Nanosecond laser-based high-throughput surface nano-structuring (nhsn) process

Abstract

Embodiments of the present invention are directed to a surface modified metal piece comprising a first major surface, wherein at least one portion of the first major surface: comprises the reaction product of a surface modifier; has a random micro- and nanoscale structure; and has at least one of a water contact angle when exposed to water of at least about 120° and a spectral reflectance of less than about 25% within the visible spectrum. Other embodiments relate to processes and methods for making such a surface modified metal piece.

What is claimed is: 
     
         1 . A surface modified metal piece comprising:
 a first major surface, wherein at least one portion of the first major surface:   comprises the reaction product of a surface modifier;   has a random micro- and nanoscale structure; and   has at least one of a water contact angle when exposed to water of at least about 120° and a spectral reflectance of less than about 25% within the visible spectrum.   
     
     
         2 . The surface modified metal piece of  claim 1 , wherein the at least one portion of the first major surface comprising the surface modifier has a water contact angle when exposed to water of at least 150°. 
     
     
         3 . The surface modified metal piece of  claim 1 , wherein the metal piece is made of steel, titanium, aluminum, magnesium, and alloys thereof. 
     
     
         4 . The surface modified metal piece of  claim 1 , wherein the metal piece is AISI 4130 steel, titanium Ti-6Al-4V alloy (Ti-6Al-4V), aluminum alloy 6061 alloy (AA-6061) or magnesium AZ31B alloy (Mg AZ31B). 
     
     
         5 . The surface modified metal piece of  claim 1 , wherein the surface modifier is the reaction product of a silane of the formula:
   X 1   3 SiR 1      
       wherein each X 1  is halogen or a C 1 -C 6 -alkoxy group; and R 1  is a C 8 -C 20 -fluoro-substituted alkyl group; and
 reactive sites on a major surface of the metal piece. 
 
     
     
         6 . The surface modified metal piece of  claim 5 , wherein R 1  is a group having the formula C n —F 2n+1 —(CH 2 ) 2 -(organofunctional group), wherein the “organofunctional group” is 1H, 2H, 2H-perfluoralkyl; and n is an integer from 8 to 20. 
     
     
         7 . The surface modified metal piece of  claim 1 , wherein the at least one portion of the first major surface has a spectral reflectance of less than 60% within the IR-A spectrum. 
     
     
         8 . The surface modified metal piece of  claim 1 , wherein the at least one portion of the first major surface has a spectral reflectance of less than 30% within the IR-A spectrum. 
     
     
         9 . The surface modified metal piece of  claim 1 , wherein the at least one portion of the first major surface has a spectral reflectance of less than 60% within the IR-B spectrum. 
     
     
         10 . The surface modified metal piece of  claim 1 , wherein the at least one portion of the first major surface has a spectral reflectance of less than 40% within the IR-B spectrum. 
     
     
         11 . A surface modified metal piece made by the process comprising:
 immersing a metal piece having a first major surface in an aqueous medium;   texturing at least a portion of the first major surface along a nanosecond laser scan path at a laser scanning time of at least about 0.25 seconds/in 2  to obtain a textured metal piece having a textured surface along the scan path;   removing the textured metal piece from the aqueous medium; and   immersing the textured metal piece in a solution comprising a surface modifier, wherein the surface modifier reacts with the textured surface to obtain a modified metal surface; wherein:   at least one of the textured surface along the scan path and the textured surface that reacts with the surface modifier has a random micro- and nanoscale structure;   the nanosecond laser emits pulses of an appropriate energy onto the first major surface along the scan path;   the nanosecond laser has a laser power intensity of greater than about 0.2 GW/cm 2 ;   the surface modifier reacts substantially only with the textured surface along the scan path; and the textured surface along the scan path that reacts with the surface modifier has at least one of a water contact angle when exposed to water of at least 120° and a spectral reflectance of less than 25% within the visible spectrum.   
     
     
         12 . The surface modified metal piece of  claim 11 , wherein the laser power intensity is from 0.2 GW/cm 2  to about 20 GW/cm 2 . 
     
     
         13 . The surface modified metal piece of  claim 11 , wherein the textured surface along the scan path that reacts with the surface modifier has a water contact angle when exposed to water of at least 150° 
     
     
         14 . The surface modified metal piece of  claim 11 , wherein the metal piece is made of steel, titanium, aluminum, magnesium, and alloys thereof. 
     
     
         15 . The surface modified metal piece of  claim 11 , wherein the metal piece is AISI 4130 steel, titanium Ti-6Al-4V alloy (Ti-6Al-4V), aluminum alloy 6061 alloy (AA-6061) or magnesium AZ31B alloy (Mg AZ31B). 
     
     
         16 . The surface modified metal piece of  claim 11 , wherein the surface modifier is the reaction product of a silane of the formula:
   X 1   3 SiR′ 1  
   
       wherein each X 1  is halogen or a C 1 -C 6 alkoxy group; and R 1  is a C 8 -C 20 -fluoro-substituted alkyl group; and reactive sites on a major surface of the metal piece. 
     
     
         17 . The surface modified metal piece of  claim 16 , wherein R 1  is a group having the formula C n —F 2n+1 —(CH 2 ) 2 -(organofunctional group), wherein the “organofunctional group” is 1H, 2H, 2H-perfluoralkyl; and n is an integer from 8 to 20. 
     
     
         18 . The surface modified metal piece of  claim 11 , wherein the at least one portion of the first major surface has a spectral reflectance of less than 60% within the IR-A spectrum. 
     
     
         19 . The surface modified metal piece of  claim 11 , wherein the at least one portion of the first major surface has a spectral reflectance of less than 30% within the IR-A spectrum. 
     
     
         20 . The surface modified metal piece of  claim 11 , wherein the at least one portion of the first major surface has a spectral reflectance of less than 60% within the IR-B spectrum. 
     
     
         21 . The surface modified metal piece of  claim 11 , wherein the at least one portion of the first major surface has a spectral reflectance of less than 40% within the IR-B spectrum. 
     
     
         22 . A method of making a surface modified metal piece, the method comprising:
 immersing a metal piece having a first major surface in an aqueous medium;   texturing at least a portion of the first major surface along a nanosecond laser scan path at a laser scanning time of at least about 0.25 seconds/in 2  to obtain a textured metal piece having a textured surface along the scan path;   removing the textured metal piece from the aqueous medium; and   immersing the textured metal piece in a solution comprising a surface modifier, wherein the surface modifier reacts with the textured surface to obtain a modified metal surface; wherein:   at least one of the textured surface along the scan path and the textured surface that reacts with the surface modifier has a random micro- and nanoscale structure;   the nanosecond laser emits pulses of an appropriate energy onto the first major surface along the scan path;   the nanosecond laser has a laser power intensity of greater than about 0.2 GW/cm 2 ;   the surface modifier reacts substantially only with the textured surface along the scan path; and the textured surface along the scan path that reacts with the surface modifier has at least one of a water contact angle when exposed to water of at least 120° and a spectral reflectance of less than 25% within the visible spectrum.