Sputter deposition and characterization of MoSi{sub 2}/SiC composite coatings

Conference · Tue Sep 01 04:00:00 EDT 1992

OSTI ID:10176892

Hirvonen, J-P; Kattelus, H; Suni, I; Likonen, J ^[1]; Jervis, T R; Nastasi, M ^[2]

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1. Technical Research Centre of Finland, Espoo (Finland)
2. Los Alamos National Lab., NM (United States)

We have deposited layered structures of MoSi{sub 2}/SiC composite coatings on different substrates by using a sputtering technique. SiC was used for a constituent of this structure because of the thermodynamic stability of the MoSi{sub 2}/SiC system. DC -magnetron and rf -diode systems were used to sputter MoSi{sub 2} and SiC, respectively. The substrates were mounted on a rotating holder allowing successive deposition Of MoSi{sub 2} and SiC layers. The total number of sublayers of each kind was 90. The thickness of the MoSi{sub 2} sublayers was 10 mn and that of the SiC 3 mn. The coatings were characterized in terms of a composition and microstructure by Rutherford backscattering (RBS), secondary ion mass spectrometry (SIMS),x-ray diffraction, indentation fracture, and nanoindentation. The layered structure was still observed after the coating was annealed at 500{degrees}C for 1 h, which recrystallized the MoSi{sub 2} layer. However, hardness and indentation modulus were increased from 11.6{plus_minus}0.8 and 220{plus_minus}20 GPa to 20.8{plus_minus}1.2 and 290{plus_minus}30 GPa, respectively. Preliminary indentation fracture measurements indicate that the layered structure is more brittle than a single, amorphous as-deposited MoSi{sub 2} layer. ,Althoug no improvement in the room teruperature toughness was obtained, the hardness of the recrystallized composite coating was significantly higher than reported previously for a MoSi{sub 2}/SiC composite.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 10176892
• Report Number(s): LA-UR--92-2604; CONF-9206271--1; ON: DE92040326
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601
360602
360603
COATINGS
COMPOSITE MATERIALS
CRACKS
DEPOSITION
FRACTURE PROPERTIES
HARDNESS
LAYERS
MECHANICAL PROPERTIES
MICROSTRUCTURE
MOLYBDENUM SILICIDES
PREPARATION AND MANUFACTURE
RECRYSTALLIZATION
SILICON CARBIDES
SPUTTERING
STRUCTURE AND PHASE STUDIES
X-RAY DIFFRACTION