Often used in combination with phenolic resins which impart some rigidity and add strength and faderesistance.
经常用于与酚醛树脂的使材料有一定的刚性，提高强度和耐磨性用于弹性的刹车带材料。
2
Aluminum Oxide Specific gravity 2.4 Moh hardness 3. More a filler than an abrasive. Tends to fade, but has good wear resistance. Will polish the opposing surface.
氢氧化铝比重2.4莫氏硬度3。比磨料加得更多的填充物。有衰退趋势，但耐磨性好。将抛光对偶。
3
They are thought as high quality products for their densities are well distributed; aperture is proper, high ductile, high oil resistance, not easy to corrode and fade away, easy to wash and soft.