| 摘要 |
890,813. Soldering. CORNING GLASS WORKS. May 20, 1959 [May 23, 1958], No. 17199/59. Class 83 (4). [Also in Groups XXXVI and XL (b)] The face of a ferro-electric ceramic (e.g. 45% PbTiO 3 -55% PbZrO 3 ) element is provided with a solderable coating which is applied at a temperature below which the polarization of the element would be affected. The element is intended for operation in the shear-mode, the coated face being parallel to the direction of polarization. As shown, an element 15 is cut from an electroded block 11 of ceramic material polarized in the direction of arrows A. Coatings are applied on both broad faces of the element whereby it may be soldered to a delay line 20 and to a tin-lead back electrode. A first 300 Š layer of platinum or silver is applied by evaporation at room temperature and is baked at 200‹ C. This is followed by a 500 Š layer of chromium then a 500 Š layer of Ni-Cr alloy and finally a 500 Š layer of gold. These are all applied in vacuo by evaporation at room temperature. The alloy (80% Ni-20% Cr, approximately) layer is graded with the content of chromium highest at the chromium-alloy interface. The delay line is provided with a coating of platinum and indium is applied to the surfaces to be soldered by puddling at 200 ‹ C. The surfaces are finally soldered under pressure at about 135‹ C. A tin-indium solder (65% In-35% Sn) may be used. Specification 800,519 is referred to. |
