Presumably everyone has a lot of knowledge about PVC fo […]
Presumably everyone has a lot of knowledge about PVC foam board, so today we will talk about the roughening of PVC boards. What is the answer to this question? Please see the specific explanation below:
Whether it is mechanical roughening or chemical roughening, the purpose is to roughen the non-metallic surface to increase the bonding force between the surface and the metal coating. The metal coating is grown from the surface of the electroless coating, and whether the electroless coating can completely form a complete coating on the surface depends on the effect of roughening. In fact, the term "coating bonding force" refers to the bonding force between the electroless plating layer and the substrate to be precise. Obviously, the larger the surface area, the larger the contact surface between the plating layer and the substrate, and the stronger the bonding force. The roughening process greatly increases the surface area of non-metallic materials, so that the crystals of the electroless plating layer can effectively grow on the surface to become a continuous plating layer.
The reason why chemical roughening has stronger binding force than mechanical roughening is that the surface roughening morphology after chemical treatment is different from the surface after mechanical roughening. Generally speaking, the surface roughening form formed by mechanical roughening is many bowl-shaped small pits, that is, semi-circular pits. We assume that the spray material used is completely circular. According to the process of mechanical roughening, the best shape of these pits is the semicircular state, but in the actual process, due to the overlap effect, these semicircles will only be incomplete. Dimples that are smaller or smaller than a semicircle. The chemical roughening is based on the dissolution of surface materials. The shape of the pits left after the dissolution is often larger than a semicircle, and the pits formed are not bowl-shaped but pot-shaped. Inferring from this point alone, it can be known that the surface area obtained by the chemical roughening method is larger than the surface area obtained by the mechanical roughening method. More importantly, the surface shape obtained by the chemical roughening method produces a locking effect after the plating layer grows on it. It is also called the "dovetail effect" or "anchor effect". This effect is most obvious in ABS plastics.
PVC is a very versatile plastic and is most used in the construction industry. It can be made into products of different hardness according to needs. What is mentioned here is mainly rigid PVC. , It has good chemical resistance, but its mechanical strength decreases with the increase of temperature, so it cannot be used continuously above 601. It has poor solvent resistance and can be used for pre-roughening or surface modification. A strong oxidizing type should be used for the roughening solution. Two formulations are introduced below. Alcohol, carbon tetrachloride, and cyclohexane can be used for pre-roughening. Then use chromic acid roughening solution for roughening.