Novel composite coating technology in primary and conversion industry applications

Abstract

Historically, electroplated coatings have always represented the most cost-effective method for applying deposits of metals and alloys that were pure and dense, mirroring in general the properties of the parent metal. For engineering purposes, particularly in conversion industries, such as steel manufacturing, and primary industries, such as oil extraction, coating specifications and expectations far exceed conventional coating capabilities. In response to these requirements, a composite coating technology has been developed, which consists of a hard metal component from the tungsten carbide family of coatings and a hard refractory oxide layer produced from a slurry coating. Capable of functioning in extreme environments where temperature, corrosion, abrasion, fatigue, friction and erosion are merely starting blocks in the design of a coating system, this composite coating technology shows significant technical and commercial advantage. In the oil exploration and extraction industry, field studies have shown the composite coating to exceed by two orders of magnitude the life expectancy of conventional coatings in high-temperature, heavy particulate-laden fluids, which are therefore very abrasive, with salinity in excess of 360000 ppm of chloride ions. In the steel industry, continuous casting mould plates have shown an increase in life expectancy of between four- and eight-fold. With virtually unmeasurable low wear rates, there are marked improvements in the downstream surface quality of the billets and slabs, while at the same time the integrity of the original copper asset is maintained.