Development of wear resistant coatings using LD slag premixed with Al2O3

Linz-Donawitz slag (LDS) is a major solid waste generated in huge quantities during steel making. It comes from slag formers, such as burned lime/dolomite and from oxidizing of silica, iron, etc., while refining the iron into steel in the LD furnace. This work aims at utilization of waste LDS to develop surface coatings by plasma spraying technique. This technology has the advantage of being able to process various low-grade ore minerals to obtain value-added products and also to deposit materials, generating near homogeneous coatings with the desired microstructure. Coatings prepared for this investigation are characterized in terms of their thickness and adhesion strength. Coatability of LDS is assessed by finding deposition efficiency. Erosion wear characteristics of these coatings are also studied. Premixing of Al2O3 powder with LDS is found to substantially improve the interfacial adhesion, and the maximum adhesion strength of 33.77 MPa is recorded in such coatings with 30 wt% of Al2O3 content in the LDS-Al2O3 mix. It is found that the operating power levels of the plasma torch affect the adhesion strength, coating deposition efficiency and mean thickness of the coatings. This work opens up a new avenue for utilization of LD slag as a potential coating material.