TIN COATED METALLIC SHEET HAVING EXCELLENT BRIGHTNESS AND WHISKER RESISTANCE

摘要

PURPOSE:To easily obtain the tin coated metallic sheet having excellent gloss and whisker resistance by respectively adequately controlling the carbon contents in the plating layer at the boundary of the stock of a tin coating formed on a metallic sheet and in the plating layer on a plating surface. CONSTITUTION:The carbon content in the plating layer at the boundary of the above-mentioned tin coating stock of the tin coated metallic sheet is controlled to =0.2wt.% and the carbon content in the plating layer on the surface of the plating layer to 0.2 to 1.0%. The control of the carbon contents in the above-mentioned plating layers is executed by providing the tin coating of the respective carbon contents into two-layer or multilayered structures or forming the plating layer in which the carbon content is changed successively from the boundary of the stock toward the surface. The carbon content in the tin coating layer is rapidly managed by using an ion microanalyzer, etc., by which the generation of the whiskers is suppressed and the tin coated metallic sheet having the good glossy surface is obtd. without degrading solderability, etc.