ICMCTF1998 Session GP: G - Posters
Wednesday, April 29, 1998 5:00 PM in Room Atlas Foyer
Wednesday Posters
Time Period WeP Sessions | Topic G Sessions | Time Periods | Topics | ICMCTF1998 Schedule
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GP-1 TFEL Devices Using Oxide Thin Films Without Vacuum Process
T. Minami, T. Miyata, Y. Sakagami, S. Takata (Kanazawa Institute of Technology, Japan) Almost all conventional thin-film electroluminescent (TFEL) devices have been fabricated using vacuum processes in thin-film depositions. These TFEL devices are very expensive, because the use of vacuum processes results in low through-put and requires expensive vacuum equipment. This paper reports new methods of cheaply fabricating TFEL devices using solution coating techniques which eleminate the need for vacuum processes. The EL characteristics were investiaged using an ac single-insulating layer TFEL device structure. Metallic complex salts, Zn(C5H7O2)2, Ga(C5H7O2)3, In (C5H7O2)3, Sn(CH3COO)2 and MnCl2 were used as the zinc, gallium, indium, tin and manganese sources, respectively. First, BaTiO3 ceramic sheets (thickness of about 0.2 mm) were immersed in a solution of metallic complex salts dissolved in methanol or ethanol at 25°C. The solution coated ceramic sheets were subsequently heated in a furnace for 30 s at 500-950°C. This process was repeated many times in order to obtain a suitable film thickness. In the second step of the process, the coated ceramic sheets were annealed in air or Ar for 1 h at 950-1020°C in order to improve the crystallinity as well as the luminescent property. In addition, other phosphor thin films and transparent conducting oxide thin films were produced using the processes mentioned above. Luminances of 758 and 355 cd/m2 in green emisions were obtained in TFEL devices using dip-coated ZnGa2O4: Mn and Ga2O3:Mn thin film phosphors, respectively when driven at 1 kHz. |
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GP-2 Enhancing Corrosion Resistance of PVD Coated Tools
P.K. Vencovsky, R. Sanchez (Brasimet, Brazil); J.R.T. Branco (CETEC, Brazil); M. Galvano (Cofap, Brazil) It is known that conventional PVD coatings like TiN and CrN offer a limited corrosion resistance due to its intrinsic porosity. In the manufacturing of tools this fact restricts in some cases the option of steels that present a high hardness after heat treatment, but have a low corrosion resistance, like for example: cold work tool steels and high speed steels. To overcome this problem one can vary PVD process parameters to decrease coating porosity, increase coating thickness or use an interlayer between the coating and the substract. In the present paper the effect of varying the thickness of electroless NiP interlayer on the corrosion resistance of TiN and CrN coated AISI D2 Steels was studied, as well as its influence on the the PVD coating adhesion and hardness. |
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GP-3 New Materials for Electric Contacts Prepared by High-rate EB-PVD Techniques
M.I. Grechanyuk, V.A. Osokin (J.S. Company Gekont, Ukraine); A.V. Demehishin, E.P. Pollschuk, E.P. Kurapov, A. Yu (Paton Electric Welding Institute, Ukraine) The level of activity both in research and in the commercial development of advanced materials for electric contacts used in a wide variety of electrotechnical devices, electric transport and lifting mechanims has increased significantly over the past years. The search for cheaper materials instead of currently used contact alloys on silver and tungsten base without decreasing of the life time was the impetus of this activity. High-rate EB-PVD techniques was used in this study to prepare and investigate new Cu-Mo composite materials as electric contacts. The composite materials were obtained by simultaneous evaporation of copper and molybdenum using two electron beam sources. The vapors were deposited onto the substrate located above the sources. The volume fraction of each material was controlled by adjusting the evaporation rate of the respective material. The thickness of the sheet-type condensates separated from the substrate was within the range 1-5 mm. The structure and properties of deposits were studied. It was found the life time of the deposited composites was 1.5-3.0 times higher in comparison with the conventional silver containing contact alloys. Industrial tests of new type contact materials have showed successful results for application in electric traction transport, hoisting machinery and domestic electrotechnical devices. |
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GP-4 Designing Hard Chrome Alternative Coatings
T. Bernecki (Northwestern University) One of the major advantages of alternatives to hard chrome is that they can be designed for an optimum performance that often surpasses that of chrome plate. When replacing existing hard chrome with an alternative we must ensure that the alternative meets the engineering performance provided by traditional chrome plate. However, our ability to control the performance of the coatings can sometimes be exploited to ensure that the alternative exceeds chrome performance, providing a coating that is not just equivalent, but superior. We have found that, with proper design and control of the deposition process, HVOF WC-Co can be made to combine excellent hardness, adhesion, and structure with much better fatigue properties that those given by hard chrome. The application of proper coating process design techniques to aircraft components will be discussed. |
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GP-5 A New Cathodic Arc Source
R. Christy (Tribo Coating) A new cathodic arc source design is described. With prior designs, magnetic fields, rings of insulators, or iron rings were used to confine the arc to the front of the target. The new design confines the arc without magnetic steering or front-mounted insulators. This allows target utilization two to three times higher than previously possible, and provides a smaller, thinner cathode for the same target surface area. The simplicity of the design results in extremely low maintenance. For production applications, the cost savings from improved target utilization, larger working volume and lower maintenance are significant. |