Richard Knight

knightr@coe.drexel.edu

Research Professor

Director, Center for the Plasma Processing of Materials

B.Sc (Electronic & Electrical Engineering) 1977, M.Sc. (Electroheat and Industrial Process Heating) 1978, Ph.D. (Multiple Arc Discharges), 1985, all at Loughborough University of Technology.

Research Interests:

Plasma Devices & Systems, Thermal Spray Coating Processes, Plasma Melting, HVOF Spray Processes

Thermal Plasma Processes

The term "plasma processing" covers a diverse range of applications. Thermal plasmas utilize the intense heat generated by electric arc discharges as the source of energy for heating gases, melting particles, or the bulk melting of materials. Typical applications include chemical reactors for the production or synthesis of materials, ranging from TiO2 pigments to carbide- reinforced composites; the spray deposition of metallic, cermet or ceramic coatings; and extractive metallurgy and refining processes. Research is being carried out on several aspects of thermal plasma processing.

Thermal Spray Deposition

The performance of many engineering materials can be significantly enhanced by the surfacing technology known as thermal spray deposition, which is used to apply coatings to substrate materials to tailor or improve their performance in service. Applications include protection against wear, corrosion, erosion, oxidation or thermal degradation. Thermal spray is widely used by the aerospace, chemical and manufacturing industries. Research is being conducted to develop an understanding of the process/structure/performance relationships and to provide a science base for the technology.

Plasma Melting

Thermal plasmas can also be used in extractive metallurgy and remelting/ refining processes, including the recycling of reactive Ti-based superalloys for aerospace applications. Plasma/melt synthesis is being studied for the production of directionally reinforced composite materials.

HVOF Processes

High Velocity Oxy-Fuel (HVOF) flame spray processes are an important member of the family of surfacing technologies known as thermal spray processes. HVOF is rapidly growing in importance since it can readily produce very dense coatings due to the extremely high particle velocities achieved by powdered material injected into the supersonically expanding jets of hot gas generated. In some cases, it is not even necessary for the particles to be heated to their melting point, since their high kinetic energy causes sufficient deformation on impact at the surface being coated to produce dense, well bonded coatings. HVOF spraying of coatings offers a number of other potential advantages over alternatives like plasma spraying owing to the lower process temperature of the flames used as the heat source. The processing capabilities of current HVOF systems are currently being investigated using typical HVOF coatings.

Research is also being conducted to investigate residual stress in HVOF coatings.

Diagnostics

Laser stroboscopy is being used to study the motion of particles travelling in thermal spray jets. Techniques are being developed to measure particle velocities and trajectories. This information may ultimately be usable for "intelligent" process control.

Selected Publications

  • Twardowski, T. E., Bhargava, V. and Knight, R., “Properties of HVOF Sprayed Multi-Scale Polymer/Silica Nanocomposite Coatings”, Proc. 2004 International Thermal Spray Conference [ITSC-2004], Eds. , DVS/IIW/ASM-TSS, Osaka, Japan, May 10-12, 2004.

  • Sykes, J., Knight, R. and Twardowski, T. E., “Incorporating High Aspect Ratio Reinforcements in HVOF Sprayed Polymer/Carbon Composite Coatings”, Proc. 2004 International Thermal Spray Conference [ITSC-2004], Eds. , DVS/IIW/ASM-TSS, Osaka, Japan, May 10-12, 2004.

  • Twardowski, T. E., Saenz, A. and Knight, R., “Maximization of Silica Loading in Ball-Milled Composite Powders for HVOF-Sprayed Multi-scale Polymer/Silica Composite Coatings”, Proc. 2004 International Thermal Spray Conference [ITSC-2004], Eds. , DVS/IIW/ASM-TSS, Osaka, Japan, May 10-12, 2004.

  • Knight, R., Ivosevic, M., Kalidindi, S. R., Palmese, G. R. and Sutter, J. K., “Solid Particle Erosion Resistance of Thermally Sprayed Functionally Graded Polymer/Ceramic Coatings”, Proc. 2004 International Thermal Spray Conference [ITSC-2004], Eds. , DVS/IIW/ASM-TSS, Osaka, Japan, pp. , May 10-12, 2004.

  • Ivosevic, M., Cairncross, R. A. and Knight, R., “Heating and Impact Modeling of HVOF Sprayed Polymer Particles,” Proc. 2004 International Thermal Spray Conference [ITSC-2004], Eds. , DVS/IIW/ASM-TSS, Osaka, Japan, pp. , May 10-12, 2004.

  • Knight, R., Ivosevic, M., Kalidindi, S. R., Palmese, G. and Sutter, J. K., “Development of HVOF Sprayed Erosion/Oxidation Resistant Coatings for Composite Structural Components in Propulsion Systems”, Proc. 24th High Temple Workshop, Air Force Research Laboratory/NASA-Glenn Research Center/University of Dayton Research Institute, Holiday Inn Capitol Plaza, Sacramento, CA, 2-5 February, 2004.

  • M. Ivosevic, R. Knight, S. R. Kalidindi, G. R. Palmese and J. K. Sutter, “Erosion/Oxidation Resistant Coatings for High Temperature Polymer Composites,” High Performance Polymers, Vol. 15, No. 4, pp. 503-518, December 2003.

  • Dobbins, T. A., Knight, R. and Mayo, M. J., “HVOF Thermal Spray Deposited Y2O3-Stabilized ZrO2 Coatings for Thermal Barrier Applications,” Journal of Thermal Spray Technology, Vol. 12, No. 2, pp. 214-225, June 2003.

  • Ivosevic, M., Knight, R., Kalidindi, S. R., Palmese, G. R., Tsurikov, A. and Sutter, J. K., “Optimal Substrate Preheating Model for Thermal Spray Deposition of Thermosets onto Polymer Matrix Composites,” Proc. 2003 International Thermal Spray Conference [ITSC-2003], Eds. Marple, B. R. and Moreau, C., ASM International®, Orlando, FL, pp. 1683-1691, May 5-8, 2003.

  • Ivosevic, M., Knight, R., Kalidindi, S. R., Palmese, G. R. and Sutter, J. K., “Microstructure and Properties of Thermally Sprayed Functionally Graded Coatings for Polymeric Substrates,” Proc. 2003 International Thermal Spray Conference [ITSC-2003], Eds. Marple, B. R. and Moreau, C., ASM International®, Orlando, FL, pp. 1667-1673, May 5-8, 2003.

  • Ivosevic, M., Knight, R., Kalidindi, S. R., Palmese, G. R. and Sutter, J. K., “Microstructure and Properties of Thermally Sprayed Functionally Graded Coatings for Polymeric Substrates,” NASA/TM-2003-212119, March 2003.

  • Knight, R. “Thermal Spray: Into Its Second Century…Through the Looking Glass,” Guest Editorial, International Journal of Powder Metallurgy, Vol. 38, No. 7, pp. 33-34, 2002.

  • Lawley, A. and Knight, R., “Spray Technologies for Metal Powder Deposition – Quo Vadis,” Proc. 2002 Int'l. Conf. On Metal Powder Deposition for Rapid Manufacturing, April 8-10, 2002, San Antonio, TX, MPIF, Princeton, NJ, pp. 25-50, 2002.

  •  Ivosevic, M., Knight, R., Twardowski, T. E., Kalidindi, S. R., Kim, D-Y., and Sutter, J. K., “Development of Thermally Sprayed FGM Erosion-Oxidation Resistant Coatings for Polymeric Substrates,” Proc. International Thermal Spray Conference [ITSC-2002], Ed. Lugscheider, E., DVS/IIW/ASM-TSS, Essen, Germany, pp. 705-709, March 4-6, 2002.

  • Ding, Z., Knight, R. and Smith, R. W., “ Effect of Bond Coat Processes and Surface Characteristics on the Failure Mechanism of Thermal Barrier Coatings,” Proc. International Thermal Spray Conference [ITSC-2001], Eds. C. C. Berndt, K. A. Khor and E. F. Lugscheider, ASM International®, Singapore, pp. 173-177, May 28-30, 2001.

  • Twardowski, T. E., Reilly, M. and Knight, R., “Properties of HVOF Sprayed Multi-Scale Polymer/Silica Nanocomposite Coatings,” Proc. International Thermal Spray Conference [ITSC-2001], Eds. C. C. Berndt, K. A. Khor and E. F. Lugscheider, ASM International®, Singapore, pp. 369-373, May 28-30, 2001.

  • Knight, R., Fang, X. and Twardowski, T. E., “Structure and Properties of HVOF Sprayed Amorphous Polymer Matrix Nanocomposite Coatings” Proc. International Thermal Spray Conference [ITSC-2001], Eds. C. C. Berndt, K. A. Khor and E. F. Lugscheider, ASM International®, Singapore, pp. 361-368, May 28-30, 2001.

  • Guddeti, R. R., Knight, R., and Grossmann, E. D., "Depolymerization of Polypropylene in an Induction-Coupled [ICP] Reactor," Accepted for Publication in Industrial & Engineering Chemistry Research, February 2000.

  • Petrovicova, E., Knight, R., Schadler, L. S. and Twardowski, T. E., "Nylon 11/Silica Nanocomposite Coatings Applied by the HVOF Process: Part II. Mechanical and Barrier Properties," Accepted for publication in J. of Applied Polymer Science, November 1999.

  • Petrovicova, E., Knight, R., Schadler, L. S. and Twardowski, T. E., "Nylon 11/Silica Nanocomposite Coatings Applied by the HVOF Process Part I: Microstructure and Morphology," Accepted for publication in J. of Applied Polymer Science, November 1999.

  • Stratton, B.C., Knight, R., Mikkelsen, D. R., Blutke, A. and Vavruska, J., "Synthesis of Ozone at Atmospheric Pressure by a Quenched Induction-Coupled Plasma Torch," Plasma Chemistry and Plasma Processing, Vol. 19, No. 2, pp. 191-216, 1999.

  • Knight, R., "Thermal Plasma Spraying," Course Notes, Plasma Technology Training School, Buxton, UK, IEE, London, June 6-11, 1999.

  • Zhangxiong, D. and Knight, R., "Factors Influencing the Surface Roughness of TBC Bondcoats," Proc. 2nd United Thermal Spray Conference [UTSC'99], DVS, D¸sseldorf, Germany, pp. 825-829, March 17-19, 1999.

  • Han, J. J., Knight, R. and Schadler, L.S., "Residual Stresses in HVOF-Sprayed Cr3C2/NiCr Coatings," Proc. 2nd United Thermal Spray Conference [UTSC'99], DVS, D¸sseldorf, Germany, pp. 771-776, March 17-19, 1999.

  • Petrovicova, E., Knight, R., Twardowski, T. E. and Schadler, L.S., "Structure and Barrier Properties of Nano-Reinforced Polymer Coatings," Proc. 2nd United Thermal Spray Conference [UTSC'99], DVS, D¸sseldorf, Germany, pp. 577-581, March 17-19, 1999.

  • Eminoglu, C. M., Knight, R., DeFalco, J. and Dorfman, M., "Potentiodynamic Corrosion Testing of HVOF Sprayed Stainless Steel Alloy," Proc. 2nd United Thermal Spray Conference [UTSC'99], DVS, D¸sseldorf, Germany, pp. 39-44, March 17-19, 1999.

  • Knight, R. and Smith R.W., "Thermal Spray Forming of Materials," Chapter in ASM HandbookÆ, Volume 7 "Powder Metal Technologies and Applications," ASM Int'l.Æ, pp. 408-419, December 1998.

  • Knight, R., Zhangxiong, D., Kim, E.-U., Smith, R.W., Sahoo, P. and Bucci, D., "Influence of Bondcoat Surface Characteristics on the Performance of TBC Systems," Proc. 15th Int'l. Thermal Spray Conference [ITSC '98], [Ed. Coddet, C.], Nice, France, pp. 1549-1554, May 25-29, 1998.

  • Petrovicova, E., Knight, R., Smith, R. W. and Schadler, L. S., "Structure and Properties of HVOF Sprayed Ceramic/Polymer Nanocomposite Coatings," Proc. 1st United Thermal Spray Conference [UTSC '97], ASM Int'l., Indianapolis, IN, pp. 877-883, September 15-18, 1997.

  • Ding, Z., Knight, R. and Smith, R. W., "Abrasive Wear Characteristics of Ni-base Self-fluxing Alloy Spraywelding Overlays," Proc. 1st United Thermal Spray Conference [UTSC '97], ASM Int'l.Æ, Indianapolis, IN, pp. 91-95, September 15-18, 1997.

  • Smith, R.W. and Knight, R., "Thermal Spraying II: Recent Advances in Thermal Spray Forming," JoM, Vol. 48, No. 4, pp. 16-19, April, 1996.

  • Lawley, A., Knight, R. and Zavaliangos, A., "Reactive Spray Processing of Advanced Materials," Proc. European Conference on Advanced PM Materials, PM'95, EPMA, Birmingham, U.K., October 23-25, Vol. 1, pp. 158, 1995.

  • Knight, R., Smith, R.W., Mohanty, M. and Shtessel, E., "Low Pressure Plasma Sprayed SHS MoSi2/SiC Composite Coatings," Proc. 8th National Thermal Spray Conference [NTSC '95], ASM Int'l.Æ, Houston, TX, pp. 743-748, September, 1995.

  • Smith, R.W., Mutharasan, R., Knight, R., Luu, D. Malladi, K., Serino, J., Vavruska, J., Persoon, J. and Garrison, M., "Induction-Coupled Plasma Energy Recycle and Conversion [PERCô] of Military Waste Streams," Proc. 12th Int'l. Symp. on Plasma Chem. [ISPC-12], IUPAC, Minneapolis, MN, August 21-25, Vol. II, Paper N.1.06, pp 1057-1062, 1995.

  • Smith, R.W. and Knight, R., "Thermal Spraying I: Powder Consolidation - From Coating to Forming," JoM, Vol. 47, No. 8, pp. 32-39, August, 1995.

  • Knight, R., Smith, R.W. and Lawley, A., "Spray Forming Research at Drexel University," International Journal of Powder Metallurgy, APMI International, Princeton, NJ, Vol. 31, No. 3, pp. 205-213, August, 1995.

  • Smith, R.W., Mutharasan, R., Knight, R., Luu, D. Malladi, K., Serino, J., Vavruska, J., Persoon, J. and Garrison, S., "Plasma Energy Recycle and Conversion [PERCô] of Hazardous Waste Materials," Proc. 3rd European Congress on Thermal Plasma Processes [TPP-3], VDI, Aachen, Germany, September 19-21, pp. 667-674, 1994.

  • Knight, R., Smith, R.W., Xiao, Z. and Hoffman, T. T., "Particle Velocity Measurements in HVOF and APS Systems," Proc. 7th National Thermal Spray Conf. [NTSC '94], ASM Int'lÆ, Boston, MA, pp. 331-336, June 1994.

  • Smith, R.W. and Knight, R., "Reactive Plasma Spray Forming of Nitride/Nitrogen Composite Materials," Proc. 11th Int'l. Symposium on Plasma Chemistry [ISPC-11], IUPAC/IEE, Loughborough, UK, Vol. 1, pp. 139-144, August, 1993.

  • Irving, R., Knight, R. and Smith, R.W., "The HVOF Process - The Hottest Topic in the Thermal Spray Industry," Welding Journal, AWS, Vol. 72, No. 7, pp. 25-30, July 1993.

  • Sampath, S., Khatri, S., Knight, R., Smith, R.W., Shtessel, E. and Koczak, M. J., "Synthesis of Intermetallic Composite Powders via Self-propagating Synthesis," Proc. PM '93 Conference, Kyoto, Japan, 1993.

  • Knight, R. and Smith, R.W., "Residual Stress in Thermally Sprayed Coatings," Proc. 5th National Thermal Spray Conference [NTSC '93], Thermal Spray Coatings: Research, Design and Applications, eds. Berndt, C. C. & Bernecki, T. F., ASM Int'lÆ, Anaheim, CA, USA, pp. 607-612, June 1993.

  • Knight, R. and Smith, R.W., "HVOF Sprayed 80/20 NiCr Coatings - Process Influence Trends," Proc. 13th Int'l. Thermal Spraying Conference [ITSC '92], Thermal Spray: International Advances in Coatings Technology, ed. Berndt, C.C., ASM Int'lÆ, Orlando, FL, USA, pp. 159-164, June 1992.

  • Knight, R., Smith, R. W. and Apelian, D., "Application of Plasma Arc Melting Technology to Processing of Reactive Metals," International Materials Reviews, Vol. 36, No. 6, pp. 221-252, 1991.

  • Knight, R., Smith, R. W. and Apelian, D., "Plasma Technology for Reactive Metal Melting: Current Devices and Process Limitations," Presentation at Conf. "Plasma for Industry and Environment," BNCE, Wadham College, Oxford, UK, Paper No. 1.3, September 1990.

  • Reid, K.J., Knight, R., Murawa, M.J. and Girgis, N.M., "Arc Characteristics in Small-Scale D.C. Plasma Furnaces Using Graphite Cathodes," Plasma Chem. and Plasma Proc., Vol. 10, No. 2, pp. 359-373, 1990.

  • Reid, K.J., Knight, R., Murawa, M.J. and Pridgeon, J., "Characteristics of High-Power SSP Magnetically Rotated Electric Arcs," Proc. 8th Int'l. Symp.on Plasma Chem., IUPAC, Tokyo, Japan, Vol. 1, Paper P.035, pp 455-460, September 1987.

  • Harry, J.E. and Knight, R., "Multiple Electric Discharges," Proc. IEE, Vol. 133, Part A, No. 1, pp. 50-57, January 1986.

  • Harry, J.E. and Knight, R., "High Current Multiple Electrodes for Use in Arc Furnaces," Steel Times, Vol. 213, No. 10, pp. 486-487, October 1985.

  • Hodge, D., Harry, J.E. and Knight, R., "A Plasma Furnace System for Chemical and Metallurgical Processes," Presented at Workshop at 7th Int'l. Symp. on Plasma Chem., IUPAC, Eindhoven, Holland, July 1985.

  • Harry, J.E. & Knight, R., "A Multiple Arc Discharge Reactor for Material Processing," Proc. 7th Int'l. Symp. on Plasma Chem., IUPAC, Eindhoven, Holland, Vol. 4, Paper No. B-8-5, July 1985.

  • Harry, J.E. and Knight, R., "The Application of Large Volume Plasmas Produced by Multiple Arcs to High Temperature Material Processing," Gordon Conf. on Plasma Chem., Tilton School, Tilton, NH, USA, August 1984. [No Proceedings].

  • Harry, J.E. and Knight, R., "High Current Multiple Electrodes for Use in Arc Furnaces," Proc. 10th Int'l. Cong. on Electroheat [UIE], Stockholm, Sweden, June 1984.

  • Harry, J.E. and Knight, R., "Investigation of the Intensity Distribution of Large Volume Multiple Arc Discharges," J. Phys. D: Appl. Phys., Vol. 17, pp. 343-350, 1984.

  • Harry, J.E. and Knight, R., "Multiple Arc Discharges for Metallurgical Reduction or Metal Melting," Proc.1983 Annual Meeting, Materials Research Society [MRS], Boston, MA, USA, Abstract No. L5.3, pp. 460, 1983.

  • Harry, J.E. and Knight, R., "Power Supply Design for Multiple Discharge Arc Processes," Proc. 6th Int'l. Symp. on Plasma Chem., IUPAC, UniversitÈ de ShÈrbrooke, Montreal, Canada, Vol. 1, Paper No. A-5-3, pp. 150-155, July 1983.

  • Harry, J.E. and Knight, R., "Simultaneous Operation of Electric Arcs from the Same Supply," IEEE Trans. on Plasma Sci., Vol. PS-9, [4], pp. 248-254, December 1981.

  • Harry, J.E. and Knight, R., "A System for the Production of a Large Volume of Ionized Gas for Chemical and Metallurgical Synthesis," Proc. 14th Universities Power Engineering Conf., Loughborough Univ. of Tech., pp. 5B1.1- 5B1.4, April 1979.

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