Dynamic Corrosion and Wear Testing of Corrosion Resistant Thermal Spray Coatings and Wrought Materials in Chlorine Containing Conditions with Low pH Values

Thermal spray coatings are widely used in constructions where specific seal material is sliding on the coating surface. Such applications are often highly corrosive and therefore limiting the lifetime and increasing wear of the seal and the coating.

 In this work special test equipment was build up to study corrosion and wear performance of the specific test materials introduced in this kind of low pH and chlorine containing conditions. In the test procedure rotating seal material was forced with certain pressure against the thermal spray coating material and the wear of the seal and the weight loss of the coating material was measured during the test. Coating samples for the tests were prepared using HVAF, twin wire arc spray and atmospheric plasma spray techniques. Several corrosion resistant stainless steel materials were tested as reference together with the thermal sprayed coatings.

 Altogether four different seal materials were tested and the seal material was found to effect to the weight loss of the tested base material during the corrosion wear test. Clear differences in corrosion wear resistance were found between tested thermal spray coatings. Best performance was achieved with plasma sprayed chromium oxide coating compared to the other tested coatings.