Abstract: As phosphorus content greatly influences physico-chemical properties of nickel phosphorus alloy,fast and accurately determinating phosphorus content in Ni-P alloy,is very important for monitoring and controlling the quality of alloy.Ni-P alloy (coating) according to the suitable craft standard was prepared at first,then EDTA titrating nickel indirect conversion method,phosphorus molybdenum vanadium yellow spectrophotometric method,and ammonium phosphomolybdate volumetric method were used to determine phosphorus content in the alloy respectively,finally,the contrast with the result by the standard determination method was carried on.Good and bad points of each method were investigated from result accuracy,data precision and simplicity three aspects.Results indicated EDTA titrating nickel indirect conversion method was more simple,rapid,accurate,and precise,and was worth to promote the application in production process and experimental study.

Key words: nickel phosphorus alloy； , phosphorus content；EDTA titrimetric method；accuracy;precision