SURFACE PREPARATION OF NICKEL BASE ALLOYS FOR BRAZING

摘要

In order to remove undesirable oxides from the surface of nickel-base or nickel-iron base alloys containing oxidizable aluminium and/or titanium prior to brazing, the alloy is heated in an oxygen containing atmosphere 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 aluminium and a second layer beneath the first comprised of the alloy composition substantially depleted of aluminium 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.