Study On The Stability Of SiC Oil-based Precision Lapping Suspension

In the field of precision grinding and polishing,silicon carbide particles(SiC)are used as abrasives on a large scale in the past several decades.However,the application of SiC powder is greatly limited due to its super-hydrophilic surface.Therefore,in terms of the researches on SiC powder,the water-based grinding fluid are much more than oil-based grinding fluid.With the increasing demand for oil-based grinding fluid in machinery manufacturing,the oil-based grinding fluid are concerned by many fields.In the article,SiC powder is selected as abrasives to discuss the suspension stability,which is the key research direction in this work.Since SiC powder is easliy agglomerated in organic medium,this paper analyse the suspension stability on two sides: the modification of SiC powder and suspension stability of powder in organic medium.On one hand,SiC powder has small particle size and large specific surface area which makes it unstable.As a result,KH570 is used as silane coupling agents to modify the surface of SiC powder.At last,double coated is used for a better hydrophobicity.On the other hand,the effect of hyperdispersant and thickening agent is explored to improve the stability of suspensions.To analyze the coating effect of KH570,the contact angle measurements were used to measure the hydrophobicity of SiC powder.Subsequently,the microstructure and morphology of SiC powder before and after modification are analysed by XPS,FTIR and SEM.And then,this article probe the modification mechanism of double-coated powder by TG-DSC analysis of OP-7.Finally,a series of experiments are operated to determine the best range of the double ester,hyperdispersant and thickener.In the treatment schemes of KH570,the experiment indicated that when the content of KH570 was 2.4%,the reaction time was 5 h and the reaction temperature was 90 ?,the modified SiC powder had better hydrophobicity.Compared with using KH570 alone,SiC powder modified by KH570 and OP-7 showed better water resistance,and also an increased contact angle from 73.8° to 136.4°,resulting thus an improved hydrophobicity.A later experiments indicated that when the content of double ester was 15%,the content of hyperdispersant was 1%~3% and the content of thickener was 10%,the suspension had better suspension stability.