ST. PAUL, Minn.--(BUSINESS WIRE)--3M (NYSE:MMM) announced today that it has completed its acquisition of Ceradyne, Inc. effective as of November 28, 2012, pursuant to the previously announced merger agreement among Ceradyne, 3M, and 3M’s wholly owned subsidiary, Cyborg Acquisition Corporation, through the merger of Cyborg Acquisition Corporation with and into Ceradyne. As a result of the merger, Ceradyne is…