Primers electrically conductive

Zinc-Rich Primer an anticorrosive primer for iron and steel incorporating zinc dust in a concentration sufficient to give electrical conductivity in the dried films, thus enabling the zinc metal to corrode preferentially to the substrate, i.e. to give cathodic protection. 

Sealant, ablative, silicone base, room temperature curing and primer Sealant, silicone rubber, room temperature vulcanizing Sealing compound, high tear strength Sealant, electrically conductive... 

Aluminum or aluminum coatings should not be anodized if electrical conductivity is required. Fully heat-treated aluminum alloys, prior to painting, should be primed with chromate primer... 

Electric Primer. This type is fired by the heat generated when an electric current passes thru a resistance wire or conductive primer mixture embedded in a primer compn. It was formerly used in harbor defense and railroad artillery ammunition (Ref 15, p 117), but is... 

The coating is applied electrostatically. The powder is pumped by air through a gun, which generates an electric field and imparts a static charge to the powder particles. These charged particles are attracted uniformly to a grounded part. The part has to be conductive or coated by a conductive primer coat so that it can be grounded (see Section 7.7.2). 

Instrument for electrical testing of misconnected circuits. The current intensity used in the testing must be well below the minimum detonation intensity of the electric primer the circuit tester is accordingly equipped with resistances at both poles. Only officially approved testers should be employed. The testers are of two kinds conduction testers which show, by means of a visual indicator, whether or not current is flowing in the circuit, and ohmmeters which measure the resistance of the priming circuit. 

The electrocoat process for primer coating involves the electrophoretic deposition of charged colloidal resinous particles in aqueous dispersion onto a conductive substrate such as an automobile body. The process is universally favored because once the paint particles are deposited, they insulate the body from further deposition at that point. The impressed electric field thereby causes the migration of paint particles to uncoated areas. The result is an extremely uniform, coherent and defect free coating-even on sharp edges and in recessed areas inaccessible to other methods. 

Carbon bridges, consisting of nothing more than a dab of water-based colloidal carbon black between two closely-set conductive areas in a molded plastic plug, are the resistors in the most sensitive electric primers and they use one of the most heat-sensitive, stable prime explosives, i.e. normal lead styphnate with some lacquer, as in the Electric Fuze Primer Mk 121. 

Concerning incorporation of reinforcement fibers, the conductive or non-conductive characteristic was a very important variable. The first ones improved notably the primer performance since they increased the electrical contact between particles and with the metallic substrate, particularly in the higher levels in the formulations the performance is correlated with the higher useful zinc in the film. On the other hand, non-conductive reinforcement fibers did not modify the primer efficiency as compared with reference panels (without reinforcement fibers) and for this reason their incorporation is not justified from technical and economical viewpoints. 

In vacuum metallising, a metal is heated in a vacuum chamber to its vaporisation point, which is lower than the melt temperature of plastics. The metal vapour deposits on the cooler plastic surface. In electroplating, an electric current is used to deposit metal from a metal salt solution onto a plastic rendered conductive by electroless plating. Arc flame, arc spraying, and sputtering are other techniques used. Metallising requires very clean surfaces, free from mould release agents. Primers or pre-cleaners can be used to improve the adhesion of the metal to the polymer surface. 

Examples are listed in table 7-10. In these detonators the wire or film is heated by an electric current. The heat causes ignition of the charge which may then undergo a deflagration to detonation transfer. The functioning of a conductive mixture or spark gap primer is readily apparent from the name. These two types of primers are not commonly used. 

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