Abstract
The effect of rhenium, boron, and carbon on Ni-Re-B-C alloy films deposited from electroless Ni-B plating bath containing ammonium perrhenate was studied. Results were assessed with differential scanning calorimetry, X-ray diffraction analysis, scanning electron microscopy, and transmission electron microscopy.
The rhenium content of deposited films increased steeply to about 55wt% and then slowly increased to about 60wt% as ammonium perrhenate concentration in the bath increased. In contrasts, the boron and carbon content steeply decreased. Rhenium was deposited in greater amounts than boron and carbon.
The structure of Ni-Re-B-C alloy films was analyzed in terns of rhenium and boron content due to the low C content, which was less than 0.3wt%. Films with a low rhenium and high boron content (over 2.0wt%) films had a rich phase that was amorphous. Films crystallized into nickel and Ni3B after heat-treatment at over 400°C. However, films with a high rhenium content had a marked by extremely fine crystals during deposition. The electron diffraction pattern of finely crystallized films did not change even after heat-treatment at 500°C for 1hr. Under these conditions, grain growth occurred at over 500°C, and a crystallized Ni3B spot appeared at 700°C.
