First, it is necessary to determine the volume, which takes 100 grams of composite material (we assume the material is non-porous):

90/6,1 + 10/ 3,99 = 14,744 cm3 + 2,506 cm3 = 17,25 cm3

Then it is necessary to divide the volume of each component by the sum of the volumes of both components and multiply the results by 100%:

ZrO2: 14,744x100%/ 17,25 = 85,472%

Al2O3: 2,506x100%/ 17,25 = 14,528%

That's all

There is a good explanation: http://www.cadfil.com/help/html/cadh3rty.htm

Dear Andrey,

Please follow Prof. Vadim's answer. It is quite correct, and I too did the same for my compositions. It is 100% correct.

Wish you good luck.

Dear Andrey,

www.researchgate.net/post/How_to_convert_Volume_Fraction_into_Mass_fraction_or_Mole_fraction

www.researchgate.net/post/how_to_calculate_volume_fraction_weight_fraction_in_polymer_composites_and_mmcs

www.researchgate.net/post/When_do_I_use_weight_percentage_and_when_to_use_volume_fraction_in_composites

You may want to check also the following related discussion: https://www.researchgate.net/post/How_might_I_determine_glass_fiber_content_in_composite

Dear Carlos Araújo Queiroz , thank you very much for the suggested discussion.

Vadim Verlotski when i used this equation I get on a different solution?

This link may help you too

https://onlineconversion.vbulletin.net/forum/main-forums/convert-and-c​a​l