\"This research focuses on the joining of ultra-high temperature ceramics to either themselves or refractory metals/alloys via fusion welding and the mechanical strength of produced joints. The ceramics studied consisted of compositions within a diboride-carbide-carbide ternary system while metals studied consisted of molybdenum and a molybdenum alloy. SiC-ZrB2-ZrC ceramics on a binary join between pure SiC and the ternary eutectic composition were found to be weldable when SiC content was below ~57.5 vol%. Compositions above 57.5 vol% SiC were unweldable based on pitting and off-gassing behavior. Welded strength of ceramics was ~180-300 MPa in the SiC-ZrB2-ZrC ternary eutectic composition, ~180-220 MPa in the SiC-ZrB2 binary eutectic composition, and ~130-180 MPa in a 60 vol% SiC – 40 vol% ZrB2 composition at room and elevated tempeatures. Welded strength was limited by pore size within the fusion zones. Thermal conductivity and electrical resistivity of parent materials in metal-ceramic welds were investigated to determine their effect on weldability. Welds were formed between molybdenum, or a molybdenum alloy, and ceramic compositions on a binary join between nominally pure ZrB2 and the SiC-ZrB2-ZrC ternary eutectic composition. Neither thermal conductivity nor electrical resistivity was found to affect weldability; however, melting temperature of ceramic coupons affected overall weld symmetry and penetration. Welded strength of joints between a molybdenum alloy and a 70 vol% ZrB2 – 19.5 vol% SiC – 10.5 vol% ZrC ceramic were ~10-100 MPa and failed due to the pores and cracks within produced samples. Removal of SiC from ceramics was found to reduce porosity and cracking in fusion zones\"--Abstract, p. iv
","abstract_html":"<p>"This research focuses on the joining of ultra-high temperature ceramics to either themselves or refractory metals/alloys via fusion welding and the mechanical strength of produced joints. The ceramics studied consisted of compositions within a diboride-carbide-carbide ternary system while metals studied consisted of molybdenum and a molybdenum alloy. SiC-ZrB2-ZrC ceramics on a binary join between pure SiC and the ternary eutectic composition were found to be weldable when SiC content was below ~57.5 vol%. Compositions above 57.5 vol% SiC were unweldable based on pitting and off-gassing behavior. Welded strength of ceramics was ~180-300 MPa in the SiC-ZrB2-ZrC ternary eutectic composition, ~180-220 MPa in the SiC-ZrB2 binary eutectic composition, and ~130-180 MPa in a 60 vol% SiC – 40 vol% ZrB2 composition at room and elevated tempeatures. Welded strength was limited by pore size within the fusion zones. Thermal conductivity and electrical resistivity of parent materials in metal-ceramic welds were investigated to determine their effect on weldability. Welds were formed between molybdenum, or a molybdenum alloy, and ceramic compositions on a binary join between nominally pure ZrB2 and the SiC-ZrB2-ZrC ternary eutectic composition. Neither thermal conductivity nor electrical resistivity was found to affect weldability; however, melting temperature of ceramic coupons affected overall weld symmetry and penetration. Welded strength of joints between a molybdenum alloy and a 70 vol% ZrB2 – 19.5 vol% SiC – 10.5 vol% ZrC ceramic were ~10-100 MPa and failed due to the pores and cracks within produced samples. Removal of SiC from ceramics was found to reduce porosity and cracking in fusion zones"--Abstract, p. iv</p>","abstract_has_math":false,"creators":["Jarman, Jecee"],"institution":"Missouri University of Science and Technology","degree_name":"Ph. D. in Ceramic Engineering","degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":null,"date_issued":"","date_published":null,"updated_at":"2026-07-24T03:18:18Z","subjects":["borides","carbides","fusion welding","joining","Ceramic Materials","Engineering"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarsmine.mst.edu/doctoral_dissertations/3201","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Jarman, Jecee"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:type","label":"Dc Type","values":["Dissertation - Open Access"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph. D. in Ceramic Engineering"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Missouri University of Science and Technology"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["borides","carbides","fusion welding","joining","Ceramic Materials","Engineering"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarsmine.mst.edu/doctoral_dissertations/3201"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["\"This research focuses on the joining of ultra-high temperature ceramics to either themselves or refractory metals/alloys via fusion welding and the mechanical strength of produced joints. The ceramics studied consisted of compositions within a diboride-carbide-carbide ternary system while metals studied consisted of molybdenum and a molybdenum alloy. SiC-ZrB2-ZrC ceramics on a binary join between pure SiC and the ternary eutectic composition were found to be weldable when SiC content was below ~57.5 vol%. Compositions above 57.5 vol% SiC were unweldable based on pitting and off-gassing behavior. Welded strength of ceramics was ~180-300 MPa in the SiC-ZrB2-ZrC ternary eutectic composition, ~180-220 MPa in the SiC-ZrB2 binary eutectic composition, and ~130-180 MPa in a 60 vol% SiC – 40 vol% ZrB2 composition at room and elevated tempeatures. Welded strength was limited by pore size within the fusion zones. Thermal conductivity and electrical resistivity of parent materials in metal-ceramic welds were investigated to determine their effect on weldability. Welds were formed between molybdenum, or a molybdenum alloy, and ceramic compositions on a binary join between nominally pure ZrB2 and the SiC-ZrB2-ZrC ternary eutectic composition. Neither thermal conductivity nor electrical resistivity was found to affect weldability; however, melting temperature of ceramic coupons affected overall weld symmetry and penetration. Welded strength of joints between a molybdenum alloy and a 70 vol% ZrB2 – 19.5 vol% SiC – 10.5 vol% ZrC ceramic were ~10-100 MPa and failed due to the pores and cracks within produced samples. Removal of SiC from ceramics was found to reduce porosity and cracking in fusion zones\"--Abstract, p. iv
"]},{"key":"dc:title","label":"Title","values":["JOINING OF ULTRA-HIGH TEMPERATURE CERAMICS TO THE SAME AND REFRACTORY METALS VIA FUSION WELDING"]}]}],"canonical_facts":{"dc:creator":["Jarman, Jecee"],"dc:description.abstract":["\"This research focuses on the joining of ultra-high temperature ceramics to either themselves or refractory metals/alloys via fusion welding and the mechanical strength of produced joints. The ceramics studied consisted of compositions within a diboride-carbide-carbide ternary system while metals studied consisted of molybdenum and a molybdenum alloy. SiC-ZrB2-ZrC ceramics on a binary join between pure SiC and the ternary eutectic composition were found to be weldable when SiC content was below ~57.5 vol%. Compositions above 57.5 vol% SiC were unweldable based on pitting and off-gassing behavior. Welded strength of ceramics was ~180-300 MPa in the SiC-ZrB2-ZrC ternary eutectic composition, ~180-220 MPa in the SiC-ZrB2 binary eutectic composition, and ~130-180 MPa in a 60 vol% SiC – 40 vol% ZrB2 composition at room and elevated tempeatures. Welded strength was limited by pore size within the fusion zones. Thermal conductivity and electrical resistivity of parent materials in metal-ceramic welds were investigated to determine their effect on weldability. Welds were formed between molybdenum, or a molybdenum alloy, and ceramic compositions on a binary join between nominally pure ZrB2 and the SiC-ZrB2-ZrC ternary eutectic composition. Neither thermal conductivity nor electrical resistivity was found to affect weldability; however, melting temperature of ceramic coupons affected overall weld symmetry and penetration. Welded strength of joints between a molybdenum alloy and a 70 vol% ZrB2 – 19.5 vol% SiC – 10.5 vol% ZrC ceramic were ~10-100 MPa and failed due to the pores and cracks within produced samples. Removal of SiC from ceramics was found to reduce porosity and cracking in fusion zones\"--Abstract, p. iv
"],"dc:identifier":["https://scholarsmine.mst.edu/doctoral_dissertations/3201"],"dc:subject":["borides","carbides","fusion welding","joining","Ceramic Materials","Engineering"],"dc:title":["JOINING OF ULTRA-HIGH TEMPERATURE CERAMICS TO THE SAME AND REFRACTORY METALS VIA FUSION WELDING"],"dc:type":["Dissertation - Open Access"],"thesis:degree_name":["Ph. D. in Ceramic Engineering"],"thesis:institution_name":["Missouri University of Science and Technology"]},"updated_at":"2026-07-24T03:18:18Z"}