Diamond Polycrystal Nano- Composite for Industry STCU\NATO Workshop 12 October 2006 Kyiv Prof. Aleksandr A. Shulzhenko Dr. Oleksandr Bochechka V. N. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine Kyiv

Talk outline What is needed in the market? Brief technology description. Experimental results Stage of development. Competitive Matrix Opportunities

The technology material presented in this talk is available for licensing or joint product development. None of the slides contain any confidential or proprietary information which would prevent patenting the technology. Proprietary information statement

What is needed in the market? To finishing cutting of workpieces from nonferrous metals and alloys the tool from a monocrystal of natural diamond is used. Such tools approximately in 4 times are dearer than tools from polycrystalline synthetic diamonds which are applied for usual cutting. The purpose of the present work is creation of an inexpensive material from synthetic diamond for replacement of natural diamond in the tool for finishing cutting Inserts in tools for purposed cutting At present one of the most important line in solving the problem of the development of superhard materials with qualitatively and quantitatively new complex of physico-mechanical properties is the use of nanodispersed materials as the initial ones. Under the adequate conditions a unique complex of mechanical properties, e.g., a combination of very high hardness and fracture toughness, can be realized in a nanodispersed polycrystal.

Brief technology description The initial diamond nanopowder Typical electron microscopic image of the the statically synthesized diamond nanopowder :a, b – a TEM image, c– a microdiffractogram, d - a TEM dark- field image. TEM -transmission electronic microscope

High pressure-high temperature sintering The scheme of a toroid-type high pressure apparatus cell : 1 - the container from a lithographic limestone, 2 - the graphitic heater, 3 - pyrophyllite disks, 4 - graphitic disks 5 - a shell from hBN, 6 - the metal soldered container, 7 - a sintered powder Scheme of a toroid-type high-pressure apparatus

Mechanical properties of polycrystals are highly structure-sensitive, which is particularly distinct in using nanomaterials. In the present paper developed conditions of preparative treatment of diamond nanopowders, and their effective compacting, including at heightened temperature, before a sintering, are presented. Effect of prior compacting conditions on process of obtaining of qualitative polycrystals by sintering is studied. Thermobaric conditions of production of polycrystal materials based on diamond powders of nanometric range are investigated and optimized. The obtained results have allowed to develop optimum conditions of production of tool materials based on the diamond nanopowders ba Typical electron microscopic image of the granular structure of a diamond nanocomposite produced by sintering from the mixture of ACM5 0.1/0 diamond nanopowder and a sintering aid: a – a TEM image, b – a microfractogram

Experimental results The mechanical preactivation of the initial reaction mixture by adding sintering aids allows one to essentially increase physico-mechanical characteristics of the high pressure-high temperature sintered diamond nanocomposite. In this case, the composite hardness increases by a factor of 1.7 and fracture toughness almost doubles. This is achieved first of all because of the homogeneity of the nanostructure of the sintered composite and because of the solid boundaries between diamond grains. Table Physico-Mechanical Properties of Diamond Polycrystalline Nanomaterials MaterialSintering parameters Vickers hardness, GPa, at an indentation load, N Nanohardness (HF), GPa Fracture toughness, MPa m 1/ Monocrystal of natural diamond --~ 807,5 Diamond nanostructural composite* р = 8 ГПа; Т = 2000 К 64,850,043,671,314,5 Polycrystal from ACM5 0.1/0** р = 8 ГПа; Т = 2000 К 46,235,4--6,8 Polycrystal from ACM5 0.1/0*** р = 8 ГПа; Т = 1700 К 38,4---7,3 * Prepared by sintering from the mixture of the ACM5 0.1/0 nanopowder and a sintering aid preactivated by cold isostatic pressing ** Prepared by sintering of the ACM5 0.1/0 nanopowder preactivated by cold isostatic pressing. ***Prepared with the preliminary vacuum degassing and hermetic sealing of the HPA working volume.

Stage of development Prototype available for testing Cutting plates and cutting tool The cutting tool made from diamond nanocomposite, is tested at precision turning of aluminium alloy AMG-6. The roughness of the processed surface makes Ra = 0,015-0,018 microns. Form of cutting inserts

Competitive Matrix Important product or technology characteristics V.Bakul ISHM, Diamond nano - composite General Electric, Compax diamond The Ukrainian center of super precise technologies, Natural diamond Approach of a cutter, μm /Rev Radius of a cutting edge, μm 0.06 – Degree of roughness of AL- alloy (AMG-6), μm – Cost, $

Opportunities Drawing die Deforming tools Drilling tools The patent of Ukraine for useful model N u Date of delivery

Contact information Shulzhenko Aleksandr Aleksandrovich Bochechka Oleksandr V. N. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine Kyiv

Thank you!