Lightning-arrester resistance material is composed of silicon carbide particles and a binder therefor composed of cordierite formed of a fired mixture of cordierite-forming glass material and cordierite-forming crystalline material.
A fired, electrically semi-conducting ceramic body is disclosed. The body consists essentially of silicon carbide particles having a median particle size from about 3 to about 25 microns dispersed in a bonding matrix. The silicon carbide particles constitute from about 50 to about 70 percent of the body. The body has an "apparent porosity" as subsequently defined herein from 20 to 40. The production of such a body from a batch composed of silicon carbide, alumina, silica and at least one oxide, carbonate or hydroxide of calcium, magnesium, barium or strontium is also disclosed. The batch is milled and pressed into a shape, and the resulting shape is then fired in an inert gas atmosphere to a temperature from about 2,300.degree. to 2,800.degree. F. for a time sufficiently long to produce a semi-conductor body having the requisite apparent porosity of from 20 to 40 percent.
Ceramics incorporating fibrous crystals of silicon carbide, optionally, in combination with an electroconductive substance have high electroconductivity and are amenable to electric discharge machining.
A varistor includes a voltage-nonlinear resistor and varistor electrodes provided on the upper and lower surfaces of the voltage-nonlinear resistor. The voltage-nonlinear resistor is primarily composed of SiC (silicon carbide) particles which are doped with at least one dopant such as N (nitrogen) and P (phosphorus). The varistor electrodes are composed of a metal, e.g., Ag, Pd, Pt, Al, Ni or Cu. The SiC particles of the voltage-nonlinear resistor further contain at least one element of Al (aluminum) and B (boron) in an amount of about 0.01 to 100 parts by weight with respect to 100 parts by weight of the SiC particles.
Lightning arrester resistance material is composed of silicon carbide particles and a binder therefor composed of cordierite formed of a fired mixture of cordierite-forming glass material and cordierite-forming crystalline material.
A micro-crystalline material and method for making the same wherein a vitreous material known as magnesium aluminum silicate or cordierite glass is caused to undergo a high temperature solid state conversion to a crystalline material and wherein the crystallization is catalyzed by using a nucleating agent on the surface of the base material to trigger microscopic grain formation, the base material that is used being in the form of a fine frit or powder.
