Tribological Analysis of Manganese Phosphate Coating on Steel Pistons for Internal Combustion Engines

Aluminum, steel, and cast iron pistons all function in the automotive market, each possessing specific properties. The most common type of piston is aluminum, but in recent years, there has been a noticeable increase in the production of steel pistons. One of the manufacturing processes used in the production of steel pistons is manganese phosphating. The coating obtained through this process provides corrosion resistance and enhances the sliding properties of the working surfaces, thereby extending the lifespan of the internal combustion engine piston. When conducting a tribological analysis of the surface created in the chemical process, it is essential to pay particular attention to the grain size and the thickness of the coating to ensure that the pistons have the appropriate properties. The analysis was carried out using both micro and macroscopic examination. A grain growth analysis was conducted over time, and a comparative analysis was performed to evaluate the impact of operating time in an internal combustion engine on the working surface of the piston. The grain size affects the amount of oil carried during operation. These grains tend to wear down during operation, losing their properties, and the degree of change occurring on the surface was described using a piston with a mileage of approximately 100,000 kilometers as an example.