Stress in Ni-Mo Alloys Electrodeposited from Ammoniacal Citrate Solution

Abstract

To understand the relation between the intemal stress and molybdenum content in electrodeposited Ni-Mo aUoys， measurement of the st置曹ess was carried out using both strain gauge and x-ray diffrac on methods． The alloy was electrodeposlted from an ammoniacal citrate bath containing nlckel sulfate and sodium molybdate． Molybdenum content in the alloy increased with an increase in molybdate ion concentration and a decrease in cathodic current density． The intemal stress measured by the strain gauge method decreased with an increase in molybdenum content and cathodic current density． On the other hand， the stress measured by the X-ray diffraction method only siightly changed， but both crystalhte size an4 crystalhnity decreased with an increase in molybdenum content These dala suggest that the intemal stress in the alloy is dependent upon the conditlon of c【ystaUite coalescence． 1 1NTRODUCTION and citrate solution． Landa et a1．6) examined Electrodeposited Ni-Mo alloys are of practical interest because・f their high c・rr・一 sion resistance，especially in hydr・chloric acid1・2)． Their abihty to protect a substrate