TM Malzemelerin Korozyon Direncine Sıcak Daldırma Alüminyum Kaplamanın Etkisi - The Effect of Hot Dip Aluminizing on the Corrosion Resistance of PM Materials

TM Malzemelerin Korozyon Direncine Sicak Daldirma Aluminyum Kaplamanin Etkisi Bu calismada, demir esasli TM malzemelere sicak daldirma yontemi ile aluminyum kaplanmistir. Numuneler ergiyik sicakliklari 700 °C ve 750 °C olan Al-Si12CuFe icerisine, 30 s ve 300 s sure ile argon koruyucu gaz ortaminda daldirilmistir. Yuzeyde aluminyum ile hemen altinda intermetalik bir ara tabaka olusmustur. Korozyon dayanimi icin, kaplamali ve kaplamasiz TM numunelere ayni yogun tuz ortaminda korozyon testi uygulanmistir. Kaplamasiz numuneler 7 gun, kaplamali numuneler ise 90 gun sure ile test edilerek kutle degisimleri ve metalografik yontemlerle incelenmistir. Numunelerin kimyasal bilesiminin korozyon uzerinde belirgin bir etkisinin olmadigi ve aluminyum kaplanmis numunelerin yogun tuz ortaminda korozyona karsi cok daha iyi direnc gosterdigi belirlenmistir. Kaplamasiz numunelerin yuzeyinde cukurcuk tipi korozyon olusumu gozlemlenirken, aluminyum kaplanmis numunelerin yuzeyinde ise beyaz renkli sert aluminyumoksit tabakasi olusumu gozlemlenmistir. Yogun tuz ortamina karsi Al kapli TM numuneler, kaplamasiz TM numunelere gore cok daha iyi direnc gostermistir. Test sonunda yapilan mikroskobik incelemelerde, kaplama yuzeyinde olusan pitting tipi korozyonun kaplama icerisine dogru kilcal catlaklar halinde nufuz ettigi ve bazi yerlerde intermetalik faza kadar ulastigi belirlenmistir. The Effect of Hot Dip Aluminizing on the Corrosion Resistance of PM Materials In this study, ferrous based PM samples aluminium were coated by using hot dip aluminizing method. Samples were dipped in Al-Si12CuFe aluminium bath under argon gas cover, at 30- 300 sec dipping time and at 700 °C and 750 °C temperature. Aluminium coating and inferior intermetallic compound were occurred on surfaces. PM and aluminized PM samples were examined under same intensive salt environment for defining corrosion resistance properties. For that purpose, uncoated PM samples and coated PM samples were tested along 7 day, and 90 day respectively in the corrosion incubator. At the end of the test, the mass changes were measured from samples and microstructural propagating of corrosion on PM samples were investigated by using metallographic techniques. The chemical composition of samples had no effect on corrosion resistance. Hot dip aluminized PM samples showed stronger corrosion resistance than uncoated samples. While pitting type of corrosion occurred on surface of the uncoated PM samples, white colour aluminium oxide was observed on aluminized PM samples. According to microscopic investigations, pitting type of corrosion on aluminium layer propagated through the surface as micro cracks and at some regions they reached into the intermetallic phase