Should brake pad adhesives be made of green carborundum, black carborundum, white fused alumina or brown fused alumina?

Should brake pad adhesives be made of green carborundum, black carborundum, white fused alumina or brown fused alumina?
In the field of brake pad adhesives, green carborundum (GC) and brown fused alumina (BFA) are better choices, while black carborundum (C) and white fused alumina (WFA) are less applicable. The specific analysis is as follows:
‌1. Detailed explanation of preferred materials‌
‌Green carborundum (GC)‌
‌Advantages‌:
‌Highest hardness‌ (second only to diamond), excellent friction performance, can significantly improve the wear resistance of brake pads‌;
‌Strong chemical stability‌, still maintains performance at high temperature (＞1600℃), suitable for high-frequency heating environment of braking‌;
‌Concentrated particle size‌ (such as F1000 mesh), can form a dense wear-resistant layer and reduce brake loss‌.
‌Application‌: Core material of wear-resistant layer of motor vehicle/aircraft brake pads‌.
‌Brown fused alumina (BFA)‌
‌Advantages‌:
‌High toughness‌, can withstand greater pressure, and improve the structural strength of brake pads‌;
‌Outstanding cost-effectiveness‌, lower cost than white corundum, suitable as reinforcing filler‌.
‌Application‌: Added to adhesives to enhance friction stability and extend life‌.
‌Second, secondary or unrecommended materials‌
‌Black carborundum (C)‌
‌The hardness is close to that of green silicon carbide, but the toughness is lower. It is mainly used for processing low-strength materials such as glass and ceramics. It is easy to break in brake pads due to brittleness‌.
‌White fused alumina (WFA)
‌High hardness but poor toughness‌, mainly used for precision grinding (such as metal polishing), lacking the impact resistance and friction stability required for brake pads.
3. Comprehensive recommendations
Green carborundum is the first choice: used for the wear-resistant layer on the surface of the brake pad, directly improving the braking performance and durability;
Brown fused alumina is used as a composite filler to enhance the toughness of the matrix and optimize the cost;
Avoid black carborundum/white fused alumina: the former is mismatched in application scenarios, and the latter does not meet the requirements.
Key points: Brake pad adhesives need to balance hardness, toughness, and temperature resistance. The combination of green carborundum + brown fused alumina can cover the core needs while ensuring economy.