Metal coloring solution for chemical conversion treatment and method for coloring metal

Abstract

Provided is a metal coloring solution for chemical conversion treatment and a method for coloring a metal, which can color a metal surface into a yellowish to brownish color tone with good treatment efficiency. The metal coloring solution for chemical conversion treatment contains: permanganic acid or a salt thereof; one or both of an inorganic acid and a salt thereof; and a condensed phosphate.

1 . A metal coloring solution for chemical conversion treatment, comprising:
 permanganic acid or a salt thereof;   one or both of an inorganic acid and a salt thereof; and   a condensed phosphate.   
     
     
         2 . The metal coloring solution for chemical conversion treatment according to  claim 1 , wherein the permanganic acid or the salt thereof is permanganic acid, sodium permanganate, potassium permanganate, zinc permanganate, magnesium permanganate, calcium permanganate, ammonium permanganate, or a combination thereof. 
     
     
         3 . The metal coloring solution for chemical conversion treatment according to  claim 1 , wherein the inorganic acid and the salt thereof are phosphoric acid, sulfuric acid, nitric acid, carbonic acid, hydrochloric acid, and salts thereof, or combinations thereof. 
     
     
         4 . The metal coloring for chemical conversion treatment according to  claim 1 , wherein the condensed phosphate is potassium pyrophosphate, sodium tripolyphosphate, or a combination thereof. 
     
     
         5 . The metal coloring solution for chemical conversion treatment according to  claim 1 , wherein the metal coloring solution for chemical conversion treatment contains 0.5 to 50 g/L of the permanganic acid or the salt thereof. 
     
     
         6 . The metal coloring solution for chemical conversion treatment according to  claim 1 , wherein the metal coloring solution for chemical conversion treatment contains 0.5 to 100 g/L of the inorganic acid and the salt thereof. 
     
     
         7 . The metal coloring solution for chemical conversion treatment according to  claim 1 , wherein the metal coloring solution for chemical conversion treatment contains 1 to 150 g/L of the condensed phosphate. 
     
     
         8 . The metal coloring solution for chemical conversion treatment according to  claim 1 , further comprising an oxo acid or a salt thereof. 
     
     
         9 . The metal coloring solution for chemical conversion treatment according to  claim 8 , wherein the oxo acid or the salt thereof is perchloric acid, chloric acid, chlorous acid, hypochlorous acid, bromic acid, boric acid, or a salt thereof, or a combination thereof. 
     
     
         10 . The metal coloring solution for chemical conversion treatment according to  claim 8 , wherein the metal coloring solution for chemical conversion treatment contains 0.5 to 100 g/L of the oxo acid or the salt thereof. 
     
     
         11 . The metal coloring solution for chemical conversion according to  claim 1 , wherein the metal to be treated is at least one selected from the group consisting of aluminum, aluminum alloys, copper, copper alloys, iron, iron alloys, zinc, zinc alloys, magnesium, and magnesium alloys. 
     
     
         12 . A method for coloring a metal, comprising a step of coloring the metal by a chemical conversion treatment using the metal coloring solution for chemical conversion treatment according to  claim 1 . 
     
     
         13 . The method for coloring the metal according to  claim 12 , wherein the step of coloring the metal by the chemical conversion treatment comprises immersing the metal in the metal coloring solution for chemical conversion treatment at a temperature of 10° C. to 80° C. for 30 seconds to 20 minutes to color the metal.