Influence of hydrogen etching on the adhesion of coated ferrous alloy by hydrogenated amorphous carbon deposited at low temperature

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGSFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCarbonaceous thin films show poor adhesion when deposited on steels. Chromium, titanium, and silicon containing interlayers are generally used in order to prompt adhesion. This work shows a systematic study of the hydrogen effect on the physical-chemical properties of a-SiCx:H interlayers deposited by using hexamethyldisiloxane on AISI 4140 at low temperatures (85 degrees C-180 degrees C). In particular, the effect of the treatment on the adhesion of a-C:H thin films is reported. The results show that hydrogen radically modifies the tribological behavior inducing the adhesion of a-C:H thin films at temperatures as low as 85 degrees C. The adhesion's improvement is associated with the hydrogen chemical etching that seems to remove more silicon than carbon atoms from the outermost face of the a-SiCx:H interlayer promoting the formation of stronger carbon-carbon bonds. The results are also discussed showing the efficiency obtained by the use of the electrostatic confinement deposition technique.144243246CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGSFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGSFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP554336/2010-3087/11Sem informação2012/10127-5The authors are grateful to UCS, INCT-INES (# 554336/2010-3), CAPES (Brafitec 087/11), FAPERGS and Plasmar Tecnologia Ltda. for financial support. A.E.C., L.M.L., C.A., F.A., and C.A.F. are CNPq or CAPES fellows. FA was supported by FAPESP project 2012/10127-5. The authors would like to thank to LCMIC-UCS for microscopy facilities and S.S.C. Jr for helping A.E.C. in the nanoscratch measurements