Joint, a laminate, and a method of preparing a nickel-titanium alloy member surface for bonding to another layer of metal

Method of soldering an alloy member including nickel and titanium and having oxidation thereon to an other member, comprising the steps of:

• applying a pickling solution to at least partially remove said oxidation from a surface of said alloy member;
• wetting said surface with a flux of at least one of chlorides and fluorides having an activation temperature below an annealing temperature of said alloy, said annealing temperature representing that temperature above which certain properties of said alloy member are impaired;
• heating said flux to said activation temperature;
• suspending said contaminant in said flux heated to said activation temperature;
• leaching at least partially said titanium from said surface to form a nickel-rich interface surface with said flux heated to said activation temperature;
• suspending said titanium at least partially leached from said surface in said flux heated to said activation temperature;
• coating said nickel-rich interface surface with said flux having said contaminant and said titanium suspended therein;
• scrubbing from said nickel-rich interface surface said flux having said contaminant and said titanium suspended therein;
• wetting said nickel-rich interface surface with an additional amount of said flux;
• flowing a silver solder in a molten state on said nickel-rich interface surface and said other member;
• displacing from said nickel-rich interface surface said additional flux with said solder flowing on said nickel-rich interface surface;
• cooling said solder on said nickel-rich interface surface and said other member;
• and
• cleaning said flux from said alloy member and said other member.

A joint comprising:

• a nickel-titanium alloy member;
• an interface surface formed in a surface of said alloy member, being substantially contaminant free, and having titanium at least partially removed therefrom with a flux heated to its activation temperature;
• a bonding material flowed on and adhering to said interface surface;
• and
• a second member adhering to said bonding material.

A joint comprising:

• a base structure of a metal alloy having by weight a first percentage of nickel and a second percentage of titanium, superelastic and shape memory properties, and an annealing temperature above which said superelastic and shape memory properties are impaired;
• an interface surface on said base substrate and having by weight a third percentage of nickel greater than said first percentage and a fourth percentage of titanium less than second percentage;
• and
• a solder material having a melting temperature less than said annealing temperature of said metal alloy adhering to said interface surface.

A laminate comprising:

• a base member of a nickel-titanium alloy having superelastic properties;
• an upper surface of said base member having a lower percentage of titanium than throughout the base member as a whole;
• a layer of solder material bonded to the upper surface;
• and
• a second member bonded to the solder layer;
• wherein the bond between the base member and said second member is at least 3.5 pounds.

A method of preparing a surface of a nickel-titanium alloy member having an annealing temperature above which selected properties are impaired and a contaminant on the surface thereof for bonding an other metal member thereto, the method comprising the steps of:

• applying to said member surface an aluminum flux paste having an activation temperature below said annealing temperature of said alloy member, said flux having a composition suitable for removing said contaminant from said surface member;
• removing with said flux said contaminant from said member surface to form a substantially contaminant-free bonding surface on said alloy member;
• flowing a solder material in a molten state on said bonding surface and thereby displacing said flux from said bonding surface;
• and
• cooling said solder material to a solid state.

A method of soldering an alloy member including nickel and titanium and having oxidation thereon to an other member, said alloy member having at least one of superelastic and shape memory properties and an annealing temperature above which said superelastic and shape memory properties are impaired, said method comprising the steps of:

• applying a pickling solution to at least partially remove said oxidation from a surface of said alloy member;
• wetting said surface with an aluminum flux paste having an activation temperature below said annealing temperature of said alloy;
• heating said flux to said activation temperature;
• suspending said contaminant in said flux heated to said activation temperature;
• scrubbing from said surface said flux having said contaminant suspended therein;
• wetting said surface with an additional amount of said aluminum paste flux;
• flowing the solder in a molten state on said surface and on said other member to thereby displace from said surface said additional flux with said solder flowing on said surface;
• cooling said solder on said surface and on said other member;
• and
• cleaning said flux from said alloy member and said other member.

A method of flowing a solder material on a surface of a nickel-titanium alloy member having TiO.sub.2 on the surface thereof and an annealing temperature above which superelastic and shape memory properties are impaired, comprising the steps of:

• applying to said member surface an inorganic acid based flux having an activation temperature below said annealing temperature of said alloy member, said flux having a composition suitable for removing said TiO.sub.2 from said member surface;
• removing with said flux said TiO.sub.2 from said member surface to form a bonding surface substantially free of said TiO.sub.2 ;
• flowing a solder material in a molten state on said bonding surface;
• and
• cooling said solder material to a solid state.

A method of flowing a solder material on a surface of a nickel-titanium alloy member having TiO.sub.2 on the surface thereof and an annealing temperature above which superelastic and shape memory properties are impaired, comprising the steps of:

• applying to said member surface an aluminum flux paste having an activation temperature below said annealing temperature of said alloy member, said flux having a composition suitable for removing said TiO.sub.2 from said member surface;
• removing with said flux said TiO.sub.2 from said member surface to form a bonding surface substantially free of said TiO.sub.2 ;
• flowing a solder material in a molten state on said bonding surface;
• and
• cooling said solder material to a solid state.