Diamond deposition on copper treated hardmetal substrates

The adhesion of diamond coatings onto hardmetal substrates is improved by a copper deposition produced by a cementation from aqueous CuSO4 solutions. During this reaction Co is dissolved from the substrate surface and copper is deposited. To obtain homogeneous Cu deposits, the influence of CuSO4 con centration and reaction time on cementation were investigated. During diamond deposition, Cu reduces the surface mobility of Co, which is necessary to decrease deposition of non-diamond carbon and therefore increa se adhesion. Indentation tests showed the good adhesion of the diamond coat ings qualitatively. Cu precipitation and diamond deposition were examined by scanning electron microscopy (SEM). The diamond quality was detected by Raman spectroscopy. U sing secondary ion mass spectroscopy (SIMS) depth profiles the interface an d the Cu distribution were characterized indicating that during diamond dep osition Cu is dissolved and forms an intermetallic Co-Cu mixed crystal. (C) 2000 Elsevier Science S.A. All rights reserved.