紫外線可以作為一種低成本,快速的方法來檢測涂層中的針孔。添加包含紫外線熒光添加劑的底漆涂層。當紫外線燈照在涂層上時,未覆蓋底涂層的區(qū)域發(fā)出熒光,從而確定了針孔的位置。
手電筒式紫外線燈LUYOR-3180由電池供電,并裝在堅固的鋁制外殼中,提供了一種快速,低成本的方法來檢查涂層的針孔。LUYOR-3180紫外線手電筒具有一顆5w 365nm紫外發(fā)光二極管,LUYOR-3180紫外線燈采用專門的漫射鏡設計,可發(fā)出平滑的光束圖像(無條紋,熱點或暗斑),并與美國表面處理中心認可的安全眼鏡配合使用,可提高對比度,可提供更佳的視覺完整性和可靠性檢查。LUYOR-3180紫外線燈可以檢測底漆上面的油漆的針孔。將紫外線反射熒光劑添加到底漆,并涂敷在需要防腐的材料上。檢查熒光底漆時,請尋找指示針孔的黑點或灰色區(qū)域。檢查非熒光面漆時,請尋找發(fā)光點,這些發(fā)光點指示面漆中有針孔(從底漆中透出)。
涂層針孔和孔隙率檢測
基體的過早腐蝕通常是由涂層被破壞而造成的。引起涂層破壞的一個主要原因是覆蓋的涂層存在一些裂縫。這些裂縫統(tǒng)稱為孔隙,主要類型有:
垂流&流掛:涂層在重力作用下流走,剩下一層薄的干涂層。
塌凹:涂層表面氣泡脹破后沒有涂料回流來填補空隙而造成。
坑狀:基體潮濕或涂層流動性差,產(chǎn)生空隙。
針孔:滯留氣泡從表面上脹破后引起,或陷入涂層的粒子(灰塵、沙等)脫落后引起。
涂層過厚:若涂裝了太厚的涂層,固化后涂料的內(nèi)應力會引起裂化。
涂層不足:沒有涂層的部位,或涂料從基體或焊縫的邊角處流走的部位。粗糙表面上不充分的涂層同樣會使輪廓峰尖處暴露。
濕海綿技術(shù)
適合探測導電基體上500μm(20mils)以內(nèi)的絕緣涂層,濕海綿技術(shù)適用于不想被破壞的粉末涂層和較薄涂層的檢測。
濕海綿加上低電壓。海綿在涂層上移動,遇到缺陷時,液體會滲入基體,形成一個完整的電流回路,引起警報。
紫外線針孔檢測
紫外線檢測可作為檢測涂層針孔的成本低廉且快速的方法。涂上一層含紫外線熒光添加劑的基礎涂層。當紫外線燈照射涂層時,看到基礎涂層沒有熒光覆蓋的區(qū)域,即為針孔所在處。
高壓技術(shù)-電火花檢測儀
高壓或孔隙技術(shù),可用來檢測7.5mm (300mils)以內(nèi)厚度的涂層,適合于檢驗管道和其它保護性涂層。此方法還可檢驗混凝土上的涂層。電源向探頭產(chǎn)生高壓直流電。當探頭通過裂縫,接觸點會產(chǎn)生火花,發(fā)出警報。該技術(shù)適用于定位上述各種類型的裂縫,在薄涂層上需要小心操作。
The LUYOR-3180 UV Pinhole Flashlight is battery powered and housed in a rugged aluminium case providing a quick, low cost method of testing coatings for pinholes.
Featuring a three-Watt purple light emitting diode, the LUYOR-3180 UV flashlight has a beam wavelength of 365nm (±5nm), which the human eye perceives as a purple light.
Designed with a specialised diffuser lens that emits a smooth beam image (with no streaks, hot spots or dark spots) and used with National Surface Treatment Centre approved safety glasses for improved contrast, the LUYOR-3180 UV flashlight provides optimum integrity and reliability of the visual inspection.
The LUYOR-3180 UV flashlight can detect pinholes from both the base and top coats. A UV reflective additive is applied to the base coat. When inspecting the fluorescent base coat look for black spots or grey areas that indicate pinholes. When inspecting the non-fluorescent top coat, look for glowing spots that indicate pinholes in the top coat (shining through from the base coat).
Low cost and easy to use: Use UV reflecting base coat and shine the purple light onto the surface. Any fluorescence identifies pinholes
Rugged: Manufactured from aluminium alloy and O’ring sealed to protect it from moisture and dust
Portable and secure: Battery powered and features a recessed click-on/push off button to prevent accidental activation during transport or storage.