US 2014/0210139 A1 · METHOD OF INCREASING THE HARDNESS OF WURTZITE CRYSTALLINE MATERIALS

Abstract

The method of increasing the hardness of wurtzite crystalline materials is directed to the production of tool bits and inserts having a hardness approaching that of diamond, while simultaneously providing greater toughness and fracture resistance than diamond. The method includes forming a workpiece of boron nitride having a wurtzite crystal structure (wBN), and optionally combining boron nitride having a cubical crystal structure (cBN) with the wBN material. The workpiece is heat-treated by a defocused laser beam moved across the surface at a rate sufficient to preclude melting or deformation of the workpiece. The heated area is quickly quenched by a water jet, and a gas jet immediately follows the laser path to assure separation of the water from the laser contact area. The result is an increase in hardness of about 88%, from an initial hardness of about 40 GPa to a treated hardness of about 75 GPa.

Claims20

Dependent claims

A method of increasing the hardness of wurtzite crystalline materials, comprising the steps of:

(a) selecting a workpiece from a material at least partially composed of a wurtzite crystalline structure;
(b) heating the workpiece with a moving laser applied to the surface of the workpiece, the laser defining a laser-heated contact area on the workpiece;
and
(c) quenching the laser-heated contact area with a water jet in tandem with the moving laser and immediately following the laser.

1 more element

Dependencies are inferred from the claim text.

Method of increasing the hardness of wurtzite crystalline materials

Life of this patent

Method of increasing the hardness of wurtzite crystalline materials

Life of this patent

Abstract

Claims20