Chad Samuel Watson

Failure analysis of rutile sleeves in MC3080 lightning arrestor connectors.

The purpose of this SAND Report is to document efforts in the extraction and failure analyses of sleeve-style Lightning Arrestor Connectors (LACs). Several MC3080 and MC3079 LACs were recovered from the field and tested as part of the Enhanced Surveillance Campaign. A portion of these LACs failed retesting. Terry Ernest (01733), the LAC Component Engineer, provided eleven MC3080 LACs for evaluation where four of the LACs failed IR/DCW and one failed FRB requirements. The extraction of rutile sleeves from failed LACs was required to determine the source of failure. Rutile sleeves associated with connector function failures were examined for cracks, debris as well as any other anomalies which could have caused the LAC to not function properly. Sleeves that failed FRB or that experienced high FRB exhibited high symmetry, smooth surface, long-flow amicon, and slightly over-sized inside diameter. LACs that failed DCW or IR requirements had rutile sleeves that exhibited breakdown tracks.

Strength and Reliability of Lead Zirconate Titanate Ceramics

The influences of temperature and processing conditions (unpoled or poled-depoled) on strength, Weibull parameters and the stress-strain behavior of tin-modified lead zirconate titanate (PSZT) were evaluated in four-point bending. PSZT exhibited temperature-dependent non-linear and non-symmetric stress-strain behavior. A result of temperature dependent non-linearity was an apparent reduction in the flexural strength of PSZT as temperature increases. At room temperature the average stress in the outer-fiber of bend bars was 84 MPa, whereas, for specimens tested at 120°C the average failure stress was only 64 MPa. The load-carrying capacity, however, did not change with temperature, but the degree of deformation tolerated by PSZT prior to failure increased with temperature.

Elastic Recoil Detection of Depletion Layer Formation During Anodic Bonding

Conventional elastic recoil detection (ERD) techniques have been employed in an attempt to elucidate the effects time, temperature and alkali ion content have on depletion layer formation during anodic bonding. Hydrogen and/or lithium ion concentration profiles were evaluated for both untreated and lithium‐treated sodium borosilicate glass. From in situ ERD, depletion layer formation is highly dependent on temperature and alkali ion content. Lithium‐treated sodium borosilicate glass improves depletion layer formation at low temperatures and at high temperatures increased ion mobility results in rapid depletion layer formation.