Polymer phosphate passivator

The primaiy role of sulfur species in the tribochemical processes is passivation by sulfur species on nascent surfaces caused by a severe wear process (extreme pressure conditions) Fe2+ + S2" - FeS, the heat of formation AHf (FeS) = -1.04 eV. The sulfide can prevent adhesion and also the attack of oxygen species, AHf (FeO) = - 2.82 eV (Mori, 1995). There is enough sulfur in engine oil to initiate acid-base reactions in the formation of zinc sulfide (Martin, 1999). Organic sulfur species other than in thiophosphate form can react with the ZnO produced by the phosphate reactions according to the following ZnO + S2 - ZnS + O2. The zinc sulfide can also be directly produced if the polyphosphate contains sulfur atoms in the polymer chain (thiophosphate), for example ... 

The waterborne basecoat consists of a urethane or an acrylic dispersion with passivated aluminum for metallic glamour. The aluminum must be passivated to prevent reaction with water and the evolution of hydrogen gas. Passivating agents can include polymers, hexavalent chromium (now mandated for removal), or phosphate esters. The basecoat is pre-baked (with infrared or thermal ovens) to release the majority of the water prior to clear-coat application. 

Electrodeposition of conducting polymers on copper has been investigated by several groups, and various salts have been tested to achieve the electrochemical polymerization of pyrrole from aqueous solutions in a one-step process. No serious difficulty was found, and electrolytes used previously on iron, such as oxalic acid [115,116], salicylates [117,118], and tartrate [119] were found suitable for PPy electrodeposition on copper and its alloys aqueous phosphate solutions were also found to provide highly adherent and homogenous films [120]. In all cases, PPy electrodeposition occurred after the preliminary passivation of copper through a mixed copper salt, copper oxide, or copper hydroxide layer. A two-step process, where an oxalate-doped PPy underlayer (PPy-Oxalate) is first deposited, followed by a dodecylbenzenesulfonate-doped PPy layer... 

The VC was first explored as an electrolyte solvent,which affords a good electrolytic conductivity due to its extremely high relative permittivity (e = 127). However, it became a typical compound as an anode passivation film-forming agent, after it was found that the addition of a small amount of VC suppressed gas evolution during the initial charge with the enhanced cycle efficiency, and protected the decomposition of reduction-susceptible solvents such as trimethyl phosphate (TMP). The excellent stability of the passivating layeE was demonstrated by the fact that the addition of 1 wt% of VC in 1 M LiPE /EC + DMC + DEC (33 33 33 wt%) improved the cycle life of commercial lithium-ion polymer ceUs. ... 

---