EB Surface Alloying and Plasma Nitriding of Different Al Alloys

Abstract

Within the last years, considerable progress was achieved in the research field of plasma nitriding of Al alloys. However, due to large property differences between the very hard AlN layer and the soft Al matrix material the load capacity of the nitride layer is limited. Electron beam (EB) surface alloying modifies the chemical composition of the area near the surface up to a certain depth. This, for instance, results in high hardness levels, and therefore this layer acts as support for the hard and wear-resistant thin AlN layer generated by plasma nitriding. In the present study, surface modifications produced by a combination of EB alloying with Fe based additives and plasma nitriding of wrought, cast and spray-formed Al alloys were investigated. After the EB treatment the layers were examined regarding their influence on the structure, the nitride layer growth mechanism, the effect of the EB layer for the support of the AlN layer and the resulting duplex layer properties, e.g. hardness and wear behaviour.

Interfacial bonding of low-pressure plasma-sprayed Fe-based amorphous coating on 8090 Al–Li alloy

“…The range of application of aluminium alloys needs to be expanded and the surface wear resistance of aluminium alloys must be improved. Although aluminium alloys can be surface-strengthened using surface treatments, such as plasma nitriding, plasma electrolytic oxidation and laser surface alloying [5][6][7][8] at present, there are problems such as lower hardness and thinner protective layer.…”

Untersuchungen zum Elektronenstrahl‐Randschichtumschmelzen einer sprühkompaktierten übereutektischen eisenhaltigen Al‐Si‐Legierung

“…Die dabei erreichten Härtesteigerungen sind generell abhängig von den Legierungszusätzen des Grundwerkstoffs bzw. des Zusatzstoffes im Fall des Legierens [19,20].…”

“…In bisher durchgeführten wissenschaftlichen Untersuchungen erfolgten Kombinationsbehandlungen aus Elektronenstrahlumschmelzlegieren mit an-schließendem Plasmanitrieren [19,20]. Die thermische und chemische Stabilität sowie die hohe Schmelztemperatur des Aluminiumnitrids im Vergleich zur niedrigen Schmelztemperatur des Aluminiumwerkstoffs ermöglichen eine Kombinationsbehandlung in umgekehrter Reihenfolge (Nitrieren + Elektronenstrahlumschmelzen).…”

Plasma Nitriding of Spray‐Formed Aluminum Alloys

“…[2] Therefore, the use of sprayformed aluminum alloys is considered. [3,4] The specific production process enables design of a load-related chemical composition in a wide range, e.g., high contents of Fe or Ni for improved heat resistance and higher application temperatures, respectively. Due to their typically high Si contents of between 15 and 35 wt% spray-formed Al alloys have a higher level of wear resistance than conventional Al alloys.…”

“…Due to their typically high Si contents of between 15 and 35 wt% spray-formed Al alloys have a higher level of wear resistance than conventional Al alloys. [3,4] However, if spray-formed Al materials are used in high-load applications, additional surface protection treatments have to be taken into consideration.…”