Where is the better Cerium metal powder

Where is the better Cerium metal powder? Many people are unfamiliar with this item, and here's the introduction to it:

Cerium are periodic system first Ι Ι Ι clan subgroup lanthanides, a rare earth element. Atomic number 58. Stable isotopes: 136, 138, 140, 142. Grey metal, malleable. Density: positive crystal 6.9, cubic crystal 6.7. Melting point 799 ℃, boiling point of 3426 ℃

Cerium is a kind of silver-grey and active metal. The powder is easy to ignite in the air and is soluble in acid. Cerium's name comes from the asteroid Ceres' English name, [2]. Cerium is about 0.0046 percent in the earth's crust, which is the most abundant of rare earth elements. Metal cerium is the primary reducing agent.