| 1. |
|
|
| 2. |
|
|
| 3. |
- Oertel, CM, et al.
(author)
-
Acetic Acid Vapor Corrosion of Lead-Tin Alloys Containing 3.4 and 15% Tin
- 2009
-
In: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 156:12, s. C414-C421
-
Journal article (peer-reviewed)abstract
- Lead-tin alloy pipes in historic organs frequently suffer from damaging atmospheric corrosion. Organic acids emitted from the wood of organ cases had been established previously as the cause of deterioration in pure lead pipes. In the present study, lead-tin alloy samples containing 3.4 and 15 atom % tin were subjected to laboratory exposure experiments under atmospheres of 1100 ppb acetic acid, 350 ppm CO2, and 60 or 95% relative humidity (RH). Wet and dry corrosion mass gains were monitored, and corrosion product compositions and morphologies were characterized by grazing incidence angle X-ray diffraction and scanning electron microscopy. Cross sections were cut through corrosion sites using a focused ion beam milling method, and elemental information was obtained using wavelength dispersive and energy dispersive X-ray analyses. The corrosion products and morphologies observed in the alloys are the same as those reported for pure lead, but the corrosion susceptibilities of the alloys show a much stronger dependence on RH. The presence of 3.4 or 15 atom % Sn provides corrosion protection at moderate humidity, but this protective effect breaks down at high humidity. These findings highlight the importance of humidity control as well as pipe material selection in the conservation of historic and newly constructed organs.
|
|
| 4. |
- Oertel, CM, et al.
(author)
-
Focused ion beam and electron microscopy analysis of corrosion of lead-tin alloys: Applications to conservation of organ pipes
- 2008
-
In: Materials Research Society Symposium Proceedings. - 0272-9172. - 9781558999886 ; 1047, s. 115-125
-
Journal article (peer-reviewed)abstract
- Across Europe, lead-tin alloy organ pipes are suffering from atmospheric corrosion. This deterioration can eventually lead to cracks and holes, preventing the pipes from producing sound. Organ pipes are found in compositions ranging from >99% Pb to >99% Sn. For very lead-rich (>99% Pb) pipes, organic acids emitted from the wood of organ cases have previously been identified as significant corrosive agents. In order to study the role of alloy composition in the susceptibility of pipes to organic acid attack, lead-tin alloys containing 1.2-15 at.% Sn were exposed to acetic acid vapors in laboratory exposure studies. Corrosion rates were monitored gravimetrically, and corrosion product phases were identified using grazing incidence angle X-ray diffraction. In a new method, focused-ion beam (FIB) cross sections were cut through corrosion sites, and SEM and WDX were used to obtain detailed information about the morphology and chemical composition of the corrosion layers. The combination of FIB and SEM has made it possible to obtain depth information about these micron-scale layers, providing insight into the influence of acetic acid on alloys in the 1.2-15 at.% Sn range.
|
|
