Among ceramic oxides, alumina is one of the varieties with the largest consumption and wide application. Plasma sprayed alumina ceramic coating is widely used in industry. This is possible due to the superior properties of alumina itself and the relatively low production costs. Since the main crystalline form of α-Al2O3 in alumina is an inorganic substance with high hardness (Mohs hardness up to 9), the wear-resistant coating is also the benchmark of alumina ceramic coatings.

Alumina ceramic coating has roughly gone through the stages of alumina coating, aluminum oxide titanium coating, and nano alumina coating. The powder is refined from micron to nano and converted from a single component to a composite. The coating structure transitions from a layer to a multi-layer or gradient layer. The use of aluminum oxide plasma spraying to obtain structural composite coatings and functionally graded coatings is one of the hot research areas at home and abroad to study the microstructure, wear resistance, corrosion resistance and high-temperature oxidation resistance of ceramic coatings.

Plasma spraying is a technology for hardening and modifying the surface of materials. It uses a DC-driven plasma arc as a heat source to heat ceramic materials to a molten or semi-molten state and spray them onto the surface of a pre-finished workpiece at high speed, and form a strong surface layer by fastening. The alumino-ceramic coating obtained by plasma spraying has high adhesive strength, low porosity and low surface roughness and is widely used in repair and hardening in various industries.