Is TiCN resistant to hydrochloric acid, formic acid and hydrofluoric acid? I'm going to mix powder particles with a kind of powder high-speed steel to prepare steel-bonded cemented carbide. I want to know about TiCN. TiCN (titanium carbonitride) is a hard coating material with excellent wear resistance and corrosion resistance, which is widely used in tools, molds and other parts that need high strength, high hardness and good wear resistance. Regarding its resistance to specific corrosive chemicals, we can analyze it from its chemical structure and general performance characteristics.

Tolerance of TiCN to corrosive acids

Hydrochloric acid (HCl): Hydrochloric acid is a strong inorganic acid, which is very corrosive, especially to metal materials. As a hard ceramic material, TiCN has better corrosion resistance than metal materials, but long-term contact or high-concentration hydrochloric acid environment may still lead to surface corrosion or erosion, especially at edges or defects. Therefore, although TiCN has certain corrosion resistance, it is necessary to evaluate the specific working conditions and take additional protective measures when it is used in hydrochloric acid environment.

Formic acid (HCOOH): Formic acid is a weak organic acid. Although it is less corrosive than hydrochloric acid, it can still corrode some metals and alloys. Because of its high chemical stability, TiCN has better tolerance to formic acid than most metal materials in theory, but under certain conditions, long-term exposure may still cause slight surface changes.

Hydrofluoric acid (HF): Hydrofluoric acid is a very corrosive inorganic acid, which can react with most metals and their oxides and even corrode glass. Although TiCN is corrosion resistant, its resistance to hydrofluoric acid, a special acid, is relatively weak. Hydrofluoric acid can react with most silicon-containing substances and many metals including titanium alloys, so TiCN may have poor tolerance in hydrofluoric acid environment and be easily corroded.

Preparation of steel bonded cemented carbide

You mentioned that mixing powder particles (assuming TiCN) with a kind of powder high-speed steel to prepare steel-bonded cemented carbide is a typical powder metallurgy process, which usually involves the following steps:

Powder selection and pretreatment: First, choose proper TiCN powder and high-speed steel powder. The powder should have high purity, fine particle size, uniform chemical composition and good fluidity. TiCN powder may need surface modification to improve its bonding performance with high speed steel powder.

Mixing: TiCN powder and high-speed steel powder are evenly mixed according to a predetermined ratio. This step may need to be carried out in special mixing equipment to ensure that the two powders are fully and evenly distributed.

Molding: the mixed powder is pressed or injected to form a green body with the required shape. The choice of molding pressure needs to consider the powder fluidity and the density requirements of the final product.

Sintering: the green body is densified by liquid phase sintering process in powder metallurgy. In this process, the powder particles melt at high temperature and re-solidify through the binder phase, forming a compact whole. It is necessary to accurately control the sintering temperature and time to ensure the distribution and properties of hard phase (TiCN).

Heat treatment and post-treatment: The sintered product may need further heat treatment to optimize its mechanical properties and microstructure. In addition, according to the application requirements, post-processing steps such as machining and coating may be required.

Matters needing attention

When mixing TiCN and high speed steel powder, it is necessary to consider their compatibility, and how to ensure the uniform distribution of hard phase and the full formation of bonding phase, so as to obtain good mechanical bonding and interface bonding.

Considering the corrosion resistance of TiCN, the comprehensive corrosion resistance of the final composite should be evaluated in a specific application environment, such as exposure to the above corrosive acids, and corresponding design or surface treatment measures should be taken to enhance its durability.

In the whole preparation process, it is very important to control the impurity content and the stability of process parameters to ensure the product quality.