Surface modification of WE43 Mg alloy via combination of cold spray and micro-arc oxidation for wear related applications at high temperatures.

This study investigates the high temperature wear behaviour of a WE43 Mg alloy after covering it with single and dual layer coatings. For this purpose, cold spray and micro-arc oxidation processes were employed individually and sequentially. Single-layer coatings fabricated by cold spray and micro-arc oxidation processes were Al/Al 2 O 3 composite and MgO-based ceramic, respectively. Sequential application of cold spray and micro arc oxidation processes induced dual layer coating upon synthesizing an external Al 2 O 3 –based layer over the Al/Al 2 O 3 composite layer. Results of the wear tests conducted under the load of 2 N revealed the superior resistance of the dual layer coated sample against the rubbing action of the counterface compared to single layer coatings. Thus, the presence of a relatively hard and tough external Al 2 O 3 -based layer over the Al/Al 2 O 3 composite layer sustained protection up to the temperature of 320 °C, where the dominant wear mechanism was fatigue wear. However, the increase in the test temperature to 350 °C caused detachment of the external Al 2 O 3 -based layer. Reduction of the wear test load from 2 to 1 N resulted in the remaining of external Al 2 O 3 -based layer intact with the underlying Al/Al 2 O 3 composite layer even at a test temperature of 350 °C. It is therefore concluded that the combination of cold spray and micro-arc oxidation processes is promising to broaden the reliable use of WE43 and other Mg alloys in wear related applications at high service temperatures. [Display omitted] • Sequential application of CS and MAO processes formed dual layer coating on WE43. • Dual layer coating provided superior protection against wear up to 320 °C under 2 N. • Protectivity of dual layer coating is sustained at 350 °C under 1 N. • Dual layer coating is promising for high temperature wear related applications. [ABSTRACT FROM AUTHOR]