SIGNATURES Pursuant to the requirements of section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized: CABOT MICROELECTRONICS CORPORATION Date: November 20, 2012 /s/ WILLIAM P. NOGLOWS William P. Noglows Chairman of the Board, President and Chief Executive Officer [Principal Executive Officer] Date: November 20, 2012 /s/ WILLIAM S. JOHNSON William S. Johnson Vice President and Chief Financial Officer [Principal Financial Officer] Date: November 20, 2012 /s/ THOMAS S. ROMAN Thomas S. Roman Corporate Controller [Principal Accounting Officer] Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated: Date: November 20, 2012 /s/ WILLIAM P. NOGLOWS William P. Noglows Chairman of the Board, President and Chief Executive Officer [Director] Date: November 20, 2012 /s/ ROBERT J. BIRGENEAU* Robert J. Birgeneau [Director] Date: November 20, 2012 /s/ JOHN P. FRAZEE, JR.* John P. Frazee, Jr. [Director] Date: November 20, 2012 /s/ H. LAURANCE FULLER* H. Laurance Fuller [Director] Date: November 20, 2012 /s/ RICHARD S. HILL* Richard S. Hill [Director] Date: November 20, 2012 /s/ BARBARA A. KLEIN* Barbara A. Klein [Director] Date: November 20, 2012 /s/ EDWARD J. MOONEY* Edward J. Mooney [Director] Date: November 20, 2012 /s/ STEVEN V. WILKINSON* Steven V. Wilkinson [Director] Date: November 20, 2012 /s/ BAILING XIA* Bailing Xia [Director] *by H. Carol Bernstein as Attorney-in-fact pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934. 68