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

				ALUMINIUM OXIDE (Al2O3)
		The product		Aluminium oxide (Al2O3), also known as alumina, is obtained from bauxite, a natural raw material, after chemical treatment and calcination. Alumina, in different grades of purity, allows the production of a family of products with various properties and applications.
		Properties		Excellent mechanical and electrical properties, excellent resistance to acids (except hydrofluoric), and excellent wear resistance.
		Applications		Thread guides for high performances for fairly aggressive yarns. Particular components for the formation of textile yarns as for instance: ceramic navels, mirror polished, for Open End spinning machines; compressed air intermingling tubes and plates; friction discs for texturizing machines; thread guides for oil application.
		Production processes		Extrusion; dry and isostatic pressing; injection moulding.
		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 CERMICS ALUMINIUM OXIDE (Al2O3) MATERIAL CODE   BX-6 BX-7 BX-8 BX-9 BX-2 Al2O3 % 96.0 97.5 99.0 99.7 99.9 COLOUR   Brown Pink / White White White White SPECIFIC WEIGHT g/cm3 3,80 3,75 3,85 3,90 3,92 H20 ABSORPTION % 0 0 0 0 0 VICKERS HARDNESS (HV, 500g) GPa 15,5 16,0 17,0 18,0 19,0 COMPRESSIVE STRENGTH MPa 2200 2300 2400 2900 2900 FLEXURAL STRENGTH MPa 320 330 350 380 400 YOUNG’S MODULUS (E) GPa 310 310 340 360 400 FRACTURE TOUGHNESS (Kic) MPa m1/2 4,0 4,0 5,0 5,2 4,9 MAX. SERVICE TEMPERATURE °C 1300 1500 1600 1650 1600 THERMAL CONDUCTIVITY W / m K 25 23 30 31 30 THERMAL EXPANSION COEFFICIENT 20°C - 400°C x 10-6/°C 7,1 7,4 7,3 7,5 8,0 20°C - 800°C x 10-6/°C 7,5 7,9 7,8 8,0 8,9
		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. NEAR-NET SHAPE can be obtained by injection moulding reducing hard machining operations.
		Surface finishings		The sintered products are manufactured with the following surface finishings. Ground Ra from 0,6 to 1,6 µm; Satin Ra ≤ 1,2 µm; Polished satin Ra up to 0,5 µm; Diamond-polished Ra ≤ 0,3 µm
		Some examples of microstructure		As fired Ra 0.6905 µm Polished Ra 0.1125 µm LOW FRICTION quality Ra 0.2684µm magnified 250X, SEM micrograph. 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		The materials BX-8 and BX-9 can be supplied with Low Friction surface quality. Friction coefficient diagram for Low Friction material with Ra ≤ 0,4µm.

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