Unraveling The Mysteries Of Passivation in Titanium Alloys

Passivation, a term that may sound a bit strange, actually refers to the process by which a metal is transformed into a state that is less susceptible to oxidation by a specific method, thereby slowing down the rate of corrosion. Among them, a special active metal or alloy, when its chemical activity is significantly reduced, as metamorphosed into a precious metal-like phenomenon, also known as passivation.
In the world of metals, titanium and titanium alloys are known for their excellent passivation properties. In a very short time, they can form a layer of a few nanometers to tens of nanometers thick oxide film, which is like a layer of strong armor, guarding the titanium alloy from the external environment, so that it shows excellent corrosion resistance.

So, how does titanium alloy realize this amazing passivation process? There are three main methods:
First, electrochemical passivation
Imagine that when titanium alloy is exposed to an electrochemical environment, its surface will be oxidized, forming a dense oxide film. This film can not only effectively prevent the corrosion of titanium alloy in chemical media, but also resist scratches during processing. There are two main types of electrochemical passivation: anodic oxidation and cathodic reduction, among which anodic oxidation is more widely used for titanium products, such as titanium cups and titanium chopsticks. It can form a layer of colorless and transparent oxide film on the surface of titanium products, which presents colorful colors through light refraction, making titanium metal materials a fantastic existence.
Second, heat treatment passivation
Heat treatment passivation is the titanium alloy into the high temperature furnace, in a specific time and temperature, so that the surface of the formation of a thick layer of oxidation. Subsequently, through the rapid cooling treatment, this layer of oxidized layer will become more dense, thus greatly improving the corrosion resistance of titanium alloy.
Third, chemical treatment passivation
Chemical treatment passivation includes pickling and chemical passivation two steps. Pickling can remove oil, oxide film and impurities on the surface of titanium alloy, to create favorable conditions for subsequent chemical passivation. Chemical passivation is a titanium alloy into a solution containing specific chemicals, so that the surface of the formation of a layer of dense oxide film, thereby improving the durability and corrosion resistance of titanium alloy.
In the process of pickling passivation, we need to pay attention to the following points: firstly, adequate pre-treatment should be carried out to ensure that the surface of the titanium alloy is free of dirt; secondly, the process parameters in the pickling process should be strictly controlled, such as the ratio of the nitric acid solution and the pickling time, etc.; and lastly, post-treatment should be carried out, including rinsing and drying, in order to remove the residual solution and moisture on the surface.
In conclusion, the passivation process of titanium alloy is an amazing surface treatment technology. It can not only improve the surface quality and material properties of titanium alloy, but also let us enjoy the beauty of the metal while feeling the magic charm brought by technology.