Institute Advanced Ceramics

Al2O3/TiC ceramics, so-called mixed ceramic, are commonly used for dry cutting of hardened steel due to its high hardness even at high temperatures and relatively low chemical reactivity.
Still, there is a continuous interest to further improve the performance, esp. lifetime, of these cutting tools. Modification of the surface of cutting tools is one promising option for this purpose.

At the institute of advanced ceramics a novel route for the fabrication of dense Al2O3/TiC ceramic was developed. The ceramic is fabricated by aluminothermic reaction of Al with TiO2 and subsequent sintering. In a second temperature process a Ti(C,O) layer can be formed under CO containing atmosphere in-situ on the material (see figure 1).

Figure 1. Mixed ceramic cutting tool with in-situ TiC layer

As can be seen in Figure 2 the layered ceramic shows enhanced cutting performance compared to the as-sintered one and also the industrial reference ceramic, turning hardened steel.

Figure 2. Flank wear vs. cutting length for four types of inserts. The layered ceramic (green) shows
                improved wear resistance than the as-sintered (blue) and also the industrial reference (black).

Aim of the current project is to understand the mechanisms which govern wear during the application and so be able to fabricate cutting tools with optimized properties. This will be realised by combination of functional testing and material characterization on nano- to macroscopic scale.

The project is realised in cooperation with the institute of production management and technology
(Prof. Dr. W. Hintze).

Publications:

K. Zimmermann, A.K. Bhattarcharya, W. Hintze, G.A. Schneider, „Surface Modification of Al2O3/TiC cutting ceramics”, J. Am. Ceram. Soc., 90 [12] 3773-3778, 2007

A.K. Bhattarcharya, K. Zimmermann, G.A. Schneider, W. Hintze, „Influence of Surface Modification on the Cutting Performance of Reaction-Sintered Al2O3–TiOC Ceramics“, J. Am. Ceram. Soc, 2008, in press