The term ‘matrix retention’ denotes

The term ‘matrix retention’ denotes the capacity of a metallic matrix material to retain diamond particles at the surface of a segment during cutting. This property is important in the case of matrices of metal-bonded diamond segments used for cutting difficult -to-machine materials. When diamond particles are retained in the matrix, the embedment results from large differences in the coefficient of thermal expansion between diamond and the matrix material. The term ‘matrix retention’ denotes the capacity of a metallic matrix material to retain diamond particles at the surface. Technologically, cobalt is the most valued matrix metal, especially in professional tools. Cobalt powders are available in the different purity, shape and size of particles. Cobalt powders can be compacted to a nearly theoretical density if the temperature is not higher than 850 °C During hot pressing, cobalt is reported to moderately affect graphitization. Sintered cobalt alloys show high tensile strength properties and good ductility. A cobalt matrix has very good retentive properties [4]. The main problem concerning the application of cobalt is that its price is highly unstable and it has increased significantly over the past decades [5]. Although cobalt is the best material for diamond tools, the current trend is towards a broader application of inexpensive iron-base powders. Fine carbonyl iron powders are the most suitable candidates for preparation of powder premixes [6]. This paper discusses the properties of sintered materials fabricated form two powders based on carbonyl iron and copper.