Form of Cabot Microelectronics Corporation 2012 Omnibus Incentive Plan Performance Share Unit Award Agreement (employees (including executive officers))

Award; Performance Goals.  As of the Award Date, the Company hereby grants the Participant an Award of PSUs, consisting of the target number of PSUs specified above (the "Target PSUs"). Each earned PSU is a notional amount that represents one unvested share of Stock and constitutes the right, subject to the terms and conditions of the Plan and this Agreement, to distribution of a share of Stock following the vesting of such PSU and satisfaction of the other requirements contained herein.

"Beginning Stock Price" means the average closing price of a share of Stock for the period of thirty (30) trading days ending the day before the first day of the Performance Period.

"Ending Stock Price" means the average closing price of a share of Stock for the last thirty (30) trading days during the Performance Period, with all dividends deemed reinvested.

"Peer Group" means the companies in the S&P SmallCap 600 Index.

"Relative Total Shareholder Return" means the Company's total shareholder return performance (i.e., (Ending Stock Price – Beginning Stock Price) divided by Beginning Stock Price), relative to the total shareholder return performance of the Peer Group.

"Three-Year Average Revenue Growth" means the three-year average of the annual change in the Company's revenue over the Performance Period, as reported in the Company's Annual Report on Form 10-K ("Form 10-K") for each completed fiscal year of the Company during the Performance Period.

"Three-Year Cumulative Earnings per Share" means the sum of the Company's diluted earnings per share for each completed fiscal year of the Company during the Performance Period, as reported in the Company's Form 10-K for each such year.

Termination of Service; Change in Control. Except as otherwise provided in this Section 2, the Participant must remain continuously in Service through the last day of the Performance Period for the PSUs to vest (if at all) in accordance with Section 1.

Death. In the event of the Participant's death prior to the end of the Performance Period, the Award shall become fully vested and the Participant's beneficiary, surviving spouse or estate, as applicable, shall be entitled to receive the corresponding number of shares of Stock underlying the Target PSUs as soon as reasonably practicable following the date of the Participant's death.

Disability; Retirement; Position Elimination Termination. In the event of the Participant's Disability, Retirement or an involuntary termination of Service due to Position Elimination ("Position Elimination Termination"), in each case, prior to the end of the Performance Period, the Participant shall be entitled to receive, at the same time as the PSU awards for the same Performance Period held by other participants in the Plan are settled, the corresponding number of shares of Stock underlying the Final Earned PSUs based on actual performance through the end of the Performance Period, prorated based on a fraction, the numerator of which is the number of days in which the Participant was in Service during the Performance Period through the date of such Disability, Retirement, or Position Elimination Termination, and the denominator of which is the total number of days in the Performance Period.

Any Other Termination of Service. Unless otherwise specifically provided herein, upon the Participant's termination of Service with the Company prior to the end of the Performance Period for any reason other than death, Disability, Retirement or Position Elimination Termination, the Participant shall immediately forfeit the Award. Notwithstanding the foregoing, upon the Participant's termination of Service with the Company for Cause prior to or after the end of the Performance Period (but before settlement of the PSUs), the Participant shall immediately forfeit the Award.

Committee Discretion. Notwithstanding anything herein to the contrary, in the event of an involuntary termination of Service for any reason other than Cause, the Committee may, in its sole discretion, accelerate the vesting of all or any portion of the Award.

Change in Control.

In the event that a Change in Control is consummated prior to the end of the Performance Period and the Award is assumed by the acquirer or surviving corporation, as applicable, the Award will be converted upon the Change in Control to a time-vested Restricted Stock Unit ("RSU") award, based on the Target PSUs, and such RSU award will vest in full, based on the passage of time, at the end of the Performance Period (provided that the Participant does not experience a termination of Service prior to such vesting date, except as otherwise set forth herein). If the Participant experiences an involuntary termination of Service without Cause or terminates Service for Good Reason (or experiences any other type of termination that would qualify the Participant to receive payment of benefits pursuant to his or her Change in Control Severance Protection Agreement with the Company, if and to the extent the Participant has such an agreement in place), in each case, within the twelve (12) months following the Change in Control, such RSU award will immediately vest in full, to the extent not already vested. For purposes of this Agreement, "Good Reason" shall have the meaning given to such term in the Participant's Change in Control Severance Protection Agreement with the Company (if and to the extent the Participant has such an agreement in place).

If the Award is not assumed by the acquirer or surviving corporation, as applicable, upon a Change in Control, the Award shall vest as of the date of such Change in Control, and the Participant shall be entitled to receive, within thirty (30) days following the Change in Control, the corresponding number of shares of Stock underlying the Target PSUs.

Certain Definitions. For purposes hereof:

The definition of "Change in Control" shall be deemed modified, only to the extent necessary, to avoid the imposition of an excise tax under Section 409A, to mean a "change in control event" as such term is defined for purposes of Section 409A.  For purposes of clarity, if an Award would, for example, vest and be paid on a Change in Control, but payment of such Award would violate the provisions of Section 409A, then the Award shall vest but will not be paid until the Participant experiences a "separation from service" within the meaning of Section 409A.

"Disability" shall have the meaning provided under: (a) first, an employment agreement between the Participant and the Company; (b) second, if no such employment agreement exists, the terms of the Plan.  In addition, for purposes of this Agreement, the Participant's date of termination of Service (for any reason other than death or Disability) shall be the earlier of: (i) the date on which the Participant ceases to render Service to or be employed by the Company, as determined by the Company in its sole discretion; (ii) the date on which the Company first provides notice of termination of Service; or (iii) the first date of any statutory notice period provided under local law.

"Position Elimination" shall mean the involuntary termination of the Participant's Service by the Company due to the Company's determination that the Participant's position with the Company will be eliminated because of a staffing adjustment or other organizational change, expense reduction considerations, office closings or relocations (including but not limited to adjustments in the number of staff in a department or unit or the elimination of all or some of the functions of a department or unit), in which the Participant will not be replaced by another person in the same position.

"Retirement" shall mean the termination of the Participant's Service following the Participant's attainment of a combination of age and years of Service of at least seventy (70), with a minimum of fifty-five (55) years of age; provided, however, that the Participant's termination of Service will not be deemed to have occurred by reason of Retirement if the Participant's Service has been terminated by reason of Cause, as determined by the Company in its sole discretion.

A "termination of Service" shall be deemed to occur only if it is a "separation from service" within the meaning of Section 409A.

Termination / Cancellation / Rescission / Recovery / Revocation.  The Company may terminate, cancel, rescind, recover, or revoke the Award immediately under certain circumstances, including, but not limited to, the Participant's:

actions constituting Cause, as defined in the Plan, or the Company's By-laws or Articles of Incorporation, and as otherwise enforceable under local law;

rendering of services for a competitor prior to, or within six (6) months after, the exercise of any Award or the termination of Participant's Service with the Company;

unauthorized disclosure of any confidential/proprietary information of the Company to any third party;

failure to comply with the Company's policies regarding the identification, disclosure and protection of intellectual property;

violation of the Cabot Microelectronics Corporation Employee Confidentiality, Intellectual Property and Non-Competition Agreement; or

violation of the Cabot Microelectronics Corporation Code of Business Conduct, including those provisions related to financial reporting.

Purpose of Award.  The Award is intended to promote goodwill between the Participant and the Company and shall not be considered as salary or other remuneration for any employment or other services the Participant may perform for the Company or any of its affiliates.  The Company's grant of the Award does not confer any contractual or other rights of employment or service with the Company.  Benefits granted under the Plan shall not be considered as part of the Participant's salary in the event of severance, redundancy or resignation. Granting of the Award shall also not be construed as creating any right on the part of Participant to receive any additional benefits including awards in the future, it being expressly understood and agreed that any future awards shall be made solely at the discretion of the Company.

Rights and Restrictions Governing Underlying Stock.

As of the Award Date, and until such time as the Participant becomes vested in a PSU and receives a share of Stock as provided in Section 6 of this Agreement, the Participant shall have no rights of a shareholder (including, to the extent applicable, voting rights) as to each share of Stock subject to a PSU, except as provided in Section 5(b) of this Agreement.

If the Company declares a cash dividend on its shares of Stock, then, on the payment date of the dividend, the Participant will be credited with dividend equivalents equal to the amount of such cash dividend per share of Stock, multiplied by the number of Target PSUs credited to the Participant through the record date. The dollar amount credited to the Participant under the preceding sentence will be credited to an account ("Account") established for the Participant for bookkeeping purposes only on the books of the Company. The balance in the Account will be subject to the same terms regarding vesting and forfeiture as the Participant's PSUs awarded under this Agreement. The balance in the Account, adjusted to correspond to the Final Earned PSUs, will be paid, if at all, in cash at the time that the corresponding shares of Stock associated with the Participant's Final Earned PSUs are delivered (or forfeited at the time that the Participant's PSUs are forfeited). For purposes of clarity, any accrued dividend equivalents that become payable to the Participant pursuant to this Section 5(b) will be paid with respect to the Final Earned PSUs, which may be a greater or smaller amount than the dividend equivalents originally credited to the Account with respect to the Target PSUs.

Timing and Form of Payment; Delivery of Stock.

Except as otherwise provided in Section 2, after the Committee has certified attainment of the Performance Goals following the end of the Performance Period, the Participant will be entitled to receive a number of shares of Stock equal to the total number of Final Earned PSUs, if any, that are earned and vested as determined in Sections 1 or 2. The Committee shall automatically include or exclude, as applicable, each of the following items in evaluating the level of attainment of the Performance Goals, to the extent that any such item affects a Performance Goal and depending on which approach results in a higher number of Final Earned PSUs (subject to any exercise of "negative discretion" by the Committee): any unusual or non-recurring events, including, but not limited to, exogenous events, financing activities, acquisitions, divestitures, recapitalizations (including stock splits and dividends), impact of charges for restructurings, discontinued operations, the cumulative effects of accounting or tax changes, and other items determined to be unusual in nature and/or infrequent in occurrence, each as defined by generally accepted accounting principles or as identified in the Company's financial statements, notes to the financial statements, management's discussion and analysis or other Company filings with the Securities and Exchange Commission.

As soon as reasonably practicable following the Committee's certification of the attainment of the Performance Goals, or, as applicable, upon such earlier termination of Service to the extent set forth in Section 2 (and in any event, no later than December 15 next following the end of the Performance Period), one or more stock certificates for the appropriate number of shares of Stock shall be delivered to the Participant or such shares shall be credited to a brokerage account if the Participant so directs; provided however, that such certificates shall bear such legends as the Committee, in its sole discretion, may determine to be necessary or advisable in order to comply with applicable federal and state securities laws.

Tax Treatment. The Participant will generally be taxed on the Fair Market Value of the shares of Stock subject to the Award on the date(s) such shares of Stock are payable to the Participant according to the vesting terms above. This income will be taxed as ordinary income and will be subject to income and FICA withholding taxes. The Company is required to withhold and remit these taxes to the appropriate tax authorities. The Participant will be required to provide the Company with an amount of cash sufficient to satisfy the Participant's tax withholding obligations or to make arrangements satisfactory to the Company with regard to such taxes.  The income will be reported to the Participant as part of the Participant's employment compensation on the Participant's annual earnings statement Form W-2.

Tax Withholding.  All deliveries and distributions under this Agreement are subject to withholding of all applicable taxes. The various methods and manner by which tax withholding may be satisfied are set forth in Section 8.4 of the Plan.  If the Participant is subject to Section 16 (an "Insider"), of the Securities Exchange Act of 1934 ("Exchange Act"), any surrender of previously owned shares to satisfy tax withholding obligations arising under an Award must comply with the requirements of Rule 16b-3 promulgated under the Exchange Act ("Rule 16b-3").

Transferability.  The Award is not transferable other than: (a) by will or by the laws of descent and distribution; (b) pursuant to a domestic relations order; or (c) to members of the Participant's immediate family, to trusts solely for the benefit of such immediate family members or to partnerships in which family members and/or trusts are the only partners, all as provided under the terms of the Plan.  After any such transfer, the Award shall remain subject to the terms of the Plan.

Adjustment of Shares.  In the event of any transaction that is a Share Change or a Corporate Transaction, each as described in Section 8.6 of the Plan, the terms of this Award (including, without limitation, the number and kind of shares subject to this Award) shall or may be adjusted, as applicable, as set forth in Section 8.6 of the Plan.

Severability.  In the event that any provision of this Agreement is found to be invalid, illegal or incapable of being enforced by any court of competent jurisdiction for any reason, in whole or in part, the remaining provisions of this Agreement shall remain in full force and effect to the fullest extent permitted by law.

Waiver.  Failure to insist upon strict compliance with any of the terms and conditions of this Agreement or the Plan shall not be deemed a waiver of such term or condition.

Notices.  Except as provided in Section 14, any notices provided for in this Agreement or the Plan must be in writing and hand delivered, sent by fax or overnight courier, or by postage paid first class mail.  Notices are to be sent to the Participant at the address indicated by the Company's records and to the Company at its principal executive office.

Electronic Delivery.  The Company may, in its sole discretion, decide to deliver any documents related to the PSUs or other awards granted to the Participant under the Plan by electronic means.  The Participant hereby consents to receive such documents by electronic delivery and agrees to participate in the Plan through an on-line or electronic system established and maintained by the Company or a third party designated by the Company.

Section 409A. The PSUs are intended to be exempt from the requirements of Section 409A. The Plan and this Agreement shall be administered and interpreted in a manner consistent with this intent. If the Company determines that this Agreement is subject to Section 409A and that it has failed to comply with the requirements of Section 409A, the Company may, at the Company's sole discretion, and without the Participant's consent, amend this Agreement to cause it to comply with Section 409A or be exempt from Section 409A.

Governing Law.  This Agreement shall be construed under the laws of the State of Delaware.

Providing a personal check, bank draft or money order payable to the Company at the time of vesting (instructions for doing so will be provided in advance of each vesting date) ___________.

Selling enough shares of those that vest from the Award at the time of vesting ("withhold to cover") to satisfy my tax liability ___________.   My initialed election of this option confirms that at the time that I am making this election, I am not in possession of any material non-public information regarding the Company and am in compliance with the Company's Insider Trading Guidelines.

I prefer to decide whether to "withhold to cover" or pay my tax obligation through personal check, bank draft or money order payable to the Company in advance of vesting (instructions for doing so will be provided in advance of vesting) ___________.