查看“Valenka7857”的源代码

Various ways of Corrosion Testing

All metals and certain polymers and ceramics are inclined to corrosion, which is typically produced by the existence of moisture in the air or direct experience of water. In metals this process is oxidation: the alteration of electrostatic charge where oxides or salts are produced, resulting in damage to the structure of the metal. Rusting, the creation of red oxide in an iron structure, is a common instance of this. The phrase 'degradation' is applied to the corrosion of non-metals, even so the process is the same: the corroding material surrenders electrons in a chemical reaction and drops its structural integrity. Corrosion testing can be applied for the following sorts of damage. Galvanic corrosion develops when two metals come into contact in a electrolytic medium or one metal is subjected to two different electrolytes. Microbiologically Influenced Corrosion is caused by micro-organisms assaulting a metallic or non-metallic material either with or without the presence of oxygen; by way of example Accelerated Low Water Corrosion damages steel piles round the low-water mark, leaving behind an orange sludge for a deposit. Aerospace materials, engines or power-generation materials are normal instances of substances at risk from High Temperature Corrosion. Metal Dusting takes place in high-carbon-dioxide contexts, developing a tell-tale film of graphite on metal and reducing the metal to powder. Corrosion testing requires the promotion of degradation in test samples to find out the extent and rate of any damage by corrosion within the environment. Accelerated Corrosion Testing is an approach intended to calibrate the long-term effects on a system of alternating wet and dry cycles, creating the production of partially dry corrosion agents that aggravate degradation in the system. Typical could be the ISO 11474 test, which employs an outside intermittent salt water spray. Weld testing for corrosion damage or any other structural compromise can be carried out via Dye Penetrant Inspection. Penetrant is applied to a test surface and left for 5-30 minutes. Developer, either dry powder or Non-Aqueous Wet Developer (e.g. acetone), draws penetrant from defects in a visible ‘bleed-out’ process. Alternative weld testing methods include Magnetic Particle Testing, X-rays, 3D X-rays and microscopy: all considered as Non-Destructive Inspection procedures. [http://rotechlabs.co.uk/ impact tests]