Fast High-Temperature Surface Processing
Fast High-Temperature Surface Processing of Different Materials by Using Superadiabatic Gas Compression Ballistic Plasmatron
Tech Area / Field
- MAT-SYN/Materials Synthesis and Processing/Materials
- PHY-PLS/Plasma Physics/Physics
3 Approved without Funding
Institute of Biochemical Physics, Russia, Moscow
- Russian Academy of Sciences / Semenov Institute of Chemical Physics, Russia, Moscow
- Los-Alamos National Laboratory, USA, NM, Los-Alamos\nUniversity of Illinois / College of Engineering, USA, IL, Chicago\nINHA University, Korea, Inchon
Project summaryThis project is directed on development of novel technology “Fast High-Temperature Surface Processing” (FHTSP). This technology treats materials using dense plasma produced by superadiabatic gas compression. Such plasma is able to emit powerful light radiation that causes surface hardening of treated material or sintering of treated powder.
Superadiabatic compression of gas is a modification of thermodynamic gas compression process (e.g. in a ballistic installation), when temperature in superadiabatic mode changes so that energy density of gas (related to initial volume) is considerable more (up to 10-20 times) than one in conventional adiabatic mode under given compression ratio or given final pressure.
De facto, superadiabatic gas compression executes in ballistic plasmatron of double step compression, and dense plasma is generated with unique parameters: the temperature more than 10000 oC and pressure up to 1000 atm. Such parameters cannot be achieved by any other currently available methods of gas heating (the explosion is not considered).
Very high heating rates under compression and cooling rates under expansion (up to 5*106 oC/s), and controlled plasma retention time (from 10-4 to 1 second) characterize the process of high temperature and pressure creation.
In general, the range and ratio of possible temperatures and pressures is very wide that allows using this technology for different purposes in science and industry applications.
Fast High-Temperature Surface Processing of materials by using superadiabatic gas compression is very short-term treatment of materials surface surrounding plasma of heated inert gas. Such plasma is able to emit light radiation with intensity up to 50 J/cm2 and causes melting and negligible evaporating of thin surface layer of treated materials. Fast cooling can lead to modification of surface structure, surface deep hardening or even creation of an amorphous metallic film, because the films are created by fast cooling of a melted metal with the rate of 106dg/sec that corresponds to the rate of gas cooling.
Our preliminary experiments with steel samples have indicated a positive effect. Durability of milling cutters and drills is 2-6 times higher after such high-temperature surface processing. The surface microhardness of steel improves and reaches 104 MPa on the depth of 100 µ. Surface deep hardening is caused by high temperature and pressure and results in recovering microcrack, reducing surface roughness, considerable increasing surface hardness and strength.
FHTSP is principally novel technology, which have not direct analogue. There is practically no background in this subject, no reference publications.
Fast High-Temperature Surface Processing has evident advantages:
– The treatment will be especially effective for complex-shape objects, because the technology allows fast simultaneous treating of the whole object surface, even cavities.
– The process is very fast, ecologically clean, cost- and energy-efficient, easily repeatable and automated.
– The process recovers microcracks, reduces surface roughness and considerably increases surface hardness and strength.
The unique advantages of FHTSP are the following:
– Simultaneous treatment of internal and external surfaces that is very important for parts and tools with complex geometry;
– Process duration - a few milliseconds (for conventional surface treatment technologies, like laser or PVD/CVD, this value is in the range from some minutes to hours);
– Wide range of treated layer thickness (1-100 microns);
– Possibility of simultaneous treatment of large amount of parts situated inside of the Superadiabatic Reactor.
Expected cost of this treatment is 100 times less in comparison with the existing surface treatment technologies.
In our opinion, the technology of fast heating and cooling materials surface can add new approach, techniques, equipment and processes for surface research. Due to its fundamental nature and unique parameters of the tool, this technology can be used in many research areas such as: material science, surface science, nanotechnology, laser techniques, plasmochemistry, machine science, etc. The proposed technology can help open new materials and effects, and study complicated and unconventional processes.
General goal of this project is to develop technology of Fast High-Temperature Surface Processing and equipment (treatment chambers) of superadiabatic gas compression for it.
The main objectives of this Project are:
– Computer modeling of process and calculation of working parameters of ballistic plasmatron and the technological chamber for plasma generation with optimum parameters for materials treatment.
– Design and manufacturing of treatment chamber with optimized plasma parameters.
– Determination of metal, ceramic and other materials surface structure changing (phase, graininess, treatment depth, microhardness, dislocation density, etc) depending on plasma parameters (temperature, pressure, treatment duration, cooling rates).
– Investigation of melting-evaporating effects including roughness reduction and amorphous film creation.
– Investigation of diffusion and chemical effects in nitrogen plasma.
Demonstration of significant treated surface hardening, roughness reduction and surface quality improvement.
The project contains two related Tasks.
The first Task is «Development of technique and equipment for Fast High-Temperature Surface Processing by superadiabatic ballistic plasmatron». It includes the following stages: Theoretical analysis of plasma generation with necessary parameters and modelling of treatment process; Study of the plasma dynamics; Design and manufacturing of treatment chambers.
The second Task is «Comprehensive study of Fast High-Temperature Surface Processing»: Experimental research of changing and hardening effect versus plasma parameters.
It will be prepared samples of different materials, such as: alloys of iron (excepting tool steel), alloys of nonferrous metals, ceramics, glass, plastic, etc. Surfaces of initial and treated samples will be compared and tested by optic, acoustic, atomic force and electronic microscopy methods. It will also be determined mechanical parameters of metal surfaces depending on plasma parameters. Plasma parameters will be measured and calculated including such parameters as temperature, pressure, treatment duration, heating and cooling rates for each experiment on surface processing. At the project, no less than 20 experiments on hardening with different types of materials will be carried out during study of surface processing.
The proposed new plasma-based technology can be applied in electronic and engineering industries, as dense plasma with different temperature, pressure, heating and cooling rates can be used for treatment of different metal and ceramic materials. All the large, most part of medium and small companies active in electronics and engineering industry would be potential consumers of the proposed technology. Practically all of the manufacturing companies would be the potential customers of the proposed technology. Obviously, the market of surface processing technologies and equipment is multibillion-dollars market of very persified products, which intensively grows together with total technological development.
The research group includes, mainly, scientists of Institute of Biochemical Physics of RAS and Institute of Chemical Physics of RAS. Within the framework of the created temporary working collective, as researchers and consultants will be involved the research fellows of Moscow State Institute of Steel and Alloys. The performance of the team-work design can bring in the essential contribution into development of new methods surface treatment. Most of participants of the project were earlier connected with the military industry, and have necessary competence in science of materials and physics of plasma, studying processes of change of properties of a surface and plasmadynamics.
The project has practical importance for implementation of the ISTC purposes, as it grants to Russian weapon scientist and experts possibility for reorientation of the abilities on peace activity; encourages their integration in international scientific community; supports applied researches and development of technologies in the field of surface science.
Role of Foreign Collaborators:
– information exchange in the course of project implementation;
– cross-checks of results obtained in the course of project implementation;
– testing and evaluation of equipment/technologies developed in the course of the project;
– conduction of joint seminars and workshops;
– carrying out of joint experiments on basis of Collaborators.
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