Anderson. — Electrical Deposition of Nickel. 501 



Art. XL VI. — A Study of the Electrical Deposition of Nickel in the 



Presence of Nitrate. 



By James G. Anderson, M.Sc, Collegiate School, Wanganui. 



Communicated by Mr. L. J. Wild. 



[Read before the Philosophical Institute of Canterbury, 6th December. 1016; received by 

 Editors, 30th December, 1916 ; issued separately, 10th December, 1917.] 



The modern method usually employed in the electrical separation of nickel 

 originated in the use of the double sulphate of nickel and ammonium first 

 suggested by Professor Boettger in 1843. The deposition, however, was 

 very slow, and the conductivity of the electrolyte was extremely small. 

 To remedy this latter defect a number of substances were suggested, 

 ammonium sulphate being most frequently used for the purpose. Under 

 suitable conditions a good coherent deposit can be obtained, and the process, 

 though lengthy, admits of a quantitative estimation of the amount of 

 nickel present in a solution. 



Numerous experimenters have observed that nitrates exert a most 

 disturbing effect on such estimations. In recent years Thiel* found 

 that the presence of nitrites yields high results owing to deposition of 

 nickel oxide on the cathode. The present investigation was undertaken 

 to study the effect of the addition of known amounts of nitrate on the 

 deposition of the metal, and to eliminate the disturbing products of the 

 electrolysis. 



Experimental Details. 



The apparatus used consisted of a glass beaker containing the solution 

 to be electrolyzed, in which were suspended the electrodes. These were 

 of iridio-platinum, and were of the form devised by Perkin.f The cathode 

 was made of gauze, and possessed a total surface of 50 sq. cm. ; the anode 

 is opposed to both sides of the cathode during electrolysis, and conse- 

 quently an even current-density is obtained on all parts of the cathode. 



The conditions under which the investigations were conducted were 

 those recommended by Marshall,! viz., — 



Amount of nickel to be deposited (approx.) . . 0-3 grm. 



Volume of solution . . . . . . . . 150 c.c. 



Ammonium sulphate . . . . . . . . 5 grm. 



Ammonia . . . . . . . . . . 5 grm. 



The experiments were made at the ordinary temperature, and about four 

 hours was found necessary to complete the electrolysis. 



The solution of nickel sulphate to be used in the subsequent course of 

 the work was carefully standardized ; a large number of determinations 

 were made under precisely similar conditions, and the results showed close 



* A. Thiel, Zeitsch. Elektrochem, vol. 14, 1908,*pp. 201-8. 



t W. Perkin, A New Form of Electrode, Joum. Faraday Soc, vol. 1, 1903. 



% A. Marshall, Some Polarisation Phenomena, Prcc. Roy. Soc. Edin., 1899. 



