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                                                                     Exhibit 3.3

                            CERTIFICATE OF AMENDMENT

                                       OF

                          CERTIFICATE OF INCORPORATION

                                       OF

                THE AMERICAN MATERIALS & TECHNOLOGIES CORPORATION



        It is hereby certified that:

        1. The name of the corporation (hereinafter called the "Corporation") is
The American Materials & Technologies Corporation.

        2. The Certificate of Incorporation of the Corporation is hereby amended
by deleting Article FIFTH thereof in its entirety and substituting therefor the
following new Article:

        "FIFTH. (a) (1) The business and affairs of the Corporation shall be
        managed under the direction of a Board of Directors, consisting of not
        less than three nor more than twelve Directors, the number of which
        shall be determined from time to time by resolution adopted by
        affirmative of a majority of Directors then in office. The Directors
        shall be classified with respect to the time for which they shall
        severally hold office by dividing them into three classes, Class I,
        Class II and Class III, each consisting as nearly as possible of
        one-third of the whole number of the Board of Directors. All Directors
        shall hold office until their successors are chosen and qualified, or
        until their earlier death, resignation, disqualification or removal. At
        the first election of Directors following adoption of this provision by
        the stockholders of the Corporation, Class I Directors shall be elected
        for a term of one year; Class II Directors shall be elected for a term
        of two years; and Class III Directors shall be elected for a term of
        three years; and at each annual election thereafter, successors to the
        class of Directors whose terms shall expire that year shall be elected
        to hold office for a term of three years, so that the term of office of
        one class of Directors shall expire in each year. Any vacancy on the
        Board of Directors that results from an increase in the number of
        Directors may be filled by the affirmative vote of a majority of the
        Directors then in office, and any other vacancy on the Board of
        Directors may be filled by the affirmative vote of a majority of the
        Directors then in office, although less than a quorum, or by a sole
        remaining Director. Any Director elected to fill a vacancy not resulting
        from an increase in the number of Directors shall serve for a term
        equivalent to the remaining unserved portion of the term of such newly
        elected Director's predecessor.


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                Notwithstanding the foregoing, whenever the holders of any one
        or more classes or series of preferred stock issued by the Corporation
        shall have the right, voting separately by class or series, to elect
        Directors at an annual or special meeting of stockholders, the election,
        term of office, filling of vacancies and other features of such
        directorships shall be governed by the terms of the Certificate of
        Incorporation applicable thereto, and such Directors shall not be
        divided into classes pursuant to this Article FIFTH (a)(1) unless
        expressly provided by such terms.

                        (2) No amendment to the Certificate of Incorporation of
        the Corporation shall amend, alter, or repeal any of the provisions of
        this Article FIFTH (a) unless the amendment effecting such amendment,
        alteration or repeal shall receive the affirmative vote of or consent of
        the holders of seventy-five percent (75%) of all shares of stock of the
        Corporation entitled to vote at a meeting of stockholders held for the
        purpose of voting on such amendment, considered for the purposes of this
        Article FIFTH as one class; provided that this paragraph FIFTH (a)(2)
        shall not apply to, and such seventy-five percent (75%) vote shall not
        be required for, any such amendment recommended to the stockholders
        pursuant to a resolution of the Board of Directors approved by
        two-thirds of the Continuing Directors. For purposes of this paragraph
        FIFTH (a)(2), a "Continuing Director" shall mean any Director of the
        Corporation who is or becomes a Director on the date that this Article
        FIFTH is first adopted by the Corporation's stockholders or any Director
        elected by a majority of the Continuing Directors then in office to
        succeed any Director or to fill any vacancy on the Board of Directors
        whether resulting from an increase in the number of Directors or
        otherwise.

                (b) In furtherance and not in limitation of powers conferred by
        statute, it is further provided that:

                        (1) election of Directors need not be by written ballot
        unless so provided in the By-Laws of the Corporation; and

                        (2) the Board of Directors is expressly authorized to
        adopt, amend or repeal the By-Laws of the Corporation."

        3. The Certificate of Incorporation of the Corporation is hereby amended
by (a) amending Article Seventh thereof by deleting the word "SEVENTH" and
inserting in its place the word "EIGHTH," and (b) by inserting, after Article
Sixth, the following new Article:

        "SEVENTH: (a) No action shall be taken by the stockholders of the
        Corporation except at an annual or special meeting of the stockholders
        of the Corporation."

                (b) No amendment to the Certificate of Incorporation of the
        Corporation shall amend, alter, or repeal any of the provisions of this
        Article SEVENTH unless the amendment effecting such amendment,
        alteration or repeal shall receive the affirmative vote of or consent of
        the holders of seventy-five percent (75%) of all shares of stock of the
        Corporation entitled to vote at a meeting of stockholders held for the
        purpose of



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        voting on such amendment, considered for the purposes of this Article
        SEVENTH as one class; provided that this paragraph SEVENTH (b) shall not
        apply to, and such seventy-five percent (75%) vote shall not be required
        for, any such amendment recommended to the stockholders pursuant to a
        resolution of the Board of Directors approved by two-thirds of the
        Continuing Directors. For purposes of this paragraph SEVENTH (b), a
        "Continuing Director" shall mean any Director of the Corporation who is
        or becomes a Director on the date that this Article SEVENTH is first
        adopted by the Corporation's stockholders or any Director elected by a
        majority of the Continuing Directors then in office to succeed any
        Director or to fill any vacancy on the Board of Directors whether
        resulting from an increase in the number of Directors or otherwise."

        4. The amendments to the Certificate of Incorporation herein certified
have been duly adopted in accordance with Section 242 of the General Corporation
Law of the State of Delaware.

        IN WITNESS WHEREOF, the Corporation has caused this Certificate of
Amendment to be signed as of May 30, 1997 by its Secretary.


        Signed as of this 30th day of May, 1997.



                                             THE AMERICAN MATERIALS &
                                             TECHNOLOGIES CORPORATION


                                             By: /s/ David A. Broadwin
                                                 ------------------------------
                                                 David A. Broadwin
                                                 Secretary