{"682158":{"#nid":"682158","#data":{"type":"event","title":"PhD Proposal by Kayla Chuong  ","body":[{"value":"\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EKayla Chuong\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003E\u0026nbsp;\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EAdvisor: Prof. Lauren M. Garten\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003Ewill propose a doctoral thesis entitled,\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003E\u0026nbsp;\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003E\u0026nbsp;\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EDeveloping ZnO-based MOVs using Cold Sintering for DC Circuit Breakers\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EOn\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EFriday, May 2, 2025\u003C\/p\u003E\u003Cp\u003E2pm \u2013 4pm\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EPettit Microelectronics Building, Rm102A\u003Cbr\u003Eand\u003C\/p\u003E\u003Cp\u003EVirtually via MS Teams\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022https:\/\/teams.microsoft.com\/l\/meetup-join\/19%3ameeting_ODc3ZWM5ZTEtNzYzMC00OTA0LWE4NjAtOTAyMTI3ZjQ1MWNj%40thread.v2\/0?context=%7b%22Tid%22%3a%22482198bb-ae7b-4b25-8b7a-6d7f32faa083%22%2c%22Oid%22%3a%228d91f8a7-c576-444c-81ba-fe3f468c93ec%22%7d\u0022 title=\u0022https:\/\/teams.microsoft.com\/l\/meetup-join\/19%3ameeting_ODc3ZWM5ZTEtNzYzMC00OTA0LWE4NjAtOTAyMTI3ZjQ1MWNj%40thread.v2\/0?context=%7b%22Tid%22%3a%22482198bb-ae7b-4b25-8b7a-6d7f32faa083%22%2c%22Oid%22%3a%228d91f8a7-c576-444c-81ba-fe3f468c93ec%22%7d\u0022\u003EMeeting Link\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003E\u0026nbsp;\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECommittee:\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EProfessor Lauren M. Garten, Primary Co-Advisor, MSE\u003C\/p\u003E\u003Cp\u003EProfessor Lukas Graber, Co-Advisor, ECE\u003C\/p\u003E\u003Cp\u003EProfessor Mark Losego, MSE\u003C\/p\u003E\u003Cp\u003EProfessor Rosario Gerhardt, MSE\u003C\/p\u003E\u003Cp\u003EDr. Eric Neuman, Sandia National Laboratory\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EAbstract\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EZnO-based Metal oxide varistors (MOVs) are currently used for surge arrestors but show great potential for high voltage DC circuit breakers (HV DCCBs) due to their ability to quickly dissipate energy in an overcurrent event. However, under higher voltage conditions and a different circuit configuration, the performance, reliability, and lifetime of MOVs must be reevaluated and improved. Under high voltages, effective current dissipation is paramount for device reliability and lifetime, which is controlled by the microstructure. Cold sintering is proposed as a processing route to improve microstructural homogeneity and reduce grain size in ZnO-based MOVs. Furthermore, by adjusting the composition of the MOV and tailoring the grain boundary interface, the rate of degradation can be decreased and lifetime improved. This research will provide the critical missing insight into cold sintering processing and intergranular phase control, which will enable MOVs to be used in HV DCCBs due to their improved microstructural homogeneity and electrical response.\u003C\/p\u003E\u003Cp\u003ETo improve MOV reliability by achieving a homogenous microstructure and reduced grain size, cold sintering is proposed as an alternative sintering method that uses high pressure coupled with a transient liquid phase to densify the ceramic rather than high temperatures. The transient liquid phase, such as acetic acid or zinc acetate, is used as a medium to promote the diffusion of zinc ions at low temperatures. ZnO samples were cold sintered with different liquid phases to observe the effects of the choice of the transient liquid phase on the grain size. Overall, cold sintering is shown to minimize grain growth while achieving similar densities to commercial varistors.\u003C\/p\u003E\u003Cp\u003EDegradation is a critical issue for MOVs used in DCCBs. Over time, the gradual electromigration of Zn interstitials towards the GB and device electrodes leads to a decrease in insulation resistance of the MOV. Multiple routes have been suggested to mitigate the degradation of the double Schottky barrier (DSB) height, but the most straightforward solutions are decreasing the concentration of Zn interstitials in the dielectric and interfering with the migration of Zn interstitials. If doping with MnO2,\u0026nbsp;TiO2, and Co2O3\u0026nbsp;causes changes in the ZnO lattice that must be compensated with Zn vacancies (or oxygen interstitials), then the formation (or migration) of Zn interstitials is limited, which will increase MOV lifetime by slowing the decrease in DSB height at the GB. Alternatively, doping with MnO2,\u0026nbsp;TiO2, Mn2O3,\u0026nbsp;and Co2O3\u0026nbsp;may be electrically compensated, making ZnO further n-type, which would increase the potential gradient between the p-type intergranular phase and the ZnO grains thus increasing barrier height. This work proposes to use cold sintering to improve microstructural homogeneity while adding MnO2,\u0026nbsp;TiO2, and Co2O3 to suppress Zn interstitials to improve cold sintered MOV lifetime for DCCBs.\u003C\/p\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003E\u003Cstrong\u003EDeveloping ZnO-based MOVs using Cold Sintering for DC Circuit Breakers\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Developing ZnO-based MOVs using Cold Sintering for DC Circuit Breakers"}],"uid":"27707","created_gmt":"2025-05-01 15:49:17","changed_gmt":"2025-05-01 15:49:51","author":"Tatianna Richardson","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2025-05-02T14:00:00-04:00","event_time_end":"2025-05-02T16:00:00-04:00","event_time_end_last":"2025-05-02T16:00:00-04:00","gmt_time_start":"2025-05-02 18:00:00","gmt_time_end":"2025-05-02 20:00:00","gmt_time_end_last":"2025-05-02 20:00:00","rrule":null,"timezone":"America\/New_York"},"location":"Pettit Microelectronics Building, Rm102A and Virtually via MS Teams","extras":[],"groups":[{"id":"221981","name":"Graduate Studies"}],"categories":[],"keywords":[{"id":"102851","name":"Phd proposal"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78771","name":"Public"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}