Method for modifying nickel microparticles and method for producing nickel microparticles

Abstract

The purpose of the present invention is to provide a method for modifying nickel microparticles weight loss of which occurs due to heat treatment such as burning and a method for producing nickel microparticles comprising the modification method. Provided is a method for modifying nickel microparticles comprising a step of making an acid and/or hydrogen peroxide act on nickel microparticles weight loss of which occurs due to heat treatment such as burning and a method for producing nickel microparticles comprising the modification method. The step of making an acid and/or hydrogen peroxide act reduces a rate of weight loss due to heat treatment of the nickel microparticles, nitric acid or a mixture of acids that include nitric acid is preferably used as the acid, and the nickel microparticles and acid and/or hydrogen peroxide are preferably made to act in a ketonic solvent.

1 . A method for modifying nickel microparticles comprising a step of making an acid and/or hydrogen peroxide act on nickel microparticles weight loss of which occurs due to heat treatment such as burning. 
     
     
         2 . The method for modifying nickel microparticles according to  claim 1 , wherein the step of making an acid and/or hydrogen peroxide act reduces a rate of weight loss due to heat treatment of the nickel microparticles. 
     
     
         3 . The method for modifying nickel microparticles according to  claim 2 , wherein the rate of weight loss due to heat treatment of the nickel microparticles is a weight loss rate in simultaneous thermogravimetry-differential thermal analysis measurement, and
 the weight loss rate in a simultaneous thermogravimetry-differential thermal analysis measurement under a nitrogen atmosphere of the nickel microparticles is 1% or less in a range of 40° C. to 400° C.   
     
     
         4 . The method for modifying nickel microparticles according to  claim 1 , wherein nitric acid or a mixture of acids that include nitric acid is used as the acid. 
     
     
         5 . The method for modifying nickel microparticles according to  claim 1 , wherein the nickel microparticles and acid and/or hydrogen peroxide are made to act in a ketonic solvent. 
     
     
         6 . The method for modifying nickel microparticles according to  claim 1 , wherein a molar ratio of the acid to the nickel microparticles is in a range of 0.001 to 0.1. 
     
     
         7 . The method for modifying nickel microparticles according to  claim 1 , wherein a molar ratio of the hydrogen peroxide to the nickel microparticles is in a range of 0.001 to 2.0. 
     
     
         8 . The method for modifying nickel microparticles according to  claim 1 , wherein the step of making an acid and/or hydrogen peroxide act includes an ultrasonic processing, a stirring processing, or a microwave processing. 
     
     
         9 . The method for modifying nickel microparticles according to  claim 8 , wherein the stirring processing is performed using a stirrer provided with a rotating stirring blade. 
     
     
         10 . The method for modifying nickel microparticles according to  claim 1 , wherein powder of the nickel microparticles on which the acid and/or hydrogen peroxide was made to act is stored under an air atmosphere. 
     
     
         11 . The method for modifying nickel microparticles according to  claim 1 , wherein the nickel microparticles are nickel microparticles separated by a microreactor which makes at least two kinds of fluids to be processed react. 
     
     
         12 . A method for modifying nickel microparticles comprising a step of making a substance which reacts with nickel hydroxide act on nickel microparticles on at least surfaces of which nickel hydroxide is present to reduce the nickel hydroxide. 
     
     
         13 . A method for producing nickel microparticles comprising the modification method according to  claim 1 . 
     
     
         14 . The method for producing nickel microparticles according to  claim 13 , being a method for producing the nickel microparticles using a microreactor,
 the said microreactor comprising:   a first processing surface and a second processing surface which are disposed facing each other so as to be able to approach and/or separate from each other, at least one of which rotates relative to the other, comprising:   a step of introducing at least two kinds of fluids to be processed between the first processing surface and the second processing surface;   a step of generating a separating force which acts in a direction to separate the first processing surface and the second processing surface from each other by an introducing pressure of the at least two kinds of fluids to be processed imparted to between the first processing surface and the second processing surface;   a step of forming a thin film fluid by making the at least two kinds of fluids to be processed converge with each other between the first processing surface and the second processing surface kept at a minute distance and pass through between the first processing surface and the second processing surface while keeping the minute distance between the first processing surface and the second processing surface by the separating force; and   a step of making the fluids to be processed react with each other in the thin film fluid and separating nickel microparticles by the reaction.   
     
     
         15 . The method for modifying nickel microparticles according to  claim 2 , wherein nitric acid or a mixture of acids that include nitric acid is used as the acid. 
     
     
         16 . The method for modifying nickel microparticles according to  claim 3 , wherein nitric acid or a mixture of acids that include nitric acid is used as the acid. 
     
     
         17 . The method for modifying nickel microparticles according to  claim 2 , wherein the nickel microparticles and acid and/or hydrogen peroxide are made to act in a ketonic solvent. 
     
     
         18 . The method for modifying nickel microparticles according to  claim 3 , wherein the nickel microparticles and acid and/or hydrogen peroxide are made to act in a ketonic solvent. 
     
     
         19 . The method for modifying nickel microparticles according to  claim 4 , wherein the nickel microparticles and acid and/or hydrogen peroxide are made to act in a ketonic solvent. 
     
     
         20 . The method for modifying nickel microparticles according to  claim 2 , wherein a molar ratio of the acid to the nickel microparticles is in a range of 0.001 to 0.1.