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Friction and wear of ZrO 2 ‐TiO 2 surface‐alloyed Al 2 O 3 ceramics in unlubricated sliding contact
Author(s) -
Zum Gahr K.H.,
Lee SangZoon
Publication year - 1994
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.19940250307
Subject(s) - materials science , tribology , ceramic , abrasive , microstructure , porosity , metallurgy , grain size , composite number , friction coefficient , scanning electron microscope , wear resistance , composite material
Slightly and highly porous Al 2 O 3 ceramics were surface remelted and alloyed by adding ZrO 2 and TiO 2 using infrared CO 2 laser radiation. The resulting composite layers of thickness of about 200 m̈m contained about 31 vol.% of ZrO 2 ‐ and TiO 2 ‐rich phases which were homogeneously distributed at the grain boundaries of the alumina matrix. Microstructures and worn surfaces were analysed by electron microscopy and EDX analysis. Tribological tests were carried out unlubricated using conditions of abrasive wear and oscillating slinging wear, respectively. The results showed that the average grain size and hardness of the ceramics were reduced due to alloying. Despite decreasing hardness the wear resistance was substantially increased. Friction and wear of the untreated ceramics depended strongly on the amount of porosity which was removed or substantially reduced by laser treatment. Surface alloying of Al 2 O 3 ceramics can offer an effective process for producing components showing very different surface and bulk properties and particularly improved tribological behaviour. For the alloying elements and experimental conditions used, the improvement was more pronounced in wear resistance than in friction coefficient.