Porosity Test on coating
Porosity test on Coatings applied can have irregularities due to different circumstances. Surface uncleanness, paint differences and dust or air bubbles enclose also causes pinholes, thin spots, cracks etc. To prevent an early breakdown of the coating system causing corrosion underneath.
What Does Porosity Mean?
Porosity is the open spaces between grains or trap in grains in a micro structure — the presence of tiny openings or spaces within a material. Porous materials can absorb fluids or moisture, which causes corrosion. Porosity is a fraction between 0 and 1, typically ranging from less than 0.01 for solid granite to more than 0.5 for peat and clay. It may also be represented in percent terms by multiplying the fraction by 100.
Porosity is a measure of the void spaces in a material, and also is a fraction of the volume of voids over the total volume. It is a phenomenon that occurs in materials, especially castings. It is weld metal contamination in the form of a trapped gas. Porosity causes a casting to leak and makes it unusable for holding pressure in applications like pumps, compressors, transmissions and also plumbing fixtures.
Porosity is used in multiple fields, including : Pharmaceutics, Ceramics, Metallurgy, Materials, Manufacturing, Earth sciences, Soil mechanics, and also Engineering.
There are two types of porosity:
Surface porosity – Occurs on the surface of the metal and also can be detecting with the naked eye.
Subsurface porosity – Occurs within the metal and also can be detect only with specialized testing.
There are many ways to test porosity, such as industrial CT scanning. Pores transmit water, so smaller pores and smaller void ratios are important in increasing barrier performance. In general, high total void ratios result in higher permeability.
Porosity also causes poor results in decorative coatings on structural castings. And also many times porosity is the root cause of coating failures, which manifest themselves as surface pitting, spotting or corrosion. Any of these types of failures can ultimately make a cast part unacceptable for its intended purpose. Impregnation is a cost-effective, permanent solution to the problems that may be encounter as a result of such porosity in castings.
Porosity Test Process
Porosity test must be made to find the weak spots. Action can be taken before problems occur over time. Available on both High Voltage Holiday Detectors & Low Votage Pinhole Detector. The Instruments provide an accurate way for locating faults in non-conductive coatings and linings. Detection of pinholes, flaws, inclusions, thin spots and also bubbles in a coating.
A High Voltage Holiday Detector is specifically design to revolutionize high voltage DC testing of coatings, making it safer, easier and more reliable than previously possible. The gauge can only be use to find flaws in coatings whose substrate is made from a conductive material (metal, concrete etc.). The units have variable sensitivity and are fit with audible and also visual fault alarms either.
The high voltage technique can be use to test coatings up to 36 mm thick. This method is ideal for inspecting paint on pipelines, tank bottoms and other protective coatings. Coatings on concrete can also be test using this method. We provides both of the PosiTest HHD Kit and also the TQC HHD Kit to meet our clients jobs requirement.
Another test system should be use when the high voltage testing is not desirable due to thin coating thicknesses up to 500 micron. For these a Low Voltage Pinhole Detector is used with select-able voltages of 9, 67.5 and 90 volts. Depending on the coating thickness under test. Use 9 volt for coatings up to 300 micron, 67.5 volt for coatings up to 400 micron and 90 volt for coatings until 500 micron. We also provides both of PosiTest Low Pinhole Detector and also the TQC Low pin hole to meet our clients jobs requirement.
Showing all 2 results