Evaluation and optimization of sol-gel coatings for oil and gas applications

摘要

Corrosion is a major oilfield flow assurance problem. Organic paints are often used in oil production environment as a barrier to corrosion. In recent studies sol-gel materials draw increasing interest due to many promising properties like hardness, durability, scratch resistance and thermal stability. Beside the protection of metals and its alloys in corrosive environments, sol-gel-based coatings also exhibit high potential as an alternative to coatings that contain toxic compounds like chromate. The objective of this work is to optimize the physico-chemical properties of sol-gel derived coatings for oil and gas related environments with particular attention to their corrosion resistance properties. To evaluate the protective properties carbon steel X65 and stainless steel 316L coupons coated with inorganic coatings and hybrid materials were subjected to a highly corrosive environment. The kinetics of the degradation process were monitored throughout by electrochemical impedance spectroscopy (EIS). The obtained results were compared to the performance of organic coatings under same conditions. Besides EIS, electron microscopy was used to characterize the coating morphology before and after exposition to the corrosive environment. Chemical changes of the coating materials were determined by Raman spectroscopy. The achieved data allow to understand the failure mechanisms of these coatings and help to improve the formulation to enhance their resistance to corrosion.