FOR IMAGE INTENSIFIERS

IMAGE INTENSIFIER TUBE ASSEMBLIES ARE EXPERIENCING FAILURE DUE TO LEAKAGE CURRENTS ALONG THE GLASS/POTTANT INTERFACE. IN MOIST ENVIRONMENTS, WATER PENETRATES THE RTV SILICONE TO THIS INTERFACE, RESULTING IN LEAKAGE CURRENTS LARGE ENOUGH TO OVERWHELM THE POWER SUPPLY. THIS FAILURE IS BEING AGGREVATED BY POOR COUPLING (ADHESION) BETWEEN THE GLASS AND THE SILICONE POTTANT, HYDROPHILIC SI-OH GROUPS AT THE SURFACE OF THE GLASS, AND POSSIBLY BY RESIDUAL CURE BYPRODUCTS IN THE CONDENSATION-TYPE RTV BEING USED. THIS PHASE I PROGRAM WILL INVESTIGATE SILANE-BASED COUPLING AGENTS AND PRIMERS TO REACT WITH THE SI-OH GROUPS AND RENDER THEM HYDROPHOBIC AND TO ENHANCE ADHESION BETWEEN THE GLASS AND POTTANT. THIS PROJECT WILL ALSO EVALUATE ADDITION-CURE TYPE RTV SILICONES AND ALSO EVA RESINS AS POTTANTS LOW IN BY-PRODUCTS AND LESS SENSITIVE TO A MOIST ENVIRONMENT. THE MOST PROMISING COUPLING AGENT/POTTANT SYSTEMS WILL BE USED TO POT INTENSIFIER TUBE ASSEMBLIES WHICH WILL BE SUBJECTED TO HIGH RELATIVE HUMIDITY AND MONITORED FOR INTENSIFIER OPERATION. THE MOST PROMISING POTTANT SYSTEM WILL BE RECOMMENDED TO THE COMMUNICATION-ELECTRONICS COMMAND FOR MORE EXTENSIVE TESTING.