Patent CA-1079131-A (CA)
Title: Base metal article with a discontinuous coating of discrete refractory metal particles in clusters and process for depositing same
Inventor: WARNER JOSHUA B
IPC: C25D15/00
Filed: 1976-10-08
Granted: 1980-06-10
Abstract: ABSTRACT OF THE DISCLOSURE           An article of improved wear characteristics and com-posed of a relatively low wear resistant base metal coated by a particulate refractory metal having a melting point of at least 1490°C deposited within the near surface region thereof compris-ing a base metal or alloy of relatively low wear resistance, a refractory metal deposited within said near surface region, said refractory metal being selectively deposited in the form of discrete particles, and the particles being idiomorphic or blocky or equiaxial or spheroidal or acicular or dendritic and a plurality of these particles having dimensions of less than 10 micrometers, a plurality of the particles being contiguous to form clusters of the particles that are spaced from each other.          The clusters of particles may form microscopic regions of refrac-tory metal which in turn may produce macroscopic regions of refractory metal having the appearance of a continuous coating.          The refractory metal is selected from the group including: boron, chromium, cobalt, iridium, molybdenum, niobium, osmium, palladium, platinum, rhenium, rhodium, ruthenium, tantalum, thorium, titanium, tungsten, vanadium, yttrium, and zirconium and all alloys incorporating these refractory metals.         The process of providing protective coatings of refractory metals and alloys on to any metallic base such as: iron, aluminum, chromium, cobalt, copper, nickel, magnesium, tin, titanium, or on to any metallic alloy base such as:  steels, cast irons, brasses, bronzes, and solders at temperatures as low as ambient or below, including selecting an electrolyte material capable of dissociation into ions, such that at 25°C the equi-valent conductance of 0.1 normal solution of electrolyte divi-ded by that of the electrolyte solution at infinite dilution is between 0.13 and 0.93, providing a particulate refractory metal having a melting point of at least 1490°C, to be deposited within the near-surface region of the base metal, admixing 99 to 50 percent by weight of said refractory metal and 1 to 50 percent by weight of said electrolyte, the refractory metal having a nascent surface capable of producing ions in solution, ionizing said refractory metal to a concentration of about 1 to 60,000 mg. of refractory metal per liter of solution, and at least partially surrounding said refractory metal with said electrolyte, contacting and at least partially coating the base metal with the refractory metal and the electrolyte admixture, reacting the electrolyte in the admixture with the base metal at temperatures between 0°C and 200°C, and depositing discrete particles that may be randomly distributed or may appear as clusters of particles forming a coating of microscopic or macro-scopic metallic regions of said refractory metal within the near-surface region of the base metal, whereby to provide a protective and wear-resistant surface for the base metal.