Aharon Inspektor

The new diamond-coated carbide cutting tools

Abstract CVD diamond sheet (thick film, > 250 μm) tools have been available for several years. However, commercially useful thin-film (

Theory and practice in diamond coated metal-cutting tools

Abstract The development of low pressure deposition of continuous, high quality, diamond film was a major breakthrough in materials science that has allowed an economical use of diamond as an engineering material. It has also precipitated similar research in other superhard materials, such as cBN, C3N4 and superlattice nanolayer structures. This paper will highlight basic and applied aspects of diamond coatings, and present a technology perspective on the preparation of diamond-coated tools. Some of the key factors affecting the adhesion of diamond to cemented carbide will be discussed. The performance characteristics of the diamond tools and the anticipated applications will be reviewed.

Superhard coatings for metal cutting applications

Abstract An effective metal cutting tool is usually a combination of a hard coating and a tough substrate. The successful deposition of diamond outside its thermodynamic stability range has stimulated the development of a new class of cutting tools: those with diamond coated inserts at any desired style and edge geometry. The successful implementation of diamond coatings also expedited similar research in the deposition of cubic boron nitride. This paper presents superhard coated tools, with an emphasis on diamond coated WC-Co tools, the corresponding deposition technologies and the foreseen metal cutting applications.

A comparative machining study of diamond-coated tools made by plasma torch, microwave, and hot filament techniques

An effective metal-cutting tool is usually a combination of a hard coating and a tough substrate. The successful deposition of diamond outside its thermodynamic stability range has stimulated the development of a new class of cutting tools: those with diamond-coated inserts of any desired style and edge geometry. The successful implementation of diamond coatings also expedited similar research in the deposition of cubic boron nitride. This paper presents superhard coating tools, with emphasis on diamond-coated WC-Co tools, the corresponding deposition of technologies and the foreseen metal-cutting applications.

Controlling stress in cubic boron nitride coatings

Using the method of ion-assisted plasma deposition under conditions of reduced-bias growth, we have been able to achieve thick coatings of cubic boron nitride on silicon. A key aspect of our technique is to monitor the accumulation of compressive stress in the film and to reduce its effects by appropriate choice of deposition parameters and strain-relieving buffer layers. For this purpose, we employ a battery of real-time in situ characterization tools, which are capable of accurately tracking important film growth parameters, such as nucleation density, surface roughness, crystallographic structure and texture, and residual film stress. We use a combination of electron (reflection high-energy electron diffraction, RHEED) and laser beam (multi-beam optical stress sensor, MOSS) probes to provide this information during growth. Our results demonstrate that we can successfully produce superhard cubic boron nitride coatings up to 2 μm in thickness.

Process and property relationships in hard coatings made by plasma- and ion-assisted methods

This paper discusses the basic phenomena and process- property relations in the deposition of hard coatings. Two approaches are considered: the plasma assisted chemical vapor deposition and ion assisted physical vapor deposition methods (PA-CVD and IA-PVD respectively). In PA-CVD the plasma is used to activate the gaseous precursors and the film is formed during ion-molecule and radical- molecule reactions in the plasma bulk and at the plasma-surface boundary. In IA-PVD partially ionized metal vapor is admitted into an argon supported plasma together with a reactive gas. These are the film precursors which react at the substrate surface under intense ion bombardment and at reduced pressure. The correlation between experimental variables and properties of the deposits is illustrated with hard nitride films namely silicon nitride Si,N, made by PA-CVD and titanium nitride TiN made by IA-PVD. Two picostructural examples are illustrated: argon entrapment in TiN made by IA-PVD, and lattice strain effects on the Raman spectrum of diamond films made by (microwave) PA- CVD .