Hexagonal WO3 (h-WO3) has caught a great attention due to its unique tunnel structure. In h-WO3, six-membered rings composed of WO6 octahedra are arranged along the (001) plane by sharing corner oxygens, with formation of open tunnels that have a theoretical intracrystalline tunnel size of 0.39 nm, along the c-axis throughout the entire unit cell.

Molybdenum disulfide(MoS2) is a kind of solid powder which is made from natural molybdenum concentrate powder by chemical purification and changing its molecular structure. It is black with slight silver gray, metallic luster, slippery to the touch, and insoluble in water.

Milling processing is divided into down milling and up milling. Down milling is a milling method in which the rotation direction of the contact part of the milling cutter and the workpiece is the same as the cutting feed direction. Up milling is a milling method in which the rotating direction of the contact part of the milling cutter and the workpiece is opposite to the cutting feed direction.

Molybdenum disulfide (MoS2) is a type of transition metal sulfide with glossy lead gray solid powder. It is synthesized and appears black, which has stable chemical property.