Copper beryllium displays all the desirable plating and joining characteristics for which the copper alloys are well known. However, because copper beryllium is frequently specified for precision applications, surface cleanliness should be considered a critical factor when articles are to be plated, or joined by soldering, brazing or welding.
All foreign substances, including oil, grease, paint, dust, dirt, tarnish and oxide, must be removed before these operations are undertaken.
This cannot be emphasized too strongly because most problems related to plating or joining quality can ultimately be traced to improper or inadequate cleaning.
The first step in the preparation of copper beryllium for subsequent plating or joining is the removal of all soils, particularly oils and greases. These are normally present as residual traces of lubricants used during forming or as contaminants from exposure to oil-mist-laden shop atmospheres. Sulfur-bearing lubricants, if not removed quickly, can stain copper beryllium. Surface soils also result from handling; fingerprints and oily work gloves are notorious offenders.
Conventional cleaners, such as organic solvents, and alkaline solutions, are normally adequate for removing oily residues. Normal care should be taken to insure that solution concentrations, temperatures and flow rates are within proper limits and that recirculation or filtration systems are adequately maintained. Vapor degreasing is especially effective for removing oils and greases. Trisodium phosphate and similar alkaline solutions, including the many available proprietary for mulations, are likewise satisfactory, and ultrasonic or electrolytic agitation can supplement these media for best results. Cleaning solutions should be thoroughly rinsed from all surfaces. Any questions regarding a cleaner’s effectiveness should be resolved by testing on representative copper beryllium samples.
Like all copper alloys, copper beryllium can form a thin surface oxide, or tarnish, when exposed to air . Tarnish formation is accelerated by the presence of moisture and elevated temperature. Oxidation normally results from heat treatment. Even when protective atmospheres are used, the formation of sufficient sur- face oxides to cause plating or joining problems should be anticipated. Mill-hardened strip however, is thoroughly cleaned and inhibited before delivery.