Acoustic emission detection of macroindentation cracking of diamond coated silicon

1
Acoustic emission detection of macro-indentation
cracking of diamond coated silicon

• M. Belmonte, A.J.S. Fernandes, F.M. Costa, F.J.
  Oliveira, R.F. Silva

2
Introduction

• To analyze the cracking mechanisms and the effect
  of the diamond thickness of chemical vapor
  deposited diamond coatings on silicon
• A Brale diamond cone indenter was adopted to a
  universal testing machine coupled to a
  piezoelectric transducer for recording the AE
  signal of the cracking event.
• SEM observations were a complementary tools to
  infer the cracking mechanisms and to assess the
  interfacial cracking resistance.

3
Experimental Results and Discussion
4
Experimental Results and Discussion
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Experimental Results and Discussion
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Experimental Results and Discussion
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Experimental Results and Discussion
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Experimental Results and Discussion
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Conclusions

• During the indentation process, on one side the
  silicon substrate deforms plastically and lateral
  cracks develop and propagate to the
  diamond-silicon interface, and on the other side,
  radial cracks are induced in the diamond film.
• The conjunction of such events leads to the lack
  of adhesion of the film.
• The 40µm diamond film exhibited a better adhesion
  than the 10µm one, based on the absence of
  delamination and on a higher interfacial cracking
  resistance of 1650kNm-1.
• An abrupt change of this parameter for the thick
  film indicates a threshold load of 270N for
  debonding at the diamond film-Si interface.
• Thicker films produced lower deformation areas in
  the silicon and a delay on the crack formation
  and propagation through the diamond-substrate
  interface.