BOC Edwards made three appointments in its Electronic Materials business: Vasu Mohan was named director of operations, Fluorine, and will continue to manage BOC Edwards' NF3 plant in South Africa. Rob Limouze was named business development manager, and Brian Zieves was promoted to the new position of global technical manager.   . . .   Michael von Mackensen recently joined Munich-based NanoPierce Card Technologies GmbH as head of sales and marketing for the introduction of its WaferPierce technique to applications such as smart card chip modules and LEDs.