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Surface Modification of Superhard Materials

#0198


Development of Surface Modification Techniques for Superhard Materials.

Tech Area / Field

  • MAT-SYN/Materials Synthesis and Processing/Materials

Status
8 Project completed

Registration date
27.06.1994

Completion date
29.01.1999

Senior Project Manager
Coevering G van de

Leading Institute
Institute of General Physics named after A.M. Prokhorov RAS, Russia, Moscow

Supporting institutes

  • VNIITF, Russia, Chelyabinsk reg., Snezhinsk

Collaborators

  • Bremer Institute of Aplied Beam Technology (BIAS), Germany, Bremen\nRockwell International, Rocketdyne Division, USA, CA, Canoga Park\nUniversität Stuttgart / Institut für Strahlwerkzenge, Germany, Stuttgart

Project summary

Introduction and Project's Purpose

Successful development of fast growth processes in recent years of Chemical Vapor Deposition (CVD) of such superhard materials as diamond and cubic boron nitride (CBN) opened new, extremely broad and exciting opportunities for the development of different unique devices based on these thick or thin films (X-ray and optical components, diamond tools and surgical instruments, various sensors, etc.). Successful introduction of all these novel materials into practice requires the solution of two main tasks: a) to develop the technology of efficient production of high quality CVD diamond material and b) to develop the post-growth fabrication processes that convert these unique materials into useful components and products. The goal of this project is to advance the state of art in these areas, to identify and solve currently existing problems and to develop various production processes of microstructurized (protective) diamond coatings to be used in advanced optical components over broad spectral ranges.

Surface processing of superhard materials (such as diamond or cubic boron nitride, CBN) by using various ultraviolet (UV) laser assisted ablation techniques offers important potential in many applications. Still, at present this is a much unexplored area of commercial utilization. In recent years various approaches to diamond surface ablation by focused UV laser beams have been successfully demonstrated in Russia under laboratory conditions. At the center of these activities are the various pulsed UV lasers, such as excimer lasers or frequency doubled or quadrupled solid state lasers and specific, ingenious UV beam forming optical components.

For manufacturing of homogeneous and very smooth polycrystalline diamond films and for developing novel processes for their surface modification, it is proposed to use the cumulative experience of the General Physics Institute in Moscow. In the fields of ultrafine diamond powder production, thin diamond film deposition and UV laser assisted, spatially resolved diamond film surface microtreatment it is proposed to use the experience of the Technical Physics Institute in Snejinsk - Chelyabinsk Region

Diamond films of me desired homogeneity and smoothness will be grown at GPI's laboratories. The ultrafine diamond powders which will be needed to achieve the uniform nucleation and growth on the substrate surfaces will be manufactured with an implosion assisted technique that was developed at the Research Institute of Technical Physics (Technical Physics Institute or TPI) of the Russian Federal Nuclear Center.

In recent years, investigations of various applications of controlled powerful implosions performed at TPI lead to the discovery of a unique process of creating ultrafine diamond powders (particle size approximately 50 Angstroms). As a result of this discovery, several technological facilities for this purpose had been built at TPI and being operated at present. By using these extremely small diamond crystals as seeds, extremely smooth (and homogeneous) diamond films with sub micron grain size may be fabricated and precision surface treated further by various pulsed UV laser photo-ablation techniques.

At the Light Induced Surface Phenomena (LISP) Department of the General Physics Institute, (GPI) demonstrations of different successful approaches for diamond optical coatings as well as their surface polishing and microstructuring with the use of high power UV laser radiation had been done in recent years. These studies were focused on developing a good understanding of the role the different laser parameters play in the ablation process.

Purpose of this project is very closely aligned with the objectives of the International Science and Technology Center. This project will provide meaningful and peaceful technical activities to Russian scientists and engineers. More than 60% of this effort will be conducted by scientists with specialized training and skills in high power E/M radiation & laser technologies, high intensity "Directed Energy" - Material interaction and other disciplines related to nuclear, missile & directed energy, and to the technologies of other weapons of mass destruction. Participation of scientists from the Russian Academy of Sciences, who have valuable experience in international scientific cooperation, will make much easier the conversion of previously militarily engaged industries and to introduce TPI's scientists to the international scientific community. The peaceful technical tasks as described below will result in the development of new, commercially valuable production processes and fabrication methods. By using high performance, Russian built UV lasers and by utilizing the talents of experienced and highly trained Russian scientists and engineers, this project will develop novel techniques for ptoducing CVD diamond components and devices and microstructuring of diamond surfaces to create unique optical surface properties.

Scientific and Commercial Significance

Scientific: Definition and development of understanding of processes of nucleation, growth kinetics, structure and optical properties of CVD diamond films and nonlinear electrodynamic and thermodynamic problems relating to the action of focused, high-power pulsed, coherent UV laser beams on materials with high thermal conductivities and hardness.

Commercial: This project will develop high output techniques of ultrafine diamond powders fabrication for their further application in superfine optical polishing, material surface modification by implosion assisted diamond particle implantation, preliminary treatment of the substrates for diamond film deposition. This project will also develop novel surface ablation methods by using fine focussed UV laser beams, that will allow efficient fabrication of various periodic structures with microscopic and submicroscopic accuracy on surfaces of hard materials, such as diamond and boron nitride.

Potential Commercial Applications: The following is a sample list of commercial applications, several of which have already been successfully demonstrated in the former Soviet Union. One important application is the production of specific optical properties on very hard surfaces. Examples of optical properties of microstructured surfaces are: parallel grooves acting as optical gratings, and for special applications as "buried" optical gratings, concentric circles of grooves behaving as optical lens (Fresnel lens), rectangular 2 dimensional arrays of submicroscopic pyramids on a surface acting as an antireflection layer. It is fully expected, that results of this technology will be extendable into the Micro-machining, Microfabrication area for diamond. Presently this technology is restricted to be used with only a few materials (silicon). Diamond is by far the best material to use in fabrication of microscopic components, due to its top hardness, slipperiness and excellent thermal properties. Successful transfer of microfabrication technology to the commercial sector depends greatly on availability of a process that allows micromachining of diamond (and a few other superhard materials, such as cubic boron nitride and diamondlike films).

Commercial Applications of Microfabrication Technology: Microinstruments in the biomedical area, miniature sensors and actuators, 2 dimensional (surface) motors and other limited motion actuators, specialized miniature tools (diamond files, knives, surgical tools), high power mm wave components.


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