Influence of F– Ions as Flux from Different Resources on Vitrified Bond for Cubic Boron Nitride Grinding Tools

Abstract

In this article, the selection of more appropriate flux applied to Na₂O-B₂O₃-Al₂O₃-SiO₂ bonding glass for cubic boron nitride grinding tools was studied. The bending strength of the specimens was tested by three-point bending strength tester and microstructure characteristics of specimens were observed by scanning electron microscopy. Thermal expansion coefficient of bonding glass was tested by high-temperature dilatometer. The results presented that the type of flux had a great effect on the performance of vitrified bond grinding specimens. The refractoriness, fluidity and wettability were improved with the introdution of F^– ions no matter in the form of Na₃AlF₆ or CaF₂. Better properties of vitrified bond, such as refractoriness, fluidity and wettability, could be obtained when F^– ions was introduced in the form of Na₃AlF₆, however, the mechanical properties of specimens was better when CaF₂ was introduced owing to the feasible expansion value of bonding glass with CaF₂. Therefore, the selection of appropriate resource of F^– was determined by various properties of vitrified bond.