The principle of the method specified is dissolving a test portion in hydrochloric and nitric acids, decomposing resistant boron compounds (e.g. boron nitrides) by fuming the sample solution with phosphoric and sulfuric acids at not less than 290 C, forming the boron curcumin complex in a buffered acetic acid and sulfuric acid medium, and measuring the absorbance of the test solution in a molecular absorption spectrometer at 543 nm. Applies to nickel and nickel alloys having a total boron content in the range of 4 g/t to 240 g/t.