Complete Guide to Metal Surface Treatment Processes: Comprehensive Analysis from Principles to Applications

Complete Guide to Metal Surface Treatment Processes: Comprehensive Analysis from Principles to Applications

Metal surface treatment is a key process that optimizes the surface properties of metals through physical, chemical, or electrochemical methods. Its core purposes are to enhance corrosion resistance, wear resistance, aesthetics, and adhesion. The following sorts out the principles and application scenarios of mainstream processes to help you fully understand the core value and applicable needs of various processes.

Electrochemical processes: represented by electroplating and anodizing. Electroplating deposits a metal coating on the workpiece surface through electrolysis, such as galvanizing for rust prevention and chrome plating for hardness improvement, which is widely used in auto parts and hardware accessories; anodizing is mainly applicable to aluminum alloys, forming a dense oxide film through electrolysis that can be dyed for beautification, and is often used in doors, windows, and electronic device casings. These processes have strong adhesion and excellent protective performance.

Chemical conversion processes: including phosphating, passivation, etc. Phosphating forms a phosphate protective film on the metal surface through chemical reactions, enhancing coating adhesion, and is a core pre-treatment process before painting, suitable for auto bodies and construction machinery; passivation targets stainless steel, removing surface oxide scale and forming a passivation film through chemical reagents to improve corrosion resistance, mostly used in food machinery and chemical equipment.

Physical and mechanical processes: such as sandblasting, polishing, and spraying. Sandblasting uses high-speed abrasive impact to clean the surface and increase roughness, suitable for precision instrument casings; polishing improves surface gloss through grinding, often used in decorative metal parts; spraying atomizes the coating and adheres it to the surface through high pressure, divided into powder spraying and liquid spraying, suitable for architectural hardware and home appliance casings, with both protection and aesthetics.

When selecting a process, it is necessary to consider material characteristics, service environment, and performance requirements: electroplating and passivation are preferred for corrosive environments; anodizing and polishing can be selected for decorative needs; phosphating and sandblasting are preferred for pre-painting treatment. Reasonable selection of processes can greatly extend the service life of metal products and increase product added value.