Walter P. Murphy Professor Emeritus

BS, Mining Engineering, 1956
PhD, Ceramics Engineering, 1962 University of Utah

Contact Info

 

 

Fundamentals of novel materials processing

     We are investigating novel synthesis methods for nanophase materials and catalysts. Nanophase metals and dispersed metals on alumina are synthesized in induction coupled evaporators. Gamma alumina was synthesized by combustion of aluminum powder in a microwave-excited oxygen plasma.
     We developed the master sintering curve (MSC), which enables prediction of sintering under arbitrary temperature-time excursions. Recently we extended the MSC into the pressure regime, yielding the pressure master sintering surface (PMSS). Once known, the PMSS can be used to specify the pressure-temperature- time treatment required to obtain any given final density. In one application we used the PMSS to calibrate the pressure in a complex sintering die assembly.
     We have shown that ß''- alumina can be sintered to high-density and high-phase conversion by rapid translation through an oxygen plasma. Full-density and phase conversion occurs in 15 to 20 seconds.

Associations and Awards

Outstanding Educator Award, American Ceramic Society, 2001

Fellow, American Association for the Advancement of Science, 1997

Department Teacher of the Year, 1996, 1997

Academy of Ceramics, 1989

NSF Award for creativity in research for work on plasma sintering of ceramics, 1985

Technological Institute Teaching Award, 1982

Fellow, American Ceramic Society, 1974

Selected Publications

“Tantalum Oxide Coatings as Candidate Environmental Barriers,” Monica Moldovan, C.M Weyant, D. Lynn Johnson, and K.T. Faber, J. Thermal Spray Tech., 13 [1], 51-56 (March 2004).

"Microwave Plasma Synthesis of Nanostructured γ-Al2O3," Lei Fu, D. Lynn Johnson, Jian G. Zheng, and Vinayak P. Dravid, J. Am. Ceram. Soc., 86 [9] 1635-37 (2003).

"The Pressure-assisted Master Sintering Surface," K. An and D. Lynn Johnson, J. Mat. Sci., 37 1-5 (2002).

Hardening process of cement-based materials monitored by the instrumented penetration test, part I: neat cement paste and mortar [with D. Sohn]. Cement Concrete Res. 32 [4]: 557-563 (2002).

"Self-assembled (SA) bilayer molecular coating on magnetic particles," Lei Fu, Vinayak P. Dravid, and D. Lynn Johnson, Applied Surface Science, 181 173-178 (2001).

Ultra-rapid phase conversion in ß''- alumina tubes [with M. Henrichsen, J. Hwang, and V. P. Dravid]. J. Am. Ceram. Soc. 83(11): 2861-62 (2000).

Microwave curing effects on the 28-day strength of cementitous materials [with D. Sohn]. Cement Concrete Res. 29(2): 241-47 (1999).