Continued from page 1
Much as traditional process, Microplasmic process is an electrochemical process, but there ends similarity. The Microplasmic process is radically different from traditional anodizing processes in many respects. The distinguishing features of process may be summarized as follows.
· The process employs alkaline electrolytes whose composition is extremely critical to coating rate and properties of anodic film that is formed. The pH of electrolyte is in range 8 -12 and is thus environmentally sound. · The process employs Alternating Currents at high voltage and high current. Because of high voltage, a microplasma surrounds electrodes and oxygen ions produced in plasma diffuse through anodic film into aluminum substrate to react and form more anodic film. · The high voltage and high current allow production of anodic films of same thickness as that of traditional process in a fraction of time. · Because voltages are higher than breakdown voltage of film formed, open channels are not necessary for sustaining process and hence dense thick layers of nonporous film can be readily formed. · Because process employs AC power, productivity is increased. · The power from an electrical utility supply can be used with proper controls to electrochemical tank thus making process less capital intensive. There is no need for power rectification and waveform smoothing. · The temperature of electrolytic bath need not be precisely maintained. Indeed, successful coatings can be obtained even if temperature excursions are as much as 10-20 oC, further simplifying process. · The electrolytic composition itself is quite variable for different types of coatings. · Because of high density of coating, practically there is no change in dimension of anodized part, and a completely finished part can be coated without major post processing finishing operations. The Microplasmic Process, however, produces an outer soft coating of about 15% that may be buffed off; remaining inner layer, is an extremely hard ceramic layer. · Above all, unlike with traditional anodization process, aluminum alloy parts of any composition can be successfully anodized by Microplasmic Process. Even more importantly, a variety of ceramic "alloy" coatings, such as Al2O3.SiO2, Al2O3.MgO, Al2O3..CaO etc. can only be produced by Microplasmic Process. · The Microplasmic Process is also suited for a hard coating inside surface of a part i.e. cylindrical, conical or spherical hollow parts. Many coating processes in market, like CVD, PVD, IVD, PEPVD, Sputtering, Thermal Spraying etc. are unable to coat inside surface of a long part.
Because microplasmic process produces a thick, well bonded ceramic coating on a variety of reactive light metal alloys, it can be used for a broad range of applications. The primary application could be replacement of heavier metallic alloys or more expensive composite materials required by aerospace and automotive industries by light metals (e.g., Al, Ti, Mg, and their alloys) coated by Microplasmic Process. Other applications can be divided into following categories: Chemical, Mechanical, Thermal, Electrical and Electronics, and combinations of these.
· Chemical: The ceramic coating can resist both aqueous and moderately high temperature and is resistant to strong acids and bases. Thus it can be used in chemical, and food processing industries. · Mechanical: The hardness of film is over 1300 kg/mm2 and thus film can be used to resist sliding, abrasive and erosive wear. In addition friction coefficient is low and thus can be used in marginally lubricated systems. · Thermal: The thermal conductivity of anodic film is much less than of metals. Thus anodized parts can be used to maintain uniform distribution of temperature and resist thermal shock. · Electrical and Electronic: The dielectric breakdown strength of Microplasmic film is comparable to that of alpha Al2O3 and hence can be used as an insulating film on electrical and electronic components.
Additionally, Microplasmic Process is also well suited for hard coating interior surfaces (such as those of hollow cylindrical and conical parts), recesses, blind holes, threaded sections, and so on.
Many coating processes in market, such as Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), Plasma Enhanced Physical Vapor Deposition (PEPVD), Sputtering, Thermal Spraying, etc. are unable to coat inside surface of a long part. Thus, where appropriate these expensive coating processes can be readily replaced by Microplasmic Process.
Contact Information: Microplasmic Corporation 17 Esquire Drive Peabody, MA, USA Tel (978) 531-9145 Fax (978) 531-3671 Email: firstname.lastname@example.org Company Website http://www.microplasmic.com/ Public Relations Website http://www.microarcanodizing.com/
Jerry Patel: BS degree Mechanical Engineering - Fairleigh Dickinson University MS degree Engineering Management - Northeastern University Nannaji Saka, Ph.D: BS - Mechanical Engineering - Andhra University in India MS - Metallurgical Engineering - Indian Institute of Technology PH.D - Materials Engineering from - Department of Materials Science and Engineering at MIT.