Diamond nanogrinding

Abstract

Nanoscale fabrication requires a substrate made from an engineering material to be truly flat so that “bottom-up” nanofabrication techniques such as lithographically induced self-assembly and soft lithography can be used to deposit nanofeatures. The coating of piezoelectric materials with sub-micron size diamond particles has enabled the production of truly flat substrates so that nanofeatures can be created on engineering materials using a new manufacturing process known as “piezoelectric nanogrinding”. The principle of the process relies on applying an electric current to the diamond coated piezoelectric material that causes the material to strain. When the diamond-coated piezoelectric material is placed in close proximity to the substrate, the diamonds remove extremely small fragments of the substrate when the electric current is applied to the material. The magnitude of the applied current controls the material removal rate. The process can be used to process biomedical materials especially in the production of nanoscale ducts and channels in micro-and nanofluidic devices. To achieve the generation of truly flat surfaces, the process must be executed within a specially constructed vibration dampening space frame. The chapter describes the principle of the process of nanogrinding using coated piezoelectric materials, and correlates the wear of diamonds with stresses induced into the diamonds when an electric current is applied to the piezoelectric in order to remove very small amounts of material. The removal of material can also be performed using a porous tool with abrasive materials embedded in them such as diamonds that increases the material removal rate as long as the porous tool is engineered in such a way that the loss of abrasive fragments is eliminated. This is achieved by laser assisted dressing, by engineering the bond of the porous tool to resist wear, and by laser assisted microstructural modification of the surface of the porous tool. The chapter describes how the bonds in porous tools are engineered to minimize abrasive grain loss and how vitrified bonding bridges can be processed using a laser to form extremely sharp nanoscale cutting wedges. The porous nanogrinding tool can be bonded to a piezoelectric material so that it can be used in the piezoelectric nanogrinding process.