1. Technical principle
AOC -160 alloy powder is coated on the surface of the sucker rod coupling by special surface treatment technology, to achieve a wear/corrosion-resistant and low-friction coating. Its thickness is more than 0.25mm, the wear resistance ability is over 10 times better than common couplings and reduce 75% abrasion of tubing.

2. Features
1. Self-protection.
AOC coating can ensure that the couplings keep high resistance to wear and corrosion under the complicated downhole conditions.
The coating materials’ components, structures and rigidity are greatly different from tubing, which can prevent and delay initial adhesive wear. High hardness of coating increases coupling’s anti- wear/abrasion ability.
   
2. Tubing protection
The special anti-abrasion elements (ε phase) in AOC-160 coating, during wearing between the coating and tubing, are uniformly adhered to the tubing surface, forming solid lubrication to protect and release the wear on surface and also reduce the friction between the coupling and tubing..

3. Products
⅝、¾、⅞ and 1 couplings are available and special size couplings can be sprayed and treated as required by the customers

4. Application
By June 2008, the bidirectional protection couplings had been widely used in nearly 10000 wells in various oilfields in China. It had been proved in complicated operating conditions and been recognized by customers.