Methods for Improving the Coating adhesion of Chrome Plating on TC6 Titanium Parts

Titanium and its alloys are very reactive metals, it ' s easy to generate a natural oxide film on their surfaces, and its difficult to obtain good coating adhesion in plating process. Peeling and blister oflen curred after the chrome plating process for a certain model aircraft landing gear（ TC6 titanium parts hich has seriously affected normal delivery of the product. Through analyzing influencing factors of the coating adhesion, several commonly used methods for improving the adhesion are briefly summarized, and methods for detecting the adhesion are briefly introduced

Titanium and titanium alloys have a high strength-to-mass ratio, excellent corrosion performance, and good mid-temperature performance. They have been widely used in various fields, especially the aerospace industry. 2. However, due to their poor wear resistance, the surface is easy to scratch and bond. , Poor welding performance and other shortcomings limit its application range. At home and abroad, the electroplating process is usually used for surface treatment of titanium and titanium alloys to improve the surface properties of titanium, give it new physical properties, and expand the scope of application of H. For example, chromium plating or electroless nickel plating on titanium and rental alloys can increase the surface hardness and improve wear resistance; copper or silver plating can improve the surface condition of parts under high-temperature load-bearing conditions, preventing glue bonding and micro-seismic corrosion. This is very important for titanium parts connected by mechanical methods, such as compressor discs, blades, etc.; in the aerospace industry, gold-plating titanium parts can improve their surface light reflection performance; copper or nickel plating can change normal titanium Brazing performance of parts 3. Titanium is a very active metal, but usually titanium and titanium alloys show stable properties. This is because titanium has a strong affinity with oxygen and nitrogen in the air, and it is easy to A thin and dense passivation film is formed on the surface. When titanium alloy electroplating, in order to obtain a coating with good bonding force, the passivation film on the surface must be completely removed, but the oxidation rate of titanium is fast, and the passivation film is removed It will regenerate at the moment, which is also the main reason why titanium alloy has excellent corrosion resistance. At the same time, this oxide film also makes it difficult to electroplating on titanium alloy. If electroplating is carried out in accordance with the conventional process, it will not be able to obtain good adhesion. Coating. For this reason, this work focuses on experiments to summarize some methods that are beneficial to improving the bonding force of the chromium layer of titanium alloy parts.