Chemical Phase Analysis for Nitrogen in Low Alloy Steel Samples of Small Sizes

Two portions of 0.5 g of steel sample,which had been machined into definite shape and size,were tired up with thin Pt-wire and hanged into collodion bags filled with electrolyte.The samples in the bags were taken as anode and electrolyzed under prescribed conditions to separate nitrides from the sampe.The residues separated out at the anode were transferred to 2 test tubes.The residue from one of the 2 samples was fumed with conc.H2SO4 and used for determination of nitride-N by the indophenol blue photometry after separation by distillation.And the residue from the other sample was dissolved with HCl and used for determination of aluminum by ICP-AES.The results of N and Al contents obtained were converted into contents of free nitrogen,M(C,N) phase and nitrogen in AIN according to formula given in the paper.