Beryllium Copper Strip
Proper use of Beryllium Copper
(4) Surface Treatment
Beryllium copper alloys tend to form oxide film on the surface during heat treatment.The oxide film must be removed when further processing such as plating and soldering is necessary. Typical cleaning methods are as follows:
for loose parts, dip them into a 20% solution of sulfuric acid heated up between 50°C to 90°C. The oxide film will be removed in a few minutes. When time allows, the parts can be immersed in the solution at room temperature over night. Since oxide film generated by burnt oil or grease cannot be removed by acid cleaning, degreasing before age hardening is required.
Any residual oil or grease on the surface of beryllium copper may cause the discoloration on the surface or may give an adverse effect on down stream processes such as heat treatment, plating, soldering and welding. When stamping oil is used, thorough degreasing is required after stamping. If the stamping oil contains high chlorine or sulfur, the method of degreasing should be carefully determined, or the use of such oil should be avoided.
Preventive treatment against discoloration
Benzotriazol (C6H4N2-NH) is generally used for preventing the discoloration of copper alloys caused by the air. It forms cupric benzotriazol (C6H4N3)2Cu on the surface of copper alloys, which is insoluble in water or other solvents. It will not cause any adverse effect on normal pretreatment for plating or age hardening, because it will be sublimated at 100°C.