Wall Colmonoy Ltd has developed a new generation of Iron-based powder alloys providing superior resistance to dry wear and excellent corrosion resistance. These alloys are economically interesting because they contain none or very low levels of expensive and market sensitive metals such as nickel and cobalt. These powders are marketed under the trade name Colferoloy. This paper details the properties and advantages of Colferoloy when compared to current “traditional” surface treatment methods and consumables. Metallurgical examination of the Colferoloy deposits showed that the alloy formed sub-micron structures which afford excellent dry-wear resistance, whilst the high chromium content provides good resistance to corrosion. Colferoloy alloys were applied using HVOF techniques to engineering components producing dense coatings with a hardness in the range of 950-1000 Vickers. The cost benefits of using an Iron-based alloy with low density hard phases were studied and comparisons with traditional materials were performed. This study showed that Colferoloy is a viable alternative to current hardfacing alloys and treatments.

Iron based materials are classified as being more health and environmentally friendly as well as cost-effective (material and machining costs) compared to typical materials used for wear protection applications (e.g. cermets). The advantage which is seen in using very fine powders (< 15 μm), is their potential to spray relatively thin, dense near-net-shape coatings with comparable smooth surfaces. This can lead to lower coating as well as machining costs. In this work fine Fe-based powders (-15+5 μm) have been used in order to produce wear resistant coatings for applications in the printing industry by means of air plasma spraying (APS). With regard to oxidation problems of such fine Fe-based materials a shroud for the air plasma spraying system has been developed and deployed. The resulting coatings have been analysed with respect to the microstructure, micro hardness, chemical and phase composition as well as surface roughness (as-sprayed). The economical aspects have also been considered.

Zn, Zn-Al and Zn-Mg coatings have been produced by cold spraying. By careful tuning alloy compositions and spray conditions, dense coatings are produced with a hardness of 200 HV0.01 that are up to four times harder than pure bulk Zn, thus meeting the requirements for print applications. These new developments open opportunities for producing harder and more wear resistant coatings, which may allow for the production of larger number of copies without compromising quality.