SUGGESTIONS	CATALOGUE	MATERIALS & PROCESSES	COMPANY	NEWS	CONTACTS

GLAZED HARD PORCELAIN TITANIUM OXIDE ALUMINIUM OXIDE ALUMINA - ZIRCONIA ZIRCONIUM OXIDE SILICON CARBIDE SILICON NITRIDE PRODUCTION PROCESSES

				SILICON CARBIDE (SiC)
		The product		Silicon carbide is a non-oxide material artificially produced in electric kilns at high temperature, two crystalline phases exist: ALPHA and BETA. Our types are all in the ALPHA phase.
		Properties		Excellent resistance to wear, thermal shock and corrosion. Low thermal expansion, high thermal conductivity, high strength at low and high temperatures, good electrical conductor, low friction coefficient.
		Applications		Thanks to the typical high thermal conductivity, silicon carbide thread guides are particularly suitable for highly aggressive yarns and where there are thread guide over heating problems. Low temperature of thread guide drastically reduces problems connected with spin finishes. In addition, thanks to its good electrical conductivity antistatic thread guides can be produced, to discharge the electrostatic charges, which can form on man-made fibres at high speeds.
		Production processes		Dry and isostatic pressing; injection moulding; hot pressing.
		Technical data		The following table gives physical and mechanical data. Material data are obtained from specimens according to international test specifications. The indicated values can’t be extended to components and parts with different shapes and surface finishings. Bettini S.r.l. reserves the right to make technical modifications. BETTINI CERAMICS SILICON CARBIDE (SiC) MATERIAL CODE   BC-4 COLOUR   Black SPECIFIC WEIGHT g/cm3 3,10 H20 ABSORPTION % 0 VICKERS HARDNESS (HV, 500g) GPa 26,0 COMPRESSIVE STRENGTH MPa 2200 FLEXURAL STRENGTH MPa 530 YOUNG'S MODULUS (E) GPa 420 FRACTURE TOUGHNESS (Kic) MPa m1/2 4 MAX. SERVICE TEMPERATURE °C 1300 THERMAL CONDUCTIVITY W/ m K 110 THERMAL EXPANSION COEFFICIENT 20°C - 400°C x10-6 / °C 3,8 20°C - 800°C x10-6 / °C 4,4 Bettini also produces infiltrated silicon carbide and hot moulded silicon carbide for mechanical applications (see Bettini technical catalogue).
		Dimensional tolerances		Standard tolerances: up to 10mm: ± 0.2mm, above 10mm: ± 2% Bending deformation: max. 0.5% of part length Very close tolerances can be reached by grinding and polishing sintered parts, normally up to quality class IT8. Few microns tolerances can be achieved if needed.
		Surface finishings		The sintered products are manufactured with the following surface finishings Ground Ra from 0,3 to 0,8µm; Satin Ra ≤ 0,4 µm; Polished satin Ra up to 0,3 µm; Diamond-polished Ra ≤ 0,1 µm
		Some examples of microstructure		Polished, magnified 250X, SEM micrograph. Ra 0.0485 µm Roughness metre: Gauss cut off 7*0.8mm, diamond tip cone 60° 2 micron The examples reported are indicative only. For further information please contact our technical staff.
		Friction coefficient		Friction coefficient diagram for material with Ra ≤ 0,4µm

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