In the industrial world, diamonds are not only a symbol of wealth and luxury but also a key component in the manufacture of cutting and grinding tools. Now, thanks to the electroplating process, it is easier and more efficient to apply this precious substance to the tool substrate. Diamonds are known for their incredible hardness and scratch resistance, making them a valuable resource in tool production.
Traditionally, manufacturers had to manually set diamonds into tools, a tedious and expensive process. However, with the advent of electroplating, manufacturers were able to create diamond-coated tools quickly and easily.
Electroplating is a process that bonds thin layers of metal to conductive surfaces. In the case of diamond tool production, a layer of metal is applied to the tool substrate, and diamond particles are then electroplated onto the metal surface. This approach not only creates a cohesive bond between the diamond particles and the tool matrix but also ensures a consistent and uniform distribution of diamonds throughout the tool.
The principle behind diamond plating is that when the electroplating solution is energized with the workpiece, diamond particles are deposited on the pre-plated workpiece. The electric field then causes the nickel to break down, releasing nickel atoms that were deposited on the surface along with the diamond particles. Over time, the diamonds on the surface are gradually encased, forming a diamond coating.
According to the process division, the preparation of electroplated diamond tools needs to go through pre-processing, pre-plated, upper sand, unload sand, thicken, and post-processing.
Pre-processing
Pretreatment is a critical step in the electroplating process to ensure the best results and product quality. In the field of metal plating, the two key steps of pretreatment are substrate pretreatment and diamond particle pretreatment. Matrix pretreatment involves a series of steps to ensure that the matrix is clean and free of any unwanted material. The process includes grinding, caustic washing, pickling, activation, cleaning, and drying. These steps work together to remove any oxides, fatigue, or oil stains from the surface of the substrate. This ensures uniform coverage of the nickel layer and improves adhesion to the substrate. Pretreatment of diamond particles is equally important to obtain high-quality plating results. In order to achieve the best pretreatment of diamond particles, a combination of magnetic separation and acid-base mixed treatment is adopted. This removes metallic element and metal compound impurities that can mix in and weaken the inherently weak magnetic properties of the diamond grains. At the same time, oil that may have accumulated on the surface of the diamond particles is removed, improving their wetting properties.
Pre-plated
Pre-plating is to plate a simple nickel layer on the surface of the substrate to act as a transition layer and closely bond with the substrate.
Upper sand
The process of fixing diamond particles on the surface of the substrate by mechanical or physical methods is called sanding. The sanding method is divided into the falling sand method and the buried sand method.
The first method allows sanding to be done on one side of the substrate at a time. This method is very suitable for products with diamond plated on one side. It requires only a small amount of sand, creates a thin regolith, and the top side of the sand is efficient, making it ideal for large-scale production. However, this method is not suitable for cylindrical or irregularly shaped products.
On the other hand, the buried sand method can sand multiple surfaces in different directions at the same time. This technique is more suitable for cylindrical or irregularly shaped products and requires a larger amount of sand. It also results in thick regolith and has lower sanding efficiency.
Unload sand
After the sand loading process is completed, the sand can be unloaded. Upright the substrate and vibrate slightly to shake off the diamond particles that are not firmly adhered to the end face and not consolidated by the nickel coating.
Thicken
The thickening process uses the same plating solution formula as the pre-plating process to further thicken the nickel layer. During the entire pre-plating, sanding and thickening plating, attention should be paid to precisely controlling process parameters such as current, temperature and pH value.
Post-processing
Soak the electroplated diamond tool in acetone solution and rinse with distilled water. Take it out, dry it, and undergo moderate heat treatment to further improve the bonding strength between the nickel plating layer and the substrate, and at the same time increase the hardness of the nickel plating layer.
Post time: Jun-14-2023