In-situ Synthesis of Lead Naphthenate andLead Alkylsalicylate as by Microwave-assisted Technique and Tribological Behaviors

Oil soluble lead naphthenate(LN) and lead alkylsalicylate(LAS) were in-situ synthesized by microwave assisted-technique in liquid paraffin. The tribological properties of LN , LAS and corresponding carboxylic acid were evaluated with four-ball tribo-tester under the condition of high speed (r=1500±10rpm) low load (P=196~392N) and low speed (r=300±10rpm)high load(P=800N). The anti-wear and friction-reducing of LN and LAS as additives were also evaluated with reciprocation tribo-tester. The results indicated that LN additive exhibited good anti-wear property, good friction-reducing efficiency and middling extreme pressure property, and all tribological properties of LN as additive was better than LAS. The reason producing the performance difference of tribological behaviors was analyzed for revealing tribological mechanism, and wear scar surface was characterized with photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Analytical results showed that LN and LAS could formed adsorbing film on steel-steel friction pair and part of film transformed oxidic film protecting the rubbing surfaces from wear by means of tribochemical reaction, but the thickness of films was different.