Papers by Keyword: Nanostructured Ceramic Coatings

Abstract: In diamond wheel precision grinding process, the grinding force of nanoceramic coating materials can be divided into single grain grinding force and wheel unit area grinding force, this paper studied the two grinding force, results showed that, with the increase of grinding depth, grinding wheel per unit area grinding force and single grain grinding force increased. The two kinds of grinding force increased also with the increase of workpiece feeding speed, the normal grinding force and the tangential grinding force decreased with grinding wheel speed increase. grinding parameters, as diamond wheel grit size and binder type, effected also on the grinding force.

Abstract: The paper used indentation fracture mechanics model or cutting model to deal with the grinding removal mechanism of nanostructured ceramic coatings, the interaction between the abrasive grains and the workpiece was approximately regarded as ideal small-scale indentation phenomenon, it was used to evaluate the surface quality in ceramic machined processing that formation of grinding crack and its propagation process, the material removed process and the surface defects of the ceramic grinding, the cutting model proved that although the removed material is usually brittle removal, most of the grinding energy consumption was related with plastic deformation.

Abstract: The surface of the nanostructured ceramic coatings after grinding appears cracks, these cracks will reduce components intensity, and the cause of these cracks is grinding surface residual stress. The surface residual stress makes the distance change regularly with crystal orientation and stress changing on the cognate crystal plane of different crystal grain, therefore the X ray diffraction line offset, according to the size of the offseted position, the residual stress can be calculated by using σ = K • M.

Abstract: Residual stress produced on the surface of nanostructured ceramic coatings when they were grinded by diamond superhard abrasive wheel, these residual stresses affected directly the fracture strength, fatigue strength and corrosion resistance of the ceramic parts, they affected the surface quality of machined ceramic parts, and thus they affected the working reliability and the service life of ceramic parts. The tests show that the distribution of residual stress is directional, the residual compressive stress can make the hardness of the material increase, they can reduce the wear rate of the material, for the tested specimen, grinding surface whole residual stress σ is the sum up original residual stress σ₀ (existed in the part’s surface ) and grinding residual stress Δσ (formed by grinding process.), σ=σ₀ + Δσ.

Abstract: Surface microgrinding of the nanostructured WC/12Co coatings have been undertaken with diamond wheels under various conditions. Nondestructive and destructive approaches were utilized to assess damage in ground nanostructured coatings. Different surface and subsurface configurations were observed by scanning electron microscopy. This paper investigates the effects of microgrinding conditions on damage formation in the surface and subsurface layers of the ground nanostructured WC/12Co coatings. And the material-removal mechanism has been discussed.