Electrochemistry of stress corrosion cracking of brass

Observations of Corrosion Product Formation and Stress Corrosion Cracking on Brass Samples Exposed to Ammonia Environments

“…SCC is a form of environmentally assisted cracking that occurs as a result of internal strains. It was known that brasses stored in a dry and clean atmosphere, although carrying high internal strains, cracked only after a long time; while a damp atmosphere was especially active in producing such cracking, particularly if it carried ammonia vapor from decaying organic matter 1 . SCC of brass was first identified when brass cartridge cases used by the British Army in India were found to suffer from cracking in ammonia from the decay of horse urine 2 .…”

“…Past experience has also indicated that cracking was more frequent in brasses carrying a higher percent of zinc (Zn). The identified two modes of cracking are intergranular and transgranular, for which extensive systematic studies were initiated by Mattsson's work, published in 1961 1 .…”

A STUDY OF STRESS CORROSION CRACKING RESISTANCE FOR COLD FORMING PLASTIC DEFORMED Cu-30Zn ALLOY

“…Cartridge brass dapat digunakan dalam berbagai hal seperti inti radiator otomotif, komponen amunisi, alat pencahayaan, flashlight shells, dan kickplates (William D.Callister Jr, 2007 (Seleet, 1986). Kehilangan berat berhubungan dengan lepasnya kation Cu dari ruahan sampel dan membentuk lapisan tarnish Cu 2 O pada permukaan logam (Mattsson, 1961).…”

“…Hasil pengamatan visual pada permukaan sampel memperlihatkan perubahan warna menjadi coklat hitam, dengan proses pengusaman yang terjadi. (Seleet, 1986). (Pugh.E.N, 1980):…”

“…Patahan yang berbentuk belahan terjadi pada paduan Cu-30Zn hasil rol dingin di larutan tarnish (Seleet, 1986). Propagasi (perambatan) terjadi secara diskotinyu sama dengan hasil dari penelitian saat ini.…”