Verneuil flame fusion process

Question 1

What is the verneuil flame fusion process?

Answer 1

~ the first commercially successful method of forming synthetic sapphire and ruby, continues to be the least expensive method

Question 2

What happens during this process?

Answer 2

~ powdered Al2O3 is fused in a free flight by an oxy-hydrogen flame and deposits onto a support rod from which a single crystal nucleates and grows

Question 3

What additions make what kind of crystals?

Answer 3

~ + nothing to make clear sapphire
~ + Fe2O3 and TiO2 to make blue sapphire
~ +Cr2O3 to make ruby

Question 4

What are the applications?

Answer 4

~ other than synthetic gemstones, it’s used for jewel bearings in mechanical watches (durable and low-friction components)