SURFACE PREPARATION OF NICKEL BASE ALLOYS FOR BRAZING

摘要

A method is disclosed for the removal of undesirable oxides from the surface of nickel-base or nickel-iron base alloys containing oxidizable aluminum and/or titanium prior to brazing. The alloy is heated in air at an elevated temperature for a time sufficient to form on the alloy surface a bilayered film comprised of a first oxide top layer containing at least titanium or aluminum and a second layer beneath the first comprised of the alloy composition substantially depleted of aluminum and/or titanium. The surface of the alloy is cleaned to remove the first oxide layer whereupon the remaining surface is in condition for brazing.