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

				ZIRCONIUM OXIDE
		The product		Zirconium oxide is obtained by chemical or electro-fusion processes from natural products such as zirconium silicate and baddeleyte. Pure zirconium oxide is useless as a ceramic because it undergoes a phase change as it passes through temperatures around 1000°C. The resulting change in volume disrupts any sintered article. It is then stabilised with MgO or Y2O3.
		Properties		Zirconium oxide stabilised with yttrium (ZrO2Y-PSZ): excellent toughness; high bending strength; excellent cutting qualities, low friction coefficient. Zirconium oxide stabilised with magnesium (ZrO2Mg-PSZ): good wear resistance, low friction coefficient, good thermal shock resistance, low thermal expansion, good toughness and very low thermal conductivity (one of the lowest among ceramic materials).
		Applications		Thread guides with mechanical stresses; mechanical components particulary wear resistant; the material BZ-1 has a good “flexibility” and is particularly suitable for scissors blades, for thread cutters, for selvedges-cutters, etc.
		Production processes		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 CERAMICS STABILIZED ZIRCONIUM OXIDE WITH YTTRIUM OXIDE WITH MAGNESIUM OXIDE MATERIAL CODE   BZ-1 BZ-2 COLOUR   White Black Yellow SPECIFIC WEIGHT g/cm3 6,00 5,85 5,65 H20 ABSORPTION % 0 0 0 VICKERS HARDNESS (HV, 500g) GPa 13,0 12,5 12,0 COMPRESSIVE STRENGTH MPa 2800 2500 2500 FLEXURAL STRENGTH MPa 1000 800 450 YOUNG'S MODULUS (E) GPa 200 190 200 FRACTURE TOUGHNESS (Kic) MPa m1/2 10 NA 7 MAX. SERVICE TEMPERATURE °C 1000 800 1000 THERMAL CONDUCTIVITY W / m K 2 2 2 THERMAL EXPANSION COEFFICIENT 20°C - 400°C x 10-6 / °C 9,6 9,9 9,7 20°C - 800°C x 10-6 / °C 10,7 10,3 11,0
		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 ≤ 0,8 µm; Polished satin Ra up to 0,4 µm; Diamond-polished Ra ≤ 0,2 µm.
		Some examples of microstructure		Polished of magnesia-stabilised zirconia with the typical “tiled” structure, magnified 250X, SEM micrograph. Ra 0.0467 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 ≤ 0,4 µm

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