LOW-TEMPERATURE COATING OF ALUMINUM-ALLOYS BY PLASMA-CVD USING METALLOORGANIC COMPOUNDS

The deposition of Zr(C,N) layers on the aluminium alloy AlMgSil by the pulsed d.c. PACVD technique using the metallo-organo compound tetraki s(diethyl)amidozirconium (Zr(N(C2H5)(2))(4)) in H-2-N-2-plasmas is des cribed. The deposition temperature could be lowered down to 150 degree s C. The content of carbon and nitrogen is extremely dependent on the process parameters. The hardness of the layers reached up to 1.400 HK. Polymeric carbon incorporated in the layers reduces the hardness of t he layers. The plasma is investigated by the optical emission spectros copy (OES) during the coating process. Ionized atomic zirconium, atomi c carbon in the neutral and ionized state, carbon-containing molecules (CH, C-2) and atomic and molecular nitrogen are detected. The dissoci ation of the metallo-organic compound is strongly influenced by the hy drogen content in the process gas and the discharge voltage. (C) 1998 Elsevier Science S.A.