Barite as a filler of the friction material in the brake pads.
Barite as a filler of the friction material in the brake pads, mainly have the following advantages:
Product Property: Non qualitative Greyish white powder. Non soluble in water, no toxic, soluble in smoking Sulphuric Acid and slightly soluble in boiling Hydrochloric Acid. Chemical property is stable, it'll reduce to Barium Sulfide when heat with carbon. It will not change color when meeting the hydrogen sulfide or toxic gas in the air.
Specific gravity 4.4,moh hardness 3.0-3.5,a popular low cost filler,although its high specific gravity means a lot of barite is required to fill a little space.Increase density some customers still think a heavier block is superior to a light weight block!Relatively inert high heat stability.
Improves wear,lowers friction level a little.Many of the best formulas on the market are heavily loaded with barite.Yet some manufacturers have difficulty making products with more than 5%.The secret is in the process.Barite is normally a fine powder(2%〈200mesh,98%〈325mesh)and large quantities produce a dense product impervious to the diffusion of gases during baking.Those manufacturers using copious amounts of barite rarely open bake above 345F otherwise blistering would occur.To bake at higher temperatures requires the extra expense of confined baking on baking forms.Beware,barite can be contaminated with metal oxides like silicon and iron oxides.The more silica in the barite the higher the friction level of the finished products.Barite with silica content at say,10% is not necessarily bad.Just recognize it is there and it is affecting friction level. Making sure your supplier sells a consistent product. In some places what is sold as barite is, in fact, a mixture of barium and strontium sulphates. This does no have to be bad either. Just don’t switch back and forth from one “barytes” to another.
Physical properties of barite highest density of any extender contributes to particle packing density.
1. Improves holdout.
2. Noise absorption.
3. Contributes to improved adhesion.
4. Extremely low solubility chemically inert.
5. Not affected by acids or alkalis.
6. Insoluble in water.
7. Low reactivity with binders(extremely low MgO and CaO content).
8. Low oil absorption low resin demand/reduction in needed binder low moh’s hardness.
Oil Absorption :