Diamond-like carbon (DLC) has been a candidate for various applications due
to its excellent tribological and mechanical properties. However, poor adh
esion on tool steels limits its applications over a wide range. In the pres
ent work, we investigated the effect of W and W-C intermediate layers on th
e adhesion of DLC films to AISI D2 tool steels. The intermediate layers wer
e deposited by de magnetron sputtering and the DLC films were deposited on
the various intermediate layers by rf-PACVD. Adhesion of the DLC film was s
ignificantly improved by introducing W and W-C intermediate layers. The adh
esion was strongly dependent on the thickness of W layer and the CH4 fracti
on in the sputtering gas during the intermediate layer deposition. TEM cros
s section revealed that, in addition to the chemical compatibility between
carbon and the intermediate layer materials, the microstructure of the inte
rmediate layer is also important to improve the adhesion. Columnar grains o
f the intermediate layers and structural continuity between the W and W-C m
ixed layers were the significant factors affecting the adhesion of DLC film
s. (C) 2000 Elsevier Science B.V. All rights reserved.