| 摘要 |
PURPOSE:To measure the pin hole generating state accurately and conveniently, by treating the surface of a ternesheet, which undergoes hole sealing treatment by a phosphoric acid compound by a solution of sodium acetate, and thereafter measuring the configuration of pin holes by an electron microscope or the like. CONSTITUTION:A test piece of a ternesheet has a plated layer comprising Sn- 15%/Pb on the surface of a steel plate with a thickness of 0.8mm.. The test piece is immersed in an aqueous solution of sodium acetate of 10-15% at 40-70 deg.C for 10-30min. Then, a phosphoric acid compound on the surface is selectively dissolved and removed. After the test piece is washed and dried, gold is evaporated on the surface to be measured, and the shape and numbers of pin holes in the surface of the test piece are measured by a scanning type electron microscope or the photograph thereof is taken. The vicinity of the pin holes can be readily judged from lump shaped tin 2 because the edge effect due to electrons appears at the vicinity of the holes and it is turned into white. In this method, the pin hole yielding state can be accurately and conveniently measured. |
