APPLICATION OPPORTUNITIES OF DIFFERENT GLAZES TO AL 2 O 3 TECHNICAL CERAMICS

1. 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

2. 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

3. Materials – Composition • 4 sorts of glazes • 1: earthenware glaze material • 2, 3, 4: porcelain glaze materials microCAD 2005

4. Materials – Grain structures • 1 • 3 • 2 • 4 • Inhomogenity, grain size 0,5 – 30 m microCAD 2005

5. 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

6. Unusable results • Glazes marked 2, 3 and 4 did not develop perfect coatings • Glaze skips • Pinholes microCAD 2005 • Too thin coating

7. 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

8. 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

9. Testing methods – Scratch test • Table speed: 10 mm/min • Loading gradient: 10 N/mm • Starting load: 10 N • Final load: 100 N microCAD 2005

10. Results – Microhardness microCAD 2005

11. Results – Scratch test microCAD 2005

12. Results – Scratch test microCAD 2005

13. Results – Roughness microCAD 2005

14. 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

15. Acknowledgement • Department of Physical Metallurgy and Metallforming • Department of Mechanical Technology microCAD 2005

16. Many thanks for your attention!