3M Co. announced Thursday that it had completed its $860 million purchase of California ceramics firm Ceradyne Inc.

Analysts generally applauded the deal and said the acquisition expands 3M's advanced ceramics offerings into auto and military markets.

3M already makes advanced ceramics to manufacture paints and durable coatings for windmill blades, wires, pipes and other products. But with Ceradyne, 3M will now make ceramics for use in automobile engines, military helmets, helicopter armor, soldier body armor and even missile nose cones.

Ceradyne also will give 3M 2,100 new employees and contribute $500 million in annual sales.

3M recently received regulatory clearance to proceed with the deal from the governments of Austria, Germany and the United States. This week, it completed its tender offer of $35 a share.

Ceradyne will join 3M's advanced materials division, which is part of 3M's industrial business group, the largest of 3M's five business groups.