CORRELATION BETWEEN STRUCTURE OF ELECTROCHEMICALLY DEPOSITED (Fe,Co,Ni)-P LAYERS AND PROCESS CONDITIONS

A study has been made of the structure of the electrochemically deposited amorphous (Fe, Co, Ni)-P layers with relation to the process conditions, e.g. pH value, current density, metallic salt concentration, etc., by means of X-ray analysis, SEM and EPMA. Results showed that the effect of the process on the structure is realized by changing the P content of the layer. While P contained over 8%, below 3% or between 3 and 8%, a layer may be constructed as amorphous alloy, supersaturated solution or mixed structures respectively. The major factors affecting the structure of the deposited layer are found to be the concentration of NaH_2PO_2 and pH value of the bath. The structure of the layer may be also influenced by the potential of electro-deposition. The Fe-P, Co-P or Ni-P system is similar in amorphous structure of which the highest thickness of stack of the atomic face is 2.0, 2.5 or 6.5nm respectively.