Abstract: A method for manufacturing a high strength isotropic graphite including a kneading step to mix an aggregate consisting of carbonaceous fine powder with a pitch binder a molding step to mold the raw material prepared by re-pulverizing the kneaded mixture using rubber press method and a carbonizing and graphitizing step to fire carbonize and graphitize the molded product. The aggregate uses a fine mosaic coke powder as the aggregate, which mosaic coke powder is finely pulverized in a jet mill to an average particle size of 1 .mu.m or less and a maximum particle size of 5 .mu.m or less, and has a surface average electrostatic field intensity of 1.2.times.10.sup.4 esu/cm.sup.2 or more. The invention provides a high strength isotropic graphite having a high bending strength of 120 MPa or more, which is suitable for piston components of gasoline engines and provides a method for manufacturing high strength isotropic graphite.

Abstract: A process for producing a magnetite-coated electrode which comprises kneading an iron oxide powder, water and an organic binder under pressure sufficient to prepare a molded article, baking the molded article in a gas atmosphere mainly composed of a member selected from the group consisting of carbon dioxide and steam to prepare a magnetite sinter having an Fe to 0 ratio of 3:3.7 to 4.0, pulverizing the sinter to prepare a powder, and subjecting a metallic substrate to plasma spray coating, plasma jet spray coating, explosive spray coating and water plasma spray coating by making use of the powder as the spray coating source in a neutral gas atmosphere to form a magnetite coating on the surface of the metallic substrate.