Microstructure and Properties of New Developed Fe-Cr-C-B Powders for Wear-Protection Purposes

In wear protection of machinery parts from cement-, mining-, metallurgy- and agriculture industry it is state-of-art to apply durable and cheap coatings with alloys from the system Fe-Cr-C-B. Since these parts are often exposed to extreme abrasive wear there is a need for thick coatings which are usually welded with cored wires. These wires can also be designed for the use in arc-spraying or flame spraying process to produce coatings within the range from 0.2mm to some mm. Due to the characteristic of both processes are the spraying results not always suitable for all technical requirements which often need more dense coatings with higher bond strength. In this article the development works on an effective manufacturing method of new completely alloyed Fe-Cr-C-B powders which can be applied with HVOF spraying techniques is presented. To achieve a high wear protection the content of chromium lies in the range of 30weight% and carbon content is about 5weight% which causes a unique powder structure and coatings with a homogeneous high carbide content. The powders and coatings are examined by metallographic analysis including SEM microscopy. The tested wear and corrosion behaviour is presented and underlines the use of this material for several wear protection purposes. Besides this it is discussed how far these completely alloyed powders - manufactured by an effective process - can partially substitute conventional carbide coatings.