The Study Of The Principle And Countermeasure Of Colbat Exposure In Cemented Carbide Tools

Cutting fluid is the important related material in metal cutting process. The influenceof triethanolamine-containing solution on cobalt leaching of cemented carbide tools isstudied with the aid of spectrophotometer and electron microscope equipment in this paper.We have discussed its mechanism, and chosen the effective inhibitor. The result of studyshows:1.In metal cutting process, cutting liquid can leach the cobalt of cemented carbidetools, Especially the influential of triethanolamine-containing cutting liquid is the mostobvious. Triethanolamine additive can leach cobalt from cemented carbide tools. Becausetriethanolamine can coordinate with cobalt ion and form stable coordination compound.This coordination compound accelerates the leaching of cobalt from cemented carbidetools. The leaching of cobalt will reduce the ability of resisting mechanical wallop andworking life of cemented carbide tools greatly.2.Add triethanolamine oleate or borax to the solution can obviously inhibit theleaching of cobalt from cemented carbide tools, and it has a best proportion andconcentration; The mixture of triethanolamine oleate and borax can inhibit the leaching ofcobalt cemented carbide tools better. Because the hydroxyl has been reduced in thetriethanolamine oleate molecule, and the molecule structure becomes bigger, thecoordinate reaction ability reduce between it and cobalt ion. Because the entering of theborax,the hydroxyl ion can combine with some cobalt ion, which have reduced thecoordination probability of triethanolamine oleate and cobalt ion.3.Triethanolamine oleate should not be mixed with molybdic acid sodium, asmolybdic acid sodium can reduce the inhibiting function of the leaching of cobalt oftriethanolamine oleate. Because the reversibility of the esterifiable reaction,triethanolamine oleate compounded may be resolved again, and make the oleic acid andthe sodium ion in the solution combine and form the sodium soap of oleic acid, thus maketriethanolamine distribute in the solution again, which have accelerated the the leaching ofcobalt ion. This has reduced the inhibiting function of triethanolamine oleate instead.Finally we concluded: using the mixture of triethanolamine oleate and borax as theadditive of cutting fluid, can obviously reduce the leaching of cobalt from the cementedcarbide tools, thus improve the working life of the cutter and reduce the danger of the fluidto human body.