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

Conference · Wed Jan 01 00:00:00 EST 1992

OSTI ID:7164646

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; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 7164646
• Report Number(s): LA-UR-92-2604; CONF-9206271-1; ON: DE92040326
• Resource Relation: Conference: NATO Advanced Study Institute on mechanical properties of materials having ultra-fine microstructure, Porto Novo (Portugal), 17 Jun - 1 Jul 1992
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
DEPOSITION
MOLYBDENUM SILICIDES
SILICON CARBIDES
COATINGS
CRACKS
FRACTURE PROPERTIES
HARDNESS
LAYERS
MICROSTRUCTURE
RECRYSTALLIZATION
SPUTTERING
X-RAY DIFFRACTION
CARBIDES
CARBON COMPOUNDS
COHERENT SCATTERING
CRYSTAL STRUCTURE
DIFFRACTION
MATERIALS
MECHANICAL PROPERTIES
MOLYBDENUM COMPOUNDS
REFRACTORY METAL COMPOUNDS
SCATTERING
SILICIDES
SILICON COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360601* - Other Materials- Preparation & Manufacture
360602 - Other Materials- Structure & Phase Studies
360603 - Materials- Properties