Study of polycrystalline diamonds produced by infiltration method using natural and synthetic diamond powders

Abstract

Diamond tooling is used to machine a broad range of materials. Due to their strength, diamond tools can be used to machine extremely hard alloys. At the same time, diamond tooling is also widely used to machine soft nonferrous alloys and polymers. This paper examines polycrystalline diamond (PCD) composites which are used in diamond tooling designed for various applications. A few types of diamond composites are known today, which are produced by different techniques. Such materials can be produced both by sintering diamond powders together with activating agents and by converting graphite into diamond using catalyst alloys. Production of such materials is always associated with the use of high pressures and temperatures. Depending on the production technique applied, the composition, properties and application of the resultant PCD composites can vary greatly. This paper looks at the infiltration method, i.e. when the binding melt infiltrates in pressed diamonds under high pressures and temperatures. Even though the obtained specimens have a lower strength than the ones produced by other methods, this technique proves to be optimum. Unlike it is with the other methods, the sintering operation in this one is not technically difficult (the applied pressure does not exceed 4 GPa), and PCD composites of bigger sizes can be produced. A study was conducted in the framework of this research to better understand the key physical and mechanical properties of PCD composites, which were produced by infiltration method using two binding materials (Ni – Si and Mn – Si alloys) and two diamond powders (the ASM grade of synthetic powder and the AM grade of natural powder). A comparative analysis of their properties was also carried out.This research study was carried out as part of the research initiative 2.2. “Material Qualification and Studies” (“Strategic Areas in the Development of Materials and Processing Technology till 2030”).