Process for chemically treating surfaces to increase wettability

Abstract

Methods and systems are disclosed for chemically treating surfaces of metal parts to increase wettability by contacting the metal parts with a treatment fluid. Metal parts are disclosed that have surfaces free of burrs and with wettability suitable for, as examples, adhesion, bonding, painting, welding, and other processes.

I claim: 
     
         1 . A method for controlling a treatment process, the method comprising:
 providing a metal part in a recirculating supply of a fluid to chemically treat the metal part, the fluid having an initial concentration of hydrochloric acid and an initial concentration of ferric chloride in water;   monitoring a conductivity of the recirculating supply of the fluid to determine a current concentration of the hydrochloric acid;   maintaining the current concentration of the hydrochloric acid in the recirculating supply of the fluid within a threshold range of the initial concentration of hydrochloric acid by adding more hydrochloric acid to the recirculating supply of the fluid based on the conductivity;   monitoring a specific gravity of the recirculating supply of the fluid to determine a current specific gravity of the recirculating supply of the fluid; and   maintaining the specific gravity of the recirculating supply of the fluid within a threshold range of a specific gravity set point by adding more water to the recirculating supply of the fluid based on the current specific gravity.   
     
     
         2 . The method of  claim 1 , wherein the monitoring the conductivity and the maintaining the current concentration of the hydrochloric acid occur for a first period of time to ensure that the current concentration of the hydrochloric acid is at steady-state prior to providing the metal part in the recirculating supply of the fluid. 
     
     
         3 . The method of  claim 2 , wherein the monitoring the specific gravity and the maintaining the specific gravity in the recirculating supply of the fluid occur for a second period of time to ensure that the current concentration of the hydrochloric acid is at steady-state after the monitoring the conductivity and the maintaining the current concentration of the hydrochloric acid and prior to the providing the metal part in the recirculating supply of the fluid. 
     
     
         4 . The method of  claim 1 , wherein the initial concentration of hydrochloric acid in the fluid is a first set point based on a composition of the metal part within a range of 9.5 to 22.1 vol. %, and the initial concentration of ferric chloride in the fluid is a second set point based on the composition of the metal part within a range of 13.5 to 31.5 vol. %, the method further comprising maintaining a temperature of the recirculating supply of the fluid at about 52° C. 
     
     
         5 . The method of  claim 1 , wherein a composition of the metal part includes iron, nickel, copper, or an alloy having one or more of iron, nickel, and copper, and the metal part is provided in the recirculating supply of the fluid for about 45 seconds to remove about 0.01 mm of material from each surface of the metal part. 
     
     
         6 . The method of  claim 1 , wherein the providing the metal part in the recirculating supply of the fluid includes spraying the recirculating supply of the fluid on the metal part as the metal part passes through a treatment chamber. 
     
     
         7 . A system for chemically treating a surface of a metal part, the system comprising
 a treatment chamber having a recirculating supply of a fluid to chemically treat the surface of the metal part, the fluid including an acid and a salt in water;   a conductivity probe configured to measure conductivity of the fluid;   a specific gravity probe configured to measure specific gravity of the fluid; and   a controller configured to adjust the conductivity of the fluid by adding more of the acid to the fluid and configured to adjust the specific gravity of the fluid by adding more of the water to the fluid.   
     
     
         8 . The system of  claim 7 , further comprising:
 a conductivity measurement loop configured to withdraw a portion of the fluid from the treatment chamber, for measurement of the conductivity, and deposit the portion of the fluid back into the treatment chamber, after the measurement of the conductivity,   wherein the conductivity probe is within the conductivity measurement loop.   
     
     
         9 . The system of  claim 7 , further comprising:
 a specific gravity measurement loop configured to withdraw a portion of the fluid from the treatment chamber, for measurement of the specific gravity, and deposit the portion of the fluid back into the treatment chamber, after the measurement of the specific gravity,   wherein the specific gravity probe is within the specific gravity measurement loop.   
     
     
         10 . The system of  claim 7 , further comprising:
 a heater, a chiller, or a combination thereof to maintain a temperature of the recirculating supply of the fluid.   
     
     
         11 . The system of  claim 10 , wherein the temperature of the fluid is maintained at about 52° C. 
     
     
         12 . The system of  claim 7 , wherein the acid is hydrochloric acid at a concentration of 9.5 to 22.1 vol. % and the salt is ferric chloride at a concentration of 13.5 to 31.5 vol. %. 
     
     
         13 . The system of  claim 12 , wherein the specific gravity of the fluid is about 1.395 g/cm 2 . 
     
     
         14 . A method for chemically treating a surface of a metal part, the method comprising:
 providing the metal part in a treatment chamber;   contacting the surface of the metal part with a treatment fluid within the treatment chamber to chemically treat the surface of the metal part, the treatment fluid including about 9.5 to 22.1 vol. % hydrochloric acid and about 13.5 to 31.5 vol. % ferric chloride in water, and the treatment fluid having a specific gravity of about 1.1 to 1.5 g/cm 2 ;   providing the metal part in a rinse chamber after exiting the treatment chamber; and   contacting the surface of the metal part with a rinse fluid in the rinse chamber to rinse the treatment fluid off of the surface of the metal part.   
     
     
         15 . The method of  claim 14 , wherein the temperature of the treatment fluid is about 52° C. and the specific gravity of the treatment fluid is 1.395 g/cm 2 . 
     
     
         16 . The method of  claim 14 , wherein the metal part is contacted with the treatment fluid for about 45 seconds. 
     
     
         17 . The method of  claim 16 , wherein about 0.01 mm of material is removed from the surface of the metal part from contacting the surface with the treatment fluid. 
     
     
         18 . The method of  claim 14 , wherein a composition of the metal part includes iron, nickel, copper, or an alloy having one or more of iron, nickel, and copper. 
     
     
         19 . The method of  claim 14 , wherein contacting the surface of the metal part with the treatment fluid within the treatment chamber includes spraying the treatment fluid on the metal part as the metal part passes through the treatment chamber on a conveyor belt. 
     
     
         20 . A metal part treated according to the method of  claim 14 . 
     
     
         21 . The metal part of  claim 20 , wherein a surface tension of the metal part is about 35 to 60 milliNewtons/meter. 
     
     
         22 . The metal part of  claim 20 , wherein the metal part has a composition including iron, nickel, copper, or an alloy having one or more of iron, nickel, and copper. 
     
     
         23 . The metal part of  claim 20 , wherein the metal part has a thickness of about 0.12 to 6.3 mm. 
     
     
         24 . The metal part of  claim 20 , wherein the metal part is a laser cut metal part, a stamped metal part, a mechanically fabricated metal part, a milled metal part, or an etched metal part, and the metal part is free of surface pits and metal burrs. 
     
     
         25 . The metal part of  claim 24 , wherein the metal part is the stamped metal part and includes burrs prior to being treated and is free of the burrs after being treated. 
     
     
         26 . The metal part of  claim 20 , wherein the metal part is treated for about 45 seconds. 
     
     
         27 . A metal part comprising:
 a composition including iron, nickel, copper, or an alloy having one or more of iron, nickel, and copper; and   a surface tension of to about 35 to 60 milliNewtons/meter.   
     
     
         28 . The metal part of  claim 27 , further comprising:
 a thickness of about 0.05 to 6.3 mm.   
     
     
         29 . The metal part of  claim 27 , wherein the metal part is a laser cut metal part, a stamped metal part, a mechanically fabricated metal part, a milled metal part, or an etched metal part. 
     
     
         30 . The metal part of  claim 29 , wherein the stamped metal part is free of burrs.