Obtaining uniform ceramic-like coatings on compact details made of metal alloys of the valve group by microarc oxidation in the internal cavities of the counter electrodes

Abstract

Background. The object of the study is ceramic-like coatings formed by microarc oxidation on details made of valve metal alloys. The subject of the study is the processes of formation of the structure and properties of ceramic-like coatings when they are obtained without the use of traditional electrolytic baths in the internal cavities of special counter electrodes. The purpose of the study is to establish the possibility of obtaining highquality ceramic-like coatings on compact details made of valve metal alloys. Materials and methods. During the research, ceramic-like coatings were used on spherical, cylindrical and flat surfaces of details made of AMg3 and VT5 alloys, in which thickness and hardness were measured using a PMT-3M micro hardness tester. Results. Studies have found that the thickest and most uniform coatings are formed in the cavities of the counter electrodes corresponding to the shape of the oxidized details, but exceeding the corresponding external dimensions of the details by 8-20 mm, with the flow rate of the solution passing through the counter electrodes 4-10 liters per minute per 1 dm2 of the oxidized surfaces of the detailss with the mandatory change in the direction of the flow of the solution to the opposite after half processing time. Conclusions. Microarc oxidation of compact details made of valve metal alloys in the internal cavities of the counter electrodes ensures the formation of more uniform ceramic-like coatings on them compared to traditional technology. Micro-arc oxidation of valve metal alloy details in the cavities of counter electrodes requires a smaller production area, is associated with a lower risk of harm to health, can be implemented without exhaust ventilation, water cooling and emergency power outage, but requires special equipment.

Keywords

• valve metals
• aluminum
• titanium
• microarc oxidation
• electrolytic bath
• counter electrode
• coating
• thickness
• hardness