Brazing rod for depositing diamond coating to metal substrate using gas or electric brazing techniques

A brazing rod for use in depositing an abrasive metal coating on a metal substrate, wherein the metal coating contains an abrasive material selected from the group consisting of diamond particles and mixtures of diamond particles and carbide particles, said brazing rod comprising

• a particulate abrasive material selected from the group consisting of diamond particles and mixtures of diamond particles and carbide particles;
• and
• a matrix comprising particles of braze alloy in which one component of the braze alloy is a member selected from the group consisting of nickel, nickel alloy, silver, silver alloy, gold, gold alloy, copper, copper alloy and mixtures thereof, and in which a second component of said braze alloy is selected from the group consisting of iron, iron alloy, cobalt, cobalt alloy, tin, tin alloy, boron, silicon, chromium, chromium alloy and mixtures thereof,
• wherein (a) the diamond particles have been coated with a material selected from the group consisting of tungsten, molybdenum, chromium, nickel, iron, cobalt, palladium, tungsten carbide, molybdenum carbide, chromium carbide and iron carbide, and (b) the carbide particles are selected from the group consisting of tungsten carbide, molybdenum carbide and chromium carbide and (c) the particles of said braze alloy in said matrix is sufficiently sintered together to bind the particulate abrasive material into a rigid rod.