Influence of Alloying Elements on the Surface Morphology of Electroless Deposits for Ni-P Based Alloy Systems

摘要

We used SEM (scanning electron microscopy) to study the amorphous and crystalline deposits of Ni-P, Ni-Sn-P and Ni-Sn-Cu-P alloy systems with magnifications of 500x, 1000x, 5000x, 10000x and 20000x. We found first that the morphology only can be displayed clearly with magnifications of 5000x for most of these deposits, some of them must be up to 10000x. It is very difficult to see any features with magnifications below 1000x. The features look like cauliflower, some like arranged oranges with nearly uniform size, or like arranged potatoes. Our results also show that the size of these features decreases with increasing contents of P, Sn+P, and Sn+Cu+P in the deposits. A formula relating the size and content could be worked out, which is an inverse proportional relationship. The SEM pictures of these deposits indicate that the deposits are really dense, thus causing them to have superior properties.