The Ion beam enhanced deposition (IBED) process is a new metal coating process that can be used to effectively coat tableting punches and dies with a variety of hard, wear and corrosion resistant coatings. IBED coating technology is ideal for use on tableting tooling and has two main advantages over conventional metal coating methods:
1.) IBED coatings can be applied at temperatures that do not exceed 150 degrees Fahrenheit, thus maintaining the original integrity of the tooling, including exact dimensions and bulk hardness. 2.) IBED coatings replicate the tooling's original surface finish exactly, thus eliminating the need for post-coating repolishing.
Unlike conventional electro- chrome plating or high-temperature vacuum coating processes, IBED is entirely a physical process (chrome plating and vacuum coating are chemical and thermal processes, respectively). Ion beam enhanced deposition processing combines the benefits of thermal diffusion processing and conventional coating technologies because the coating atoms first penetrate into the substrate to form a case layer in the surface, and then are grown out from this case layer as a thick coating. Driven in kinetically instead of thermally, IBED coatings are "ballistically bonded" to the substrate, thus forming a metallurgical bond that is much stronger than a mechanical or chemical bond.
The IBED coating process is implemented by the simultaneous bombardment of a growing coating with an independently controllable beam of energetic atomic particles. The growing coating is generated either by vacuum evaporation or ion beam sputtering. The independent beam of particles consists primarily of charged atoms (ions) extracted at high energy from a broad beam ion source. Beams of either inert species (Ne+, Ar+, or Kr+) or reactive species (N+ or O+) can be utilized for the process.
Because control of the ion beam is independent of the coating vapor flux, a high degree of control over coating nanostructure can be achieved. This allows optimization of coating properties such as adhesion and composition, and guarantees that the properties can be duplicated repeatedly. Essentially a line of sight process, sources of the reactant fluxes are located so that they simultaneously illuminate the components to be coated. The components are mounted to an angling, rotating platen assembly that is used to uniformly expose all surfaces of the components to both reactant fluxes. The entirely physical nature of the coating process allows temperatures to be held under 150 degrees Fahrenheit. This removes the possibility of deforming structural integrity and altering the precise dimensions critical to optimizing pharmaceutical tooling performance.
A variety of types of metallic and hard ceramic coatings can be deposited on the working surfaces of punches and dies. The metallic coatings include chromium and nickel, and the ceramic coatings include metallic nitrides like titanium nitride and chromium nitride. For most tableting applications the family of hard ceramics is the coating of choice. They are much harder and abrasion-resistant than nickel or even chrome plating, and provide a corrosion-resistant seal on all coated surfaces.
Because of the hardness and durability of the coatings, the wear and corrosion experienced during normal tableting operations does not degrade and roughen the tooling surface and the tableting tooling performs better and longer. If powders begin to stick because of physio-chemical adhesion, the coated surfaces can be cleaned with detergents, solvents, or mild abrasives without the risk of scratching or roughening the original surface finish. The use of IBED performance coatings offers an excellent way to preserve the critical surfaces of punches and dies thereby improving tableting efficiency and manufacturing productivity.