rh) is then accurately machined on to the coated mandrel. Then a thin layer of platinum is electro-plated on to the mandrel followed by a thin layer of gold also by electro-plating. The composite mandrel is then heat treated so that the platinum and gold interfuse to give a gold-rich surface.ALSO:A method of making a precision-shaped internal surface on a glass vessel comprises inserting a pre-shaped mandrel having a gold-rich surface composed of a gold-platinum alloy into a glass vessel, heating the glass vessel to at least a soft condition and shaping the internal surface thereof on the mandrel to the contour of the mandrel surface, permitting the glass vessel to cool and then removing the vessel from the mandrel. The method is particularly applicable to the manufacture of rotameter tubes wherein a tube of borosilicate glass is fitted over the mandrel, heated to softening point and then vacuum collapsed on to the mandrel to become precision shaped, allowed to cool and then removed. The mandrel comprises a stainless steel or molybdenum base having a tapered end portion which is first coated with fused aluminia or zirconia. A thin sleeve of a platinum-rhodium alloy (90-40% Rh) is then accurately machined on to the coated mandrel. Then a thin layer of platinum is electroplated on to the mandrel, followed by a thin layer of gold also by electroplating. The composite mandrel is then heat-treated so that the platinum and gold interfuse to give a gold-rich surface. |
