A common misconception about coatings is that wear resistance equals impact resistance, such as when using heavy objects for striking. We all understand that harder materials are more brittle, and the more brittle they become, the more prone they are to cracking. Take sealing rings as an example: they were traditionally processed through two wear-resistant methods—inlay tungsten steel or silicon carbide inlays. However, during assembly and use, these tungsten steel and silicon carbide inlays often crack easily. Why do such hard materials crack so easily? The answer lies in excessive brittleness—especially for ceramic products, where the brittleness is even more pronounced.

A customer once damaged a coating by hammering it with a metal rod, telling me: "This coating is too soft—it breaks when struck." I explained for long time, but he stubbornly insisted hard materials can't be damaged. I often compare coatings to tempered glass, saying: "If you think applying tempered glass to products works, then coatings should work too." Of course, some impacts aren't problematic—like plastic particle impacts—which we assess based on actual operating conditions. However, coatings aren't suitable in harsh environments. one customer's piston rods frequently broke despite have coating application. After thorough field inspections, we discovered iron fragments from production processes were lodged in the rods. Though no high temperatures or corrosion existed, this situation proves coatings alone can't ensure adequate protection. Relying solely on coating zones isn't enough.