Nickel is conventionally used as a coating material for the electroplated production of grinding tools. Due to the toxicity of nickel, the project team members are developing a new non-toxic material combination for the machining of dental crowns. As an alternative, they are investigating a copper-titanium carbide bond in which the grain retention strength of the diamonds is comparable to the conventional bond form.
"We have to compensate for the low bonding capacity of copper compared to diamond in this case," explains IFW employee Michael Maier. We therefore use an intermediate layer for adhesive bonding" The scientist uses a carbide layer for this, which is realized by titanium-coated diamond grains.
By heating diamond together with selected metals from subgroups 4 to 6 of the periodic table, such as titanium, metal carbides can be produced. Carrying out this process is challenging, as titanium and diamond must be made to react at high temperatures and pressures. The resulting layer allows diamond grains to bond with the copper matrix.
Maier says, "This allows us to realize an innovative material combination of a copper-diamond bond with high grain retention force. From this sustainable approach, we can thus develop a new class of tools with new properties that are both more environmentally friendly and more powerful." Currently, the project team members are producing the new tool concept for machining dental crowns. According to scientist Maier, "It is conceivable that other materials could be machined with this tool in addition to dental crowns."
In addition to the sustainable aspect of copper bonding with diamond grains in the tool, the physical properties of copper also hold significance. Copper boasts a significantly higher thermal conductivity compared to nickel and many other metals, resulting in better dissipation of process heat during grinding. Improved cooling of workpieces leads to higher turnover rates, achieved through increased feed rates. Consequently, the successful development of this material combination enables the creation of a more efficient grinding tool.
Another advantage of the new grinding tool is that copper is a cost-effective raw material that is already converted in large quantities as a pure substance. As a result, copper is one of the most frequently recycled metals in the world. IFW employee Maier sees considerable added value in the new tool combination: "Due to the simple recycling management, the biocompatibility as well as the low price, copper is an interesting replacement for the nickel matrix in the galvanic production of grinding tools, which was still conventional until now."
Contact:
For further information, please contact Michael Maier, Institute of Production Engineering and Machine Tools at Leibniz Universität Hannover, via telephone +49 511 762 19936 or by e-mail (maier@ifw.uni-hannover.de).
