Polycrystalline Cubic Boron Nitride
One of the most fascinating materials of our time is polycrystalline cubic boron nitride PcBN - the second hardest material after diamond. At CeramTec, PcBN is used as a cutting material from which indexable inserts are manufactured for machining.
PcBN is produced synthetically and is a "composite material" made of cubic boron nitride and a mostly ceramic binder phase. The ratio of cBN to binder content and the cBN grain size determine the application.
PcBN cutting materials are used in the machining of hard and/or highly abrasive workpiece materials. The high hardness and the extremely high hot hardness (up to temperatures above 1,000°C), the edge stability and inertness towards ferrous materials as well as the basically good chemical resistance give CBN cutting materials a high potential for use in machining. On the cutting material side, a distinction is made between high- and low-cBN cutting material grades.
This results in two main areas of application:
High-cBN cutting materials are particularly suitable for machining cast iron materials such as grey cast iron, chilled cast iron and CR chilled cast iron. Typical workpieces are brake discs and drums, engine blocks, flywheels, cylinder liners, machine parts and rollers.
Low-cBN cutting materials are mainly used for hard materials: hardened steels, cold and hot work steels, weld-on and wear alloys based on nickel, cobalt and iron, sintered steels, hard metals. Workpieces such as large bearings, shafts, punches, gear wheels, pressed parts, valve seats and turbine components are machined.
PcBN vs. cBN vs. PKB
In practice, various abbreviations are used to designate the cutting material, but they always refer to the same basic material: cBN, C-BN, PCBN, PcBN or PKB.
cBN is the most commonly used abbreviation. PcBN is the technically correct abbreviation for the English material designation "Polycrystalline Cubic Boron Nitride". In German-speaking countries, the abbreviation PKB, which stands for "Polykristallines Kubisches Bornitrid", is used occasionally. In the ISO standard for cutting material designations, the abbreviation BN is used for "Boron Nitride".