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This paper discusses the development and evaluation of different glazes for technical ceramics, with a focus on alumina (Al2O3) substrates. The research investigates the effects of glaze composition, grain structure, and density on the surface smoothness and performance of ceramics. Key findings highlight the significance of glaze density and particle geometry in achieving optimal coatings. Moreover, microhardness and scratch tests are employed to assess the durability and bonding strength of the ceramic glazes. The results demonstrate the potential to enhance the longevity of technical ceramics through improved glazing techniques.
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APPLICATION OPPORTUNITIES OF DIFFERENT GLAZES TO AL2O3 TECHNICAL CERAMICS Nikoletta PUSKÁS Dr. László A. GÖMZE Ildikó LUKÁCS University of Miskolc, Department of Ceramics and Silicate Engineering microCAD 2005 Miskolc 10-11 March 2005
Introduction How develop the smoothness of the technical ceramics? • Experiments and investigations at the Department of Ceramics and Silicates Engineering • Using of porcelain and earthenware glazes microCAD 2005
Materials – Composition • 4 sorts of glazes • 1: earthenware glaze material • 2, 3, 4: porcelain glaze materials microCAD 2005
Materials – Grain structures • 1 • 3 • 2 • 4 • Inhomogenity, grain size 0,5 – 30 m microCAD 2005
Materials – Technology • Densities of glaze suspensions: • 1: 1450 g/l • 2: 1250 g/l • 3: 1350 g/l • 4: 1275 g/l • Firing temperature: 1270 °C • Dipping microCAD 2005
Unusable results • Glazes marked 2, 3 and 4 did not develop perfect coatings • Glaze skips • Pinholes microCAD 2005 • Too thin coating
Further examinations • Further examinations, using glaze material marked 1 in different densities: • 1350 g/l • 1450 g/l • 1500 g/l • Different dry material content alumina substrates made by casting: • Porous • Medium • Compact microCAD 2005
Testing methods – Microhardness measurement • Applied loading force: 2N • Time of loading: 10 sec • Medium compact bodies with different density of glazes • Different compact base ceramics with 1350 g/l density glaze microCAD 2005
Testing methods – Scratch test • Table speed: 10 mm/min • Loading gradient: 10 N/mm • Starting load: 10 N • Final load: 100 N microCAD 2005
Results – Microhardness microCAD 2005
Results – Scratch test microCAD 2005
Results – Scratch test microCAD 2005
Results – Roughness microCAD 2005
Conclusions • Nowadays glazing of technical ceramics exposed to heavy duty use is a current and important challenge. • The quality of the ceramic glazes strongly depends on the density of the glaze liquids and the geometrical shapes and sizes of solid ceramic particles in the glaze slurries. • Using the ceramic glazes we can considerably reduce the roughness of the surfaces of the alumina technical ceramics, increasing with this the estimated life cycles of these valuable technical items. • The scratch tests are necessary to reach the required hardness of the ceramic glazes and adhesive strength between the glazes and the alumina substrates. microCAD 2005
Acknowledgement • Department of Physical Metallurgy and Metallforming • Department of Mechanical Technology microCAD 2005
