Deposition of hard and adherent diamond-like carbon films inside steel tubes using a pulsed-DC discharge.
A new, low cost, pulsed-DC plasma-enhanced chemical vapor deposition system that uses a bipolar, pulsed power supply was designed and tested to evaluate its capacity to produce quality diamond-like carbon films on the inner surface of steel tubes. The main focus of the study was to attain films with low friction coefficients, low total stress, a high degree of hardness, and very good adherence to the inner surface of long metallic tubes at a reasonable growth rate. In order to enhance the diamond-like carbon coating adhesion to metallic surfaces, four steps were used: (1) argon ion sputtering; (2) plasma nitriding; (3) a thin amorphous silicon interlayer deposition, using silane as the precursor gas; and (4) diamond-like carbon film deposition using methane atmosphere. This paper presents various test results as functions of the methane gas pressure and of the coaxial metal anode diameter, where the pulsed-DC voltage constant is kept constant. The influence of the coaxial metal anode diameter and of the methane gas pressure is also demonstrated. The results obtained showed the possibilities of using these DLC coatings for reduced friction and to harden inner surface of the steel tubes.
Trava-Airoldi
Vladimir Jesus
VJ
Instituto Nacional de Pesquisas Espaciais, Laboratório Associado de Sensores e Materials, Av. dos Astronautas, 1758-São José dos Campos, 12227-010, SP, Brazil.
Capote
Gil
G
Bonetti
Luís Francisco
LF
Fernandes
Jesum
J
Blando
Eduardo
E
Hübler
Roberto
R
Radi
Polyana Alves
PA
Santos
Lúcia Vieira
LV
Corat
Evaldo José
EJ