A process device has a process seal for coupling to an industrial process. The process device includes a process device body having an isolation cavity and an isolation passageway extending from the isolation cavity to a pressure sensor. The isolation cavity and isolation passageway filled with an isolation fluid. An isolation diaphragm is positioned to isolate the isolation cavity from process fluid. The isolation diaphragm has a process fluid side and an isolation fluid side. A weld ring is positioned around a periphery of the process fluid side of the isolation diaphragm. The weld ring is formed of a first material compatible with the isolation diaphragm and a second material compatible with the process device body. A weld secures the weld ring to the process device body.