In the field of super-hard coatings, Diamond-like Carbon (DLC) coatings have long occupied an important position. With their high hardness (above HV 3000) and low friction coefficient (below 0.1), they are highly favored by industries such as mold manufacturing and auto parts production. However, DLC coatings have a fatal flaw - insufficient heat resistance. When the cutting temperature exceeds 400℃-500℃, carbon atoms undergo graphitization, leading to a sharp drop in hardness and rapid tool wear, making them difficult to adapt to ultra-high temperature working conditions above 800℃ such as dry cutting and high-speed machining.
    Against this backdrop, boron-based coatings such as titanium diboride (TiB₂) and cubic boron nitride (CBN) have moved from laboratory to industrial application. These coatings not only boast extraordinary hardness - TiB₂ can reach above HV 4000, second only to diamond - but their core advantage lies in strong chemical inertness. For materials prone to tool adhesion like aluminum alloys, boron-based coatings have almost no chemical affinity with non-ferrous metals. Even under high-temperature friction, they can avoid built-up edge (BUE) formation, delivering extremely high precision in machined surfaces. They have become the ideal choice in fields such as aviation aluminum processing and automotive engine block manufacturing.
    Despite their outstanding performance, boron-based coatings have not yet been widely adopted, with the core bottleneck lying in their extremely challenging manufacturing process. Firstly, boron atoms are small in size, resulting in extremely high internal stress in the coating; improper process control can easily lead to coating cracking or substrate damage. Secondly, the adhesion between the coating and steel or cemented carbide is poor, requiring laboratory-grade cleaning processes and complex transition layer designs. Thirdly, boron is a non-conductive semiconductor, making it difficult to process with ordinary arc furnaces; high-end equipment such as High Power Impulse Magnetron Sputtering (HiPIMS) is required, leading to significantly higher equipment and operational costs compared to traditional coating processes.
    It is worth noting that boron-based coatings are not intended to replace DLC coatings but to form a complementary pattern: DLC still dominates the field of sliding friction and low-temperature lubrication, AlTiN/AlCrN coatings maintain cost-effectiveness in steel cutting, while boron-based coatings focus on extreme scenarios such as non-ferrous metal processing and ultra-high temperature alloy machining. As PVD technology continues to break through the boundaries of element application, boron-based coatings are emerging as a "special forces" solution to traditional process pain points, providing a new technical path for the high-end manufacturing industry.

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