COMPOSITE GRADIENT ALLOY PLATE, MANUFACTURING METHOD THEREFOR AND COLOR CATHODE RAY TUBE HAVING SHADOW MASK USING THE COMPOSITE GRADIENT ALLOY PLATE

摘要

PROBLEM TO BE SOLVED: To provide a press mask having a large radius of curvature by self-cor recting thermal deformation such as a doming. SOLUTION: A plate material made of a composite gradient alloy plate consisting of >=3 layers 6A, 6B, 6C, in which nickel content in an iron-nickel alloy has a concentration gradient continuously changed from one surface to an other surface is provided. The internal stress in which a tensile stress and a compressive stress in the planer direction of the composite gradient alloy plate at boundary regions of the plurality of constituent layers are directed in the opposite direction from each other is made to remain. A color cathode ray tube uses the plate material in which the thermal expansion of the composite gradient alloy in an intermediate portion in the plate thickness direction is lower than that in the surface part as the shadow mask.