SiC-bonded diamond materials produced by pressureless silicon infiltration

Extremely hard, wear-resistant SiC-bonded diamond materials with diamond contents of approximately 45–60% by volume can be prepared by pressureless infiltration of shaped diamond compacts with silicon. Materials with diamond grain sizes in the range of 10–100 µm can be produced having a free silicon content of less than 5 vol%. Components with large dimensions can be prepared as graded or ungraded materials. Graded components are composed of silicon infiltrated SiC base material with diamond–SiC composite layers of 0.1 mm by dip coating technology to several mm in thickness by doubled die pressing in regions with high loading. This creates the possibility of producing low-cost, wear-resistant components of various geometries and dimensions with bending strengths of 400–500 MPa, hardness values of 48 GPa, and fracture toughness levels of 4.5–5 MPa m1/2for use in extreme wear conditions. Thermal conductivities of up to 500 W/(m K) were obtained, render these materials interesting for heat sinks.